Question

Choose the FALSE statement:

A) The Cambrian Explosion refers to an event that occurs at roughly the third point in the “Dr. D. Law of Halves”; accordingly, this event is noted for the simultaneous emergence of all 35 modern animal phyla about a billion years ago.

B) Natural selection rarely hinges on a single feature or adaptation; rather, it is usually the aggregate of many features that contribute to a species’ chances of survival and reproduction.

C) Part of the reason that animals must excrete nitrogen wastes is that the ammonia released from eating protein and the subsequent breakdown of amino acids is toxic.

Choose the FALSE statement:

A) The large rounded bodies of molluscs have a low surface area to volume ratio; accordingly they evolved complex organs and organ systems to support these dimensions.

B) The two patterns of development that distinguish protostomes (molluscs, annelids, arthropods) from deuterostomes (echinoderms and chordates) probably involved as a simple change among pattern formation genes that switched the head and tail ends of embryos.

C) Evolutionarily, your phylum, the Chordates, is more closely related to bilaterally symmetric invertebrates, e.g., Arthropods, than it is to a phylum like the Echinoderms, that have 5-pointed symmetry.

Answer 1

Ans(1): Statement B is false bacause Natural selection may also occur on change in a single gene or adaptation of single feature. For example, colour change of beetle from red to green will be selected naturally as it will to hide it in grass etc.

Ans(2): Statement C is false. Because Chordates are the more closely related to phylum echinoderms. The common ancestor of these two phyla was was likely a bilaterally symmetrical organism with a cephalized nervous system (type of nervous system centralised in head of organism).