Evolution By Natural Selection
Published on Nov 21, 2015
No Description
MORE DECKS TO EXPLORE
PRESENTATION OUTLINE
What are the Goals of Life on Earth?
Photo by VancityAllie
EVOLUTION is
change in the gene pool over time
Photo by Leo Reynolds
Charles Darwin
- Galapagos Islands
- Voyage of the Beagle
- Naturalist
- Collected Observations and Specimens
- later as old man published, "Origin of Species"
Photo by David Blackwell.
Natural Selection
Photo by Paul Mannix
Key Idea 1
- Populations produce more offspring than can survive
- Individuals are not identical
- Survival is not random
Notes this is not survival of the fittest
Random mutations cause individuals to not be identical
K and R reproductive strategies
Random mutations cause individuals to not be identical
K and R reproductive strategies
Photo by thedangler
Key Idea 2
- Traits provide advantage, so individuals are more likely to:
- SURVIVE & REPRODUCE
- Offspring survive
- Pass down traits/alleles
Note that this works for heritable traits only not learned behaviors.
Photo by Richard.Fisher
Conditions necessary for Natural Selection
- Reproduction
- Inheritable Traits
- Variation of Individuals
- Variation of fitness of organisms
Photo by 23am.com
Key Idea 3
- Individuals are selected, but only populations evolve
- populations change over time
- percentage of advantageous traits increase
- gene pool
Photo by VinothChandar
Key Idea 4
- natural selection adapts a population to an environment
- environment changes OR
- mutations occur, then
- gene pools of population changes
Photo by Stefan Cook
