1. Evolution

2. Evolution
change in a population of living things over a period of time
Descendents differ from ancestors
central theme to biology - supported by scientific evidence

3. Charles Darwin father of evolution naturalist
sailed on the British ship - Beagle

4. Darwin returned 5 years later in 1836
Darwin Left England in 1831
Darwin returned 5 years later in 1836

5. Darwin’s Observations
Variation and adaptations among the biodiversity
Adaptation feature that allows an organism to survive
he found that the observed animals were unique to where they lived
land tortoises – different shells and necks to reach food
marine iguanas- dive in the ocean and eat algae
Finches- different beaks for the different seed they eat

6. The Galapagos Islands Very Different Climates
Small Group of Islands 1000 km West of South America
Very Different Climates
Animals On Islands Unique
Tortoises
Iguanas
Finches

7. The Galapagos Islands Volcanic islands off the coast of South America
Island species varied from mainland species & from island-to-island species
Each island had long or short neck tortoises

9. The Galapagos Islands
Finches on the islands resembled a mainland finch
Finches had different types of beaks adapted to their type of food gathering

11. Darwin’s Observations
2.Observed fossils and geological evidence
3. Artificial selection humans change a species by breeding for certain traits
Darwin used these observations to formulate the theory of natural selection in his book On The Origin of Species

12. Two Points of his Book
1. He presented evidence that the many species of organisms inhabiting the Earth are descendants of ancestral species
2. He proposed a mechanism for the evolutionary process, natural selection

13. What is the Theory of Natural Selection?
Process by which individuals with better adaptations survive and produce more offspring
favorable traits become more common
Cornerstone of modern biology

14. Principles of Natural Selection
Variation
Overproduction/Competition
Adaptation
Descent with modification

15. Variation Differences in a population
Differences result from genetic differences
Inherited or result of mutations
Example Some newly hatched sea turtles are able to swim faster than others

16. F F S S F

17. F F S S F

18. F F S F

19. F F F

20. F F F F F F F F F

21. Overproduction/Competition
Having many offspring raises the chances some will survive, but increases the competition for resources
EX. amphibians or reptiles laying many eggs at one time

22. Adaptation Arise in response to environmental pressures
Allows some individuals to survive
Successful individuals are “naturally selected” to live longer and produce offspring with the beneficial adaptations
EX. antibiotic and pesticide resistance

23. Descent with Modification
All organisms arose from other species with modifications that are needed to survive
The beneficial traits will be passed on to future generations

24. Fitness
Darwin’s fitness ability of an individual to survive and produce more offspring than other members of the population
Fitness today ability of an organism to successfully pass on its genes to its offspring
Who is more fit? Bacteria or lions?