1. The Theory of Evolution: Natural Selection and Artificial Selection

2. Charles Darwin English scientist (1809 – 1882)
Took the HMS Beagle to South America
At the age of 21 took a job on HMS Beagle
Five year journey
Collected specimens
Galapagos Islands
As ship’s naturalist, Darwin studied and collected biological specimens (including fossils) at each port

11. Darwin and Natural Selection
For the next 22 years, Darwin developed his theory.
Other scientists’ findings influenced Darwin….
Charles Lyell
Geologic processes are result of gradual changes that happen over time
Malthus
Animals produce more offspring that can survive
Animals must struggle to survive

12. Darwin’s Conclusions:
Populations possess an enormous reproductive potential
Population sizes remain stable (Malthus)
Resources are limited
Individuals compete for survival
There is variation among individuals in a population
Only the most fit individuals survive to reproduce
Evolution occurs as advantageous traits accumulate over time

13. Adaptations
An adaptation is any variation that aids in an organism’s chance for survival.
Types of adaptations:
Mimicry – structural adaptation that enables one species to resemble another species
Camouflage - blending with surroundings

14. Which is dangerous? Can you tell?
Mimicry
Yellow jacket wasp
vs.
Syrphid fly
Which is dangerous? Can you tell?

15. Mimicry – one of these is poisonous.
Coral Snake
King Snake

16. Camouflage Blending in with the environment to hide from predators or prey. This includes seasonal color changes

17. Camouflage

18. Camouflage

19. Artificial Selection
Definition: breeding organisms with specific traits for those traits
Selective Breeding
Most of the time occurs because human preferences or needs.
Shows that organisms can change through breeding.

26. Evolution is…
the change in the heritable traits of a population or species from generation to generation.

27. Natural Selection Definition: mechanism for change in a population
Favorable traits are chosen
Change in genotype  genetics
a force in nature that works like artificial selection
Who or what has a better chance of survival long enough to reproduce.