Question

Which of the following is true or false

1) Natural selection favored the evolution of gill slits in the sides of the pharynx (throat region) in the Phylum Hemichordata and basal groups of the Phylum Chordata as a response to filter feeding habits (where the gill slits allowed the disposal of excess water and concentration of the food particles going down to the stomach) rather than to facilitate respiration and oxygenation of the blood.

2) Sponges (Phylum Porifera) have true tissue layers that are derived from the process of gastrulation in the embryo; gastrulation results in formation of the mesodermal tissue layer.

3) The nearest relatives of the Anthropoid Primates (monkeys, apes, humans) are the Scandentia (“tree shrews”).

4) Of the two great branches of the Bilateria, the Deuterostomes (which include the Phylum Chordata and us) have more total species diversity than do the Protostomes.

Group of answer choices

Answer 1

1- True : presence of gill slits tells us about the common ancestory with fish Although in higher chordate gills slits have no role in respiration but according to natural selection random mutation might arises which changed the heritable trait

2- False : Sponges do not possess true germ layer or tissue layer. They have only 2 derm layer ( inner choanoderm and outer pinacoderm)

3- True : Anthropoid have nearest relative as scandentia and dermoptera

4- False : Arthropod and mollusc which are largest and second largest phylum respectively comes under protostomiate so the number of species are more in protostomiate while lower in deuterostomiate.

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