Biology - Adaptation and Classification Terms

variation

The difference in phenotype between two different species from the same family

adaptation

A specific trait that allows an organism to better survive and reproduce in its environment

artificial selection

When humans intentionally change a species’ trait with selective breeding

natural selection

When individuals have beneficial adaptations produce more offspring than others

overproduction

Having too many offspring means that there will be too many individuals fighting for a limited amount of resources

descent with modification

When the same species has differences between the individuals

gene pool

Where genetic variation is stored in a population

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The combined alleles of all of the individuals in a population

allele frequency

How common a certain allele is in the population

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The ratio of one allele to the total number of the alleles for that gene in the gene pool

mutation

Causes a random change of DNA or chromosomes

recombination

A new allele combination in the environment

normal distribution of traits

The frequency is highest near the mean value and decreases toward each extreme end of the range

directional selection

An extreme event causes the phenotype of a population to shift towards an extreme

stabilizing selection

The average phenotype becomes much more favored than the extremes

disruptive selection

The extreme phenotypes become much more favored than the average

gene flow

The movement of alleles between the same or closely-related populations

genetic drift

A change in allele frequencies due to chance

sexual selection

Occurs when certain traits increase mating success

bottleneck effect

A type of genetic drift that occurs when the gene pool shrinks after an event greatly reduces the size of a population

founder effect

A type of genetic drift that occurs when the gene pool shrinks after a small amount of individuals isolate themselves from a new and larger population

speciation

The rise of multiple species from one existing species

reproductive isolation

Occurs when members of different populations can no longer mate successfully

behavioral isolation

Isolation caused by differences in courtship or mating behaviors

geographic isolation

Involves physical barriers that divide a population into multiple groups

temporal isolation

When timing prevents reproduction between populations

evolutionary gradualism

Evolutionary changes occur over long periods of time

punctuated equilibrium

Episodes of speciation occur suddenly in geologic time and are followed by long periods of little evolutionary change, or stasis

adaptive radiation

The process involving the diversification of one ancestral species into many descendant species

convergent evolution

Evolution toward similar characteristics in unrelated species

divergent evolution

When closely related species evolve in different directions and become increasingly different

coevolution

The process in which two or more species evolve in response to changes in each other

evolutionary arms races

Competitive coevolution

background extinction

One or a few species slowly and continuously die out due to local changes in a small area

mass extinction

Many species suddenly die out across the globe due to a catastrophic event

K-T boundary

A rock layer with high levels of iridium that shows the transition from the Cretaceous to Triassic period and proves the theory that dinosaurs when extinct due to an asteroid

symbiosis

A close long-term interaction between two species in an ecosystem

mutualism

Symbiosis in which both species are benefited

commensalism

Symbiosis in which one species is benefited and the other species is unaffected

parasitism

Symbiosis in which one species is benefited and the other species is detrimented

taxonomy

The science of naming and classifying organisms

Linnaean taxonomy

Classifies organisms based on their physical and structural similarities

binomial nomenclature

A system that gives each species a two-part scientific name using Latin root words; the first part is the genus and the second part is the species

kingdom, phylum, class, order, family, genus, species

The seven levels of Linnaean taxonmy

cladistics

Classification based on common ancestry

cladogram

A diagram based on patterns of shared, derived traits that shows the evolutionary relationships between groups of organisms

clade

A group of species that share a common ancestor

phylogeny

Identifying relationships using evidence from living species, the fossil record, and molecular data

derived characters

Traits that can be used to define evolutionary relationships among a group of species

node

Each place where a cladogram’s branch splits that represent the most recent common ancestor shared by a clade

biogeography

The idea that island species will most closely resemble species on the nearest mainland

island biogeography

The idea that islands that are large and close to the mainland have more biodiversity than islands that are small and far away from the mainland

vestigial structures

Structures that were useful in a common ancestor but have lost their use in the present

bacteria

A domain of single-celled prokaryotes classified by shape, oxygen needs, and ability to cause disease

archaea

A domain of single-celled prokaryotes that live in extreme habitats and have strong cell walls

eukarya

A domain of all organisms with eukaryotic cells

eubacteria

A kingdom under the Bacteria domain

archaebacteria

A kingdom under the Archaea domain

protista, fungi, plantae, animalia

Kingdoms under the Eukarya domain

Lagodon Rhomboides

Mr. Shomber’s favorite species name