Close Notes:  Species Change over Time:

________________- occur following a _____________ drastic change in the environment

        If organisms don’t ____________ quickly enough to survive, they die

The extinction of a species can affect an __________ ecosystem

Extinction is a ____________ part of evolution

Scientist s estimate that about __________ of all species that ever lived on Earth have become __________

On average a species will ___________ on Earth 2 to ______ million years

Mass Extinctions:  

________________ Extinction

______________ Extinction

Human Threats for extinction:

Threat

Description

Remedy

Habitat

Reduce human encroachment –land management

Invaders

Non - native species introduced to new locations

Contaminated land, air, water

Overgrazing

Forest burning

Land use management

Overharvesting

Species taken for food, energy, medicine

Ozone depletion, greenhouse effect

Poaching, overhunting,

overfishing

Reduce demand, laws

Answer the following questions from the video. Isn’t Evolution just a Theory?

Natural Selection:

Charles Darwin (1809-1882)                         Sailed around the world 1831-1836

What did __________  Travels reveal?

How did tortoises and birds differ among the islands of the Galapagos?

Artificial Selection:

Natural Selection and Species Fitness:

Natural Selection:

Summary of Darwin’s Theory

1.

2.

3.

4.

5.

Theory of Natural Selection

Key Principles of Natural Selection

________________  - A trait that improves an organism’s chance for survival and reproduction.

_______________- The individuals that have the adaptation increase in numbers and are able to adapt to the environment over the individuals who do not have the adaptation

Evidence of Evolution

Evolution and Speciation

C21_GenePool_2

        

Variation in Populations:

2 processes can lead to this:

Evolution of populations:      Occurs when there is a __________  in relative frequency of alleles

Speciation:  The Formation of a _______  Species

Speciation in Darwin’s Finches:

        - ___________________________________________________________________

        - Geographic Isolation which led to – Reproductive isolation and

        - Changes in the new population’s gene pool due to  __________________.

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