1. Evolution

2. History of the theory of evolution
James Hutton & Charles Lyell
Geologist who studied fossils and the stratification (layers) in rock formations
Hypothesized that geological processes happened very slowly and gradually over time

3. Thomas Malthus
Economist who studied the growth of the human population
Discovered that the human population was growing more quickly than the food supply, so eventually there would not be enough resources to support the entire population

4. Jean Baptiste Lamarck
Hypothesized that species were able to adapt to their environment and change over time
Hypothesized that organisms were able to acquire these changes during their lifetime and pass the new traits on to their offspring
This hypothesis was regarded as incorrect, but recent research is providing evidence that acquired characteristics may be passed on to future generations.
Theory of Inheritance of Acquired Characteristics

5. Example of Lamarck’s theory of inheritance of acquired characteristics

6. Charles Darwin
English naturalist who traveled around the world on the HMS Beagle
Collected many animal specimens from around the world and made detailed observations about the similarities and differences between them

7. Studied the organisms of the Galapagos Islands in great detail and compared them to species from the mainland, which he hypothesized were the ancestors of the island species

8. Darwin’s Theory of Natural Selection
Darwin supported his theory with evidence he collected while on the Beagle
Darwin is important for developing and demonstrating a mechanism for evolution not for inventing the theory of evolution. He called the mechanism or cause “natural selection” or “survival of the fittest”
He presented his theory in a book called On the Origin of Species by means of Natural Selection

9. Conditions for Natural Selection
Overproduction
Organisms produce more offspring than their ecosystem can support
Limited Resources + Too many organisms = Competition

10. Variation
Members of the same species have genetic variations that make them different from each other

11. Causes of Variation Sexual Reproduction Mutations
Offspring are different from their parents and from each other
Independent Assortment, Crossing Over, etc.
Mutations
Change in the genetic material of the organism
Mutations may harmful, neutral, or advantageous

12. Adaptation
A trait that helps an organism survive and reproduce in a particular ecosystem

13. Selection (Natural Selection or “Survival of the Fittest”)
The individual most well adapted to a particular ecosystem will have a better chance of surviving and reproducing than individuals of the same species with fewer adaptations.
In other words, the most well adapted individual ‘wins’ the competition for resources and produces more offspring than the less well adapted individuals

14. Evolution
Over time, entire species change as beneficial genes become more common in populations and detrimental genes become less common or eliminated entirely

15. Evidence of Evolution Fossil Evidence
Fossils show that different organisms existed in the past compared to organisms that exist today

16. Fossils show changes in organisms over time
Archaeopteryx is the oldest bird fossil. It shows the link between birds and their reptilian ancestors

17. Tiktaalik is a transitional form between fish and amphibians

18. The fossil record provides us with a history of life on Earth

19. Comparative Anatomy Evidence
Homologous Structures: body structures that have the same basic form, but may not necessarily have a similar function
Homologous structures suggest a common ancestor

20. Analogous Structures: body structures that serve the same function but do not have the same form

22. Biochemical Evidence
All living things are made of the same building blocks: nucleic acids, proteins, carbohydrates, lipids
ATP is used universally among living things as a source of chemical energy

24. Closely related organisms have similar DNA sequences

25. Because DNA is used to store the information cells need to make proteins, amino acid sequences can also be used to determine relationships

26. Example: humans share over 98% of their DNA with chimpanzees, yet only 85% with mice.