AP Biology (AP Bio) Most Comprehensive Vocabulary

Natural selection

A process in which individuals that have certain inherited traits tend to survive and reproduce at higher rates than other individuals because of those traits.

Evolutionary adaptation

An accumulation of inherited characteristics that enhance organisms' ability to survive and reproduce in specific environments.

Evolution

The gradual change in a species over time

Linnaeus (taxonomy)

Developed the first standardized scientific classification for life on Earth by body structure, function, and growth sequence (Kingdom, Phylum, Class, Order, Family, Genus, Species)

Darwin (descent with modification/natural selection)

English natural scientist who formulated a theory of evolution by natural selection

Artificial selection

Breeding organisms with specific traits in order to produce offspring with identical traits.

Homology

similarity resulting from common ancestry

Homologous structures

Structures in different species that are similar because of common ancestry.

Analogous structures

Body parts that share a common function, but not structure

Vestigial organs

organs that serve no useful purpose for the organism, but suggest that sometime in the past they were useful (i.e. an ancestor who used it)

Convergent evolution

Process by which unrelated organisms independently evolve similarities when adapting to similar environments

Divergent evolution

evolution of one or more closely related species into different species; resulting from adaptations to different environmental conditions

Biogeography

Study of past and present distribution of organisms

Fossils

Preserved remains of once-living organisms

Phylogeny

Evolutionary history of a species

Systematics

study of the diversity of life and the evolutionary relationships between organisms

Analogy

resemblance of organism structures with different origins but similar functions

Cladogram

Diagram that shows the evolutionary relationships among a group of organisms

Clade (cladogram)

A group of species that includes an ancestral species and all its descendants.

Phylogenetic tree/phylogram

a branching diagram or "tree" showing the inferred evolutionary relationships of their phylogeny—based upon similarities and differences in their physical or genetic characteristics.

Molecular clock

Model that uses DNA comparisons to estimate the length of time that two species have been evolving independently

Microevolution

Change in allele frequencies in a population over generations.

Population genetics

Study of allele frequency distribution and change under the influence of evolutionary processes.

Modern synthesis

A comprehensive theory of evolution that incorporates genetics and includes most of Darwin's ideas, focusing on populations as the fundamental units of evolution.

Population

A group of individuals that belong to the same species and live in the same area

Gene pool

Combined genetic information of all the members of a particular population

Hardy-Weinberg equilibrium

condition that occurs when the frequency of alleles in a particular gene pool remain constant over time

Mutation

A change in a gene or chromosome.

Point mutation

gene mutation in which a single base pair in DNA has been changed

Duplication

change to a chromosome in which part of the chromosome is repeated

Sexual recombination

Crossing over and shuffling of genes during meiosis.

Genetic drift

A change in the allele frequency of a population as a result of chance events rather than natural selection.

Bottleneck effect

A change in allele frequency following a dramatic reduction in the size of a population

Founder effect

change in allele frequencies as a result of the migration of a small subgroup of a population

Gene flow

Movement of alleles into or out of a population due to the migration of individuals to or from the population

Genetic variation

Differences among individuals in the composition of their genes or other DNA segments

Phenotypic polymorphism

The existence of two or more discrete forms, each represented in a population in high enough frequencies to be readily noticeable.

Genotypic polymorphism

Traits that have many phenotypic outcomes due to multiples genes working together. Ex. Skin color

Average heterozygosity

the percent, on average, of a population's loci that are heterozygous in members of the population

Geographic variation

Difference in variation between population subgroups in different areas.

Fitness

Ability of an organism to survive and reproduce in its environment

Directional selection

Form of natural selection in which the entire curve moves; occurs when individuals at one end of a distribution curve have higher fitness than individuals in the middle or at the other end of the curve

Disruptive selection

form of natural selection in which a single curve splits into two; occurs when individuals at the upper and lower ends of a distribution curve have higher fitness than individuals near the middle

Stabilizing selection

Natural selection that favors intermediate variants by acting against extreme phenotypes

Diploidy

two sets of chromosomes

Balanced polymorphism

situation in which selection maintains two or more phenotypes for a specific gene in a population

Heterozygote advantage

Greater reproductive success of heterozygous individuals compared to homozygotes; tends to preserve variation in gene pools.

Sexual selection

A form of natural selection in which individuals with certain inherited characteristics are more likely than other individuals to obtain mates.

Speciation

the formation of new and distinct species in the course of evolution.

Macroevolution

large-scale evolutionary changes that take place over long periods of time

Species

A group of similar organisms that can breed and produce fertile offspring.

Biological species concept

Definition of a species as a population or group of populations whose members have the potential to interbreed in nature and produce viable, fertile offspring, but are not able to produce viable, fertile offspring with members of other populations.

Morphological species concept

A definition of species in terms of measurable anatomical criteria.

Paleontological species concept

Definition of species based on morphological differences known only from the fossil record.

Ecological species concept

A definition of species in terms of ecological niche, the sum of how members of the species interact with the nonliving and living parts of their environment.

Phylogentic species concept

defines a species as the smallest group of individuals that share a common ancestor, forming one branch on the tree of life

Reproductive isolation

Separation of species or populations so that they cannot interbreed and produce fertile offspring

Prezygotic barriers

Barriers that impede mating or hinder fertilization.

Postzygotic barriers

Barriers that prevent the hybrid zygote from becoming a fertile adult.

Allopatric speciation

The formation of new species in populations that are geographically isolated from one another.

Sympatric speciation

The formation of new species in populations that live in the same geographic area

Polyploidy

A chromosomal alteration in which the organism possesses more than two complete chromosome sets.

Adaptive radiation

the diversification of a group of organisms into forms filling different ecological niches.

Punctuated equilibrium

Pattern of evolution in which long stable periods are interrupted by brief periods of more rapid change

Gradualism

The theory that evolution occurs slowly but steadily (ie small modifications in genome)

Allometric growth

The variation in the relative rates of growth of various parts of the body, which helps shape the organism.

Heterochrony

an evolutionary change in the rate or timing of developmental events

Paedomorphosis

the rate of reproductive development accelerates compared with somatic development

Homeotic genes

Genes that determine basic features of where a body part is.

Oparin and Haldane

proposed in the 1920s that the primitive atmosphere contained the following gases: methane, ammonia, hydrogen, and water; believed that these gases collided, producing chemical reactions that eventually led to organic molecules.

Miller and Urey

simulated the conditions of primitive Earth in a laboratory, by putting gases theorized to be abundant in the early atmosphere into a flask, struck them with electrical charges in order to mimic lighting, and organic compounds similar to amino acids appeared.

Protobionts

collections of abiotically produced molecules surrounded by a membrane-like structure

Ribozymes

RNA molecules that function as enzymes

Radiometric dating

the process of measuring the absolute age of geologic material by measuring the concentrations of radioactive isotopes and their decay products

Half-life

length of time required for half of the radioactive atoms in a sample to decay

Geologic record

The division of Earth's history into time periods, grouped into three eons—Archaean, Proterozoic, and Phanerozoic—and further subdivided into eras, periods, and epochs.

Mass extinction

event in which many types of living things become extinct at the same time

Stromatolites

Oldest known fossils formed from many layers of bacteria and sediment.

Prokaryotes

Cells that do not contain nuclei (bacteria, archaea)

Eukaryotes

Cells that contain nuclei (animal, plant)

Endosymbiosis

A theorized process in which early eukaryotic cells were formed from simpler prokaryotes.

Continental drift

The hypothesis that states that the continents once formed a single landmass, broke up, and drifted to their present locations

Archaea

Domain of unicellular prokaryotes that have cell walls that do not contain peptidoglycan

Bacteria

Domain of unicellular prokaryotes that have cell walls containing peptidoglycan

Eukarya

Domain of all organisms whose cells have nuclei, including protists, plants, fungi, and animals

Monera

the kingdom that includes bacteria

Protista

Kingdom composed of eukaryotes that are not classified as plants, animals, or fungi

Fungi

A kingdom made up of nongreen, eukaryotic organisms that have no means of movement, reproduce by using spores, and get food by breaking down substances in their surroundings and absorbing the nutrients

Plantae

Kingdom of multicellular photosynthetic autotrophs that have cell walls containing cellulose

Animalia

kingdom of multicellular eukaryotic heterotrophs whose cells do not have cell walls

Competition

the struggle between organisms to survive in a habitat with limited resources

Resource partitioning

The division of environmental resources by coexisting species such that the niche of each species differs by one or more significant factors from the niches of all coexisting species

Herbivory

interaction in which one animal (the herbivore) feeds on producers (such as plants)

Mutualism

A relationship between two species in which both species benefit

Competitive exclusion

Strong competition can lead to local elimination of one of the species.

Character displacement

The tendency for characteristics to be more divergent in sympatric populations of two species than in allopatric populations of the same two species.

Symbiosis

A close relationship between two species that benefits at least one of the species.

Commensalism

A relationship between two organisms in which one organism benefits and the other is unaffected

Ecological niche

the sum of a species' use of the biotic and abiotic resources in its environment

Predation

An interaction in which one organism kills another for food.