Work through the list without notes. If you cannot do a statement, follow its link, then come back. Guide = study guide; Practice = practice questions.
Understanding
- I can state the biological species concept, explain why reproductive isolation is the key to speciation, and give two limits of the concept. (Guide: “What is a species?”)
- I can name the five pre-zygotic and three post-zygotic barriers and give an example of each. (Guide: “Reproductive barriers”; Practice Q1, Q5)
- I can explain why a mule is sterile using chromosome numbers. (Guide: “Why is a mule sterile?”)
- I can compare allopatric and sympatric speciation and describe three ways gene flow can be cut without a geographic barrier. (Guide: Figure 1; Practice Q2)
- I can contrast gradualism with punctuated equilibrium and recognise each in fossil data. (Guide: Figure 2; Practice Q3)
- I can explain divergent evolution and why speciation is fast during adaptive radiation, and contrast it with convergent evolution. (Guide: “How fast does speciation happen?”; Practice Q6)
Calculation and skills
- I can use chromosome counts to explain why a polyploid plant is isolated from its parents. (Guide: Worked example 1; Practice Q4)
- I can calculate percentages from mating, fertilization or hybrid data and compare them with random mating. (Guide: Worked example 2; Practice Q5, Q7)
- I can calculate and compare rates from species-count data. (Practice Q6)
Reasoning
- I can decide from data whether two populations are fully separate species or still exchanging some genes. (Guide: Worked example 2; Practice Q7)
- I can predict how a change in the environment that removes a barrier affects gene flow and the species boundary. (Guide: Worked example 2 (d); Practice Q5, Q7)
- I can explain why similar traits in unrelated lineages are evidence of similar selection pressures, not of close relationship. (Guide: “Convergent evolution”; Practice Q6)
All ticked? Move on to Topic 7.11, Variations in Populations, or return to the course roadmap.