VARIATION OF TRAITS

Variation: variety of; different kinds or types

VARIATION OR NOT???

Examples of Human Variations

Human Variations

Eye Color Variation

Dog Variations

Charles Darwin

• Darwin was a naturalist (what we today call biologists)

• He traveled the world and made observations and sketches

• Aboard the H.M.S. Beagle, he traveled to the Galapagos Islands

Darwin’s Finches on the Galapogos Islands

What is meant by a Changed Environment?

Peppered Moth & The Industrial Revolution

• The Industrial Revolution began in the middle of the eighteenth century. Since then, tons of soot have been deposited on the country side around industrial areas. The soot discolored and generally darkened the surfaces of trees and rocks. = ( ENVIRONMENTAL CHANGE)

Soot produced from the Industrial Revolution caused the Environment to change from Light Surface Bark and Rocks to a Darkened Surface

Bark and Rocks.

Before the Industrial Revolution

Larger population of light colored moths

After the Industrial Revolution

Larger population of dark colored moths

How the Moth population changed over time after the Environmental Change.

Peppered Moth Simulation

• http://www.techapps.net/interactives/peppermoths.htm

• Say in a species of Blobs….there exists blobs of all shapes and sizes (variation)

Blobs eat the little purple organisms that live underground and on the surface.

During a particularly hot year, food became less abundant (competition), blobs that had the ability to dig into the soil to get food had a better chance of survival.

Many blobs died that year…….

What is the environmental change???

The ones that survived mated and passed their genes to the next generation. (reproduction)

Over time, there will be more blobs with the pointed noses. The pointed noses was the most favorable variation of the nose trait for the Changed Environment! This is called NATURAL SELECTION.

1. Variation2. Competition3. Survival4. Reproduction

= Natural Selection

1. Variation exists among individuals in a species.

2. Individuals will compete for resources (food, mates, and space)

3. Competition would lead to the death of some individuals while others would survive4. Individuals that had advantageous variations are more likely to survive and reproduce.

This process came to be known as Natural SelectionThe favorable variations are called Adaptations