Without genetic variation, evolution cannot occur. Sexual reproduction leads to increased genetic variation, but male bdelloid rotifers have never been observed. Which of the following are correct statements with regard to evolution in bdelloid rotifers?
A) As we learn more about bdelloid rotifers, we find males in more and more species.
B) Bdelloid rotifers gain genetic variation by absorbing DNA from the external environment.
C) Protists infect bdelloids and bring DNA from other rotifers with them.
D) Bdelloid rotifers have lost the ability to reproduce sexually only recently.

Question

Quizplus · Accepted Answer

Bdelloid rotifers are remarkable in their ability to survive and reproduce without males. However, they can still gain genetic variation through a process called horizontal gene transfer, where they absorb DNA from their environment, including other organisms, such as bacteria and fungi. This mechanism for genetic variation has been documented in multiple studies, making choice B the correct answer. Choices A, C, and D are incorrect because there is no evidence to support the presence of males in bdelloid rotifers, the role of protists in genetic variation, or that bdelloids have lost the ability to reproduce sexually recently.

Without Genetic Variation, Evolution Cannot Occur