•Darwin based evolutionary change on two major propositions: 1. Species are not
immutable, they change over time 2. The process that produces these changes is
•Populations of all species grew exponentially having the potential for rapid increases
in numbers. Therefore, Darwin argued that death rates in nature must also be high
to keep the population in check.
•Natural selection which was a theory proposed by Darwin is a differential
advantageous genotype that allows a certain species to survive and reproduce.
•Artificial selection is taking certain desirable traits of different animals to produce a
unique offspring with all those traits.
•A population is a group of individuals of a single species that live and interbreed in a
particular geographic area at the same time.
•Adaptation refers to a phenotypic characteristic that has helped an organism adjust
to conditions in its environment.
•The features of a phenotype are its characters such as eye color for example.
•The specific form of a character is a trait, such as brown eyes
•A heritable trait is a characteristic of an organism that is partly determined by its
•Gene flow is the migration of individuals and movements of gametes between
•Genetic drift is a random change in allele frequency that may produce large changes
in allele frequencies from one generation to the next.
•Population bottlenecks can reduce genetic variation when a large population shrinks
to a small population.
•Founder effect is the opposite of population bottlenecks and can reduce genetic
variation when a small population increases to a big population.
•Nonrandom mating is when a population choose other individuals of particular
phenotypes as mates
•Fitness is the reproductive contribution of a phenotype to subsequent generations
relative to the contributions of other phenotypes.