Question

3. According to the molecular sequence-based phylogenetic tree of animal life, which of the following is correct? a. Eucolomate animals evolved from pseudocoelomate animals, which in turn evolved from acoelomate animals. b. Segmentation probably evolved in only one clade, which includes more than one phylum showing segmentation. C. Segmentation evolved in some protostomes and some deuterostomes. d. Deuterostomes are more closely related to eucoelomate protostomes than to other protostomes that are pseudocoelomate or acoelomate. e. None of the above is correct. ola 4. Which of the following statements concerning protists is false? a. All protists are eukaryotic; many are unicellular and a few are colonial. b. Malaria, trypanosomes, and toxoplasma are all transmitted to humans via insect bites. c. All trypanosomes are parasitic. d. All apicomplexans are chemoheterotrophic. e. The flagella of bacteria and protists generate the same kind of propulsive force despite having different mechanisms and independent evolution.

Answer 1

Eucoelomate animals are evolved from pseudo coelomate animals which in turn evolved from acoelomate animals.

Answer: incorrect

Reason: This is believed that the evolutionary sequence is from acoelomate to pseudo coelomate to coelomate. The coelomic cavity performs various functions like a hydro skeleton, transport of gases, nutrients and waste products, etc. also the sperms and ovum storage all these features also enable us to understand that it should be present in higher organisms with complex functioning. Thus, extends our understanding to evolution in the later stage.

Segmentation probably evolved in only one clade, which includes more than one phylum showing segmentation

Answer: incorrect

Reason: Segmentation is one of the important features of metazoans that belongs to one clade and that can also be seen among different phyla. But, the evolutionary evidence still is unclear and is a central problem for developmental biologists .but, still much indication belongs to this.

Segmentation evolved in some protostomes and some deuterostomes:

Answer: incorrect

Reason: It has been found that genes that control the segmentation are almost the same in both the group of organisms. Therefore, the taxonomic value does not prove to be acceptable.

Deuterostomes are more related to eucoelomates protostomes than to other protostomes that are pseudo coelomate or acoelomate.

Answer: correct

Reason: This is true because deuterostomes and protostomes are a subdivision of Eucoelomates and are distinguished by their early embryonic development. In the protostomes, the mouth is formed near and at blastopore, whereas in deuterostome the mouth is formed opposite to blastopore. Similarly, there are other differences present in them. But, the pseudo coelomate protostomes offer more differences as they are held loosely and not organized that well as in the case of eucoelomates. .There is one underlying fact that all pseudo coelomates are protostomes but all protostomes are not pseudo coelomates.