MagBio Unit 5 Vocabulary: Evolution and Classification F23

evolution

the frequency of alleles in a population's gene pool changes over time; population experiences at least ONE of the following: mutation, genetic drift, gene flow, sexual selection, and natural selection

vestigial structures

body parts that have a reduced outward appearance because they have lost their function, but have retained an internal structure because they were inherited from a common ancestor

analogous structures

body parts that have a similar outward appearance because they have the same function, but have a different internal structure because they were not inherited from a common ancestor

homologous structures

body parts that have a different outward appearance because they have different functions, but have a similar internal structure because they were inherited from a common ancestor

natural variation

phenotypic differences among individuals in a population

artificial selection

the offspring of individuals with traits that are more desired by humans increase over time

natural selection

the offspring of individuals with traits that are better suited to the environment increase over time

biological adaptation

a genetic trait that increases an individual organism's relative ability to survive and reproduce

biological species

a group of organisms capable of exchanging genetic information (interbreeding) and producing fertile offspring

mutation

a change in DNA, primary source of natural variation

camouflage

when an individual looks similar to the environment

mimicry

when an individual looks similar to an individual of another species

fossil

preserved evidence of an organism's existence; the primary evidence for evolution

adaptive radiation

the emergence of many different species from a single common ancestor

convergent evolution

when two unrelated species evolve in similar environments becoming more similar over time; results in analogous structures

divergent evolution

when two related species evolve in different environments becoming more different over time; results in homologous and/or vestigial structures

gene pool

all the alleles in a population; the combined genetic information of all members of a particular population

embryo

developing stage of a multicellular organism

fitness

a measure of how well an organism can survive and reproduce in its environment

gradualism

pattern of evolution in which small changes occur steadily over long periods of time

punctuated equilibrium

pattern of evolution in which long stable periods are interrupted by short periods of rapid change

coevolution

when two species evolve in response to changes in each other; species closely interact

Hardy-Weinberg equilibrium

the frequency of alleles in a population's gene pool remains constant over time; population experiences ALL of the following: no mutation, no genetic drift, no gene flow, no sexual selection, and no natural selection.

p + q = 1

the Hardy-Weinberg equation that models the relative allele frequencies of population that is not evolving

bottleneck effect

a random event causes a small group of individuals to survive while a significantly larger population dies off but their survival is not related to their fitness

founder effect

a random event causes a small group of individuals to become separated from a significantly larger population but their separation in not related to their relative fitness

directional selection

occurs when the environment selects against one end of the phenotypic spectrum

stabilizing selection

occurs when the environment selects against both extremes of the phenotypic spectrum

disruptive selection

occurs when the environment selects against the mean of a phenotypic spectrum

hybrid sterility

a post-zygotic barrier where offspring cannot produce functional gametes, as in mules

temporal isolation

a pre-zygotic barrier formed when a group of individuals breed at a different time of year than another group of individuals in a population

behavioral isolation

a pre-zygotic barrier formed when a group of individuals are not attracted by the mating rituals of another group of individuals in a population

geographical isolation

a pre-zygotic barrier formed when a group of individuals are physically separated from another group of individuals in a population

gene flow

genes entering or leaving a population due to migration

allopatric speciation

the divergence of a new species from two populations living in separate geographical areas

sympatric speciation

the divergence of a new species from one population living in the same geographical area

genetic drift

a random change in the gene pool of a population; not due to selection

pre-zygotic isolation

when some individuals are unable to mate with other individuals in a population of a sexually reproducing species

post-zygotic isolation

when some individuals are sterile in a population of a sexually reproducing species

phenotypic spectrum

a broad range of phenotypes that overlap to create a continuous series where each individual blends into the next in a continuous way

chitin

polysaccharide that forms fungal cell walls

cellulose

polysaccharide that forms plant cell walls

peptidoglycan

protein-carbohydrate that forms bacterial cell walls

plant

an organism that is: eukaryotic, multicellular, autotrophic, and has a cell wall made of cellulose

animal

an organism that is: eukaryotic, multicellular, heterotrophic, and does not have a cell wall

fungus

an organism that is: eukaryotic, heterotrophic, and has a cell wall made of chitin

protist

an organism that is: eukaryotic and does not fit the description of plant, animal, or fungus

bacteria

an organism that is: prokaryotic, unicellular, and has a cell wall made of peptidoglycan

archaea

an organism that is: prokaryotic, unicellular, and is considered to be an extremophile

domain

a taxon that contains one or more related kingdoms

kingdom

a taxon that contains one or more related phyla

phylum

a taxon that contains one or more related classes

class

a taxon that contains one or more related orders

order

a taxon that contains one or more related families

family

a taxon that contains one or more related genera

genus

a taxon that contains one or more related species

species

a group of similar organisms that can breed and produce fertile offspring

binomial nomenclature

Genus species; Genus is capitalized, species is lowercase. Both words are underlined or italicized.

protist classification

animal-like: heterotrophic; plant-like: autotrophic; fungus-like: external absorption

molecular clocks

models that use mutation rates to measure evolutionary time

clade

evolutionary branch of a cladogram that includes a single common ancestor and all of its descendants

cladogram

a model of common ancestry that is based on patterns of ancestral and derived traits

phylogenetic tree

a model of common ancestry that shows the relationships between clades over a specified period of time

common ancestor

the shared ancestor of new, different species that arose from one population

node

a point on a cladogram or phylogenetic tree that represent the common ancestor of two related species; represents the moment of speciation

derived trait

a trait that is not shared by other members of a clade or their common ancestor

ancestral trait

a trait shared by all members of a clade through a common ancestor

speciation

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