Evolution and Natural Selection Test Review

What is the definition of evolution?

Change over time: The process by which modern organisms have descended from ancient organisms.

What is gradualism?

The idea that organisms change a little each generation, eventually developing into another species

What is punctuated equilibrium?

The idea that organisms remain stable for a long period of time and then quickly (geologically time-wise) change into a new species.

What is a mutation?

Genetic changes that happen in DNA occur from mistakes that happen when DNA is being copied; the Ultimate source of genetic variation.

What is sexual selection? Give an example.

Acts on an organism's ability to obtain or successfully reproduce with a mate; Traits increase an organism's chances of mating. Ex: the elaborate plumage of male peacocks.

What is overproduction?

Each species produces more offspring than can survive.

What is migration?

The movement of populations, groups, or individuals enables gene flow: the movement of genes from one population into another.

What is competition?

Overproduction causes struggle; All organisms compete for food, water, and the other necessities of life; Only organisms well suited to their surrounding survive while the others die.

Name and define the different forms of evidence for evolution

• Mutations - Genetic changes that happen in DNA

• Natural Selection - Process where organisms with/ traits well suited to an environment are more likely to survive and reproduce than organisms w/o these favorable traits.

• Sexual Selection - Acts on an organism's ability to obtain or successfully reproduce with a mate.

• Migration - The movement of populations, groups, or individuals; Enables gene flow.

What are some examples of vestigial organs?

Organs that serve no useful function in an organism. Ex: Appendix, pelvic bone of snakes, miniature legs/arms

What is an example of homologous structures?

Similar anatomy in different types of animals because to a common ancestor. Ex: Human arm, Dolphin fin, Bat wing, and Bird wing

What is a phylogenetic tree?

A diagram that represents evolutionary relationships among organisms.

Who is Charles Darwin?

Father of Evolution; British naturalist and geologist; Proposed a mechanism for evolution, natural selection.

Where did Charles Darwin do his research?

On the HMS Beagle (1835), Darwin explored South America and the Galapagos Islands.

What is the name of the book Charles Darwin wrote?

The Origin of Species

Why were the Galapagos Islands important?

They were extremely isolated, Home to dozens of species of both plants and animals found nowhere else in the world; Darwin's research provided the starting point for the development of his theory of natural selection

What is natural selection?

The process by which organisms better adapted to their environment tend to survive and produce more offspring.

What is an adaptation?  Give an example

An inherited characteristic that gives an organism an advantage in its environment (can be physical or behavioral); Ex, the color of a gray moth when it lives on greyish trees.

What factors must be present for natural selection to occur?

• Overproduction

• Competition

• Variations

• Survival of the fittest

What does fitness mean?

An organism's ability to survive and reproduce is to pass on favorable traits to offspring.

What does it mean when we say survival of the fittest?

Organisms with traits that make them well adapted, or suited to the environment, survive and produce.

Why is variation important?

Because the environment changes; If everyone is the same, they are all vulnerable to the same environmental changes and diseases; More variation within a species -> more likely to survive

What causes variation in a population?

• Mutation

• Sexual Reproduction

• Migration