Name (s)________________________________________ Date __________ Period ____
Investigation: How do
species change over time?
1.
Examine these photographs in
this power point. What do these examples have in common?
2.
What is the purpose of the
specific variations the photographs show?
3.
The plants and animals that live in the hot, dry
ecosystems in the
Can
this type of adaptation help explain how evolution works?
In
this investigation, we will be working with models of the beetle species, Beetlicus coloriferii.
This species of beetle has a wide range of color variations. Before the lab,
professional beetle wranglers collected samples of 10 color variations, which
you will be working with in the investigation. Your lab team will be working
with a starting population of 20 of each color, and a fabric habitat.
4.
Graph the starting
population of beetles on the graph provided (use colors on data table) . What graph type would be most
appropriate?
_____________________________
5.
The beetle wranglers have
supplied your Game Warden with 20 individual Beetlicus
coloriferii from each color variation, for a
total of 160 beetles. Check your supplies to be sure they are correct.
6.
Examine the habitat you will
be using, and describe it here:
7.
What is the physical cause
of color variation in the beetles (or, what makes one beetle’s color differ
from another’s)?
8.
Do you believe that the
physical characteristics of this species will change over several generations
of predation by the local predator, Raptorus
beetlicii? That is, will the selection pressure
of predation cause a change in this species on your habitat? Write your
hypothesis here:
9.
If your hypothesis is
correct, what will happen to the beetles on your habitat? Write your prediction
here:
10. Now, visit another research team with a different beetle habitat. Describe their habitat, and write a second prediction for what will happen on their habitat, based upon your hypothesis:
11. Game Warden: distribute the
beetles evenly (and randomly) over your habitat. Be sure the raptors do not
break any rules during the simulation!
Predators: You are modeling the behavior of the
hawk-like bird, Raptorus beetlicii. This bird is active during low light
conditions of early morning and evening (this is known as a
________________________ lifestyle).
Your fingers will represent the bird, flying from the nest (petri
dish lid) to the habitat to capture the plump, delicious beetles. R. beetlicii never consumes the food until after the hunt,
so all beetles are deposited in the nest for later feasting. In addition, R.
beetlicii never captures more than one beetle at
a time, since they are squirmy and difficult to grasp securely during flight.
This bird is ravenous, so work fast to capture as many beetles as possible!
12. When the predators’ ideal
light conditions (and, therefore, the hunt) are over, the Game Warden should
carefully count and record the surviving beetles on the
data table. Team
members should assist with this task. Each survivor will reproduce, creating
three new baby beetles. Return the survivors and their offspring to the habitat
for the next round of predation, and be sure the data table accurately reflects
the new starting population.
13. Repeat the simulation.
Calculate the starting population for the third generation, then
graph this final population on the supplied graph.
14. Compared to the starting
population, what has happened?
15. Evaluate your hypothesis and
prediction:
16. Revisit the neighboring
habitat to view their results. Evaluate your second prediction:
17. If a change occurred in the
beetle populations’ characteristics, what caused it?
18. Did individual beetles
change? What is your evidence?
19. How does this result relate
to Lamarck’s ideas about evolution, compared to
Wallace and
Explain
Draw your graph on the whiteboard at your lab groups number. Hang your habitat on the right side of the graph. Prepare for a class discussion of the results. After the class discussion, answer the following questions:
20. Are there patterns in the
class results? What conclusions can be drawn from this data?
21. Identify any limiting
factors present in this simulation.
22. How was the model realistic?
23. How was the model
unrealistic?
24. Describe the relationship
between the chance to survive and reproduce, and the traits an organism
possesses.
25. What events in nature could
cause an environment to change? List at least five.
26. What can happen to
populations when their environment changes?
27. What would happen if the
beetles where all the same color at the start?
28. If the color yellow were a
warning color in nature (one that birds associate with being toxic and making
them ill if they eat it), how would this affect the results on either habitat
you examined?
29. In what way(s) would you
expect the results to differ if a particular color of beetle was able to
produce 6 offspring instead of 3?
Expand: Honors Biology
Section
Investigate the effects of one of the following conditions on Beetlicus coloriferii:
- Change in birth rate of
beetles.
- Climate change causes
glaciation of the habitat.
- Scoop up 20 random
beetles from your original population, then trade
habitats with a neighboring group to simulate the founder effect of a
small sample colonizing a new, isolated habitat. Allow the 20 beetles to
reproduce once before the predators attack!
- Mutation: every third
offspring is randomly selected from the available colors (or every third
offspring is a different size).
- DDT contamination
affects the birds’ reproductive success, and only one predator survives to
feed on the beetles.
- A different predator
moves in after DDT wipes out the birds. This predator uses echolocation
rather than vision to find its prey. Blindfold your predators and have
them locate prey by touch to simulate this condition.
Complete
the simulation model as before, starting with a hypothesis and prediction,
graphing the initial and final populations, and drawing conclusions from the
results.
Research Question:
Hypothesis & Prediction:
Results:
Conclusion: