1. 10.1 Early Ideas About Evolution KEY CONCEPT There were theories of biological and geologic change before Darwin.

2. 10.1 Early Ideas About Evolution Early scientists proposed ideas about evolution. EvolutionEvolution is the biological change process by which descendants come to differ from their ancestors. speciesA species is a group of organisms that can reproduce and have fertile offspring.

3. 10.1 Early Ideas About Evolution Theories of geologic change set the stage for Darwin’s theory. There were three theories of geologic change. –catastrophism – gradualism – uniformitarianism

4. 10.1 Early Ideas About Evolution Uniformitarianism is the prevailing theory of geologic change.

5. 10.2 Darwin’s Observations KEY CONCEPT Darwin’s voyage provided insight on evolution.

6. 10.2 Darwin’s Observations Darwin observed differences among island species. VariationVariation is a difference in a physical trait. –Galápagos tortoises that live in areas with tall plants have long necks and legs. –Galápagos finches that live in areas with hard-shelled nuts have strong beaks.

7. 10.2 Darwin’s Observations What he saw: Tortoises on Galapagos had: Birds on Galapagos had: Examples in the current world:

8. 10.2 Darwin’s Observations MOVIE- ROCK POCKET MICE

9. 10.2 Darwin’s Observations adaptationAn adaptation is a feature that allow an organism to better survive in its environment. –Species are able to adapt to their environment. –Adaptations can lead to genetic change in a population. What are some human adaptations?

10. 10.2 Darwin’s Observations Darwin found fossils of extinct animals that resemble modern animals. Darwin observed fossil and geologic evidence supporting an ancient Earth.

11. 10.2 Darwin’s Observations He saw land move from underwater to above sea level due to an earthquake. Darwin extended his observations to the evolution of organisms.

12. 10.3 Theory of Natural Selection KEY CONCEPT Darwin proposed natural selection as a mechanism for evolution.

13. 10.3 Theory of Natural Selection Several key insights led to Darwin’s idea for natural selection. Darwin noticed a lot of variation in domesticated plants and animals. Artificial selectionArtificial selection is the process by which humans select traits through breeding. neck feathers crop tail feathers

14. 10.3 Theory of Natural Selection Artificial selection is controlled breeding by humans to produce more individuals with specific traits. How can we see that in our world today? Dog breeding How do companies benefit from artificial selection? Food supply Medicine

15. 10.3 Theory of Natural Selection Natural selectionNatural selection is a mechanism by which individuals that have inherited beneficial adaptations produce more offspring on average than do other individuals. Heritability is the ability of a trait to be passed down. There is a struggle for survival due to overpopulation and limited resources. Darwin proposed that adaptations arose over many generations.

16. 10.3 Theory of Natural Selection There are four main principles to the theory of natural selection. –Variation- Natural selection explains how evolution can occur. – overproduction- – adaptation- – descent with modification- Fitness is the measure of survival ability and ability to produce more offspring.

17. 10.3 Theory of Natural Selection Natural selection can act only on traits that already exist. Structures take on new functions in addition to their original function. Natural selection acts on existing variation. wrist bone five digits

18. 10.3 Theory of Natural Selection Why are adaptations important? You must be born with a trait to pass it to your offspring. Some traits you acquire throughout your life. Those are not adaptations that will be passed down. Adaptations are traits that you have the are good for an environment. If a wolf has a really thick coat and the weather becomes really cold- he survives, he reproduces, and his offspring would live to pass on the thick coat. What happens if you don’t have a specific characteristic? The animal doesn’t reproduce or doesn’t survive Adaptations: are characteristics that an organisms HAS not grows: If the environment changes, which animals survive? Fitness is the measure of an animals ability to reproduce and survive.

19. 10.4 Evidence of Evolution KEY CONCEPT Evidence of common ancestry among species comes from many sources.

20. 10.4 Evidence of Evolution Evidence for evolution in Darwin’s time came from several sources. Fossils provide evidence of evolution. Fossils in older layers are more primitive than those in the upper layers.

21. 10.4 Evidence of Evolution Fossils Which is younger? Older? Fossils: fossils can be looked at over time. (Sect 12.1) Law of superposition: rock layer at the top is younger than rock layer at the bottom. (Sect 12.1) Fossils can be dated. Radiometric dating helps to use molecules to decide how old a fossil is. Half-life** Fossils can be compared between different layers of rock to decide there relative age

22. 10.4 Evidence of Evolution The study of geography provides evidence of evolution. –Geographical locations have different characteristics, but sometimes very similar animals (biogeography)

23. 10.4 Evidence of Evolution Embryology provides evidence of evolution. Larva Adult barnacle Adult crab –identical larvae, different adult body forms –similar embryos, diverse organisms

24. 10.4 Evidence of Evolution Embryology Who are you looking at? Embryology: Embryos of many organisms are VERY similar. If they are not related, why are they so similar? What do the embryos share?

25. 10.4 Evidence of Evolution The study of anatomy provides evidence of evolution. Human hand Bat wingMole foot –Homologous structures –Homologous structures are similar in structure but different in function. –Homologous structures are evidence of a common ancestor.

26. 10.4 Evidence of Evolution Human hand Bat wing Mole foot Fly wing –Analogous structures are not evidence of a common ancestor. The study of anatomy provides evidence of evolution. –Analogous structures –Analogous structures have a similar function, but different structure.

27. 10.4 Evidence of Evolution Anatomy physical structures of organisms can support evolution Homologous structures: bat wing, whale fin, and human arm Show common ancestry Similar in structure, but different function Analogous structures: bird wing & butterfly wing NOT common in ancestry Similar in function, but different structure

28. 10.4 Evidence of Evolution Vestigial structuresVestigial structures are remnants of organs or structures that had a function in an early ancestor. Ostrich wings are examples of vestigial structures. Structural patterns are clues to the history of a species.

29. 10.5 Evolutionary Biology Today KEY CONCEPT New technology is furthering our understanding of evolution.

30. 10.5 Evolutionary Biology Today Fossils provide a record of evolution. Paleontology is the study of fossils or extinct organisms.

31. 10.5 Evolutionary Biology Today Paleontology provides evidence to support evolution.

32. 10.5 Evolutionary Biology Today Molecular and genetic evidence support fossil and anatomical evidence. Two closely-related organisms will have similar DNA sequences.

33. 10.5 Evolutionary Biology Today Pseudogenes are sequences providing evidence of evolution. –no longer function –carried along with functional DNA –can be clues to a common ancestor

34. 10.5 Evolutionary Biology Today Scientist from any fields contribute to the understanding of evolution. The basic principles of evolution are used in many scientific fields. Evolution unites all fields of biology.