Unit 8: Evolution

Relative Dating

Gives an idea of where something falls in the general timeline of events based upon SUPERPOSITION.

Absolute Dating

Gives an idea of when a given event took placed based on decay of naturally occurring radioactive elements.

Half-Life

The amount of time it takes for half of a radioactive element to decay.

Evolution

Changes over time.

Charles Darwin

Person most associated with the concept of evolution.

Wrote: "On the Origins of Species"

Jean Baptiste Lamarck

Developed the theory of "Use & Disuse" to explain evolution.

Alfred Wallace

A fellow naturalist who had the same ideas as Darwin. He persuaded Darwin to publish his findings.

Natural Selection

The environment selects the favorable characteristics in a population that benefits survival.

Theory of Use & Disuse

The reasoning that we certain things become developed as a result of overuse, those characteristics are passed to future generations.

Artificial Selection

Humans choose the desirable traits for different organisms.

Ex: all domesticated plants and animals.

Fitness

Having favorable characteristics which allows them to be passed on.

Hardy Weinberg Equilibrium

Two scientists that together developed a theory of population equilibrium.

There theory is based on 4 assumptions. If all of these 4 assumptions are met, then a population will experience gene frequencies remaining constant from generation to generation.

1. There is NO Natural Selection.

2. Random mating exists.

3. No migration.

4. No significant mutations.

Carrying Capacity

Populations reproduce until they reach the maximum amount that society can contain.

Niche

The way in which an organism fits into an ecological community or ecosystem

Adaptive Radiation

The concept of members of the SAME species evolving to occupy different niches within the same environment.

Gene Pool

The combined genetic makeup of all the members of a population.

Geographic Isolation

Happens when members of the same species become separated and change independent of each other eventually becoming different species based upon WHERE they are geographically located.

Genetic Bottleneck

An evolutionary event that kills a significant percent of a population.

Industrial Melanism

The adaption of an organism in the response to the Industrial Revolution.

Punctuated Equilibrium

A theory stating that organisms are relatively unchanging, they experience little natural selections.

When changes occur, they happen suddenly.

Analogous Structures

Same function/purpose but different structure.

Ex: a birds wing and a bats wing. Serves the same purpose (ie: helps them fly) however they are structurally different.

Homologous Structures

Different function/purpose but structurally the same.

Ex: human arm and a horse leg. Structurally the same but used differently.

Vestigial Structures

Remnants from evolutionary past. Serves no function.

Ex: the human appendix or the hip bone of a whale.

Divergent Evolution

Organisms of the SAME species adapts to different environments.

Ex: Darwins finches

Convergent Evolution

Organisms of DIFFERENT species adapting to the same environment.

Ex: Sharks and Dolphins