Chapters 10 Principles of Evolution

1. Chapters 10Principles of Evolution

2. What in the world is it and what is that pink thing? This is a star-nosed mole which lives underground. The 22 fingerlike rays are used for finding food and its claws are used for burrowing. It’s eyes are basically useless therefore its hearing is sharp Write down what you think it is and what the pink thing is for.

3. What is Evolution? What comes to mind when you hear or read the term “evolution”? • Evolution is the gradual biological change in a species over time. • It is based on the concept that modern organisms have descended from other organisms

4. Human Evolution • 225 million years ago, the first mammal evolved • 65 million years ago, the first primate evolved (and the dinosaurs went extinct) • 6 million years ago, the first hominid evolved (man like primate) • 2 million years ago, the species Homo evolved • Homo sapiens ~ 50,000 years ago.

5. This concept of Evolution, that organisms shared a common ancestry didn’t happen over night.It took many people and many years to form this theory • Carolus Linnaeus (1700’s) • Proposed a system of organization of all living things based on physical similarities • Proposed that organisms might have arisen from crossing between two similar species • Species – a group of organisms that are able to reproduce fertile offspring. - A mustang and a miniature horse can mate and produce a pony that can eventually reproduce because the two are from the same species (Equuscaballus) . - A horse and a donkey (Equusafricanus) could reproduce but the mule will never be able to reproduce.

6. What would you do if the most important things you needed were up high and you were alone, without anything to climb on? • Jean-Baptiste Lamarck (1809) a. Believe in decent from common ancestry b. Proposed that organisms have a tendency towards perfection and needed to change to better fit in with their environment. c. Through selective use and disuse of organs, organisms acquired or lost certain traits during their lifetime. d. By passing on these acquiredtraits to their offspring, a species can change over time.

7. Fossil evidence shows that the ancestors of the modern giraffe originally had shorter necks. These shorter necked giraffes had eaten all the food on the lower branches & needed to get to the food higher up. By stretching their necks, to get to the higher up leaves, after many generations, the giraffes acquired the long neck trait. The following generations would all inherit the acquired trait.

8. What parts of Lamarck’s theory do you agree or disagree with? • A need to change (Tendency towards perfection) • Use and disuse (if you use it, it develops, if not, it goes away) • Acquired traits (we can acquire traits in our lifetime) 4. Inheritance of acquired traits (passing on things we acquire or develop in our lifetime)

9. How would Lamarck have explained how the sandpiper got its shape?

10. In 8th grade, you studied Earth Science. Here are a few review questions for you. • How old is the earth? 4.6 Billion years old • What was the earth like when it first formed? It was molten, then solidified, then water forms. It was HOT!! 3. When did life begin on earth? 3.6 billion years 4. Where the 7 continents always in the same place? Plate Tectonics and continental drift. The continents were all one big mass and then moved due to the movement of the mantel below. 5. Does the earth change today? Volcanoes, earthquakes, hurricanes, global warming, ice ages, erosion, …

11. Evidence and concepts that helped shaped the concept of evolution • Fossil(traces of organisms that existed in the past) evidence showed that organisms can go extinct. b) Catastrophism – natural disasters like floods, volcanoes, asteroids… have happened and could cause mass extinctions of organisms. Like what happened to the dinosaurs!!

12. Ice Age Giant Asteroid

13. Did this happen all of a sudden? c. Gradualism • The earth is in layers that formed very slowly & has been altered over time by forces of nature.

14. What does the image on the right tell you about how the earth changed? d. Uniformitarianism • The events of earth’s past are happening today

16. History of Charles Darwin • 2/12/1809 – 1882 • Very wealthy - Married 1st cousin • Studied medicine & theology but ended up being a naturalist.

18. Starting in 1831, he took a 5 year voyage on the HMS Beagleas the ship’s naturalist, from England, around South America, to the Galapagos Islands, below Australia and and Africa, back to SA and then to England Galapagos Is

19. HMS Beagle

20. The Galapagos Islands 1000km west of S. America – Volcanic chain of Islands • Low islands were hot, dry & basically void of life. • Higher elevations islands had a lot of rainfall & therefore more variety of life • Saw much variations amongst inhabitants of the different islands. • Unique land tortoises, plants, birds, marine iguana... • Species differed from island to island, especially the tortoise shells & the “little brown birds” (finches)

21. Could these all have come from one common ancestor and evolve to be better suited or adapted to their particular environment on the island?

22. Darwin was extremely seasick throughout the voyage! • Published book: On the Origin of Species in 1858

23. How could Darwin have used some of the concepts from earlier scientists to develop his theory of evolution by natural selection? • Fossils • Shows that organisms from the past are similar to organisms of today • Organisms have gone extinct • The earth is old, not just a few thousand years old • If the earth is at least 1 million years old, there is plenty of time for a species to change • It’s really 4.6 million years old.

24. Uniformitarianism • The events of earth’s past are happening today • He can see that the earth gets changed by such events like earthquakes, volcanoes, fires… • Gradualism • Darwin saw the layers of rocks on exposed cliffs along with the fossils within these layers • Catastrophism • Though Darwin would not have known what happened to the dinosaurs, he knew that they existed at one time & were now extinct. • Questioned why organisms would go extinct

25. Suppose that when Apple came out with the new iPhone 6 and they only issued 5 new phones to each store. What do you think would have happened? Thomas Malthus (1798) stated that whenever a population gets too large, there are limited resources available to them. Sooner or later, there will not be enough food, space, fresh water … War, famine & disease are the only forces to keep the population size from outdistancing food supply

26. Darwin questioned that if organisms produce far more offspring than can survive, what factors determine which ones survive and reproduce?

27. What was the purpose of crossing a horse with a donkey to get mule? • The horse is large and can carry a heavy load over long distance but it isn’t very sure footed. • The donkey is small but very sure footed and can walk on very narrow paths. • When the two are crossed hopefully the mule will be mid-sized and sure footed. • Sometimes though, they ended up with a small, thin ankled mule. • This is artificial selection • Process where humans change a species by breeding it for certain traits. • Darwin asked himself how nature goes about selecting which traits are the most desirable.

28. Darwin puts it all together • Natural Variations Inherited variations/differences exists between organisms w/i a population (all the members of the same species in a given area) 2. Populations over populate (Malthus) Organisms in nature produce more offspring than can survivewhich leads to competition for limited resources among members of a species 3. Nature selection The organisms with the desirable variations are better adapted and out-compete those who are not. 4. Descent with Modification. Individuals with the best adaptations survive and pass on the trait to the next generation.

29. Survival of the fittest & Natural Selection Those members of the population w/ the best natural variations (adaptations), will survive & pass these traits onto their offspring. Those without the variations will not survive “Fitness is measured in the # of grandchildren one has” Nature selects which variations are the best suited to the environment.

30. Natural Selection Peppered Moth Simulation

31. Natural Selection There is natural selection. Some are selected out, some aren’t In a population, there are variations There is heredity. Survivors reproduce and are therefore fitter. Descent with Modification A new species/variety of only tan beetles

32. Natural Selection Lab Gene pool All the genes from a single population combined together 50:50 with our lab Gene frequency Number of times a particular allele occurs in the gene pool. 0.5: 0.5 at start of lab We will watch the gene frequency change through generations of the: Small Lima bean Large Lima bean

33. Natural Selection Lab

34. 1.0 Simulating Natural Selection Key: ___ = Small Lima ___ = Large Lima .5 Bean Frequency 0 2 4 5 3 6 1 1 Generation

35. If you continued this lab through other generations, what do you think would have happened to the gene frequencies? • Small Lima bean’s gene frequency would continue to go up while the large bean’s would decrease over time. • Eventually, there wouldn’t be many large beans so the small limas would be easier to pick off (that’s all there is now). • The gene frequencies would then change again. • If all the larges though were picked out, they would become extinct

36. Fossil Evidence • Fossil evidence shows that living things have been evolving on earth for millions of years. • Also showed that the geographic distribution of organisms lines up with the movement of the earth’s crusts & that newer (more modern) forms of fossilized organisms are found in the upper layers of rock

37. Comparing Embryos • Which one of these is a human, chicken, turtle, fish or salamander? • Early stages of development of many animals with backbones are very similar • Children of Evolution video

38. Look at the bones of the four animals below. What do you notice about all of them? Under each one, write down what the limb is used for in each animal Based on what you see above, what conclusion could you draw about the ancestry of the four animals? Grasping, swinging Walking Swimming Flying

39. Homologous Structures • Same structures but different functions • Bones of our forearm, the front flipper of a dolphin, the wing of a bat & legs of a dog. • Could all four limbed animals with backbones have descended with modification from a common ancestors? Homologous structures show common ancestry or divergence from a common ancestor.

40. Analogous Structureshave same function but different structure • Have similar environments • Butterfly and Bird wing • Yam and potato – both are tubers

41. What do these structures indicate about common ancestry? • Why did we have an appendix? • Why would a whale have hind leg bones? • Why do we have wisdom teeth and why are they a problem now? • What’s with our coccyx? • When eating a chicken wing, what’s with the thumb? Thumb

42. What about structures that are no longer in use? Vestigial organs • Structures which no longer have a function to the organism. • Our appendix, hair, coccyx, wisdom teeth These vestiges had a useful function at one time but since they are no longer of an adaptive use to the organisms, they have become reduced with time.