Evolution General

Evolution

The fundamental idea in all life sciences that explains how organisms change over time.

Common Ancestor

A species from which two or more different species evolved.

Biogenesis

The principle that living organisms arise only from other living organisms.

Fossils

Evidence of an organism that once lived, which can appear in amber, ice, tar pits, and sedimentary rock.

Relative dating

Determining the order of past events without giving an exact age.

Absolute dating

Determining how long ago an event occurred using radioactive isotopes.

Homologous structures

Similar structures in different species that suggest a common ancestor.

Analogous structures

Different structures in different species that perform similar functions due to similar environment.

Vestigial structures

Remnants of structures that were once functional in an ancestral species.

Natural selection

The mechanism for change in a population where individuals with favorable adaptations survive to reproduce.

Speciation

The formation of a new species as a result of evolution.

Stabilizing selection

Natural selection that favors average individuals and selects against extremes.

Directional selection

Natural selection that favors one extreme phenotype over others.

Disruptive selection

Natural selection that favors extreme phenotypes at both ends and selects against average phenotypes.

Adaptive radiation

When one species evolves into many different forms to adapt to various environments.

Genetic equilibrium

A population in which gene frequencies remain constant over generations.

Taxonomy

The branch of biology that deals with the classification and naming of organisms.

Binomial nomenclature

A two-name system used for the scientific naming of organisms.

Eukarya

One of the three domains of life that includes all organisms with complex cells.

Archaebacteria

Primitive bacteria that live in extreme environments.

Eubacteria

Common bacteria that share a common ancestor with Archaebacteria.

Fungi

Organisms such as molds and mushrooms that secrete enzymes to absorb nutrients.

Plantae

Non-motile autotrophic organisms that contain cell walls and chloroplasts.

Animalia

The largest kingdom, consisting of motile, multicellular heterotrophs.