Video Transcript
What is the advantage of the
process shown in the figure? (A) It allows Spirogyra to
reproduce rapidly when conditions are favorable. (B) It allows Spirogyra to
clone itself efficiently. (C) It allows Spirogyra to
survive when conditions are harsh. (D) It allows Spirogyra to
maintain genetic uniformity. Or (E) it allows Spirogyra
to increase its surface area for absorption of light.
The image provided by the question
shows us two individuals belonging to the genus Spirogyra, which are
free-floating green algae that are abundant in freshwater. The image is showing these two
individual Spirogyra filaments undergoing a process called conjugation.
Individual Spirogyra cells
are usually haploid, meaning that they possess only a single set of chromosomes, and
often represented as n. During conjugation, two adjacent
filaments from two different individuals grow a tube, called a conjugation tube,
which connects one cell to another in a different filament and a different
organism.
A special type of gamete is moved
from a cell in the male filament to the other female filament through this
conjugation tube. In the female filament, the genetic
material of the two haploid cells combine to form a diploid zygote with two sets of
genetic material. Remember, a diploid cell is often
represented as 2n. The zygote develops into a
zygospore, which will remain dormant before undergoing meiosis to eventually grow a
new Spirogyra filament full of haploid cells.
As it involves the fusion of two
gametes to form a zygote, we can tell that conjugation is the method that these
organisms can utilize to reproduce sexually. They tend to do this when
environmental conditions are not favorable, for example, during a drought or a
freezing cold winter.
Reproducing sexually through
conjugation allows Spirogyra, which usually reproduces asexually, to
recombine the genetic material of two different organisms, thereby increasing the
genetic variation in the offspring it produces. This can increase their chance of
survival in these harsh environmental conditions, as the zygospore form remains
dormant until conditions improve, and as it increases the likelihood of new, helpful
traits developing in the new filaments produced.
This means that we have found the
correct answer to this question. The advantage of conjugation is
(C). It allows Spirogyra to
survive when conditions are harsh.
