BIOLOGY CONTENT STANDARDS REVIEW EVOLUTION

The frequency of an allele in a gene pool of a population depends on many factors and may be stable or unstable over time. As a basis for understanding this concept:

Students know why alleles that are lethal in a homozygous individual may be carried in a heterozygote and thus maintained in a gene pool.

1. Compare and contrast the terms homozygous and heterozygous. 2. Explain how lethal alleles are maintained in a gene pool (e.g., Tay Sachs disease).

Students know variation within a species increases the likelihood that at least some members of a species will survive under changed environmental conditions.

3. What is genetic variation? 4. Explain how genetic variation is essential when it comes to the survival of a population.

Evolution is the result of genetic changes that occur in constantly changing environments. As a basis for understanding this concept:

Students know how natural selection determines the differential survival of groups of organisms.

5. What is Natural Selection? How does Natural Selection work? 6. Does Natural Selection work on a phenotype or genotype? 7. What is selective pressure and how does it relate to Natural Selection?

Students know a great diversity of species increases the chance that at least some organisms survive major changes in the environment.

8. Explain how variation within a species increases the chance that some organisms would survive a major environmental change (i.e., selective pressure). Provide at least one example.

Students know the effects of genetic drift on the diversity of organisms in a population.

9. What is genetic drift? How does genetic drift relate to biological evolution?

Students know reproductive or geographic isolation affects speciation.

10. Define geographic isolation, reproductive isolation, species, and speciation. How do these terms/processes relate?

Students know how to analyze fossil evidence with regard to biological diversity, episodic speciation, and mass extinction

11. What is a fossil? How are fossils formed? 12. Explain how the fossil record provides evidence of biological diversity (that existed in the past), episodic speciation, and mass extinction.