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Dr. Brian K. Penney Goulet 2320 603 641-7149 bpenney@anselm.edu Brian K. Penney 's web page

EvolutionLab Lab Guide Week of Monday, January 21, 2008. Reading: LM 1; C:260-263
Updated: 1/15/08

EVOLUTION LAB 1 in custom lab manual Population Genetics I (Morgan/Dickey)

A. Review of Hardy-Weinberg Theorem and evidence for evolution (CONCEPTS, above: 10 min)

B. Exercise 1: model of Hardy-Weinberg Equilibrium using sampling with replacement (10 min). Students work in pairs. Instructors briefly explain, but do not do, Chi-Squared analysis . They only have to do this simulation through one generation to get the point that sexual recombination does not affect allele frequencies in the population.

C. Exercise 2A: Model Genetic drift and bottleneck; (20 min). DO NOT do founder effect. To do this, students will need to split their population in half, i.e. use 25 individuals instead of 50, and reserve the extra beads in the spare bag provided. After one generation, they will return the population to 25 individuals, but will adjust the allele frequency using their spare beads. As they finish (probably 5-7 generations), have them graph the allele frequency versus generation on the board, so they can see the different results.

D. Exercise 2C, Natural selection (30 min). Only do the industrial melanism simulation, as the sickle cell anemia simulation is a bit complex for non-majors. Use the revised datasheet I have built; it is posted here. Have groups combine their beads to make a population of 50 individuals that is 90% light alleles. They should store their other beads in one bag. The only tricky point here compared to the other simulations is that, after determining the genotype frequencies for the new generation, they will need to subtract some due to “selection”, and THEN adjust the allele frequencies in their bags. This will take a little math, and it may be helpful to have a calculator on hand. Follow the simulation as described for 5-7 generations, and students will see obvious effects of selection.

E. Experiment 2B: Gene flow (10 min). The same two groups that worked together for Experiment 2C will work together now; each bag is one population and, by the end of 2C, the bags should have very different allele frequencies. Follow the simulation as described for 5-7 generations. Students should make a version of Table 5 on their graph-ruled pages for this experiment. Students should find that the populations return to almost exactly 50:50 ratios. Ensure students do a final check that 50 beads of each color are in each bag; no quizzes until this is done!

F. NO COMPUTER SIMULATIONS;

G. Students instead examine fossils, skeletons and embryos; see Demonstration material below. (10 min)

H. Review (10 min)

I. Quiz (10 min)

A Population Genetics Simulations (From: Custom Lab Manual, 1-23)

CONCEPTS: Hardy Weinberg Equilibrium (HWE) is a “null model” of no evolution within a population, i.e. allele frequencies remain constant through generations. Certain conditions must be met:

a. population is very large

b. no immigration or emigration

c. no mutations

d. mating is random

e. no differential reproductive success

Microevolution is any case breaking the rules of HWE

Relevant lecture information: How populations evolve

B Macroevolution Demonstrations (From: Campbell et al. 2005, 260-263)

Demonstrations of evidence for evolution, to support lectures 1 and 2. Students should be comfortable explaining how these data sets support the theory of evolution, using specific examples from the demos:

1) Comparative morphology: homology of bones in the vertebrate forelimb

Emphasize how the ancestral limb form has been modified for various tasks. Students are likely to only briefly look at specimens, so ensure they are taking the time to compare each limb to the ancestral state, region by region, using common terms (fingers, elbows). Also point out the skeletons on display in the hallway.

2) Comparative embryology: similarity in embryonic form that differs from adult form

Ensure students take the time to compare embryos and appreciate the common morphology. They must be able to identify the three major shared characters visible (pharyngeal slits, somites, post-anal tail)

3) Fossil record: I want students to get an appreciation for the similarity between fossils and living organisms, and begin to have an idea of when various groups first appeared. Emphasize the fossils that are obviously like modern examples (teeth, shells).

Note that we do not cover molecular evidence for evolution in this lab.

Relevant lecture information: The theory of evolution

A printable syllabus, with course dates, required materials, grading and other policies can be found here.

A one page printable version of the schedule can be found here.

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