Physics Lab Apparatus

Angle Indicator

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C-Clamp

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Digital Adapter

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Dynamic Cart

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Dynamic Track

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Force Sensor

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Force Table

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GLX Xplorer

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Measurement Set

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Meter Stick

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Micrometer Caliper

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Motion Sensor

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Photogate Head

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Picket Fence

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Projectile Ball

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Projectile Launcher

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Set Of Weights

knknknknk

Super Pulley

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Time Of Flight Accessory

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Triple Beam Balance

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Vernier Caliper

jijiji

Weight Hanger

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Beaker

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Calorimeter

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Glass Rod

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Stove

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Steam Generator

d

Thermometer

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Linear Expansion Apparatus

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Essay about catholic doctrines

Activity 9 and 10

Some people look at Catholic doctrine as a set of rules that Catholics are obliged to follow. Catholic teachings on social and economic issues are a very important dimension of the Church’s life and have their own long history. the Catholic Church has developed a significant body of teachings on peace and social justice and that is catholic social teachings. Through these teachings, which are geared to our time and culture, we learn through reason what God’s plan is for us as men and women, and brothers and sisters to each other. In a most compelling way, they lead one to understand true love and true freedom, and ultimately lead to the very center of the Holy Trinity.

Catholic Social Teaching (often referred to as CST) has sometimes been called ‘The Church’s Best Kept Secret”. CST is the Church reflecting on its mission in the world today, helping us to think about how we relate to the world around us and the problems that we face. In fact it is one of the greatest treasures of our Catholic tradition. However, it’s also true that these insights are sometimes called the Church’s ‘best kept secret’ because there’s such a gap between teaching and practice—between what people hear in the pew in Sunday homilies and the application of these principles to the daily lives of Catholics.

Catholic Social Teaching isn’t well known (even in the Church!). It was not always taught because some considered it a bit too radical. A second reason is that encyclicals are lengthy and complex – and many people just find them hard going. Catholic social teaching could become a tremendously effective tool for making that better world — where justice, peace and love would be the norm — if we would commit to regularly reading it, praying with it, teaching it, preaching it and living it. Many Catholics are eager to learn more about their faith, but not all parishes offer opportunities to do so. Therefore, lay Catholics need to evangelize their priests and parishes in social justice terms as well as the other way around. Catholics don’t need to wait for the go-ahead from their pastors to engage in works of peace and social justice. That way, the Church’s social teachings won’t be a secret anymore.

Guadium et Spes clearly states the task of Christians—to save this world by following the teachings of Christ. But it acknowledges our weak human nature and recognizes that we will never do this perfectly, that we are a pilgrim people who will have many stumbles on our way to achieving the perfection of our world.

The document is realistic about our humanity and our sinfulness.    When Christ became human He ennobled our human nature and raised it to great heights but this same human nature is still darkened by sin. Our actions often cause disorder in our own lives, in our relationships with others and in the wider society.

The document tells us that, in all our actions and decisions, we have to take the legitimate aspirations of others into account and these “others” are the entire human family.  We have a duty to respect the universal and inviolable rights of everyone;  the right to food, clothing, adequate housing, freedom in choosing a state in life and setting up a family, education, work, a good name, proper knowledge, following the dictates of one’s conscience, privacy and religious freedom.  These rights are frequently violated in Irish society as evidenced, for example, by the homeless, the unemployed and the extent to which the media make incursions into people’s privacy and, in the process, often destroy their good name.

Pacem in Terris provides many insights into achieving this peace that we desperately want.  First and foremost it states that peace cannot be established unless the order laid down by God is dutifully observed, an order based on truth, justice, charity and freedom.   I would venture to guess that most people do not understand what this order is, much less follow it if they do understand it. Many of these rights are incorporated into the Universal Declaration of Human Rights adopted by the United Nations in 1948.  However, the reality is that human rights are not emphasized enough in this nation or the world in general.

Pacem in Terris teaches that we not only have rights, we also have duties toward our fellow men and women.   Just as we have a right to life,   we have a corresponding duty to preserve life.  Just as we have a right to a dignified life, we have a corresponding duty to promote the welfare of others, what is often called the “common good”.

 

At the international level, we will not achieve peace on earth if there are wide disparities in the economic status of people around the globe.   These economic disparities must be reduced, and we must be willing to reduce them even if it means sacrifice on those of us who are more fortunate.     Where natural resources are scarce, they must be equally shared so that all people benefit.  We must see all people as part of the human family.  We need to develop a global vision.

The encyclical stresses the importance of virtue, he said. “Rerum Novarum says virtue is a common inheritance of many, equally within the reach of high and low, rich and poor, and that virtue and virtue alone will be followed by the rewards of everlasting happiness.” One reason compelling Leo XIII to write Rerum Novarum was his conviction that the present age has handed over the working poor to inhumane employers and greedy competitors

Leo was careful to point out that the poor are equal in citizenship to the rich (a. 49) and that their work is the source of the nation’s wealth (a. 51). In making these points, he challenged the position of those who belittle and look down on the poor, considering the poor, even the working poor, a burden on society. The working poor, Leo asserts, should be liberated from the savagery of greedy people (a. 59). Those who seek to assist the working poor can do so through three types of institutions: associations for giving material aid, privately-funded agencies to help workers, and foundations to care for dependents

The message to the working poor up to this point seems to be aimed at calming and consoling the poor, encouraging them to accept their position in society without rancor and without doing harm to others. Leo XIII was particularly concerned about harmony in society, and he sought to enlist the aid of the working poor in preserving good order. Rerum Novarum also contained a message to those who deal with the working poor. Early on in his encyclical, Leo XIII declared that the working poor must be cared for. Leo XIII wanted very much for workers to claim their rights, but he also wanted harmony and peace in society. He took the position that strikes are evil and should not be permitted (a. 56), placing his hopes on the ability of employers and employees to sort things out amicably with the help of the government and the Church.

Worksheet (6-9) for ecology lab

WORKSHEET 6

Table 6.2 – number of species present in the quadrant

  1. The quadrant size that there is no additional species added is 8 m2 (2.0 x 4.0) because that is the quadrant where the number of species starts to be the same and there are three consecutive similar number of species.
  2. It is a relationship between the area of a habitat, and the number of species found within that area. Larger areas tend to contain larger numbers of species, and empirically, the relative numbers seem to follow systematic mathematical relationships. It also shows the average number of species detected against the cumulative area sampled.

Table 6.3 – frequency of the individuals

  1. The species that has the highest frequency is the common grass. The root systems of grasses are highly branched and do not have a well-defined central taproot. The advantage of this grass is that it is very salt-tolerant. It can be irrigated with non-potable water, such as greywater, an important advantage when there are increasing restrictions on water use. The grass will be lower in quality than that irrigated with potable water, but it survives.
  2. The species that has the lowest frequency is makahiya. This plant is most often grown as an indoor annual, but is also grown for groundcover. Propagation is generally by seed. It grows most effectively in nutrient poor soil that allows for substantial water drainage. However, this plant is also shown to grow in scalped and eroded subsoils.

Table 6.4 – summary of species areas from quadrant sampling

  1. The species that has the largest area is the common grass. Grasses include some of the most versatile plant life-forms. Grasses have adapted to conditions in different habitats, and are now the most widespread plant type; grass is a valuable source of food and energy for all sorts of wildlife and organics.
  2. The species that has the lowest area is radish. Radishes are a fast-growing, annual, cool-season crop. The seed germinates in three to four days in moist conditions with soil temperatures between 65 and 85 °F. They can function as a trap crop, luring insect pests away from the main crop. Because their pungent odor deters such insect pests.
  3. The summary of importance value of the tree species in table 6.3 is:

Grass – The most important food crops are the grains of grasses such as wheat, rice, maize (corn) and barley.

Makahiya – All parts of the plant have been used to combat glandular tumors and uterine cancer.

Radish – It is a roughage and it is composed of indigestible carbohydrates. This facilitates digestion, water retention, and it fixes constipation.

Table 6.5 – calculations for quadrant sampling

  1. The species that has the highest importance value is common grass. Grass is an incredible survivor and is virtually indestructible. Because the roots will regenerate the plant when the tops are eaten, burnt, drowned, grass will survive drought, flood, fire and aggressive cropping. Grasses will survive and flourish in areas where there is insufficient rainfall to support trees
  2. The species that as the lowest importance value is radish. Radishes can be available year-around with peak season during winter and spring. As a fast-growing plant, diseases are not generally a problem with radishes, but some insect pests can be a nuisance.
  3. I therefore conclude that we can measure the plant abundance of the grassland by using the quadrant method. We also learned that plants make up the backbone of all habitats. Other species of fish and wildlife also depend on plants for food and shelter.

 

WORKSHEET 7

Table 7.1 – measurement of depth and amount of light penetration in the lake

  1. The light that is absorbed by the lake is 90.66%. Light provides the solar energy required to drive the process of photosynthesis, the major energy source of lentic systems. Green plants convert the light energy of the Sun into chemical energy through a process called photosynthesis.
  2. Factors that affect the light absorption in lake is (1) lakes may experience shading by surrounding trees, while cloud cover may affect light availability. (2) Seasonal and diurnal considerations also play a role in light availability because the shallower the angle at which light strikes water, the more light is lost by reflection. (3) Scattering of light in the water column. This scattering decreases the total amount of light as depth increases.

Table 7.2 – measurement of depth and amount of light penetration in lake

  1. The epilimnion or surface lake is the top-most layer in a thermally stratified lake, occurring above the deeper hypolimnion. It is warmer and typically has a higher pH and higher dissolved oxygen concentration than the hypolimnion. It is the part of a lake or ocean where the rate of photosynthesis is greater than the rate of respiration by phytoplankton.
  2. The hypolimnion or under lake is the dense, bottom layer of water in a thermally-stratified lake. It is the layer that lies below the thermocline. It contains no algae or phytoplankton, and its inhabitants are exclusively carnivorous animals or organisms that feed on sediment or detritus, all reliant on energy inputs from the euphotic zone.
  3. The metalimnion is a thin but distinct layer in a large body of fluid in which temperature changes more rapidly with depth than it does in the layers above or below. It divides the upper mixed layer from the calm deep water below. The thermocline varies in depth. It is semi-permanent in the tropics, variable in temperate regions (often deepest during the summer) and shallow to nonexistent in the polar-regions, where the water column is cold from the surface to the bottom. A layer of sea ice will act as an insulation blanket.

Table 7.3 – measurement of temperature

  1. Yes there is difference of 2.16oC between the temperature of the surface and bottom. Hypolimnion being at depth, it is isolated from surface wind-mixing during summer, and usually receives insufficient irradiance (light) for photosynthesis to occur. Epilimnion Being exposed at the surface, it typically becomes turbulently mixed as a result of surface wind-mixing. It is also free to exchange dissolved gases such as O2 and CO2 with the atmosphere. Because this layer receives the most sunlight it contains the most phytoplankton.
  2. The importance of temperature in the lake is Temperature is also important because of its influence on water chemistry. The rate of chemical reactions generally increases at higher temperature, which in turn affects biological activity. An important example of the effects of temperature on water chemistry is its impact on oxygen. Warm water holds less oxygen that cool water, so it may be saturated with oxygen but still not contain enough for survival of aquatic life. Some compounds are also more toxic to aquatic life at higher temperatures. Temperature is reported in degrees on the Celsius temperature scale (C).
  3. 2 factors affecting the temperature of the lake is. (1) Shade is very important to the health of a stream because of the warming influences of direct sunlight. Some human activities may remove shade trees from the area which will allow more sunlight to reach the water, causing the water temperature to rise. (2) Another factor that may affect water temperature is the temperature of the air above the water. The extent of its influence has a great deal to do with the depth of the water. A shallow stream is more susceptible to changes in temperature than a deep river would be.

Table 7.4 – measurement of TSS

  1. Yes there is 0.11 g of difference between the TSS of the surface and the bottom. The TSS of the bottom is higher than the surface water because some suspended solids can settle out into sediment at the bottom of a body of water over a period of time. The remaining particles that do not settle out are called colloidal or non-settle able solids. These suspended solids are either too small or too light to settle to the bottom and they are the ones that settle in the surface water.
  2. The importance of TSS in the lake is Turbidity is commonly used as an indicator for the general condition of the drinking water, but is an easy field water quality parameter to measure. Turbidity in water is caused by suspended matter such as clay, silt, and organic matter and by plankton and other microscopic organisms that interfere with the passage of light through the water. Turbidity is closely related to total suspended solids (TSS), but also includes plankton and other organisms.  Turbidity itself is not a major health concern, but high turbidity can interfere with disinfection and provide a medium for microbial growth. It also may indicate the presence of microbes
  3. The 2 factors affecting the TSS of the lake is (1) Soil Erosion – is caused by disturbance of a land surface. The eroded soil particles can be carried by storm-water to surface water. This will increase the turbidity of the water body. (2) High Flow Rates – The flow rate of a water body is a primary factor influencing turbidity concentrations. Fast running water can carry more particles and larger-sized sediment. Heavy rains can pick up particles from the land and carry it to surface water. A change in flow rate also can affect turbidity; if the speed or direction of the water current increases, particulate matter from bottom sediments may be re-suspended.

 

WORKSHEET 8

Table 8.1 – nitrogen, phosphorus, and hardness

  1. The main source of nitrogen compounds in water are fertilizers that mainly contain nitrate, but also ammonia, ammonium, urea and amines. Nitrogen itself is not hazardous when present in water, and therefore does not cause any environmental damage. In seawater nitrates, nitrites and ammonia are dietary requirements for plankton, causing nitrogen concentrations to be lower at the surface than in the deep. At increasing nitrogen concentrations in surface layers, plankton production increases, leading to algal blooms.
  2. Phosphorus occurs naturally in rocks and other mineral deposits. During the natural process of weathering, the rocks gradually release the phosphorus as phosphate ions which are soluble in water and the mineralize phosphate compounds breakdown.  Phosphorus is one of the key elements necessary for the growth of plants and animals and in lake ecosystems it tends to be the growth-limiting nutrient and is a backbone of the Kreb’s Cycle and DNA. Phosphorus is essential to the growth of biological organisms, including both their metabolic and photosynthetic processes.
  3. Hardness is caused by compounds of calcium and magnesium, and by a variety of other metals. Water hardness is important to fish culture and is a commonly reported aspect of water quality. It is a measure of the quantity of divalent ions such as calcium, magnesium and/or iron in water.  There are many different divalent salts; however, calcium and magnesium are the most common sources of water hardness.

Table 8.2 – measurement of salinity, conductivity, and TDS in lake

  1. The most important sources of salts, and therefore salinity, in all Earth’s waters are: (1) washing (dissolving) of salts from the soil and rock of the Earth’s crust; (2) precipitation (dust, rain and snow falling into the water) and (3) the evaporation and precipitation cycle. Salinity is also important for water uses on land by people and wildlife. The saltier the water, the more difficult and expensive it is to prepare for drinking, and the more dangerous it is to apply to crops.
  2. Total dissolved solids (TDS) is a measure of the combined content of all inorganic and organic substances contained in a liquid in molecular, ionized or micro-granular (colloidal sol) suspended form. The principal application of TDS is in the study of water quality for streams, rivers and lakes, although TDS is not generally considered a primary pollutant (e.g. it is not deemed to be associated with health effects) it is used as an indication of aesthetic characteristics of drinking water and as an aggregate indicator of the presence of a broad array of chemical contaminants.
  3. Conductivity is directly related to the concentration of ions in the water. These conductive ions come from dissolved salts and inorganic materials such as alkalis, chlorides, sulfides and carbonate compounds. Therefore, significant changes in conductivity can be an indicator that a discharge or some other source of pollution has entered the water. The composition of the water can be critical for aquatic organisms as well, as many critters have very specific ranges that they can tolerate.

Table 8.3 – measurement of pH and dissolved oxygen in the lake

  1. The pH of water determines the solubility (amount that can be dissolved in the water) and biological availability (amount that can be utilized by aquatic life) of chemical constituents such as nutrients phosphorus, nitrogen, and carbon) and heavy metals (lead, copper, cadmium, etc.).
  2. Yes there is 1.61 difference in the DO between the surface and bottom water of the lake. Aquatic organisms need oxygen to live. As water moves past their gills, microscopic bubbles of oxygen gas called dissolved oxygen (DO), are transferred from the water to their blood. In other words, oxygen can be present in the water, but at too low a concentration to sustain aquatic life. Oxygen also is needed for many chemical reactions that are important to lake functioning.
  3. 2 factors affecting the DO of the lake. (1) Dissolved oxygen concentrations may change dramatically with lake depth. Oxygen production occurs in the top portion of a lake, where sunlight drives the engines of photosynthesis. Oxygen consumption is greatest near the bottom of a lake, where sunken organic matter decomposes. (2) Seasonal changes also affect dissolved oxygen concentrations. Warmer temperatures during summer speed up the rates of photosynthesis and decomposition. When all the plants die at the end of the growing season, their decomposition results in heavy oxygen consumption.

Table 8.4 – measurement of primary conductivity

  1. The photosynthetic rate of the lake is 3.67 x10-3. If photosynthesis ceased, there would soon be little food or other organic matter on Earth. Most organisms would disappear, and in time Earth’s atmosphere would become nearly devoid of gaseous oxygen.
  2. The respiration rate of the lake is -0.06. Respiration in lakes recycles organic carbon arising from photosynthesis back to inorganic carbon. Prior to this transformation, the organic carbon is potentially available to support secondary production. The efficiency of primary and secondary production relative to respiration is an important feature of lakes and other aquatic ecosystems.
  3. The primary productivity of the lake is 0.06367. 2 factors affecting the primary productivity of the lake is (1) Land use – Levels of nutrients (nitrogen and phosphorus) and algae tend to be higher in lakes in pastoral catchments than in lakes in natural catchments. Because algal concentrations affect water clarity, the lakes in natural catchments have water that is clearer than water in lakes in pastoral catchments. (2) Lake depth – Deep lakes have a greater capacity to absorb incoming nutrients before showing definite signs of deterioration in water quality. The monitored lakes that have high levels of nutrients tend to be shallow. The monitored lakes with the lowest levels of nutrients are nearly all deep lakes

Table 8.5 – measurement of BOD5

  1. Yes there is a difference of 1.03 in the DO of the samples after 5 days. BOD is a common, environmental procedure for determining the extent to which oxygen within a sample can support microbial life. It is also important in waste water treatment, food manufacturing, and filtration facilities where the concentration of oxygen is crucial to the overall process and end products.
  2. When BOD levels are high, dissolved oxygen (DO) levels decrease because the oxygen that is available in the water is being consumed by the bacteria. Since less dissolved oxygen is available in the water, fish and other aquatic organisms may not survive. BOD value in polluted water is normally higher than the fresh water. Increased BOD can be resulted due to domestic sewage, petroleum residues and wastes of animals and crops.

 

WORKSHEET 9

Table 9.1 – total counting of planktons in the lake

  1. The species hat is the most abundant is Euglena and species C. Euglena serve as excellent bio-indicators of environment changes, not only by their presence or absence, but also by measuring the cellular changes that occur under differing environmental conditions. It is also able to photosynthesize, thus taking in carbon dioxide and releasing oxygen into the atmosphere so that other organisms can survive.
  2. The importance of planktons in the lake is Plankton are an important source of food for larger animals. Phytoplankton are the first link in the food chain. They are known as primary producers because they produce the first forms of food. Zooplankton and other small animals that graze on the phytoplankton are known as primary consumers. Phytoplankton are sometimes called the grasses of the sea. Like land plants, they produce lots of oxygen through photosynthesis. During photosynthesis they use the sun’s energy to combine carbon dioxide and water into simple foods. This process removes carbon dioxide from seawater and allows the water to absorb a lot of carbon dioxide produced in the atmosphere. This “global carbon cycle” helps regulate the temperature of our planet.

Transverse and Longitudinal Waves

College of Science and Computer Science

Physical Sciences Department

Physics 2

 

Experiment #3

TRANSVERSE AND LONGITUDINAL WAVES

 

1. Abstract

A wave can be described as a disturbance that travels through a medium from one location to another location. In this experiment we used a slinky spring to demonstrate transverse and longitudinal waves. Longitudinal waves occur when the oscillations are parallel to the direction of propagation while Transverse waves occur when a disturbance creates oscillations perpendicular at right angles to the direction of energy transfer. To introduce a wave into the slinky, the first part of the spring is displaced or moved from its equilibrium or rest position. But once moved, it is returned to its original equilibrium or rest position. As we performed the up and down, and back and forth motion on the spring we would observe a repeating disturbance moving within the slinky that endures over a prolonged period of time referred to as a wave.

 

2. Actual Materials Used

  • Helix / slinky spring
  • Stopwatch
  • Meter stick

 

3. Data and Results

A.

;lkm;mk;o 

Wave propagated – Up and Down motion – One and Steady

Type of wave: transverse

 

B.

jj;jjop 

Wave propagated – Up and Down motion – Simultaneous motion

Type of wave: transverse

 

 C.

nlihlhio 

 

Wave propagated – Back and Forth motion

Type of wave: longitudinal

 

 

4. Interpretation of Data

In the experiment we have used a slinky wave as an example. When the slinky is stretched from end to end and is held at rest, it assumes a natural position known as the equilibrium or rest position. To introduce a wave here we must first create a disturbance. We must move a particle away from its rest position. One way to do this is to jerk the slinky forward to move it away from its equilibrium position and then back. The disturbance continues down the slinky. This disturbance that moves down the slinky is called a pulse. If we keep “pulsing” the slinky back and forth, we could get a repeating disturbance.

For the first two drawing the up and down motion you can see that we have created a transverse wave. In a transverse wave the pulse travels perpendicular to the disturbance. Comparing the simultaneous vs the one and steady motion the simultaneous motion created a bigger wavelength and amplitude than the one and steady motion. It is because a Constructive interference occurred, Constructive interference happens during a simultaneous motion whenever waves come together so that they are in phase with each other. This means that their oscillations at a given point are in the same direction, the resulting amplitude at that point is much larger than the amplitude of an individual wave. For the one and steady motion Destructive interference occurred, Destructive interference occurs when waves come together in such a way that they completely cancel each other out. When two waves interfere destructively, they must have the same amplitude in opposite directions. In this experiment we have found out that the particles do not move along with the wave; they simply oscillate up and down about their individual equilibrium positions as the wave passes by.

For the last drawing the back and forth motion you can see that we created a longitudinal wave. In a longitudinal wave the pulse is transferred through the medium of the slinky, but the slinky it does not actually move. It just displaces from its rest position and then returns to it. So what is being transferred in the slinky? It is the energy that is being transferred. The metal of the slinky is the just the medium that transfers the energy pulse of the wave. The medium ends up in the same place as it started it just gets disturbed and then returns to it rest position. In this experiment we have found out that the particles do not move down the tube with the wave; they simply oscillate back and forth about their individual equilibrium positions.

 

5. Conclusion

In conclusion a wave transports energy and not matter. When a wave is present in a medium the individual particles of the medium are only temporarily displaced from their rest position. There is always a force acting upon the particles that restores them to their original position. In a slinky wave, each coil of the slinky ultimately returns to its original position. Waves are said to transport energy. As a disturbance moves through a medium from one particle to its adjacent particle, energy is being transported from one end of the medium to the other. In this experiment we used a slinky wave, a person gives energy to the first coil by doing applying a force upon it in the experiment it’s either up and down or back and forth motion. The first coil in the spring receives a large amount of energy that it subsequently transfers to the second coil. When the first coil returns to its original position, it possesses the same amount of energy as it had before it was displaced. This process of energy transfer continues as each coil interacts with its neighbor. In this manner, energy is transported from one end of the slinky to the other, from its source to another location.

In a transverse wave energy will begin to be transported through the slinky from left to right. As the energy is transported from left to right, the individual coils of the medium will be displaced upwards and downwards. In this case, the particles of the medium move perpendicular to the direction that the pulse moves. While in a longitudinal wave energy will begin to be transported through the slinky from left to right. As the energy is transported from left to right, the individual coils of the medium will be displaced leftwards and rightwards. In this case, the particles of the medium move parallel to the direction that the pulse moves.

 

 

6. Guide Questions

  1. Define superposition of waves?

The principle of superposition is sometimes stated as follows: “When two waves interfere, the resulting displacement of the medium at any location is the algebraic sum of the displacements of the individual waves at that same location.”

The principle of superposition may be applied to waves whenever two (or more) waves travelling through the same medium at the same time. The waves pass through each other without being disturbed. For example two waves pass through each other without being disturbed, and the net displacement is the sum of the two individual displacements.

 2. What happened to the waves when both ends of the spring are simultaneously moved up and down?

As both ends of the spring are simultaneously moved up and down it will create an interference. Interference is a phenomenon in which two waves superpose to form a resultant wave of greater, lower, or the same amplitude. There are 2 types of interference namely constructive and destructive interference.

When two waves come close to one another, their effects add together. If the crests, or highest parts of the waves, line up perfectly, the crest of the combined wave will be the sum of the heights of the two original crests. This is known as constructive interference, in which two waves (of the same wavelength) interact in such a way that they are aligned, leading to a new wave that is bigger than the original wave.

However, if two waves are not perfectly aligned, then when the crest of one wave comes along, it will be dragged down by the trough of the other wave. The resulting, combined wave will have crests that are shorter than the crests of either original wave, and troughs that are shallower than either of the incoming waves. This is known as destructive interference.

3. Define transverse waves. Give 3 examples.

For transverse waves the displacement of the medium is perpendicular to the direction of propagation of the wave. A ripple on a pond and a wave on a string are easily visualized transverse waves. Transverse waves cannot propagate in a gas or a liquid because there is no mechanism for driving motion perpendicular to the propagation of the wave.

Examples:

  • Surface waves are transverse waves.
  • The visible light waves are transverse waves.
  • Water wave is a transverse wave.
  • Radio waves are also transverse waves.
  • Television waves are transverse waves.
  • Gamma rays are another example.
  • The x rays are also electromagnetic as well as transverse in nature.
  • The radio and microwave is example of transverse waves.

 4. Define longitudinal waves. Give 3 examples.

In longitudinal waves the displacement of the medium is parallel to the propagation of the wave. A wave in a “slinky” is a good visualization. Sound waves in air are longitudinal waves.

Examples:

  • Sound wave
  • Earthquake P wave
  • Tsunami waves
  • Waves in a slink
  • Glass vibrations
  • Internal water waves
  • Ultra sound
  • Spring oscillations

 

 

 5. References

 

 

Simple Harmonic Motion

College of Science and Computer Science

Physical Sciences Department

Physics 2

 

Experiment #2

SIMPLE HARMONIC MOTION

(THE SIMPLE PENDULUM)

1. Abstract

In this experiment periodic motion involving a swinging pendulum was studied. The period is the time it takes for a vibrating object to complete its cycle. In the case of pendulum, it is the time for the pendulum to start at one extreme, travel to the opposite extreme, and then return to the original location. As the pendulum oscillated, we gathered its data. When analyzed, the period of the motion was found to be given by: 2 Therefore, the period, or time to complete a full oscillation, of a pendulum was found to be dependent on its length. To find out what is the experimental determination of our g we used the formula: T2 =42 (L/g). The value that we solved for g is 983.88 m/s2. With the assumption of small angles, the frequency and period of the pendulum are independent of the initial angular displacement amplitude. All simple pendulums should have the same period regardless of their initial angle and regardless of their mass.

 

 

2. Actual Materials Used

  • 5 meter light string
  • Iron stand with horizontal bar extension
  • Stopwatch
  • Protractor or angle indicator
  • Small bob (spherical object)
  • Vernier caliper
  • Meter stick and ruler
  • Triple beam balance

 

 3. Data and Results

 Mass of the bob:                              m = 11.3 g

Length of the string:                       l = 120 cm

Diameter of the bob:                     d = 3.59 cm                         r = 180 cm

Angular displacement:                  = 100

 

 

Table 1: Length of pendulum, Time per vibration, period, % error, Frequency, Angular frequency

Length of pendulum (cm) Average time for 50 vibrations Period, T (sec) Period2, T2 (sec2) Linear frequency, f (Hz) Angular frequency, w (rad/s) % error
EV TV EV TV EV TV EV TV T T2 f w
120 + r 64.42 2.15 2.22 4.62 4.93 0.47 0.45 2.92 2.83 3.15 6.29 4.44 3.18
100 + r 59.88 2.00 2.03 4.00 4.12 0.50 0.49 3.14 3.08 1.48 2.91 2.04 1.95
80 + r 51.85 1.73 1.82 3.00 3.11 0.58 0.55 3.63 3.46 4.95 9.37 5.45 4.91
60 + r 46.51 1.55 1.58 2.40 2.50 0.65 0.63 4.05 3.96 1.90 4.00 3.17 2.29
40 + r 38.40 1.28 1.30 1.64 1.69 0.78 0.77 4.91 4.84 1.54 2.95 1.30 1.45
20 + r 29.38 0.98 0.94 0.96 0.88 1.02 1.06 6.41 6.66 4.26 9.09 3.77 3.75
80 + r

300

34.2 2.04 1.82 4.16 3.31 0.49 0.55 3.08 3.46 12.09 27.68 10.91 10.98

 

 

Graph 1

  1. Based on the data recorded, plot the curve to show the relationships between the periods, T (ordinate) and length of the pendulum, L (abscissa).

 km k.JPG

Discuss the significance of the shape of the graph:

The importance of the relationship between the period and the length is to show how we can calculate the gravity. The period T increased steadily with respect to the length l (Graph 1). According to the graph for the EV, at 20 m long, the square of the cycle was 0.98 s. At the length of 120 m, it increased and reached a peak of 2.15 s. And for the TV, at 20 m long, the square of the cycle was 0.94 s. At the length of 120 m, it increased and reached a peak of 2.22 s. The Length of the string will affect the time period of a pendulum because it will mean that the pendulum travels a greater distance in its oscillation.

 

Graph 2

  1. Based on the data recorded, plot the curve to show the relationships between the square of the period, T2 (ordinate) and length of the pendulum, L (abscissa).

 l

Discuss the significance of the shape of the graph:

The importance of the relationship between the square of the period and the length is to show how we can calculate the gravity. The square of the period T2 increased steadily with respect to the length l (Graph 2). According to the graph for the EV, at 20 m long, the square of the cycle was 0.96 s. At the length of 120 m, it increased and reached a peak of 4.62 s. And for the TV, at 20 m long, the square of the cycle was 0.88 s. At the length of 120 m, it increased and reached a peak of 4.93 s. The Length of the string will affect the time period of a pendulum because it will mean that the pendulum travels a greater distance in its oscillation.

 

 1. Compute the value g, the acceleration due to gravity from the slope of the graph in question no. 2 use the equation below.

T2 =42 (L/g)

Write the computations:

 

 

2. Compare the value of g obtained in question no. 3 with the standard value of g. include the computation of the % error.

 

 

The true value is more close to the standard value of gravity 975 m/s2 vs 981 m/s2. Also the percentage error of the true value is close to zero 0.61% compare to the experimental value which is 6.12%. A percentage very close to zero means you are very close to your targeted value, which is good.

 3. Compare the period when the angle  is over 300 to that of the period  100

8 + r  100 = 1.73

8 + r  300 = 2.04

Changing the starting angle of the pendulum (how far you pull it back to get it started) has only a very slight effect on the frequency. The smaller the angle, the shorter the period will be. For larger amplitudes or angles, the amplitude does affect the period of the pendulum, with a larger amplitude leading to a larger period. However, for small amplitudes (typically around a few degrees), the amplitude has no effect on the period of a pendulum.

 

4. Interpretation of Data

In the examination of a pendulum involves the study of its periodic motion. Objects that exhibit this type of motion follow sinusoidal paths and experience oscillations between their maximum values of position. Through this experiment we are able to do an accurate way to represent and study periodic motion that is through configuring an oscillating pendulum and analyze its motion in relation to different lengths of attached string. As can be seen in the table, alterations in length definitely have an effect upon the period of the pendulum. As the string is lengthened, the period of the pendulum is increased. There is a direct relationship between the period and the length. The table shows us that in a simple pendulum system, only the change of the length affects the period, but not the change of mass.

Overall, the observed data was found to produce values for the period that were related to the length of the string by the following equation: T2 =4π2 (L/g). When the length is changed, the pendulum will take more or less time to oscillate, depending on its length and acceleration due to gravity. Therefore, the period may be varied by changing either of these two factors the length or gravity. Since acceleration due to gravity is constant on Earth (g = 9.8 m/s2), the only dependent factor is the length of the pendulum.

The sources of error in our experiment is random, systematic and human errors during the experiment and these were:

  • The human error of reaction time when counting the number of cycles completed. Because the spring and pendulum were moving quite fast, it was hard to count the number of cycles that had completed.
  • The systematic error of not using ideal equipment such as a frictionless and massless string for the pendulum.
  • The systematic error of air resistance (friction) for the simple pendulum. Due to air resistance (friction), the pendulum can started to slow down and not return to the same height as more cycles were completed.
  • The random error of not releasing the pendulum at the same height for each trial. Releasing the pendulum at slightly different heights resulted in differences of potential energy during each trial.

 

5. Conclusion

In conclusion a pendulum will exhibit a period that varies depending on its length, according to the given equation: T2 =4π2 (L/g). We also learned that pendulums move by constantly transferring energy from one form to another. Pendulums, like all simple harmonic oscillators, are great demonstrators of the conservation of energy: the idea that energy cannot be created or destroyed, only transferred. The energy you end up with has to equal the energy you start with. The reason pendulums don’t move forever is because no system is perfect. Eventually, all the energy you provided is lost to the environment and the pendulum will stop swinging.

The purpose of this lab was to test the simple harmonic motion exhibited by a pendulum, and to see how the different variables affected the motion of said pendulum. The independent variables we tested were the length of the string, and the angle of release. This experiment focused on simple harmonic motion using a pendulum. A simple harmonic motion accurately models the motion that a pendulum exhibits when it swings from side to side. A simple harmonic motion will remain in motion as long as the system does not experience any type of external force such as friction, or an opposite applied force. This experiment demonstrated how a pendulum behave in a simple harmonic motion.

 

6. Guide Questions

  1. Is the period dependent on the length of the pendulum? Explain.

Changing the length of a pendulum while keeping other factors constant changes the length of the period of the pendulum. Longer pendulums swing with a lower frequency than shorter pendulums, and thus have a longer period. The period of the simple pendulum oscillations increases as the length of the pendulum increases. The period depends only on the length L of the string and the value of the gravitational field strength g, according to:

T = 2  . The length of a pendulum affects its swing because longer pendulums swing at lower frequencies. A lower frequency causes a longer period and a slower rate of swing.

2. Would the mass of the bob affect the period of the pendulum? Explain.

Changing the mass of the pendulum bob does not affect the frequency of the pendulum. The period of the simple pendulum oscillations does not depend on the mass of the load, nor on the angle of revolution. The mass has no effect on the period of the pendulum. Since the force of gravity is proportional to the object it is acting on, the mass will end up having no effect whatsoever on the period (or frequency) of the pendulum. In F = ma, force is directly proportional to mass. As mass increases, so does the force on the pendulum, but acceleration remains the same. (It is due to the effect of gravity.) Because acceleration remains the same, so does the time over which the acceleration occurs which is the period.

3. A 100 gram sphere executes a simple harmonic motion with the frequency of 20 Hz and amplitude of 0.5 cm. What is:

a. The constant k for the restoring force acting on it?

 

 

b. The maximum acceleration?

 

 

c. The total energy at any point of the motion?

 

 

 

 

7. References

Comparative Anatomy Introduction

Comparative  Anatomy
INTRODUCTION

What is Comparative Anatomy of Vertebrates?

  • study of the structure of vertebrates (descriptive anatomy)and the functional significance of the structure (functional anatomy).
  • Also deals with the study of history and of animals that no longer inhabit the earth and are known to us only by fossil records.

Functional Anatomy

  • It is dependent on knowledge of biomechanics, physiology, ecology and ethology.
  • It studies how structures perform specific functions and compares how different taxa have adapted to similar environments; a method for understanding the proximate causation of change.

Descriptive Anatomy

  • Draws much from paleontology and evolutionary biology as well as other fields that may provide evidence of evolutionary affinity, including cytology, biochemistry, and molecular biology

Anatomy VS. Morphology?

  • Anatomy is mainly observations and descriptions of structures while Morphology mainly interprets these observed and described structures.

Fields involved in the study of Comparative Anatomy

  • Zoology
  • Physiology
  • Histology
  • Genetics
  • Ecology
  • Developmental Biology
  • Evolutionary biology
  • Phylogeny

 

History of Anatomy

  • Anatomy comes from Greek words
  • ana + tome which means “to cut up” or “to dissect”.
  • Began in prehistoric times (people cut up carcasses of animals they hunted).
  • Primitive artist made crude drawings of animals preserved in cave paintings
  • Ancient Egyptians mummified these animals.

History……..

  • Early works in anatomy was based mostly on descriptions of organ systems, muscle system (conducted on domestic animals).
  • Oldest Anatomical works in western civilization were written by Greek Philosophers and physicians during the last 400 B.C.

Aristotle

  • Described and classified about 540 different kinds of animals during the 300 B.C.

Galen

  • Greek physician (Rome) during 165-200 A.D. assembled all available Greek anatomical writings and added some of his own dissection of apes.

Middle Ages

  • Very few advancements in anatomical study (biological thoughts were relatively infrequent).

After Middle Ages

  • Include the study of functional anatomy.

Leonardo da Vinci (1452-1519) 

  • and other Italian artists began to make their own anatomical
  • Total number of bones in the human bod 206 bones

Andreas Vesalius

  • Galen’s writings remained the primary authority on human anatomy for nearly 1,500 years until the Belgian anatomist Andreas Vesalius (1514-1564) pointed out that many of the Galen’s observations were inaccurate because they were based on animal dissections.
  • In 1543 Vesalius published De Humani Corporis Fabrica (On the Structure of the Human Body) renewing the interest in anatomy of animals.

Pierre Belon (1517-1564),

  • a French naturalist and physician in 1559, published an illustration of a human and bird skeleton showing that the skeleton correspond almost bone for bone.
  • He attributed the similarity to the manifestation of a basic architectural plan or archetype in the mind of the Creator.

The Renaissance in Europe (14th -16th centuries) was a period of rapidly increasing knowledge about human anatomy, but some influential scientists continued to be interested in Comparative Anatomy.

William Harvey

  • English physician,
  • Best known for his studies on the circulation of the blood.
  • Also dissected many animals and advocated the study of Comparative Anatomy.

Nehemiah Grew (1641-1712)

  • English scientist and plant physiologist.
  • The first one to use the term COMPARATIVE ANATOMY.
  • Published a book in 1681 describing the anatomy of stomachs and intestines in several species.

Carolus Linneaus (1707-1778)

  • devised the binomial system for naming plants and animals which forms the basis of modern Taxonomy.
  • (1735) published Systema Naturae, the 1st of several publications that presented his new taxonomic arrangement for the plant and animal kingdoms.
  • He philosophically argued that species were unchangeable, created originally as we find them today (based on creation as described in the book of Genesis of the Holy Bible.

Louis Jean-Marie Daubenton

  • Compared the anatomies of many different animals in a section of Buffon’s Histoire Naturelle (Natural History), a 36 volume work published between 1749 and 1789 that contained observations about the mineralogical, botanical and zoological characteristics of the Earth.
  • This section of the Natural History is today considered the first extensive work in Comparative Anatomy.

Jean-Baptiste de Lamarck (1744-1829)

  • Made the 1st scientific division of the animal kingdom into Vertebrata and Invertebrata
  • Wrote and published Philosophie Zoologique (1809) that discusses the three issues of evolution by means of the inheritance of acquired characteristics:
    • Fact (species changes through time)
    • Course(progressive changes in species along an ascending scale)
    • Mechanism (need itself produces heritable evolutionary changes)).

Georges Leopold Chretien Frederic  Dagobert Cuvier (1769-1832)

  • Argued that species are immutable, stating that the efficient design of each animal is evidence that it could not have changed since its creation.
  • Believed that Earth suffered several mass extinctions and recreations.
  • He argued that organisms must be understood as functional wholes.
  • Historie Naturelle des Poisons (Natural History of Fishes), his final contribution.

Louis Rodolphe  Agassiz (1807-1873)

  • A Swiss –American paleontologist and geologist
  • Published “Studies on Glaciers”
  • Considered as the first modern teacher of comparative anatomy
  • His teaching was particularly famous for his ability to draw with both hands at once while still continuing to talk

Alfred Russel Wallace (1823-1913)

  • Developed the concept of “survival of the fittest” (1858) from the observation that the human population increases faster than food to correspond with Darwin’s “survival of the few”

Charles Darwin (1809-1882)

  • Developed the modern Theory of Evolution.
  • Helped to established the evolutionary basis of our modern synthesis of comparative, functional and adaptive morphology and anatomy.

Sir Richard Owen (1804-1892)

  • A British zoologist published the 3rd edition of his Comparative Anatomy in 1871
  • Developed the concept of homology and analogy.
  • He was instrumental in obtaining and describing Archeopteryx that provided evidence for the theory of evolution but opposed the theory of evolution by Natural

Thomas Huxley (1825-1895)

  • A British biologist.
  • Published his Comparative Anatomy of Vertebrate Animals in 1871.
  • Also established the modern concept of the evolution of the vertebrate skull.

Karl Ernst Von Baer (1792-1876)

  • Published Epistola de Ovi Mammalium et Hominis Genesi (Papers on the Origin of the mammalian Egg and Man) in 1872.

Ernst Heinrich Haeckel (1834-1919)

  • German biologist, contributed to the knowledge of three germ layers that are found in the early embryos of most animals and develop into the organs of adults known as the biogenetic law (ontogeny recapitulates phylogeny).

 

Phylogenetic tree or evolutionary tree:

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  • Node – represents a taxonomic unit. This can be either an existing species or an ancestor
  • Branch – defines the relationship between the taxa in terms of descent and ancestry.
  • Branch length – usually represents the number of changes that have occurred in the branch
  • Topology – the branching pattern of the tree
  • Root – the common ancestor of all taxa
  • Distant scale – scale that represents the number of differences between organisms or sequences
  • Clade – a group of two or more taxa or DNA sequences that includes both their common ancestor and all of their descendants

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  • Scaled branches – are often calibrated to represent the passage of time. Such trees have a theoretical basis in the particular gene or genes under analysis
  • Unscaled branches – the branch length is not proportional to the number of changes that has occurred, although the actual number may be indicated numerically somewhere in the branch

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  • Rooted tree – there is a particular node called the root, representing a common ancestor from which a unique path leads to any other node
  • Unrooted tree – only specifies the relationship among species, without identifying a common ancestor or evolutionary path

 

Comparative Anatomy reviewer Part 2

Homologous Structures

The bones are color-coded to demonstrate that all of the organisms in the picture must have evolved from a common ancestor. Homology (shared characteristics among different species) is presented as solid evidence for biological evolution.

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Analogy

  • anatomical features that have the same form or function in different species that have no known common ancestor.
  • established through behavioral and biomechanical analysis
  • may or may not be homologous
  • Examples: insect wing & bird’s wing, Fish fin; whale flipper

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  • Analogous structures: wing of an insect, bird bat and pterosaur
  • Bat wings consist of flaps of skin stretched between the bones of the fingers and arm.
  • Bird wings consist of feathers extending all along the arm.
  • These structural dissimilarities suggest that bird wings and bat wings were not inherited from a common ancestor with wings.

The idea that bird wings and bat wings were not inherited from a common ancestor with wings is illustrated by the phylogeny below, which is based on a large number of other characters.

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  • Bird and bat wings are analogous — that is, they have separate evolutionary origins, but are superficially similar because they have both experienced natural selection that shaped them to play a key role in flight. Analogies are the result of convergent evolution.
  • Birds and bats did not inherit wings from a common ancestor with wings, but they did inherit forelimbs from a common ancestor with forelimbs.

 

Homoplasy

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  • features of two or more organisms are related by similarity of appearance
  • similarities cannot be explained by either homology or analogy
  • non homologous structural similarities between species.  In these cases, the common ancestor did not have the same anatomical structures as its descendants.  Instead, the similarities are due to independent development in the now separate evolutionary lines.
  • Misleading similarities.
  • Homoplastic structures can be the result of parallelism, convergence, analogies, or mere chance.
  • Ex: Sail fish and Pelycosaur ; Mimicry & camouflage

 

Mimicry or Camouflage

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The Distinctions and Relations among Common Ancestry (Homology), Common Function (Analogy) and Common Appearance (Homoplasy)

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Homoplastic structures can be the result of parallelism, convergence, analogies, or mere chance.

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  • Parallelism, or parallel evolution, is a similar evolutionary development in different species lines after divergence from a common ancestor that did not have the characteristic but did have an initial anatomical feature that led to it.
  • Convergence, or convergent evolution, is the development of a similar anatomical feature in distinct species lines after divergence from a common ancestor that did not have the initial trait that led to it.  (bat and bird wings.)

 

Linnaean scheme of Classification

  • Lumps organisms together based on presumed homologies.

Assumption :

  • The more homologies two organisms share, the closer they must be in terms of evolutionary distance.
  • The higher, more inclusive divisions of the Linnaean system are created by including together closely related clusters of the immediately lower divisions.

 

The result is a hierarchical system of classification with the highest category consisting of all living things.

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Cladistics 

  • This involves making a distinction between derived and primitive traits when evaluating the importance of homologies in determining placement of organisms within the Linnaean classification system.
  • Derived traits are those that have changed from the ancestral form and/or function.
  • An example is the foot of a modern horse.  Its distant early mammal ancestor had five digits.  The bones of these digits have been largely fused together in horses giving them essentially only one toe with a hoof.
  • In contrast, primates have retained the primitive characteristic of having five digits on the ends of their hands and feet.  Animals sharing a great many homologies that were recently derived, rather than only ancestral, are more likely to have a recent common ancestor.
  • Evolutionary trees depict clades.
  • A clade is a group of organisms that includes an ancestor and all descendants of that ancestor. You can think of a clade as a branch on the tree of life. Some examples of clades are shown on the tree below.

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There are three basic assumptions in cladistics:

  1. Change in characteristics occurs in lineages over time.
    The assumption that characteristics of organisms change over time is the most important one in cladistics. It is only when characteristics change that we are able to recognize different lineages or groups. We call the “original” state of the characteristic plesiomorphic and the “changed” state apomorphic.kbbkbk
  2. Any group of organisms is related by descent from a common ancestor. This assumption is supported by many lines of evidence and essentially means that all life on Earth today is related and shares a common ancestor. Because of this, we can take any collection of organisms and hypothesize a meaningful pattern of relationships, provided we have the right kind of information.dyrjyt
  3. There is a bifurcating, or branching, pattern of lineage-splitting.
    This assumption suggests that when a lineage splits, it divides into exactly two groups.

 

Development: Ontogeny & Phylogeny

Ontogenesis

  • Developmental history of an organism affected by genes; emb; embryogenic changes due to aging and ends at death. Single lifetime

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Phylogenesis

  • Evolutionary history of a Taxon (family or group of organisms) by relation to an evolutionary (ancestral) lineage.
  • 100T to 100M of years

 

Symmetry and Segmentation

  • describes the way in which the body of the animal meets the surrounding environment.
  • is the balanced distribution of duplicate body parts or shapes.
  • Body Symmetry: orientation of the animal body in relation to environment.

 

Radial Symmetry

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  • Body is laid equally from a central axis; any several planes passing through divides the animal into equal halves.
  • Ex: Body of Starfish

 

Bilateral Symmetry

  • Body is laid equally from a mid-sagittal plane; divides the body into two, mirror halves.
  • Ex: Vertebrate Animal

 

Midsagittal and Sagittal (lengthwise)

-Divides the R & L parts

Coronal (frontal planes)

-Divides the ventral (anterior) and dorsal (posterior) parts.

Transverse (horizontal)

-Divides the body into superior (upper) & inferior (lower) parts.

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Superior – structures higher or going cranial

Inferior – structures lower or going caudad

Posterior – structures located dorsally or back part

Anterior – structures located ventrally or front (belly) part

* In a 4-legged animal (anterior-cranial; posterior-caudal; dorsal-vertebral location; ventral-belly location)

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Directional Terms

Anterior: In front of, front
Posterior: After, behind, following, toward the rear
Distal: Away from, farther from the origin
Proximal: Near, closer to the origin
Dorsal: Near the upper surface, toward the back
Ventral: Toward the bottom, toward the belly

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Superior: Above, over
Inferior: Below, under
Lateral: Toward the side, away from the mid-line
Medial: Toward the mid-line, middle, away from the side
Rostral: Toward the front
Caudal: Toward the back, toward the tail

 

Segmentation

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  • segmentation (metamerism) – Division of the body along the anteroposterior axis into a serial succession of segments.
  • Divides the body into duplicated sections or metamerism
  • Metamere – segment or unit section
  • More evident in invertebrates (ex: worms) than vertebrates.
  • Ex: Backbone; Muscles of the fish; Teeth

 

Body Regions

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  • Head/Cranium
  • Neck/Cervical
  • Thorax / Pectoral region
  • Abdomen/Peritoneum
  • Hip/Pelvis
  • Urogenital/Perineum
  • Upper extremity
  • Appendages of pectoral or chest region
  • Lower extremity
  • Appendages of pelvic or hip region

 

Cranial cavity

  • -Oral/buccal cavity; Nasal cavity; Orbits; Middle-ear cavity (auditory ossicles / ear bones)

Vertebral cavity

  • Thoracic / Pectoral cavity
  • -Mediastinum – breast plate
  • -Pleural cavity – encases the
  • lungs
  • -Pericardial cavity – encases
  • the heart

Abdominal or Peritoneal cavity

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Pelvic / Hip cavity – encases reproductive parts

  • Perineum – encases urogenital parts

 

 

 

Comparative anatomy reviewer Part 1

Evolution and speciation

  • Evolution – a change in the genetics of a population over time (generations).
  • Population – all individuals of the same species living in a defined area at the same time.

2 types

Microevolution – small genetic changes within a population

  • Occurs through several mechanisms
  • The best known is natural selection
  • Natural selection – is evolution that occurs because individuals with some traits survive and reproduce better than do individuals with other traits
  • Fitness – refers to the degree which individuals with certain traits are expected on average to survive and reproduce

Natural selection is simply the logical result of 4 features of living system:

  1. Variation – individuals from a population vary from one another
  2. Inheritance – parents pass on their traits to their offspring genetically
  3. Selection – some variants reproduce more than others
  4. Time – successful variations accumulate over many generations

Darwin’s 4 postulates on natural selection:

  1. More young are produced each generation that can survive to reproduce
  2. Individuals in a population vary in their characteristics
  3. Differences among individuals are based on genetic differences
  4. Individuals with few strong characteristics survive and reproduce better

Macroevolution

  • A series of micro evolution
  • Speciation – the formation of new species when one ancestral species evolves more than 1 typical descendants
  • Since speciation occurs when one species evolve into more than 1 new species it increases the number of species that exist

Adaptations

  • Hereditary traits expressed (phenotype) in the organism’s morphology increases it’s chance for survival – mutation of genes
  • Evolutionary process of part modification by an organism to fit to its mode of life in a particular environment
  • Environmental factors that have influenced this mutation is through natural selection, mutant genes have a survival value

Speciation

  • Arise of new species from primitive ancestor as a result of geographical isolation of a population that leads to genetic drift of species
  • (Ex: Palawan species may have the same Borneo species).
  • Genetic shift – short mutation (minor)
  • Genetic drift – long mutation ( major)
  • Consequence: reproductive isolation
  • Isolating populations in different environments can lead to the beginning of reproductive isolation. These results are consistent with the idea of geographic isolation is an important step of some speciation event.

Habitat

  • Or niche, if habitat alters rapidly without giving time for species to adapt to new condition, the habitat disappears as species remains
  • Unsatisfactory habitat – the old way of life weakens
  • Some species may suit in the offers of the new habitat. Selection pressure is strengthened, shifting towards the new habitat. (+) Evolved species in a habitat.
  • Change in form – result of the interplay between changing environment and adapting organisms
  • Habitat – nature as living conditions, acts as selection pressure for the screening process of evolution, the genetic mutation and inheritance produce the adapting model.

2 types:

  • Linear evolution – habitat alters as 1 unit = change is in a straight line. (adaptation is dependent to each other)
  • Branching evolution –if the habitat subdivides into several units = original population of organism becomes isolated from one another (adaptation is independent).

Structures that arise from evolution and habitat formation can lead to…

Structures Specialized General
Morphology Modified part; uncommon Suited adequately; common
Function Restricted/limited Less restricted
Effectivity Maximum but specific Various uses

 

Adaptability Rarely adjusts; more pressured for change Flexible; less pressured for change

 

Evolutionary Trend or Morphocline

  • Gradual adaptive change in the evolution of a feature within a phyletic line. -> moderate change
  • (+) large population
  • Prolonged by selection pressure
  • Traces evolutionary path
  • Constant directional change -> progress at constant rate with temporary arrests advantageous for survival

Parallelism and Convergence

Parallelism

  • Evolutionary change in 2 or more lineages with common ancestor
  • Corresponding features undergo equivalent similarities.
  • Independent similarities within species share common ancestry.
  • Descendants appearance is same to their ancestors but exactness is not present due to effects of natural selection. Animals with identical functional requirements lead to similar structural adaptation.
  • Ex: Rats (non-flying) & Bats (flying) mammals
  • Kangaroo rat of North America and Jerboa of Africa
  • Similarities:
  • Long limbs and Short forelimbs
  • Loss of lateral toes and Long tail with white tip,
  • Large eyes and Compacted cervical vertebrae
  • Parallelism – The ancestor is common but both A and B have evolved a primitive trait independently.

Convergence

  • Evolutionary change in 2 or more lineages that have similar features (ancestry is not common).
  • Two or more different phyletic lines had increasing similarity in features.
  • Descendants were more alike compared to their ancestor since ancestors are more remote.
  • Influenced by similar climates and habitats.
  • Ex: Sharks, Icthyosaur, Dolphins (similar habitats but different ancestors) more become similar in functional structures than phylogenetic relationship.

Divergent evolution – is when two different species share the same ancestral origins but have evolved differently.

  • Both the wooly mammoth and the elephant originated from a common ancestor, but the common ancestor eventually diverged, leading to two new species.

Convergent evolution – is when species with different ancestral origins have developed similar features.

  • These two species look very similar but are not closely related. Flying squirrels are placental mammals like whales, dogs, and humans,where as sugar gliders are marsupials like kangaroos and possums. The species Current similarity is an example of convergent evolution; they have begun to look more similar due to similar adaptations, not because of common ancestry.
  • The common ancestor was a primitive armored fish unlike any of them; shark has no terrestrial ancestor, ichthyosaur and dolphin have dissimilar terrestrial ancestors, nevertheless they have remarkable resemblance.

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Geologists divide the history of the Earth into eras and periods, the boundaries of which were times of rapid change in the Earth’s crust and in its biota.

At least five times in the past 500 MY there have been many cases of mass extinction when as many as 60% of all genera died out within the span of 5 MY.

When do species become extinct?

Species become extinct when they cannot adapt to sudden shifts in their environment as:

  • Climatic change
  • Increase in competition for resources
  • Misbalance in predator-prey relationships
  • Alteration in host-parasites relation

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  • Entire assemblages of animals become extinct when the scale of the environmental change is extreme major change in vegetation, or significant shift in sea level.
  • Catastrophic events such as impacts by asteroids and devastating volcanic activity could cause mass extinction.
  • Different phyletic lines evolve at different rates, each line evolves at different rates at different times, and different characters of one line evolve at different rates at the same time

 

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Systematics

  • Study of phylogenetic relationships
  • Active area of evolutionary biology
  • CLADISTICS –special area of systematics that studies phylogenetic relationships based on shared or derived traits.

Applications:

  • Provides in-depth knowledge about evolution of traits within groups.
  • Traces the origin & spread of diseases especially zoonotic diseases (animal human).
  • Relation of species helps in formulation of advocacy programs for conservation of species.

2 Approaches in studying relationships of species…

  • Fossils –provide a preserved record of the history of life forms; portrays the phylogeny of life.
  • Hierarchical pattern of homology –different species that share the same structures depicts that they may have evolved from the same ancestor. (common features / traits shared close relationship of species; less traits shared distant relationships)
  • CLADISTICS –answers those gaps in systematics that do not rely in the number of shared characteristics.

Phyletic Line

  • A lineage that is relatively continuous & complete in the fossil record.
  • Genera (sing. Genus) are related by evolution (linear & branching) and progressive change from extinct organisms.
  • Each phyletic line evolves at diff. rates diff. times while diff. characters of 1 phyletic line evolve at diff. rates simultaneously.

Phylogeny

  • Shows the pattern of evolutionary relationships or history of speciation.
  • Represented by a TREE that shows where points of ancestors speciated into 2 new species.

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Dendograms & Cladistics

  • Modern vertebrates differ from their ancestors; evolutionary hx. Can be traced using similarities in morphological characteristics thus, relationships between groups would imply close relationships.
  • Primitive condition – ancestral
  • Derived condition-descendants

Dendograms

  • Summary representation of evolutionary course or phylogeny
  • Branched connections between related groups like a tree PHYLOGENETIC TREE
  • Illustrates the evolutionary history of related organisms
  • It also shows abundance & diversity of species

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SLANT FORMAT

  • Legend: Every line that branches into species above the branch (descendants) arise from species below the branch point (ancestor).
  • Ex: Trees on the right shows the relationship between mouse, bird, lizard, snake.
  • Trees on the left shows relationship between salamander and frogs.

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Traits

  • Primitive Traits (plesiomorphic characters) are characters of organisms that were present in the ancestor of a certain group of related organisms
  • –Ex: Ancestor of lizard, bird, alligator = scaly skin; 3-chambered heart; (+ )teeth; (-) wings
  • Derived Traits (apomorphic characters) are characters of organisms that have evolved within the group or related organisms that were not present in the ancestor.
  • Ex: birds, lizard, alligator = gizzard; 4-chambered heart, feathers, (-) teeth; wings

SYNAPOMORPHY

  • Character/s is present in immediate ancestor only but not in the earliest ancestor.
  • Derivative traits

SYMPLESIOMORPHY

  • Character/s is present in immediate ancestor and earlier ancestor.
  • Primitive traits
  • Ex: Birds developed wings but lost the primitive 4 legs that have been present with the birds’ ancestor.

OUTGROUP COMPARISON

  • Method in determining primitive vs. derived traits.
  • Determine 1 or more species that are relatives of the group of interest (ingroup), and the species equally related to all members of the group of interest (outgroup).
  • Character/s of comparison found common in both groups is considered Primitive trait, while, character/s found common only in one group but absent to other is considered as Derived trait.

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Outgroup comparison

  • Bony skeleton
  • (+) trout, frog, mouse; (-) shark
  • Therefore, ancestor B had evolved a bony skeleton.
  • In general, provides evidence of ancestry that bony skeleton as a phylogenetic trait traced from ancestor B to trout, frog, mouse.

Grades

  • A paraphyletic group (incomplete clade); stage of evolutionary attainment (adaptation) expressed by an evolving group. (Ex: jawless to jawed fishes)
  • An incomplete clade lacks one or more component lineages.
  • If more distinct derived characters are present shared in groups a new GRADE is attained.

Clades

  • A natural evolutionary lineage which includes an ancestor +all and only descendants.
  • Descendants may have high similarity or difference from their ancestors (variation in morphology is not restricted).
  • CLADOGRAMS – a hypothetical diagram of lineages & evolutionary relationships (geological time scale is not included).

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Cladogram (family tree) of a biological group. The red and blue boxes represent clades (i.e., complete branches). The green box is not a clade, but rather represents an evolutionary grade, an incomplete group, because the blue clade descends from it, but is excluded.

Types of Clades

Monophyletic clade

  • Includes an ancestor + all descendants

Paraphyletic clade

  • Includes more than one ancestor + but not all descendants

Polyphyletic clade

  • Does not share an immediate common ancestor

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Anatomical and Evolutionary Concept

Taxonomic Principles

  • Biologists classify organisms into different categories mostly by judging degrees of apparent similarity and difference that they can see.
  • Assumption: The greater the degree of physical similarity = the closer the biological relationship.

Researchers begin their classification by:

  • looking for anatomical features that appear to have the same function as those found on other species.
  • determining whether or not the similarities are due to an independent evolutionary development or to descent from a common ancestor.
  • If the latter is the case, then the two species are probably closely related and
  • should be classified into the same or near biological categories.

 

Similarities: Homology, Analogy and Homoplasy

Homology

  • features of two or more organisms sharing common ancestry.
  • anatomical features, of different organisms, that have a similar appearance or function because they were inherited from a common ancestor that also had them.

The wing of a cat, bat, whale and your arm have the same functional types of bones as did our shared reptilian ancestor.   Therefore, these bones are homologous structures.

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The more homologies two organisms possess, the more likely it is that they have a close genetic relationship.

 

Homologous characters — characters in different organisms that are similar because they were inherited from a common ancestor that also had that character.

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An example of homologous characters is the four limbs of tetrapods Birds, bats, mice, and crocodiles all have four limbs. Sharks and bony fish do not. The ancestor of tetrapods evolved four limbs, and its descendents have inherited that feature — so the presence of four limbs is a homology.

Not all characters are homologies. For example, birds and bats both have wings, while mice and crocodiles do not. Does that mean that birds and bats are more closely related to one another than to mice and crocodiles?

 

 

 

Christian doctrines

Title (Latin)

Theme Issued By Date/Year Issues/concerns
Rerum Novarum On the condition of labor Pope Leo XIII 1891 ·         Enumerated the moral principles that should govern among other thing

·         The rights of the workers

·         The right to private property

·         Care for the poor

·         Duties of workers and employers

·         The role of public authorities

·         And the return to Christian morality

Quadragesimo  Anno On the social reconstruction Pope Pius XI 1931 ·         Commemoration of the 40th anniversary of Rerum Novarum

·         The term “social doctrine” was first used by Pope Pius XI

·         The effect of greed and concentrated economic power on working people and society

·         The demands of the common good and social justice oblige the whole country to work for an equitable distribution of good

·         The right and duty of the catholic church to make its special contribution in resolving the problems of the society

Divini Redemptoris Pope Pius XI 1937 ·         Exposed the errors and evils of communism that was more and more becoming popular at that time
Summi Pontificatus On the unity of human society Pope Pius XII 1939 ·         The church’s opposition against racial hostility, totalitarianism, and the idea of state becoming something ultimate to which everything else should be subordinated

·         The need for the state to recognize and respect freedom of religion

Mater et Magistra Christianity and social progress Pope John XXIII 1961 ·         Worldwide problem of the widening gap between the rich and the poor, the arms race, and the plight of the farmers

·         Tackles the problem of agriculture and plight of the farmers

·         Magna carta of agriculture

Pacem in Terris Peace on earth Pope John XXIII 1963 ·         Magna carta of human rights

·         The full range of human rights as the basis of peace

·         He encouraged disarmament, recognized quality of dignity, and right to self-development of each nation

·         Advocated reviewing of policies for allocation of resources and policies that concerns multinational corporations

·         Promoted the united nations organization as the worldwide public authority

·         Proposed a society based on subsidiarity

Gaudium et Spes The church in the modern world Second Vatican council 1965 ·         Human dignity as the basis for political an economical decisions

·         Warns and laments on the growing worldwide poverty and the threat of nuclear war

·         Also sees peace as an ordering of society built on justice

·         Encourages Christians to work for structures that would make a more just and peaceful world

Populorum Progressio On development of peoples Pope Paul VI 1967 ·         The pope coined the phrase:

o   “development is another term for peace”

o   “authentic development is not limited to economic growth”

·         He decried sinful structures that promote inequality

·         Stifles the fight of poor individuals and nations for human development

·         Resources be shared through aid, technical assistance, and fair trade relations

·         The core of this encyclical – The right of individuals and nations development

Octagesima Adviens A call to action Pope Paul VI 1971 ·         80th anniversary of rerum novarum

·         A synthesis of guidelines related to political activity

·         Calls for political action for change and economic justice

·         An objective analysis of the situation of one’s society with the aim of identifying action for justice

Justice in the world Synod of bishops 1971 ·         The mission of all members of the people of god to work for justice in the world

·         Bishops also show their adherence to the UN declaration of human rights

·         Emphasizing action for justice as a constituent part of being a Christian

·         The bishops also requires from Christians particularly the leaders, policies, and lifestyle that model justice so as to be credible in preaching justice

·         The reality of social sin that presently exists in every nation

Evangeliu Nuntiandi Evangelization today Pope Paul VI 1975 ·         Fighting for justice and people’ liberation from different forms of oppression

·         Personal and societal transformation and sees social justice as integral to faith

Redemptor Hominis Redeemer of mankind Pope John Paul II 1979 ·         The importance of human rights as the fundamental principle for all programs, systems, and regimes

·         A redirection of investments for armaments into investments for food at the service of life

·         A greater emphasis for the care of the environment

Laborem Execerns On human work Pope John Paul II 1981 ·         Tackles the modern meanings and problems of human work

·         The duties of all the members of the church towards it

·         Commitment to justice through the fostering of just wages, joint ownership and sharing in the management and profits of labor

Solicitudo Rei Socialis Social concerns of the church Pope John Paul II 1987 ·         Tackles the concepts of option for the poor, sinful structures, conversion to solidarity, and reform of world trade and financial systems

·         The great injustice of the few having so much and the many having almost nothing

·         Different situations of sin that worsen and perpetuate the situation

·         He also suggests plans of action towards integral and human development

Centesimus Annus The 100th year Pope John Paul II 1991 ·         Commemoration of the 100th year of rerum novarum

·         Calls for disarmament

·         Development of public policies for employment and job security

·         Establishment of institutions for arms control

·         Simplification of lifestyle, particularly those who are rich for the sake of the poor, not only individuals but also nations

Tertio Millenio Adviente The jubilee year 200 Pope John Paul II 1994 ·         Invites all Christians to a commitment to justice and peace

·         Pro-poor polices and structures

·         Substantial reduction or outright cancellation of international debt

·         Solution of problems involving unity and human rights particularly those of women

·         The jubilee year – the year of the lord’s mercy

Evangelium Vitae Gospel of life Pope John Paul II 1995 ·         Recognition of the sacred value of human life

·         He denounced the violence against life done to millions of human beings who are victims of war and poverty

·         Especially children who are forced into poverty, malnutrition, and hunger because of an unjust distribution of resources

Ecclesia in Asia Jesus Christ the savior and his mission of love and service in Asia Pope John Paul II 1999 ·         Published in the event of the pope’s visit to India

·         Deals on Asian religious, cultural, social, economic, and political realities viz a viz the catholic church in Asia

·         The Asian church’s mission is a mission of communion and dialogue

·         Clarifies the social teachings of the church

·         Particularly on the dignity of the human person, preferential option for the poor, education, peacemaking, globalization, foreign debt, and environment

The Participation of Catholics in the Political Life Pope John Paul II 2002 ·         Coherence between faith and life, gospel and culture

·         Exhorts christians to fulfill their duties faithfully in the spirit of the gospel

·         Inspires christians to be proud of the opportunity to carry out their earthly activity  in such a way as to integrate human, domestic, professional, scientific, and technical enterprises with religious values under whose supreme direction all things are ordered to the glory of god

Compendium of the Social Doctrine of the Church

(CSDC)

The pontifical council for justice and peace in Vatican 2004 ·         A compilation and systematic presentation of the social teaching of the church

·         A concise but complete overview of the church’s social teaching

·         Help the readers to understand the motives that prompt the church to intervene with her doctrine in the social sector

·         To sustain and foster the activity of christians in the social sector

·         Help the readers see the reasons for an encounter, dialogue, and cooperation in serving the common good

Deus Caritas Est God is love Pope Benedict XVI 2005 ·         Theological-philosophical reflection on love

·         Inherent link between god’s love and human love

·         Necessity of loving others as a central element of the social teaching of the church

·         Describes the social teaching of the church as a body of doctrines that helps in the attainment of social justice by forming consciousness through the purification and illumination of reason

Medellin Conference Documents Latin american episcopal conference 1968 ·         Aim to adapt the social teaching of the church to the life situations of the latin american church
Puebla Conference Documents Latin american episcopal conference 1979 ·         Aim to adapt the social teaching of the church to the life situations of the latin american church
The Documents of the Federation of Asian Bishop’s Conference

(FABC)

Jan. 10-19, 1995 ·         Denounce the forces of death that plague the continent

·         Envisions a unity in diversity among the people in asia

·         They envision a holistic life

·         Gives attention to whatever threatens, weakens, diminishes, and destroys the life of individuals, groups, or people

·         Whatever devalues human beings  conceived, born, infant, or old

·         Whatever socio-cultural, religious, political, economic, or environmental factor that threatens or destroys life in our countries

The Document of the Second Plenary Council of the Philippines (PCP II) Plenary council composed of representatives from all sectors of the Philippine church 1991

·         Aims to reanimate the filipino’s life in Christ Jesus and unite all things in him

·         It starts with an analysis of the present situation in the Philippines in the light of Christian faith

·         Suggesting ways towards the realization of its vision of a renewed church

·         Integral evangelization  and a community of disciples

·          Offers a new spirituality of social transformation towards liberation from all forms of oppression

Social analysis – ideologies

1)”Kung graduate ka ng _________, madali ka makahanap ng trabaho.”

Certainly elite colleges like Harvard, Stanford, Princeton, and Yale University and top universities in the Philippines such as UST, ADMU, UP, or DLSU have name recognition that could help you secure an interview or win a job over other candidates. However, the reputation of your alma mater does not translate directly into higher wages or career success. But enrolling in a top universities and colleges can help you build influential networks that open doors after graduation.

For example in a job prospect, when you enter an interview. The interviewers first will look at both of your skills and education. If you have high grades that is good then let us resume, but if you do not have well speaking skills, you cannot overcome your nervousness, you cannot answer their questions well, and you cannot assured them about your needed abilities for the job, do you think they will accept you? Certainly not. Education alone cannot guarantee success in life .It must be followed by skills. Education is knowledge while skill is application. One need to have both to success in life. If you have aspiration and drive, you will do well no matter where you go.

2) “If you take your studies seriously, you will succeed.”

Achieving good grades and high class position are poor predictors of future success in life. Because bad days happen in life and fortunately for all those kids who got straight A’s all the way through yes they are intelligent, how well you take a test is not an indicator of how well you will thrive in the real world. You can get all A’s and still flunk life or have trouble finding a good and stable job. High grades doesn’t guarantee you success in life.

Bad grades, failed exams and bad records do not define you after these campus years. Your grades do not translate in the real world and your worth is not dependent on a number. Your GPA may help you get that first job or give you a scholarship, the way your NMAT score helped you get into your first or second choice of medical school, but like your score, it becomes unimportant after you leave that chapter of your life. Worst things will happen to you in life and this is just a minor bump on the long road ahead of you. The important part is that you learn from this failure and work harder to make up for it. Because failure teaches us a lot more than what we learn from our textbooks, from our teachers, from our schools/universities. Failure has lessons of perseverance, determination and loss. It will teach us how to succeed in life, how to enjoy and value our life.

3) “A rich person is one who knows how to save money.”

You’ll never get rich by just saving money. It’s a simple fact of life. Unless you’re an ultra-high earner, saving alone won’t make you rich. The answer is simple and requires a small distinction. The key difference is what you do with the money you save. Just simply saving money, whether you put it under a mattress, bury it in a can in your backyard or put it in a saving account earning a 1% interest, will never allow you to grow meaningful wealth if you start from nothing. Saving money isn’t necessarily a bad idea. It can help you in lots of ways. But, in the later years, it’s not how we get rich. Instead, you must invest your savings. That is the key.

Since saving is the only way to accumulate (save) wealth. Those whose wealth has gone up have seen it go up by saving it – more accurately investing it, and being buy and hold investors. That does take discipline, but it works better than lottery tickets, trying to work triple overtime.  Saving in a saving account won’t make you rich. You don’t need to use fancy economic jargon or know this year’s “hottest stock.” You don’t have to come from an affluent family, and you don’t even have to earn a massive paycheck. For most people, it all boils down to one thing: investing. “On average, millionaires invest 20% of their household income each year. Their wealth isn’t measured by the amount they make each year, but by how they’ve saved and invested over time,”

4) “There is massive poverty in the Philippines because Filipinos are lazy to look for a job.”

The most notable cause of poverty identified by the majority, both in interviews and the training, was ‘laziness’. This is characterized as having low interest in a good life, lack of motivation and initiative, low intellect, dependency thinking, reliance on assistance from others, and lack of life skills (to plan and organize their life). The overall feeling was that these types of people are ‘no hopers’ and in need of some form of assistance to survive; they do not have the ability and life skills to manage alone.

Some people are lazy because they lack the fundamental belief that they can do something and anything good to lift themselves from their present condition. So, each thought that comes into their mind end up in in the trash bin – “I can’t do it”. So they sit back and before they know it, they become clumsy and lose all motivations, energy and drive to do anything. Therefore, as adults, we have to constantly encourage one another to try something different and to keep trying without giving up hope and more importantly that we can all do anything if we set our heart and mind on it. With this orientation people will be less afraid to try something because it does not matter if they fail, because it is also ok to fail. Stand up for yourself and do something meaningful. “Proverbs 10:4 – Lazy hands make for poverty, but diligent hands bring wealth.”