AP Biology Evolution Study Guide
Sexual Selection
A type of differential reproduction that results from variable success in obtaining mates
Prezygotic Isolation Mechanisms
A type of reproductive isolation in which the formation of a zygote is prevented; these mechanisms may range from physical separation in different habitats to gametic in which gametes are incapable of fusing
Postzygotic Isolation Mechanisms
A type of reproductive isolation in which zygotes are produced but are unable to develop into reproducing adults (ranging from inviable zygotes or embryos to adults that are sterile)
Punctuated Equilibrium
A hypothesis about the mechanism of evolutionary change proposing that long periods of little or no change are punctuated by periods of rapid evolution
Species/Speciation
A kind of organism/when one species diverges enough genetically or geographically to create two separate species
Bottleneck Effect
A loss of genetic variability that occurs when a population is reduced drastically in size (usually due to a natural disaster)
Charles Darwin
A British biologist who popularized the theory of evolution through natural selection and descent with modification
Alfred Russel Wallace
A British naturalist who developed ideas similar to Darwin's on the topic of evolution
Jean Baptist de Lamarck
A biologist who believed in the inheritance of aquired characteristics
Stabilizing Selection
A form of selection in which selection acts to eliminate both extremes from a range of phenotypes
Disruptive Selection
A form of selection in which selection acts to eliminate rather than favor the intermediate type (a graph is split in the middle - favoring the extremes of a trait, sometimes leading to speciation)
Directional Selection
A form of selection in which selection acts to eliminate rather than favor the intermediate type (a graph moves either to the right or left - favoring one trait over the other)
Genotype Frequencies
A measure of the occurrence of a genotype in a population expressed as a proportion of the entire population (see allele/allelic frequency)
Allelic Frequency
A measure of the occurrence of an allele in a population, expressed as a proportion of the entire population (see genotype frequencies)
Adaptation
A peculiarity of structure, physiology, or behavior that promotes the likelihood of an organism's survival and reproduction in a particular environment
Radioactive Dating
A process for determining the age of an object by measuring an amount of given radioactive material it contains
Gene Pool
All the alleles present in a species
Selection Pressure
An agent of differential mortality or fertility that tends to make a population change genetically
Evolutionary Bottleneck
An event that drastically reduces the size of a population, possibly eliminating certain traits (see bottleneck effect)
Inheritance of acquired characteristics
Characteristics acquired during an organism's lifetime will be passed on to their children
Evidence for Evolution: Biochemical
Embryology, biochemistry, DNA, artificial selection
Evidence for Evolution: Geologic
Fossils/fossil record, paleontology, biogeography
Gametic Isolation
Gametes of one species function poorly with the gametes of another species or within the reproductive tract of another species
Evidence for Evolution: Developmental
Homologous and analogous structures, vestigial structures
Hybrid Inviability/Sterility
Hybrids may be vigorous, but they are sterile or produce inviable offspring
Developmental Isolation
Mating and fertilization are successful, but the embryo doesn't develop properly
Variation
Minute differences in individuals of the same species
Genetic Drift
Random fluctuation in allele frequencies over time by chance
Microevolution
Refers to the evolutionary process itself. Evolution within a species (see adaptation)
Behavioral Isolation
Species differ in their mating rituals
Geographic Isolation
Species do not occur in the same area; populations can be separated by natural barriers such as mountains or manmade ones like roads
Ecological Isolation
Species occur in the same area, but they occupy different habitats and rarely encounter each other
Temporal Isolation
Species reproduce in different seasons or at different times of the day
Mechanical Isolation
Structural differences between species prevent mating
Mutation Pressure
The change in allele frequencies due to the repeated occurrence of the same mutations (not as powerful as genetic drift in the grand scheme of evolution)
Survival of the Fittest
The concept that the organisms best suited to live in their environment will survive
Genetic Equilibrium
The condition of an allele or genotype in a gene pool in which the frequency does not change from generation to generation
Macroevolution
The creation of new species and the extinction of old ones
Natural Selection
The differential reproduction of genotypes; caused by factors in the environment; leads to evolutionary change
Allopatric Speciation
The differentiation of geographically isolated populations into distinct species
Sympatric Speciation
The differentiation of populations within a common geographic area into separate species
Founder Effect
The effect by which rare alleles and combinations of alleles may be enhanced in new populations
Phylogeny
The evolutionary history of an organism
Fitness
The genetic contribution of an individual to succeeding generations. Relative fitness refers to the fitness of an individual relative to other individuals in a population
Convergent Evolution
The independent development of similar structures in organisms that are not directly related; often found in organisms in similar environments (ex. birds and bats developing wings)
Polymorphism
The presence in a population of more than one allele of a gene at a frequency greater than that of newly arising adaptations
Heterozygote Advantage
The situation in which individuals heterzygous for a trait have a selective advantage of the those who are homozygous; an example is sickle cell anemia
Gene Flow
The transfer of alleles from one population to another
Gradualism
The view that species change very slowly in ways that may be imperceptible from one generation to the next but that accumulate and lead to major changes over thousands or millions of years (in contrast to Punctuated Equilibrium)
Charles Lyell
Wrote the book Principle of Geology that influenced Darwin's conclusion that living species had arose from ancestral species