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11- Nearly all currently existing animal lineages evolved during which period? (

ID: 31789 • Letter: 1

Question

11- Nearly all currently existing animal lineages evolved during which period?

(a) Ediacaran

(b) Precambrian

(c) Cambrian

(d) Cryogenian

12. Based on information provided in the tree above, which of the following statement(s) is/are accurate?

(a) the frog, dog, turtle and lizard form a monophyletic group

(b) the fish is the ancestor of the rest of the species in the tree

(c) frogs are older than birds

(d) all of the above

(e) none of the above

13. Only a few species of garter snakes (Th. atratus, Th. couchii, and Th. sirtalis) have evolved the ability to tolerate a toxin produced by newts called tetrodotoxin (TTX). The phylogeny above shows how these three species are related. Referring specifically to Th. couchiiand Th. sirtalis, tolerance to TTX is an example of a ______ caused by - _______.

(a) reversal; homology

(b) homology; convergent evolution

(c) homoplasious trait; convergent evolution

(d) homplasious trait; homology

(e) ancestral homology; natural selection

14. Trap jaw ants have modified mandibles that function like a bear trap?when a potential prey item triggers the jaw it snaps shut with amazing speed (up to 145 mph!). The groups highlighted in the phylogeny below include species that have evolved trap jaws. With reference to this tree it appears that:

(a) the trap jaw could be a homologous trait for Formicinae and Ponerinae

(b) the trap jaw is homoplasious (analogous) for Myrmicinae and Ponerinae

(c) the trap jaw is homoplasious (analogous) for Odontomachus and Myrmoteras

(d) a and c are correct

(e) b and c are correct

15. Which of the following statements is central to the idea of uniformitarianism:

(a) natural laws that are observable today also operated in the past

(b) catastrophic events such as floods and volcanoes have played the primary role in

shaping the earth?s existing features

(c) geological change happens gradually for the most part

(d) a and c are correct

(e) all are correct

Explanation / Answer

Answer 11: Option C
It was the cambrian explosion when maximum number of animals emerged. Though it took for a relatively shorter period of time but it resulted in formation of the major animal phyla.

Answer 12: Option C
If we take only frog, dog, turtle and lizard, it will not be considered as a monophyletic group, because it does not include all the members under that ancestor. It should include birds and crocodiles also, then only it will be consisdered as Monophyletic. That's why option A is incorrect. Also fist is not the ancestor of the tree.

Answer 13: Option C
Since these two are not closely related species, this trait would be considered as homoplasious, that means analogous and thus lead to convergent evolution.

Answer 14: Option E
Since Myrmicinae and Ponerinae are not closely related species, the presence of the same physical trait will show that they are analogous. Same is the case with Odontomachus and Myrmoteras.

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