Grant Joint Union High School District Key Concepts
5. Evolution (2nd Semester)
Note: The abbreviation CCS stands for California Content Standards referenced below.
- Students will apply how natural selection affects the characteristics of an organism
and how mutations are maintained within a gene pool. (7a, 7b, 7c)
- Students will describe how greater variation within a species may lead to greater
survival of that species. (7d, 8b)
- Students will evaluate the effects of genetic drift and geographic isolation on a
species. (8c, 8d)
- Students will identify that analysis of fossil, DNA, and anatomical evidence supports
evolution. (8e, 8f)
7. 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 natural selection acts on the phenotype rather than the genotype
of an organism.
- Students know why alleles that are lethal in a homozygous individual may be carried in
a heterozygote and thus maintained in a gene pool.
- Students know new mutations are constantly being generated in a gene pool.
- Students know variation within a species increases the likelihood that at least some
members of a species will survive under changed environmental conditions.
- * Students know the conditions for Hardy-Weinberg equilibrium in a population and
why these conditions are not likely to appear in nature.
- * Students know how to solve the Hardy-Weinberg equation to predict the frequency
of genotypes in a population, given the frequency of phenotypes.
8. 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
- Students know a great diversity of species increases the chance that at least some
organisms survive major changes in the environment.
- Students know the effects of genetic drift on the diversity of organisms in a
- Students know reproductive or geographic isolation affects speciation.
- Students know how to analyze fossil evidence with regard to biological diversity,
episodic speciation, and mass extinction.
- * Students know how to use comparative embryology, DNA or protein sequence
comparisons, and other independent sources of data to create a branching diagram
(cladogram) that shows probable evolutionary relationships.
- * Students know how several independent molecular clocks, calibrated against each
other and combined with evidence from the fossil record, can help to estimate how
long ago various groups of organisms diverged evolutionarily from one another.
Standards that all students are expected to achieve in the course of their studies are unmarked.
Standards that all students should have the opportunity to learn are marked with an asterisk (*).