Artificial selection
Process of directed breeding to produce offspring with desired traits
Darwin
Scientist who studied galapagos finches and other organisms- hypothesized theory of evolution by natural selection
Natural selection
Process of evolution where certain traits make an organism more likely to survive and pass those traits on to their offspring
Variation
Individuals in a population differ from eachother
Heritability
Variations are innerited from parents
Overproduction
Populations produce more offspring than can survive
Reproductive advantage
Some variations allow those that have them to produce more offspring
Evolution
Cumulative changes in groups of organisms through time
Support for evolution
Fossil record, comparative anatomy, DNA comparison, embryology, biogeography
Ancestral traits
Primitive traits that appear in ancestral forms (examples: teeth, tails)
Homologous structures
Anatomically similar structures inherited from a common ancestor (not necessarily used for same function)
Analogous structures
Different anatomical structure in different species (not inherited from a common ancestor) but that serves the same function
Cladogram
Diagram show that shows evolutionary relationship between organisms
Biogeography
Study of plants and animals around the world (linked with climate and plate tectonics)
Adaptation
Trait shaped by natural selection that increases an organisms reproductive success
Fitness
Relative contribution of an individual trait to the next generation
Vestigial structure
Reduced form of functional structures (example: whale legs)
Hardy-Weinberg principle
When allelic frequencies remain constant, a population is in genetic equilibrium
Hardy-Weinberg conditions
Population is large, no gene flow, no mutations, random mating, no natural selection
Genetic drift
Any change in the allelic frequency in a population that results from chance
Founders effect
Example of genetic drift; When a small sample of a population settles in a location separated from the rest of geothermal population
Bottleneck
Example of genetic drift; occurs when a population declines to a low number and then rebounds
Gene flow
Random movement of individuals which increases genetic variation within a population and reduces differences between populations
Stabilizing selection
Most common form of natural selection; operates to eliminate extreme expressions of a trait when the average leads to higher fitness
Directional selection
Type of natural selection; when an extreme version of a trait makes an organism more fit
Disruptive selection
Type of natural selection; process that splits a population into two groups, tends to remove individuals with average traits
Sexual selection
Type of natural selection; change in frequency of a trait is based on the ability to attract a mate
Mechanisms of evolution
Genetic drift, gene flow, no random mating, mutation, natural selection
Allopatric speciation
Physical barrier that divides one population into two or more populations (example: mountains, rivers, etc)
Sympatric speciation
When a species evolves into a new species without a physical barrier
Adaptive radiation (divergent evolution)
Pattern of evolution where one species gives rise to many species in response to creation of new habitat or another ecological opportunity
Co-evolution
Evolution of one species affects the evolution of another species
Convergent evolution
When unrelated species evolve similar traits even though they live in different parts of the world
Gradualism
Theory that evolution occurs in small gradual steps
Punctuated equilibrium
Theory of evolution that attempts to explain abrupt transitions in the fossil record; rapid spurts of genetic change causes a species to diverge quickly
Reproductive isolation- prezygotic
isolating mechanisms that prevents gene flow among populations BEFORE fertilization occurs (geographic, ecological, behavioral, etc)
Reproductive isolation- postzygotic
isolating mechanisms that prevent gene flow among populations AFTER fertilization occurs (offspring are sterile- example: ligers and mules)
Artificial selection
Process of directed breeding to produce offspring with desired traits
Darwin
Scientist who studied galapagos finches and other organisms- hypothesized theory of evolution by natural selection
Natural selection
Process of evolution where certain traits make an organism more likely to survive and pass those traits on to their offspring
Variation
Individuals in a population differ from eachother
Heritability
Variations are innerited from parents
Overproduction
Populations produce more offspring than can survive
Reproductive advantage
Some variations allow those that have them to produce more offspring
Evolution
Cumulative changes in groups of organisms through time
Support for evolution
Fossil record, comparative anatomy, DNA comparison, embryology, biogeography
Ancestral traits
Primitive traits that appear in ancestral forms (examples: teeth, tails)
Homologous structures
Anatomically similar structures inherited from a common ancestor (not necessarily used for same function)
Analogous structures
Different anatomical structure in different species (not inherited from a common ancestor) but that serves the same function
Cladogram
Diagram show that shows evolutionary relationship between organisms
Biogeography
Study of plants and animals around the world (linked with climate and plate tectonics)
Adaptation
Trait shaped by natural selection that increases an organisms reproductive success
Fitness
Relative contribution of an individual trait to the next generation
Vestigial structure
Reduced form of functional structures (example: whale legs)
Hardy-Weinberg principle
When allelic frequencies remain constant, a population is in genetic equilibrium
Hardy-Weinberg conditions
Population is large, no gene flow, no mutations, random mating, no natural selection
Genetic drift
Any change in the allelic frequency in a population that results from chance
Founders effect
Example of genetic drift; When a small sample of a population settles in a location separated from the rest of geothermal population
Bottleneck
Example of genetic drift; occurs when a population declines to a low number and then rebounds
Gene flow
Random movement of individuals which increases genetic variation within a population and reduces differences between populations
Stabilizing selection
Most common form of natural selection; operates to eliminate extreme expressions of a trait when the average leads to higher fitness
Directional selection
Type of natural selection; when an extreme version of a trait makes an organism more fit
Disruptive selection
Type of natural selection; process that splits a population into two groups, tends to remove individuals with average traits
Sexual selection
Type of natural selection; change in frequency of a trait is based on the ability to attract a mate
Mechanisms of evolution
Genetic drift, gene flow, no random mating, mutation, natural selection
Allopatric speciation
Physical barrier that divides one population into two or more populations (example: mountains, rivers, etc)
Sympatric speciation
When a species evolves into a new species without a physical barrier
Adaptive radiation (divergent evolution)
Pattern of evolution where one species gives rise to many species in response to creation of new habitat or another ecological opportunity
Co-evolution
Evolution of one species affects the evolution of another species
Convergent evolution
When unrelated species evolve similar traits even though they live in different parts of the world
Gradualism
Theory that evolution occurs in small gradual steps
Punctuated equilibrium
Theory of evolution that attempts to explain abrupt transitions in the fossil record; rapid spurts of genetic change causes a species to diverge quickly
Reproductive isolation- prezygotic
isolating mechanisms that prevents gene flow among populations BEFORE fertilization occurs (geographic, ecological, behavioral, etc)
Reproductive isolation- postzygotic
isolating mechanisms that prevent gene flow among populations AFTER fertilization occurs (offspring are sterile- example: ligers and mules)