Chapter 16: Evidence and Theory of Evolution

Biogeography

the study of the geographical distribution of fossils and of living organisms

Comparative morphology

the scientific study of similarities and differences in body plans

Fossil

physical evidence of an organism that lived in the ancient past.

Cuvier

catastrophism; he proposed that many species that had once existed were now extinct.

Evolution

a change in a line of descent

Lineage

line of descent

Lamarck

developed the theory of evolution through acquired characteristics, through a internal drive toward perfection

Acquired trait

a trait that is not determined by genes

Lyell

leading geologist who developed uniformitarianism, belief the Earth is older than currently believed

Uniformitarianism

principle which state that the geological structure of Earth resulted from cycles of observable processes and that these same processes operate continuously through time

Malthus

said human population cannot continue to increase; consequences will be war, famine & disease

Wallace

English naturalist; developed a theory of evolution similar to Darwin's.

Darwin

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

Fitness

a single organism's genetic contribution to the next generation, how many fertile offspring are produced

Adaptation

inherited characteristic/trait that increases an organism's chance of survival (fitness)

Natural selection

theory that organisms best suited to their environment reproduce more successfully than other organisms

Mold

an imprint in the rock in the shape of an organism

Cast

a rock-like model of the organism

Law of Superposition

states that successive layers (stratum) of rock or soil were deposited on top of one another by wind or water, the lowest stratum is the oldest, the top stratum is the most recent

Stratum

layer of rock or soil

Relative age

the age of a fossil compared to other fossils within a single stratum

Absolute age

a fossils age in years estimated by radiometric dating

Half life

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

Radiometric dating

technique that uses the natural decay rate of isotopes to calculate the age of a material

Pangea

a supercontinent containing all of Earth's land that existed about 225 million years ago.

Plate tectonics

the theory that explains how large pieces of the lithosphere, called plates, move and change shape.

Gondwana

supercontinent that existed before Pangea, more than 500 million years ago.

Geologic time scale

a record of the geologic events and life forms in Earth's history.

Extinct

the disappearance of a population

Mass extinction

brief period during which a large number of species disappeared

Homologous structure

structures that have the same form but not the same function that originated in a shared ancestor

Morphological convergence

evolutionary pattern in which similar body parts evolve separately in different lineages.

Morphological divergence

evolutionary pattern in which a body part of an ancestor changes differently in its different descendants

Analogous structure

structures that do not have a common evolutionary origin but are similar in function

Vestigial structure

remnant of a structure that may have had an important function in a species' ancestors, but has no clear function in the modern species

Conserved

genes from an ancestor that have remained unchanged

Coevolution

process by which two species evolve in response to changes in each other

Convergent evolution

evolution that occurs when the environment selects similar phenotypes, even though the ancestral types were quite different from each other

Divergent evolution

when two or more closely related populations or species become more and more dissimilar

Adaptive radiation

when many related species evolve from a single ancestral species

Artificial selection

when humans breed for a select trait thus speeding up divergent evolution

Descent with modification

Darwin's first theory; newer forms of organisms are modified descendants of older species

Modification by natural selection

Darwin's second theory; groups of organisms better suited for the environment will be able to survive and reproduce; natural selection

Embryology

study of developing embryos used as evidence of evolution.

Punctuated equilibrium

a theory that states that evolution happens in quick bursts with long periods of no evolution in between

Gradualism

Theory that evolution occurs in small, gradual changes over time

Speciation

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

Macroevolution

evolutionary change above the species level (in populations)