Name: __________________________________________
Period: ___
Asexual Selection Activity
Research:
1) What is a “Paramecium”?
2) Where do you find Paramecia?
3) Paramecia reproduce asexually. Is this common for organisms like Paramecia?
Type of Reproduction
# of Parents
Are the offspring identical or different?
Sexual
Asexual
Hypothesis: If we simulate harmful, changing environments on a population of Paramecium that
reproduce asexually, then _______________________________________________________________
_____________________________________________________________________________________
Procedure:
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Using colored paper, cut out circles to represent different Paramecia
Separate the circles into four colors: purple, pink, white, and brown. Each color is a type with different genes
Count 3 of each color and place them in the middle of your desk. This will represent the environment the
Paramecia are living in.
The twelve circles will be the original population (Generation 0). Record how many of each color you have in the
data table below.
Follow the population of Paramecia through five generations by reading the Events. Be sure to record the
number of each color after each event.
# Purple
# Pink
# White
# Brown
Events
Generation 0
Original population. Record what you have on
your desk when you start.
Generation 1
Each Paramecium reproduces once except the
white Paramecia, because a chemical in the
environment kills all of them.
A disease strikes, killing 2/3 of the pink
Paramecia.
Generation 2
Each surviving Paramecium reproduces once.
# Purple
# Pink
# White
# Brown
Events
A predator moves in, killing all brown and ½ of
the purple Paramecia.
Generation 3
Each Paramecium reproduces once.
There is not enough food so ¾ of the remaining
Paramecia (rounded up) die.
Generation 4
Each surviving Paramecium reproduces once
Conclusions:
1) Which type of Paramecia had the best genes for this environment? How do you know?
2) Would the same Paramecia always be the best for all environments? Explain (1+ complete sentence).
3) With only asexual reproduction, if something kills off all of a specific type of organism (ex. all white Paramecia)
will that type ever appear again?
4) What could cause a type to reappear? (Hint: what do we call an unexpected change in the DNA?)
5) What benefit would sexual selection offer in this changing environment?