Evolution Flashcards
What is evolution?
Biological change where descendants differ from their ancestors.
What does evolution result in?
Changes to organisms.
What is the mechanism of evolution called?
Natural selection
4 principals of natural selection
- Variation
- Inheritability
- Overproduction
- Selection
Variation
individuals vary from on another in every trait, these variation occur by chance.
The sources of these variations are a result of:
1. Mutations.
2. New combinations of traits produced through sexual reproduction.
Inheritability
most variations among individuals results from differences in their genes
Only these genetic differences can be passed on to future generations
Overproduction
members of a population produce more offspring than the environment can support
This results in competition between offspring to survive
Selection
Due to competition only individuals that have traits best fit to their environment will survive
If a trait allows an individual to survive and/or reproduce better than others in the environment it will get passed on.
More individuals will have these traits in every following generation as long as the environment stays the same.
When did Darwin develop the theory of evolution
1859
Plato 384 BC
He believed in 2 worlds
Aristotle 325 BC
Organisms can be arranged on a ladder from simple to complex
Each organism on the ladder is fixed on its rung and hence cannot move
Catholic Church
God created all life the way it is
The earth is only 6000 years old
Georges Cuvier 1760
studied fossils
saw the earth was made of layers
saw each layer had unique fossils
saw that extinction was common and species have changed over time
said god created new life after a catastrophe
James Hutton 1796
Earth is transformed by slow changes and not catastrophe’s (gradualism)
Charles Lyell 1800
earth is shaped by slow moving processes such as erosion
earth is slowly changing
