Evolution in Ecosystems

1
Evolution in Ecosystems

• Environmental Science

2
Charles Darwin

• Charles Darwin introduced evolution in 1859 in
  his book On the Origin of Species
• In this book he describes the process of Natural
  Selection

3
Natural Selection

• Darwin noticed that individuals in a population
  are not exactly alike.
• He proposed that the environment exerts a strong
  influence on which individuals survive and which
  die
• The individuals that survive will pass on their
  traits to their offspring
• Traits that increase the chance that an
  individual survives and reproduces are called
  adaptations

4
Evolution

• Over several generations natural selection can
  cause the traits of a population to change.
• The change in genetics of a population over
  generations is called evolution.

5
Coevolution

• Coevolution occurs when two species evolve in
  response to long-term interactions
• Includes symbiotic relationships
• Ex. Flowers and hummingbirds

6
Artificial Selection

• There are several species that have been
  domesticated by humans
• Thus humans control how they reproduce and evolve
  - called artificial selection
• These species include plants and animals
• Ex. Corn, wheat, roses, dogs, horses, etc.

7
Evolution of Resistance

• Sometimes humans cause organisms to evolve
  unwanted adaptations
• When pesticide is sprayed, not every insect is
  killed.
• The survivors reproduce and the next generation
  is more resistant to the pesticide
• Resistance the ability of an organism to
  survive a chemical designed to kill it

8
Pesticide Resistance