Question

help me out please!

choices are non-deuterostomes and deuterostomes

Question 30 Identify each of the following characteristics as belonging to deuterostomes or non-deuterostomes. 1. ventral nerve cord [Select] 2. exoskeleton [Select] 3. blastopore developing into a mouth (Select] 4. dorsal nerve cord [Select]

Answer 1

ANSWER: The correct alternatives are-

1. Ventral nerve cord- Non -deuterostomes /Protostomes

REASON- Nerve cord in chordates, hemichordates and protostomes/non-deuterostomes evolved absolutely independently.Non-deuterostomes/ Protostomes include a variety of phylum together namely- arthropods, annelids and mollusca. The non-deuterostomes /Protostomes usually possess the nerve cord on the bottom surface of their body i.e ventral surface, thus they are called ventral nerve cords.

2. Exoskeleton - Non-deuterostomes/ Protostomes

REASON- The exoskeleton is thought to be evolved later during evolution period and is only a characeristic of Protostome /non-deuterostomes lineage found majorly in arthropods. On the other hand deuterostome,including the phylum like echinodermata and the vertebrates  tend to evolve with endoskeleton.

3. Blastopore developing into a mouth- Non-deuterostomes/ Protostomes

REASON- The non-deuterostomes or the protostomes embryonic development suggest that the first pore on the body surface i.e the blastopore is developed into mouth of the organism over the course of time.However the deuterostomic embryonic development provide evidence of the first pore i.e blastopore converting into anus.

4. Dorsal nerve cord- Deuterostomes

REASON- The deuterostomes largely consisting of the vertebrates and phylum echinodermata usually have their nerve cord on the top side of their body surfaces i.e dorsal side of their body surface, and hence they have dorsal nerve cord.