Evolution

species

A group of similar organisms that can breed and produce fertile offspring.

fossil

A trace of an ancient organism that has been preserved in rock

adaptation

A trait that helps an organism survive and reproduce

evolution

Change in a kind of organism over time; process by which modern organisms have descended from ancient organisms.

scientific theory

A well tested concept that explains a wide range of observations

natural selection

Process by which individuals that are better suited to their environment survive and reproduce most successfully; also called survival of the fittest

artificial selection

Selection by humans for breeding of useful traits from the natural variation among different organisms

variation

Difference among members of a species.

homologous structures

Structures in different species that are similar because of common ancestry.

gradualism

The theory that evolution occurs slowly but steadily

punctuated equilibrium

Pattern of evolution in which long stable periods are interrupted by brief periods of more rapid change

Charles Darwin

Traveled to the Galapagos Islands on the HMS Beagle and later wrote the book "The Origin of Species."

Overproduction

Strategy in which organisms make more offspring than will actually survive.

Competition

Driving force of natural selection in which organisms fight for food, water, and living space

Fossil Record

All the fossils throughout the history of the Earth that are used as evidence of evolution.

Common Ancestor

An ancestral species from which later species evolved

Embryology

Study of developing embryos used as evidence of evolution.

Vestigial Structures

A structure that is present in an organism but no longer serves its original purpose (ex. hip bones in whales)

DNA

Genetic information that can be used as evidence of evolution between organisms.

Isolation

When members of a species become separated which may lead to the evolution of new species.

Barrier

something that blocks the way; an obstacle (mountains, rivers, etc.)

Genetic Drift

allele frequency in a population changes by chance.

Bottleneck effect

Natural disasters, over hunting, disease, etc. can cause massive reductions in a population's size. After this event, the gene pool is altered (less diverse).

Founder effect

The gene pool of the "founding" population in a new location is different and less diverse.

Gene flow

movement of individuals into or out of a population can change the gene pool

Adds or removes alleles from a population, changes allele frequencies

Comparative embryology

Similarities between the embryonic development of organisms

Evidence of Evolution

• Biogeography

• Fossil Record

• Comparative Embryology

• Comparative Anatomy

• Molecular / Genetic* - newest and most precise

Prezygotic Barriers

an evolutionary mechanism of reproductive isolation that prevents members of different species from mating, or prevents fertilization from occurring if mating does happen

“before the zygote forms”

Postzygotic Barriers

Postzygotic barriers are evolutionary mechanisms of reproductive isolation that occur after fertilization has taken place “ after fertiziltion.”

Macroevolution

The formation of new species

The “5 fingers” of evolution add up to cause biological differences 

A new species of organisms branches off from an ancestral one.

Speciation

the evolutionary process by which a single population splits into two or more distinct, independently evolving species

5 fingers of evolution

1. Genetic Drift

2. Segsual Selection

3. Mutations

4. Gene Flow

5. Natural Selection

Biogeography

the study of the distribution of species and ecosystems across geographic space and through geological time

Microevolution

changes in the makeup of the gene pool (the genotypes and alleles of the population are shifting over time)

-small changes within a species