Unit 6 Bio Vocabulary

evolution

the process of biological change in populations over time that makes descendants genetically different from their ancestors

microevolution

evolution that occurs on a small scale affecting a single population

macroevolution

evolution that occurs on a large scale affecting changed in species across populations

natural selection

organisms with the “best” traits (adaptations) will live longer and reproduce more then others, causing changes in the population over time by acting on traits that are heritable

fitness

a measure of how well you can survive in your environment

variation

differences in the physical traits of organisms

adaptation

a feature that allows an organism to better survive in its environment

gene pool

the combined alleles of all individuals in a population

directional selection

increases the expression of an extreme version of a trait in a population

disruptive selection

a process that splits a population into two groups; removes individuals with average traits and favors the 2 extremes

stabilizing selection

eliminates extreme expressions of a trait when the average expression leads to higher fitness

allele frequency

number of times the allele appears in a population (how common it is)

mutation

any change in a DNA sequence

genetic drift

random change in the frequency of alleles in a population over time

gene flow

movement of genes into/out of a population

sexual selection

the selection of traits that aren’t necessarily good for survival fitness but without them, you can’t pass on your genes at all because you can’t reproduce

genetic equilibrium

when there are no changes in the allele frequencies in a population over time

speciation

forming of a new species by evolution from a pre-existing species

species

group of organisms that can successfully interbreed and produce viable, fertile offspring

extinction

elimination of a species

gradual extinction

extinction that occurs at a slow rate

mass extinction

occurs when a catastrophic event changes the environment suddenly

gradualism

slow, constant changes over a long period of time

punctuated equilibrium

bursts of change followed by periods of stability

divergent evolution

a number of different species arise from one common ancestor

adaptive radiation

a type of divergent evolution occurring on a small scale over a shorter period of time

convergent evolution

when unrelated species evolve similar characteristics because they live in similar environments

coevolution

occurs when two populations organisms form a specialized relationship and thus change in response to each other

paleontology

study of prehistoric life through the fossil record

morphology

study of the form of living things

biogeography

study of the geographic distribution of plants and animals

looks at where living things are located

embryology

study of embryo development

biochemistry

study of chemical processes in living things

fossils

preserved remains of organisms (bones, footprints, feces, etc)

transitional fossils

link ancestral species to their descendants

homologous structures

similar structures that suggest evidence of common ancestry

vestigial structures

structures with little or no function to an organism

analogous structures

similar structures that evolved independently in different organisms due to serving similar puposes

endemic species

species that exist only in one geographic region

pseudogenes

nonfunctional genes

taxonomy

field of biology that classifies organisms

eubacteria

prokaryotes; “true” bacteria like pathogens

archaebacteria

prokaryotes in extreme environments

eukarya

eukaryotes

binomial nomenclature

2-name naming system, Genus species

phylogeny

evolutionary history of a species

endosymbiosis

one prokaryote ended up inside of another and both organisms thrived

phylogenetic tree

a diagram used to predict evolutionary relationships among groups of organisms

maximum parsimony

use the simplest explanation for creating the tree