Download What is our impact on Biodiversity - Barbara and Kris` Division II MST

Division 2 MST
Genetics 2011-2012
What is our impact on Biodiversity?
Skill Addressed: Systems Thinking
Content: Genetics
Black-footed ferret Information
About the Ferrets
Black-footed ferrets are long, slender
animals. The average size is 18 to 24
inches long including a 5 to 6 inch tail,
and 1½ to 2½ pounds in weight. Males
tend to be slightly larger than females.
With the exception of breeding season
and females caring for their kits,
black-footed ferrets are solitary animals. They are nocturnal (most active at
night) and fossorial (live mostly underground) predators. (http://blackfootedferret.org/animalprofile)
The Problem
Having survived years of predation by golden eagles, great horned owls, and
coyotes, the black-footed ferret almost succumbed to the all-out war waged by
humans on another species, the prairie dog. Ranchers and farmers spent
decades destroying the prairie dog towns of the Great Plains. This impacted the
ferrets because they eat little other than the prairie dogs and they obtain shelter
by taking over the burrows created by the prairie dogs. It takes a lot of prairie
dogs to sustain even a small population of ferrets.
Black-footed ferret population numbers were frightfully reduced by the 1950s,
and feared extinct in 1979! A small population was discovered in Wyoming in
1981, but that population was nearly wiped out by a plague, followed by an
epidemic of canine distemper. The last 18 survivors of the population were
taken into a captive breeding program to assist in the species’ recovery. In
recent years, the ferrets have been re-introduced into the wild and their
population has grown to over 400 individuals. (Text taken from The Company We Keep by Douglas H.
Chadwick and Joel Sartore)
The goal of this assessment is for you to show your understanding of how the chances of
survival of a population and its offspring depend upon their gene pool.
Division 2 MST
Genetics 2011-2012
Your task
In this assessment you will analyze how the gene pool of a small population of a species affects their
chances of survival in their habitat. The small population in question is that of black-footed ferrets that
survived after a catastrophic mid-summer fire in their prairie habitat that decimated the original colony by
killing all but 10 survivors, 5 male and 5 female. For the assessment we will concentrate on 9 traits:
Alleles in Population
Trait*
Letter
Camouflage
Dominant
Recessive
C
10
10
Precise vision
P
12
8
Accurate sense of smell
A
10
10
Strong claws and forearms
S
14
6
Healthy jaw formation
H
16
4
Agility
G
8
12
Acute hearing
E
10
10
Healthy rate of reproduction
R
16
4
Immunity to canine distemper
D
14
6
Step 1: Determine the gene pool of your population:
1. Choose 3 traits, which you deem to be most important for survival after reading the background information
(you will need to justify your decision later so choose wisely!)
2. Write in the genotypes for the 10 ferrets in the chart below:
Female Ferrets
Ferret 
Trait 1:
Trait 2:
Trait 3:
1
2
3
4
Male Ferrets
5
6
7
8
9
10
Division 2 MST
Genetics 2011-2012
Step 2: Analyze your population
**** TYPE your answers to the following questions: ****
1. Based on the genotypes of your ferrets, which 3 ferrets are most likely to survive and produce offspring?
Support your response with evidence from the background information.
2. Based on the gene pool of the population, explain whether or not your ferret population is genetically
equipped to survive the environment in future generations. Give at least 3 different examples using
monohybrid crosses to show probabilities of offspring.
3. Ferret parent 1 (P1) is immune to canine distemper. She is crossed with male ferret parent 2 (P2), and they
produce a first generation of Ferret pups (F1) that are ALL immune to canine distemper. Because of the
small ferret population, inbreeding occurs and the F1 mate (with each other) to produce the second
generation (F2) of ferrets. A canine distemper outbreak occurs and some of the F2 offspring die. What are
the possible genotypes of: F2, F1 and both parents (P1 and P2)? Make a diagram to show the relationships
and genotypes.
4. In your own words, explain what is meant by genetic variation, and why it is important.
5. A) Explain why two ferrets have a low probability of producing two identical pups (non-twins).
B) Given the 3 traits you chose, what is the probability that ferrets 5 and 6 will produce offspring that are
non-twin identical for the 3 traits.
6. What are 2 ways that meiosis results in genetic variation? Include a description of the meiosis phases
involved. Diagrams that you create may be helpful in explaining your answer.
7. Using the ferrets’ background information and what we’ve learned in class, discuss 2 factors that would
cause a change in the allelic frequencies of the ferret population.
8. Given parents that have the genotypes CcEe and ccee, determine what percentage of offspring from the F1
generation would be in danger of an increase in the great horned owl population of this habitat. Be sure to
show your work.
Division 2 MST
Genetics 2011-2012
Step 3: Conclusion
Write a concluding statement that answers the question: how do the chances of survival of a population and its
offspring depend upon their gene pool. (Be sure to use examples from this assessment and/or class
activities to support your statements, and use the following concepts in your response: Allele
frequency, Dominant, recessive, variation, survival fitness)