Answer Key
1) Does meiosis occur during asexual reproduction? How
about mitosis? Explain.
Meiosis does not occur during asexual reproduction. Meiosis is the
process of producing gametes (eggs and sperm). Mitosis, on the
other hand, is simply the process of cell division. This is the
process that animals are going through during regeneration.
2) Is there ever any advantage of asexual reproduction
over sexual reproduction? When and Why?
Yes. Two cases:
1) If only one organism is present in a population (think
humans on deserted island), he/she can still reproduce and
found a new population.
2) If the environment is stable (unchanging), and a particular
organism is very well adapted to it, asexual reproduction
has an advantage over sexual reproduction. If however, the
environment changes (as we know it usually does), then
sexual reproduction is favored since it allows for new
combinations of genes.
3) Which evolved first- Sexual or Asexual reproduction?
Provide evidence to support your hypothesis from the
text and from the phylogenetic tree you were given as
a handout on 7/23/04.
In order to know which evolved first, we need to know the ancestral
state. If we look at the phylogentic tree, it says that all animals
evolved from an ancestral protist. Since we know that the ancestral
protist reproduced asexually, we know that asexual reproduction
evolved first.
4) What is the advantage of sexual reproduction over
asexual reproduction? (See pg 459 if you’re having
difficulty, but expand on the answer presented in the
text.)
The answer is alluded to in Question 2. Sexual reproduction is
typically advantageous over asexual reproduction because the
environment is constantly changing. Sexual reproduction allows new
combinations of genes to form. This greater genetic diversity
increases the phenotypic variation: that is, it increases the
physical variety of the organisms. This increases the likelihood
that the animal will adapt to the changing environment through a
process called evolution.
