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Natural Selection Lab- PhET Simulation
Alia nadin
Pre-Lab Questions
1.
What variables can you influence in this lab?
Mutation, Wolves, Foods, Environment.
2.
Define what a genetic mutation is. How do genetic mutations happen? How often?
Color of the fur, tail, teeth.
3.
What do the terms fitness and adaptation mean? What is the difference between the
two?
Fitness: An organism’s ability to survive and reproduce in a particular environment.
Adaptation: The process of change by which an organism or species becomes better
suited to its environment.
The difference: Fitness is a condition where an organism must survive in their
environment. While adaptation is when an organism must suit themselves to their new
environment.
4.
What selection factors might effect an animal population besides the ones used in this
lab?
-Climate change
-Other animals
Designing The Experiment
In this Lab you will be controlling the mutations and environment of a population of rabbits. Your
will create four hypotheses and design an experiment to test each one. Your hypothesis will
follow the format where you fill in the (...) with your own ideas and reasons.
I hypothesize that white rabbits will
be less likely to survive under
wolves within the equator environment, because with their fur color it’ll be harder for
them to camouflage within the environment.
***You must make at least one hypothesis for each of the three different types of phenotype mutations***
For each experiment you must have a control (no mutation) and fill in the following chart
Experiment
and
Hypothesis
Pheno
type
Sel
ecti
ve
Fac
tor
CONTROL
Group
Initial
Population
at F3
CONTROL
Group
Final
Population
Experment
Group
Initial
Population
at F3
Experiment
Group
Final Population
Conclusion/
Observation
Long tail
will make
them
faster
Long tail
w
olf
13
83
5
56
Long tail
made them
faster
White
rabbit
will less
likely to
survive
in the
equator
envirome
nt
White fur
W
olf
13
4
5
13
My
hypothesis
was correct
Long
teeth will
make it
easier
for them
to get
food
Long
teeth
W
olf
13
44
5
3
My
hypothesis
was correct
•
•
•
For each of the experiments, begin by adding a friend and a mutation. Wait until the F3
generation before adding the selective factor. After adding the selective factor let the
simulation run for another 3 or 4 generations.
Use the population numbers from the chart to get you numbers for the table, remember
you can zoom in and out on the chart to get more accurate reads.
Repeat for experiments 2, 3 and 4
Post-Lab Questions
1. Based upon your evidence from the simulation what conclusion are you able to make
about each of the three different types of phenotypes in rabbits?
The different types of phenotypes in rabbit creates a new species or types of rabbit, and
each of it has its own function and benefit for the rabbits.
2.
What happens to animals that cannot compete as well with other animals in the wild?
They have less chance to survive since animals as well as other organisms compete in
the wild in order to survive.
3.
Sometimes animals that are introduced into an area that they never lived in before, outcompete and endanger resident species, why do you think this happens?
Because they failed to adapt. Animals need the ability to adapt, especially if they are
introduced to an area that they never lived in before. They need to be able to suit
themselves to the new environment in order to survive.
4.
If only one species is considered the "fittest", why do we still have so many variations
among species. Why do some birds have very long pointy beaks, while other birds have
short flat beaks?
Because they have their own ways to survive, they have different ways to find food. That
is why there are many variations among species, because not all species can be the
same. This is also one of their ways to avoid competition, if they are different then
there’s no need for them to be in the same competition.
5.
How do you think diseases can affect natural selection?
Diseases can affect natural selection because diseases affect the organism’s health, if It
leads to the organism’s death then it could affect the population.
6.
How does this simulation mimic natural selection? In what ways does this simulation fail
to represent the process of natural selection?
This simulation shows that an organism can be a part of natural selection by adapting to
their environment. For instance, the brown rabbit is a part of natural selection because
their color is similar to the environment, it could survive with that color and produce more
species.
Extension- Changing the Dominance and Recessive Alleles
Take one of the experiments from the lab. Recreate the same experiment, EXCEPT when you
add the mutation EDIT THE GENES by switching the dominant and recessive allele for that trait.
Make a hypothesis, fill in the chart again and compare the results to your initial experiment.
Expe
rime
nt
and
Hypo
thesi
s
Pheno
type
Selective
Factor
CONTROL
Group
Initial
Population
at F3
CONTROL
Group
Final
Population
Experment
Group
Initial
Population
at F3
Experiment
Group
Final
Population
Conclusion/
Observation
Brown fur
Wolf
3
52
7
30
My hypothesis
was correct
1.
Did switching the alleles for dominant and recessive have any impact on the population
of rabbits? If so Why? In nothing changed Why not?
Yes. Before the wolves eat the rabbits, there are 3 brown rabbits and at the end there
are still 3 brown rabbits because the recessive traits makes it harder for them to produce
more brown rabbits.
2.
Two parent rabbits are both heterozygous for the trait. Create Punnet squares for the
original experiment and the new experiment (with the changed alleles). What are the
phenotype ratios of the Punnet squares? Does this evidence support your finding? and
how?
1st experiment:
Ratio: 3:1 which means 75% of rabbits will be brown and 25% will be white.
2nd experiment:
Ratio 3:1 means that 75% will be white and 25% will be brown.
3.
If this new experiment were to run longer would the end result be the same or different
from the original experiment?
In the end the population of the brown rabbit will increase and the white rabbit will
decrease because it is eaten by the wolf due to the color.
Extension- Working with Pedigrees- Switch from the population chart to the
pedigree chart
Begin by adding a friend and a mutation. Wait until the F5 generation. Copy the Pedigree for
two rabbits (described below) using the key. Assume that male rabbits are on the left and
female rabbits are on the right.
Find these two rabbits, make sure they have at
least four generations:
1. Select a rabbit that has the mutation.
2. Select a rabbit without the mutation but with parents or grandparent with the mutation.
Answer the following questions:
1. How could using a pedigree be helpful?
It shows the offspring
2.
What does it mean to have a yellow triangle above the rabbit?
The rabbits mutated
3.
What does it mean when a rabbit has a red X over it?
The rabbits are dead
4.
How accurate are the pedigrees used in this lab? Did each couple only have one baby?
It wasn’t really accurate because the offspring appeared naturally and it doesn’t have to
be based on the pedigree.