Chapter 22: Evolution by Natural Selection Vocabulary

Vocabulary flashcards covering key terms and definitions from Chapter 22: Evolution by Natural Selection.

Evolution

A change in gene frequencies in populations over time.

Natural Selection

The process explaining the pattern of evolution, in which organisms with genes that allow them to survive better produce more offspring.

Plato's View of Organisms

The belief that every organism is perfect and unchanging.

Great Chain of Being

Aristotle's proposed concept organizing organisms on a scale of lower and higher forms.

Lamarckian Evolution

The proposal that species change over time through the scale of nature and the inheritance of acquired traits.

Fossil Record

All of the fossils found on Earth.

Fossil

A remnant or trace of organisms from the past, including hard structures (bone, shells, branches, dung), impressions in soft clay/sediments, or specimens preserved in airtight environments like amber.

Sedimentary Rock

Rock formed from sand or other sediments deposited in layers over time, used to organize fossils into older and younger relative categories.

Law of Succession

The observation that fossils of extinct species are found in geographic regions near similar extant (living) species.

Transitional Features

Traits that are in-between those of ancestral and derived species, linking older and younger species in the fossil record.

Vestigial Trait

A trait that is reduced or incompletely developed with no function, or reduced function.

Homology

Similarities between organisms due to common origin.

Genetic Homology

Similarity in DNA, RNA, or amino acid sequences due to inheritance from a common ancestor.

Developmental Homology

Similarity in embryonic form or developmental processes due to inheritance from a common ancestor.

Structural Homology

Similarity in adult organismal structures due to inheritance from a common ancestor.

Internal Consistency

The powerful support gained when independent data sources—such as the fossil record, phylogenies, relative dating, and absolute dating—corroborate one another.

Speciation

The process leading to the formation of new species that arose from common ancestry.

Darwin's First Postulate

Variation exists in populations.

Darwin's Second Postulate

Traits are heritable.

Darwin's Third Postulate

Survival and reproductive success are variable.

Darwin's Fourth Postulate

Those organisms that survive best produce the most offspring and pass on their traits (non-random survival and reproduction).

Fitness

The ability of an organism to survive to produce fertile offspring relative to that ability in other individuals in the population.

Adaptation

A heritable trait that increases fitness, making an organism better able to survive than those lacking the trait.

rpoB Gene Mutation

A C-to-T point mutation in M. tuberculosis that causes antibiotic resistance, allowing mutant cells to survive drug therapy.

Fitness Trade-offs

Compromises between traits that constrain adaptation, showing that evolution does not produce perfect organisms.