Video Transcript
The table below outlines some
asexual reproductive methods and the organisms that use them. What should replace X?
To determine what should replace X
in the table, let’s first take a look at the information that’s already filled
in. The first column gives us the
organism, the second, the method of asexual reproduction, and the third column
provides a brief description of that method. In the first row, we can see that
Salmonella bacteria use the method of binary fission. This is when the parent cell copies
or doubles its genetic material before splitting into two separate daughter
cells. In the second row, we can see that
yeast use budding for asexual reproduction. In this method, the parent cell
forms a growth, or bud, that develops into a small individual and eventually
detaches.
In the third row, we’re told that
flatworms reproduce asexually when the parent splits into two parts and each of
these parts grows into a new organism. The question asks us to replace X
with the correct term for this method of asexual reproduction. The description of method X is
similar to the description of binary fission and that both involve the parent
organism splitting into two parts. However, in binary fission, these
two parts become two separate cells, while in method X, each of the new parts
eventually become new multicellular organisms. This is an important distinction
because binary fission is only used by single-celled organisms, and flatworms are
multicellular.
Many multicellular organisms,
including flatworms, use a method of asexual reproduction called regeneration. Let’s take a look at the process of
regeneration in a type of flatworm called a Planaria. If the Planaria is split into two
parts or fragments, each fragment will regrow or regenerate the parts of the body it
is missing, shown in the shaded pink regions of the diagram. The end result is two fully
functioning offspring. The process of regeneration matches
the description of method X given in the table. So we can say that the correct term
to replace X in the table is regeneration.
