Worksheet Answer Key

1) Definitions:

Anatomical Homology is the study of how different species can have similar structures.

Biogeography is the study of how animals and plants are distributed throughout the world.

Embryology is the branch of biology that deals with the formation, early growth, and development of living organisms. 

Fossils are crucial evidence for evolution because they show how different species have changed over time. It also helps us understand how far back in time each species has been around.

2)All tetrapods have Pentadactyl limbs. As seen in the picture below, all have the pattern of one bone, two bones, lotsa blobs, and digits. The one bone is the humorous, the two bones are the radius and the ulna, the lotsa blobs are carpals/metacarpals and the digits are fingers. If they did not have a common ancestor at some point, than they would not all have the pentadactyl limbs.

3) The earliest records of homologous structures are from Aristotle.

4) Homologous structures are produced by different genes.

5&6) Closely related species that look different are this way because they need different features to survive in their habitat. For example, birds are all closely related species, however, many birds have differing features. (i.e. length the beaks, wing span, ext.)

Distantly related species that look similar are this way because they require similar features to survive. A dolphin and a fish are most certainly distantly related species, however they both (may) have dorsal fins, tail fins and/or rubbery bodies. These similar physical features are shared because of their common environments. 

7) They are a great way to explain natural selection in evolution because of the way they illustrate changes in species to adapt to different eviornments.

8) Common embryological development suggests that organisms that develop the same way shared a common ancestor. This can also relate to anatomical homology. Homologous structures develop in the embryo just like any other structure, therefore organisms that develop in a similar way are more likely to have homologous structures.

 

9) Organisms are more closely related towards the beginning of development. This suggests the taxonomical structures which help prove evolution.

10) Fossils are crucial evidence for evolution because they show how different species have changed over time. It also helps us understand how far back in time each species has been around.

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