Sierra College Department of Biological Sciences

Discover the Biological Sciences

The introductory information for this site has been contributed as a joint assignment by students in Bio. Sci. 10.

Anatomy - Comparative Anatomy

By: Lucas KrallName: Sierra College Bio. Sci. 10

1) Biological field or sub-topic chosen:

Comparative Anatomy

2) Define field or sub-topic:

A very important and remarkable field of biology is Comparative Anatomy. Simply put, Comparative Anatomy is broken into the concepts of homology (homologous structures) and analogy (analogous structures). Homology is the comparison and contrast of common anatomic structures/parts of one species to another due to their common ancestry. Often times, these anatomic structures/parts are used similarly among different species. Yet, the structures/parts have evolved according to the individual species’ environment and need to maintain a high level of reproduction and their need for survival. Where as analogy is the comparison of similar structures within animals from different ancestral backgrounds but come from similar environments. A common example is the comparison of the wings on butterflies and birds. These two species come from different backgrounds. However, their wing structure is universal for flying.

3) Describe in more detail the breath and depth of what could be studied or learned within this topic:

Possibly the greatest thing to be studied in this field is evidence of evolution. Not only evidence that it exists but also as a means of tracing back the lineage of species to common ancestors. Furthermore, one can also see the evolution of different species within the same environment (i.e. air or water) and studying the various adaptations. The study of evolution is a vital link between all the different sciences. Without learning more about evolution, one can not really learn everything about biology. The importance of understanding how various organisms came to be also provides assistance when biochemists attempt to create cures. This also helps explain why viruses and bugs build up immunities (microevolution) to certain "cures" after amounts of time exposed.

4) Focusing on one major concept, principle, or group of organisms (as appropriate within the topic), describe its importance, relationships, functional aspects, or otherwise explain it in more depth as seems important to you and (potentially) the others in class:

An important concept in Comparative Anatomy is the forelimbs of all mammals. Each mammal (i.e. cat, human, whale, bat) has homologous forelimbs. At first glance one could argue that a whale’s flipper has no similarities with a human arm. However, a deeper look at the skeletal structures will reveal a different story. In fact, they’re strikingly similar. This supports the hypothesis that all mammals came from the same ancestor, but through time and differing environments various adaptations were made and the species split into their respective branches.

5) In studying and discovering more about this topic, what was the most interesting aspect, fact or some other piece of information that you have learned.

The most interesting piece of information I came across pertained to the human spine. Through evolution our ancestral spinal structures eventually became erect into the posture we know today. This is shown on the basic diagram that depicts the progression from monkey to human. But what I didn’t know is that a common cause of back problems directly relates to our ancestral spinal columns. Through evolution our spine took a new role of support for our bodies and it would appear that all the kinks have not been worked out.

6) References – provide references used and at least two Web sites with additional information on this topic (or sub-topic) for anyone that would like to learn more:

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