Question

Deuterostome conditions and characteristics of indeterminate radial cleavage are:
A. Chordates and arthropods
B. Chordates and echinoderms
C. Arthropods and echinoderms
D. Chordates, arthropods and annelids

Answer 1

Deuterostome is a condition in which the development of anus takes place prior to the development of the mouth. Radial cleavage is the term for the division of the cells in a radial manner.

Complete answer:
There are various stages after the fertilization where the further development takes place. These stages are carried out in a regulated manner where the first division occurs in the embryo itself where the differentiation of cells takes place. Now as we see this division of cells can occur in two ways, either it can divide radially or it can divide bilaterally. Mostly the organisms which are destined to divide radially generally possess the condition of deuterostome.

Now if we discuss what deuterostome condition is, then this is a condition in which the development of anus takes place after the embryo has reached a stage of blastopore and the development of the mouth takes place after the development of the anus. The condition where the blastopore is developed into the mouth instead of anus is known as protostome.

Also, one of the major characters of the deuterostomes is that the coelom or body cavity of these organisms is known to be developed inside the cell only and thus they are also called as enterocoelomates. Amongst all the plant kingdoms only three phyla are there which are known to support the deuterostome and indeterminate radial cleavage property which are basically Chordates, hemichordates and the echinoderms.

Hence, the correct answer is option (B).

Note: The arthropods are the organisms which tend to divide via bilateral mechanism and the annelids also follow the same level of division. One other difference of arthropods and annelids is that they are the protostomes.