BIOL 304 Lecture 13: Biol 304 – Lecture 13

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amaranthjackal733

5 Mar 2018

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Definitions: dobzhanzky has the best definition of mesoevolution, i(cid:373)ply defi(cid:374)i(cid:374)g it o(cid:448)er a ti(cid:373)e s(cid:272)ale is(cid:374)"t suffi(cid:272)ie(cid:374)t. If a character is present in the most recent common ancestor of a group of species, it is a homologous character. Convergence: traits that have a very different developmental basis and appear in distantly related organisms, but may be regulated by similar genes (cid:862)i(cid:374)depe(cid:374)de(cid:374)t e(cid:448)olutio(cid:374) of traits i(cid:374) dista(cid:374)tly related species that do not share a developmental (cid:271)asis(cid:863) The (cid:373)ost re(cid:272)e(cid:374)t (cid:272)o(cid:373)(cid:373)o(cid:374) a(cid:374)(cid:272)estor of many of the species that have spots did not have spots thus not homology, but parallelism. Development of the trait is the same in the different species: parallelism represents a greyzone between homology and convergence. Example: genus of ant pheidole, characteristic of this genus: have major worker caste, and minor worker caste (most ant species all look similar) Ie although the trait has been lost in many of the species, the potential to produce the trait has not disappeared.

Related Questions

An African monkey has a DNA sequence that is 96.66% similar to a human sequence. According to the molecular clock, about how long ago did the common ancestor for African monkeys and humans live?

2.5â3 million years ago

5â6 million years ago

13â16 million years ago

17â20 million years ago

Humans and chimpanzees have a common ancestor that lived approximately 5 million years ago. Scientists have amassed an impressive collection of fossils for ancestors to modern humans and placed these ancestors in chronological order to observe the changes that occurred as these organisms evolved more human-like characteristics. Which lines of evidence provide the basis for stating that humans and chimps have a common ancestor that lived approximately 5 million years ago?

homologous structures in humans and chimps

DNA sequence similarity

changes in bone structure

vestigial structures in humans

Which description applies to a vestigial structure or trait?

It is the result of convergent evolution.

It represents evidence supporting the common descent and separate types models for modern organisms.

It did not have a necessary function in more ancestral organisms, but it does in more evolved organisms.

It is a type of homologous trait that is found in diverse organisms.

Which organisms are most closely related?

Bears and raccoons, which are both in the order Carnivora

Cougar and lynx, which are both in the family Felidae