1. Principles of Evolution

2. Activate Prior Knowledge
Have you ever heard of “survival of the fittest”? What does this suggest to you?

3. Before Charles Darwin
Evolution was a topic being discussed many years before Darwin ever came up with his theory.
Vocab Builder: Evolution- the process of biological change by which descendants come to differ from their ancestors.

4. Before Charles Darwin Some people we should get to know:
Carolus Linnaeus: developed a classification system for all types of organisms based on their similarities. We still use this system.
George Louis Leclerc de Buffon: he developed a theory that the Earth was much older than we thought it was at the time.
Erasmus Darwin: Charles Darwin’s grandfather, he said that all living things came from a common ancestor.

5. Before Charles Darwin Some people we should get to know:
Jean-Baptiste Lamarck: proposed that all organisms evolved toward perfection and complexity.
Vocab Builder: species- a group of organisms so similar to one another that they can reproduce and have fertile offspring.

6. Before Charles Darwin
Some theories of evolution didn’t only involve animals.
Georges Cuvier: He believed that organisms did not change but became extinct, because different layers of rock had different fossils.
He developed the theory of catastrophism.

7. Before Charles Darwin
Vocab Builder: Fossils-traces of organisms that existed in the past; Catastrophism-theory that states that natural disasters such as floods and volcanic eruptions have happened often during Earth’s long history.

8. Before Charles Darwin
James Hutton said that the changes in landforms happened gradually over a long period of time. Ex: The Grand Canyon.
Charles Lyell expanded on this and said that the geologic processes that shape the Earth are uniform through time.

9. Before Charles Darwin
Vocab Builder: Gradualism-the theory that changes in landforms resulted from slow changes over a long period of time. Uniformitarianism- theory that proposes that present geologic processes are the key to the past.

10. Darwin and his Observations
Charles Darwin traveled to South America and the Pacific Islands where he started his research.
He was greatly influenced by Lyell’s theory of gradual geologic change and later found evidence that supported the theory.
During his travels he notice variations between similar species.

11. Darwin and his Observations
Vocab Builder: Variations- the differences in the physical traits of an individual from those of other individuals in the group to which it belongs.
Variations can be interspecific (between 2 different species) or intraspecific (within the same species)
Noticed that species from one island look different from those on nearby islands.

12. Darwin and his Observations
Noticed that some of the variations were well suited to the environments and the diets of the animals.
Realized that species were adapting to their surroundings.

13. Darwin and his Observations
Vocab Builder: Adaptation- a feature that allows an organism to better survive in it’s environment.
These adaptations can lead to genetic change in a population over time.
During his travels he found evidence in fossils that species were changing over time.

14. Darwin and his Observations
Since the fossils looked like living species, it got him thinking that modern species might have a relationship to the fossil forms.
This evidence also supported that the Earth was much older than it was thought to be.

15. Darwin and his Observations
Found marine fossils high in the Andes mountains.
Experienced an earthquake that created a landmass that came from underwater.
This supported Lyell’s theory .

16. Theory of Natural Selection
Darwin traveled the world and worked on his theory of how evolution occurs for 20 years.
Looked at breeders and noticed that domesticated species differed from their wild counterparts.
Breeders use artificial selection to get the desired traits and create diversity.

17. Theory of Natural Selection
Vocab Builder: Artificial Selection- the process by which humans change a species by breeding it for certain traits.
Started to breed pigeons to look for certain traits.
In order for artificial or natural selection to happen the trait has to be inheritable.
Vocab Builder: Heritability-is the ability of a trait to be passed down from one generation to the next.

18. Theory of Natural Selection
Compared research from his breeding and his ideas of adaptation.
Noticed that certain traits that were favored by breeders were passed on. In artificial selection we are the selecting agent.
In the wild traits were passed on based on necessity. The environment is the selecting agent. The theory of Natural Selection.

19. Theory of Natural Selection
Vocab Builder: Natural Selection- a mechanism by which individuals that have inherited beneficial adaptations produce more offspring on average than do other individuals.

20. Theory of Natural Selection
Thomas Malthus brought up the idea of resources controlling population growth.
Food, water, disease, and shelter are natural limits to population growth.
Darwin noticed this in nature and said that resources were limited and organisms were having too many offspring, some would live and some would die.

21. Theory of Natural Selection
Vocab Builder: Population-all the individuals of a species that live in an area.
Those that survived had adaptations that were suited to the environment.
These adaptations happen over many generations.
Darwin called this “descent with modification”

22. Theory of Natural Selection
Alfred Russel Wallace and Charles Darwin both proposed a theory of evolution.
4 main principles to the theory of natural selection:
Variation
Overproduction-Increases chances of survival and creates competition.
Adaptation
Descent with Modification

23. Theory of Natural Selection
Vocab Builder: Fitness- a measure of the ability to survive and produce more offspring relative to other members of the population in a given environment.
“Survival of the fittest”
Natural selection can only act on traits that already exist.
A trait that is already in the population becomes favorable for survival and then is passed on to future generations.

24. Evidence of Evolution
Let’s think: Why are prehistoric fossils so much larger than the animals on earth today?

25. Evidence of Evolution
Fossils: consider age, location, and what the environment was like when the organism was alive.
Those found in deeper layers of rock were more primitive than those found in the newer layers.

26. Evidence of Evolution
Geography: Darwin noticed that plants and animals on islands looked similar, but not exactly like the ones on the mainland.
Proposed that island species will look most like species on the nearest mainland.
At some point in time some of organisms must have migrated from the mainland to the islands.
Vocab Builder: Biogeography-the study of the distribution of organisms around the world.

27. Evidence of Evolution
Embryology: Darwin noticed that the larvae of crabs and barnacles looked the same, but the adults looked completely different.
Also noticed this with vertebrate animals.
Very important piece in his common decent theory.

28. Evidence of Evolution
Anatomy: Darwin compared the structures of different species and noticed that there was strong evidence that there was a common ancestor.
Vocab Builder: Homologous Structures- features that are similar in structure but appear in different organisms and have different functions. Different in detail, similar in structure. Different function

29. Evidence of Evolution
Some animals may have structures with similar functions, but are not from the same origin.
Vocab Builder: Analogous Structure-structures that perform the same function but come from different origins.

30. Evidence of Evolution
Some species have structures or organs that no longer have any use or function.
Vocab Builder: Vestigial Structure- remnants of organs or structures that had a function in an early ancestor.

31. Evolutionary Biology Today
Vocab Builder: Paleontology- the study of fossils or extinct organisms.
This continues to provide information that supports the current theories of how evolution occurred.
We continue to find transitional fossils.

32. Evolutionary Biology Today
DNA sequence analysis examines gene changes due to mutations that have occurred over time between different organisms. This has tons of information in regards to evolutionary history.
Pseudogenes-act like vestigial structures but in DNA. Passed down but serve no function. Similarities in pseudogenes=common ancestor.

33. Evolutionary Biology Today
Homeobox genes-genes that control the development of certain structures. Indicate a very distant common ancestor. Exists in organisms that have been around as long as 600 million years ago.
Protein Comparisons-comparing proteins using molecular fingerprinting allows us to see similarities among cell types (liver and muscle) between different organisms. Similar proteins=possible common ancestor.