Question Video: Recalling the Name of a Type of Asexual Reproduction Biology

When conditions are favorable, the freshwater crustacean π·π‘Žπ‘β„Žπ‘›π‘–π‘Ž (shown in the figure) reproduces asexually by producing offspring that develop from unfertilized diploid eggs. What is the name of this process?

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Video Transcript

When conditions are favorable, the freshwater crustacean Daphnia shown in the figure reproduces asexually by producing offspring that develop from unfertilized diploid eggs. What is the name of this process?

The question asks us to name the process by which Daphnia reproduce asexually. You may already be familiar with some of the many methods of asexual reproduction found in the natural world, including binary fission, budding, regeneration, vegetative propagation, the use of spores, and parthenogenesis. Let’s first take a brief look at the life cycle of Daphnia in order to determine the method of asexual reproduction described in the question.

During most of the growth season, Daphnia reproduce asexually. Mature females produce unfertilized diploid eggs, which are held in a part of her body called the brood chamber. Because no male gametes have fused with the eggs, both sets of chromosomes contain genes from the mother. Therefore, the offspring that arise from these eggs will be genetically identical to their mom and to each other. After one to two days, the eggs hatch while still inside the brood chamber and are born about three days later. The offspring, which are usually all female, go through about four to six stages of larval development. Once they are mature, they begin to produce their own unfertilized diploid eggs.

Changing environmental conditions such as overcrowding, food scarcity, or cooler water temperatures can stimulate females to enter asexual phase of reproduction. Cycling between sexual and asexual reproduction allows organisms to take advantage of the best parts of each. They can rapidly grow their populations in the asexual phase and increase genetic variation in the sexual phase. The particular type of asexual reproduction exhibited by Daphnia is called parthenogenesis, in which offspring are produced from unfertilized eggs. The definition of parthenogenesis matches the description given in the question. Therefore, the name of the process in which Daphnia produce offspring asexually from unfertilized diploid eggs is parthenogenesis.

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