Fishy Frequencies with Hardy- Weinberg
Fishy Frequencies ( with Hardy- Weinberg): Background Information
Targeted Standard Course of Study Goals and Objectives:
Goal 1: Learner will develop abilities necessary to do and understand scientific inquiry.
1.01 Identify biological problems and questions that can be answered through scientific investigations.
Goal 3: Learner will develop an understanding of the continuity of life and the changes of organisms over time.
3.03 Interpret and predict patterns of inheritance.
3.05 Examine the development of the theory of evolution by natural selection
Essential Question( s):
What is the significance of scientific investigation?
How do genes and the environment interact to produce a phenotype?
Do allelic frequencies change over time in response to natural conditions?
Introduction to teacher:
This activity shows allele frequencies changing over time as a result of selection and remaining stable without selection. The standard- level can be done with or without using the Hardy- Weinberg equilibrium equation, however the honors level will include Hardy- Weinberg.
The Hardy Weinberg equilibrium equation allows you to figure out the frequency of alleles and genotypes from the frequency of observable phenotypes in populations that meet the conditions for Hardy Weinberg Equilibrium. These conditions include an infinitely large population, random mating, and no selection, mutation, migration or genetic drift. Of course, no real population completely fits these conditions. When a population or sub- population is not in equilibrium, population biologists can study the factors affecting the distribution of alleles. When your students do the activity using the Hardy Weinberg equation they can see how population biologists estimate the number of organisms heterozygous for a trait from the number of organisms with the recessive phenotype. You can also relate the Hardy Weinberg equation to Punnett squares and use this as an opportunity to show students an application for squaring binomials. Punnett squares can be used to calculate expected phenotype frequencies for populations as well as the expected ratios from individual crosses. You can also take the opportunity to discuss the conditions for equilibrium and in what ways this simulation does and does not meet these conditions.
July 2007
214