Adaptations Over Time

1
Adaptations Over Time

• Chapter 17

2
Evolution The Basics!

• A species is a group of organisms that share
  similar characteristics and can reproduce among
  themselves to produce fertile offspring.
• Many characteristics are inherited.
• Changes in these inherited characteristics over
  time is called evolution.

3
Lamarck

• 1809
• Believed that characteristics developed over an
  organisms lifetime are inherited by its
  offspring.
• Ex large muscles, good manners, hair dye
• Evidence does NOT support Lamarcks theory!

4
Darwin

• 1831
• Galapagos Islands (Pacific Ocean)
• Studied the Galapagos finches, dog breeds, and
  varieties of flowers.
• Natural Selection organisms with traits best
  suited to their environment are more likely to
  succeed (survive and reproduce)

5
Natural Selection

• Environmental/climate changes
• Temperature
• Precipitation (rain, snow, drought)

6
Natural Selection

• Predator/prey pressures
• Predators (new ones, change in tactics)
• Prey (abundance, camouflage)
• Change in food source (berries, seeds)
• Competition for food sources

7
Other Factors that Affect Evolution

• Sexual Selection organisms with traits that are
  more attractive to the opposite sex are more
  likely to mate and pass on those likeable
  characteristics.
• Ex peacocks, deer, elephant seals

8
Other Factors that Affect Evolution

• Artificial Selection organisms that are forced
  to reproduce to create new characteristics.
• Ex Dog and cat breeds, carnation colors

9
Variations

• A variation is an inherited trait that makes an
  individual different from other members of its
  species.
• Ex widows peak, albinism, six fingers/toes
• Variations result from permanent changes
  (mutations) in an organisms genes.

10
Adaptations

• Adaptations are those gene mutations that make an
  organism better suited to its environment.
• Ex Camouflage

11
Variation and Adaptation cont.

• Mutations can
• be positive. If so, the mutation will be
  successful and be carried on through reproduction
  (ex. Albino squirrel in Siberia)
• be negative. If so, the mutation will die out
  and will not be carried on (ex. Albino squirrel
  in the rain forest)
• have no effect on the species (ex. Albino
  squirrel in the Tallahassee Junior Museum natural
  habitat)