Evolution

1. Evolution Change Over Time First part of student download

2. Controversial subject. But why? • Belief structures (Religion). • Evolution is difficult to conceptualize. • Lack of scientific understanding. • Misinformation

3. Religion is based on faith. Faith is a belief system Religion and the Origin of life

4. Evolution is not a religion! • It is a scientific theory that best explains the data produced from hundreds of years of observation and research. • Based on scientific observations and what we can prove scientifically. • Supported by Biological, Chemical, Genetic, and Physics Research. • You do not have to believe it but you should understand it

5. Geologic Structural Genetic Evidence for evolution

6. Geologic evidence: • Geologic timeline from fossils • Continental Drift • Plate tectonics

9. Continental Drift

10. Evidence for evolution: Fossils Observation: Fossils have been found and dated. Inference: Comparing fossils to living species today indicates living organisms have changed over time. Trilobite (extinct marine invertebrate) found in Ohio—site of an ancient sea

11. Fossils can form in several ways. 1. Permineralization The minerals form a covering over the bones. Permineralized skeleton of a Velociraptor dinosaur

12. Natural cast • Minerals fill in the spaces left from decomposition, recreating the original shape. Cast of a crinoid, a marine animal

13. 3. Trace fossils. • Leaf imprints • Footprints Fossils of footprints from a Dimetrodon dinosaur

14. Amber-preserved fossils • organisms are trapped in tree resin Wasp

15. Preserved remains • an entire organism becomes encased in ice, volcanic ash, or mud. Ice preserved 5000 year old man found in the Italian Alps.

16. Only a tiny percentage of living things became fossils. • Nevada’s state fossil: the icthyosaur which is the ancestor of the dolphin • We have the Icythyosaur State Park in central Nevada as Nevada was once underwater • Specific conditions are needed for fossilization.

17. Fossils: Links to the past… Scientists have an incomplete picture of past life on Earth because: • Not all bones become fossils. - Conditions - Predated by animals • We have not found all fossils

18. Geologic Structural Genetic Evidence for evolution

19. Fossils: Links to the past… Scientists have an incomplete picture of past life on Earth because: • Not all bones become fossils. - Conditions - Predated by animals • We have not found all fossils

20. Dating the age of Fossils • Law of superposition • Estimates the age of fossil • It compares the placementof fossils in layers of rock. Radioactive isotope dating (Uranium used for really old aging Carbon 14 dating most common)

21. Law of Superposition

22. Radioactive dating

23. Dating the age of Fossils • Law of superposition • Estimates the age of fossil • It compares the placementof fossils in layers of rock. Radioactive isotope dating (Uranium used for really old aging Carbon 14 dating most common)

24. Law of Superposition

25. Radioactive dating

26. Development of the modern theory of how evolution happened • History • The Beagle • Darwin’s Research

27. Early ideas on evolution: Lamarck • He thought salamanders lost their legs because they didn’t use them. Legless salamanders (snakes) then passed on this trait to offspring. Logic errors: • Not supported by DNA • No experimental evidence

28. Charles Darwin: “Father of Evolution” • Traveled extensively • Familiar with breeding (genetics) • Published his ideas in Origin of Species in 1859.

29. Published in1859:

30. Darwin’s Voyage on the HMS Beagle • Where it went • His Observations

31. Darwin’s Voyage on HMS Beagle

32. Darwin’s observations gave him an idea. Then he did his homework!

33. Darwin’s observation: 1. Variation exists in all living things Structural variation (what they look like) Behavioral variation (how they act) Biochemical variation (how they function) • 2. Species compete for resources: • Food • Water • Mates • Shelter

34. Darwin’s Inferences: Theory of Natural Selection 1. Due to variations, some organisms have characteristics which help them survive. 2. These organisms reproduce, passing on their genes. • Over time, more and more organisms will have this great trait, making them “different” from previous generations. • Natural selection explains how new organisms will appear over time. This is called speciation.

35. Vocabulary Adaptation An inherited variation that increases the chance of survival. Fitness Measure of the ability to survive and produce more offspring.

36. 3 Ways Evolution Happens 1. Artificial selection 2. Genetic Drift 3. Natural selection

37. neck feathers crop tail feathers 1. Artificial Selection The process by which humans change a species by breeding it for certain traits. Pigeon breeding Bred for tail feathers Bred for crop Bred for neck feathers

38. 2. Genetic Drift • “Chance” causes a small population. • Dramatic event • Small group leaves or is separated • Result: less genetic variety

39. 3. Natural Selection Its all about Variation! • Mutations - Small changes / Lots of time • Genetic Recombination (crossing over, Independent assortment & Segregation)

40. Fitness determines survival • Variation leads to differential fitness. • Some organisms survive better than others • Fitness determines which individuals survive and reproduce. • Must have a selective advantage or trait (gene) will not increase within a population.

41. Selected for: Selected against: • Helpful traits which help survival are selected for in a population and increase in frequency. • Harmful traits or unsuccessful traits are selected against in a population and decrease in frequency.

42. Examples of Evolution Occurring • Extinction • Pesticide Resistance • Antibiotic Resistance

43. Extinction • All members of a population die out. • Loss of genetic diversity. • Can be global or regional

44. Pesticide resistance: • Have to come up with new and more toxic chemicals to combat pests. • Weeds • Insects

45. Antibiotic resistance: • Need for new antibiotics • Evolutionary arms race*