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.
- 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.
- 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
- Developmental Biology
- Evolutionary biology
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.
- 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.
- Described and classified about 540 different kinds of animals during the 300 B.C.
- Greek physician (Rome) during 165-200 A.D. assembled all available Greek anatomical writings and added some of his own dissection of apes.
- 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
- 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.
- 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:
- 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
- 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
- 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