Change Over Time

Change Over TimeEssential Question:

How do species change over time?

Evolution VariationsAdaptation MutationsPhysical Genetic DiversityPhysiological Natural SelectionBehavioral Charles DarwinProtective Galapagos finches

Vocabulary

Darwin’s theory

Concepts

Why does evolution matter now?

http://www.pbs.org/wgbh/evolution/educators/teachstuds/svideos.html

Intro:

Process by which species change over time.

Slow, gradual over long periods of time.

Evolution

Traits that help organisms survive in their particular environment.

Organisms must survive long enough to produce offspring & pass on their traits.

An adaptation in one environment may not be helpful in another environment!

Adaptation

Part of organism’s body.

Examples: long neck of giraffe; pine tree needles.

Physical Adaptation

How the body functions.

Examples: Ability to regulate body temperature; produce a toxic substance.

Physiological Adaptation

Something an organism does.

Examples: Building a nest; recognizing a predator.

Behavioral Adaptation

Help protect organisms from predators.

Examples: Hedgehogs & sea urchins have sharp spines to keep predators away; Turtles & snails have protective shells.

Protective Adaptation

Differences that exist naturally among members of a population or species.

Offspring are not exactly like their parents, because parents’ genes combine in new ways.

Variations

Change in a gene or chromosome (DNA).

Have 1 of 3 possible effects…1. helps organism

survive.2. Harmful/deadly.3. Most have no effect

at all.

Mutations

Differences among members of species, meaning some individuals are better suited to survive.

Species with more variation are most likely to survive.

Genetic Diversity

Process by which organisms that are best suited to a particular environment survive and reproduce.

Works with the natural genetic variation as parents pass on traits to offspring.

“Survival of the Fittest.”

Natural Selection

British naturalist developed the theory of “Evolution by Natural Selection.”

Traveled on the ship HMS Beagle in the 1830’s to the Galapagos Islands; observed finches and tortoises.

Published theory in 1859 in book “On the Origin of Species.”

Charles Darwin

Species of finches had beaks of different shapes & sizes, depending on type of food available.

Darwin suggested the finches evolved from a single finch species (ancestor species) from the mainland, which then adapted to different island conditions.

Galapagos Finches