Transcript FORMAL LAB NATURAL SELECTION

FORMAL LAB
NATURAL SELECTION
Background
• variety in phenotype is due to differences in genetic makeup
• novel traits are produced randomly by genetic mutation
• natural selection: “survival of the fittest”
• selective pressure – environmental factor that leads to
differential fitness based on the value of a particular trait
• biotic or abiotic
• examples?
Objectives
• design and carry out a controlled experiment
• investigate the effect of mutations on the population of rabbits,
in the presence of selective pressures
General Procedure
Define three factors in an online simulation.
For a single scenario, you will pick one of each.
Mutations
 brown fur
 long tail
 long teeth
Selection factors
 predators (wolves)
 food supply (tough shrub is only available food
Environmen
t
 equator
 arctic
source)
• Design three different scenarios/hypotheses to test.
Mutations – Three to choose from:
a. brown fur (default is white rabbits)
b. long tail (default is short tail)
c. long teeth (default is short teeth)
For this lab, only pick one mutation for each scenario. The goal is
to determine the effect of that mutation alone, on the success of
the rabbit.
Selection Factors – two to choose from:
a) wolves – natural predators of rabbits
b) food supply – makes tough shrubbery the only available food.
Tooth length plays a significant role in
ability to use this food source!
Environment – two to choose from:
Equator
Arctic
For each of the three scenarios, formulate a hypothesis
It is hypothesized that (select a rabbit phenotype) rabbits will be
(more/ less) likely to survive under (type of selective factor)
within the (select type of environment) environment, because.....
(explain how their trait will help them to survive or not)
Data Collection
Population
graph
Experimental Population
Generation
number
Phenotype:
white
Phenotype:
brown
Control Population
Total
Phenotype:
white
Total
3
(beginning)
4
7
10
(final)
• pause simulation at certain generations and fill in population count
• example table shown: white vs brown fur
Control Population
• need a baseline for comparison
• want to see the effect of the mutation
• compare against scenario where there is NO mutation
(only one phenotype in the population)
• keep all other factors (selection factor, environment) the same
as your experimental population
Analysis
• formal lab report format
• intro, procedure, results, discussion, conclusion, references
• write up only one of the three experiments you designed and
carried out
• two important resources:
• general format for all formal labs (on website)
• specific requirements for this specific lab (included on lab sheet)
Additional Notes
• plan/carry out in groups of 1-2
• teacher approval before beginning simulation
• individual lab report submissions
• physical copy
• Turnitin.com, same day (9 AM)