10.3: Gene pools and speciation
Teaching time allocated: 2 hours
Practical time allocated: o hours
key vocab
prior learning & retrieval practice
Review topic 10.2 inheritance II
Review 5.2 natural selection
Gene Pools
Essential idea: Gene pools change over time.
U1: A gene pool consists of all the genes and their different alleles, present in an interbreeding population.
U2: Evolution requires that allele frequencies change with time in populations.
Exercise 1: Read the relevant section of your textbook and connect-extend-challenge
Isolation
U3: Reproductive isolation of populations can be temporal, behavioural or geographic.
Exercise 2: Complete the adjacent exercise.
Ken and Barbie.pdfS1: Comparison of allele frequencies of geographically isolated populations.
Speciation
U4: Speciation due to divergence of isolated populations can be gradual.
A1: Identifying examples of directional, stabilizing and disruptive selection.
U5: Speciation can occur abruptly. Guidance from the syllabus: Punctuated equilibrium implies long periods without appreciable change and short periods of rapid evolution.
A2: Speciation in the genus Allium by polyploidy.
NoS: Looking for patterns, trends and discrepancies—patterns of chromosome number in some genera can be explained by speciation due to polyploidy. (3.1)
