Natural Selection and Adaptations

OBJECTIVES Today, you will be able to… Explain the process of evolution by natural selection Explain adaptation

What exactly is “evolution” in THIS class? Evolution- a change in the GENETIC characteristics of population from one generation to the next “Change over time” NOT “Humans evolved from monkeys”

How does Evolution occur? Through Natural selection…. That is why it is called “The theory of Evolution by Natural Selection”

Natural Selection Process by which individuals that are better suited to their environment survive and reproduce most successfully “survival of the fittest”

Example of Natural Selection Peppered Moth After the start of the industrial revolution, the air was much more polluted. This caused the lichens to die off. This cause the dark peppered moths to increase in population. Before the Industrial revolution, the peppered moth in New England was a light gray color and blended in with the lichens that covered trees. AFTER BEFORE

How does this happen? Did the moths magically change colors?

This is how it happened… The moth DID NOT magically change colors. The light colored moths did not blend in with the trees (because they had no lichens). The light colored moths were easily eaten by birds. The dark moths were now better camouflaged. The dark moths were better suited for their environment and were able to survive, reproduce, and increase in population size.

Quantitatively (Numbers)

ADAPTATIONS

What is an “adaptation” Think about the word “adapt” Adaptation- inherited (mutations) characteristics that increase an organism’s chances for survival. Examples: Bird Beaks Mimicry Camouflage Hibernation Migration

Ex: Darwin’s Finches Charles Darwin-(1800s) a naturalist who developed the theory of Evolution via Natural Selection. He observed finches on the Galapagos Islands (as well as many other animals) Through observation, he developed the idea that things change overtime and become better suited for their environment. Finches- lived on different islands; he noticed their beak size was determined by which food source was available

Darwin’s Finches-What do you think they eat?

What type of food does this bird eat?

Examples of Adaptations

Mimicry

Camouflage

What’s the difference? Mimicry- when an animal looks like something else that is meant to be seen (not hidden) Camouflage- hides an animal (or something else). If an animal matches its background, it is harder to see.