Unit 06 Evolution Study Guide Bio

Biodiversity

The variety of all living things and their interactions

Genetic Diversity

The range of inherited traits within a species

Evolution

Populations and species of organisms change over time

Species

A group of individuals that interbreed in nature to provide fertile, viable offspring

Fossil record

A collection of fossils documenting the history of life on Earth

Gradualism

The evolutionary process in which species experience changes in characteristics gradually and incrementally

Variation

The differences between organisms in a species; provides the necessary diversity for evolution to take place

Adaptation

The evolutionary process by which an organism becomes better able to live in its habitat

Overproduction

Each generation has more children than can be supported by the environment, contributing to natural selection

Descent with modification

Definition of evolution; species change over time, give rise to new species, and share a common ancestor

Artificial selection

Evolutionary process in which HUMANS consciously select for or against certain features in an organism

Natural selection

Survival of the fittest -> organisms better adapted to their environment tend to survive and produce more offspring, thus passing on their traits

Biogeography

The study of the geographic distribution of different types of life, taking tectonic shift into account

Molecular homologies

Comparing the similarities between sequences of molecules in organisms to discern evolutionary relationships

Embryology

The study of early forms of life before birth; embryos of different species may share characteristics that indicate common ancestry

Homologous structures

Similar structure, different functions; indicate common ancestry

Convergent evolution

When organisms converge on the same optimal body plan as a result of evolution; not due to common ancestry

Divergent evolution

When parts of an interbreeding species become more dissimilar with time -> can lead to speciation

Coevolution

Evolutionary changes that occur between two or more organisms as a result of interactions between them

Analogous structures

Features of organisms that are similar in function but not in structure; DO NOT indicate common ancestry, only similar environmental pressures

Vestigial structures

Non-functional features that were fully developed in an earlier species but have little to no purpose in the current species; rudimentary remnants of evolution

Population

All of the individuals of a species in an area

Fitness

An organism’s ability to survive and reproduce in its environment

Gene pool

The combination of all possible alleles in a population available for reproduction

Allele frequency

How common an allele is in a population

DNA Mutations

Essential to evolution, raw material of genetic variation; must occur in GAMETES to be passed on

Directional selection

The change in a phenotype or genotype towards one specific direction away from the mean in a population

Antibiotic resistance

Fast evolution; occurs when bacteria develop defenses against the antibiotics designed to kill them

Stabilizing selection

A form of natural selection in which organisms with a more moderate phenotype/genotype closer to the mean have more fitness

Disruptive selection

Occurs when BOTH extreme traits are favored in an environment

Gene flow

Any movement of individuals and/or their genetic material between populations

Genetic drift

Change in allele frequencies due to random chance; reduces genetic diversity

Bottleneck effect

Type of genetic drift in which the population goes through a bottleneck that decimates much of it; survivors are not more fit than those who died

Founder effect

When a small subset of a population establishes its own population; different allele frequency in founders results in a different new population

Sexual selection

Non-random mating; natural selection arising from the preference of certain characteristics of one sex by the other sex

Speciation

A new species being created

Reproductive isolation

Organisms are not able to breed together; leads to speciation

Behavioral isolation

Reproductive isolation caused by differences in mating behaviors; leads to speciation

Geographic isolation

Reproductive isolation caused by geographic barriers; leads to speciation

Temporal isolation

Reproductive isolation caused by being active at different times/seasons; leads to speciation

Extinction

A species dying out

Punctuated equilibrium

A period of stasis, or no change, in an organism, followed by abrupt, rapid change

Adaptive radiation

Divergent evolution in which a species becomes many different species that fill different ecological niches

Cladogram

A branching diagram showing the cladistic relationships between different species

Common Ancestry

Different species sharing a common ancestor from which they have evolved

Five fingers of evolution

Mechanisms of evolution:

pinky -> small population -> genetic drift (bottleneck and founder effect)

ring finger -> non-random mating (sexual selection)

middle finger -> m for mutations (provide necessary genetic variety)

pointer finger -> move around -> gene flow

thumb -> thumbs up -> natural selection