Give examples of animals, birds or fish that appear to be well suited to their environment?

1. Give examples of animals, birds or fish that appear to be well suited to their environment?

2. The Theory of Evolution Widely accepted as the best explanation for the origin and development of human life. 2

3. Published in 1859, Darwin’s book caused public outcry from the church. 16/08/2014 Free Template from www.brainybetty.com 3

4. “Natural selection is a process in which species of plants and animals change to suit their environment...” 16/08/2014 Free Template from www.brainybetty.com 4

5. According to Evolution if we trace our ancestors back far enough we will find that they are not the same as us. They are a primitive form of man that is more like an ape than a human.

6. Newspapers made fun of Darwin and had headlines like “This man says your uncle is a monkey”

7. The proof for these ideas is that fossils have been found. Fossils show us what creatures were like millions of years ago.

8. Going through the dinosaur stage animals evolved into humans. At first they were amphibians, then complete land creatures Some sea creatures struggled on to land. Briefly, the theory is that life started in the oceans

10. And now you can meet your nearest living relative. The one you share 96% of your DNA and almost all of your genes with..

12. Monkey and Human hands

15. Evidence for Evolution • Fossil records demonstrate small changes in evolution • Similarities in bone structure • Examples of survival of the fittest and adaption to environment • DNA (though Darwin didn’t have this in his time)

16. The Theory of Evolution

17. Charles Darwin In the 1830s he went on a scientific expedition to Australasia on the HMS Beagle

18. What did he see? • Many species that were not found in Europe • Lots of fossils • Many variations of creatures on different islands

19. Finches On three tiny islands there were finches but on each there was a different kind of finch. On one the finch had a wee pointy beak and on another a wee chunky beak. He then noticed that the food available on each island was different.

20. Write down evidence for the theory of Evolution.

21. How did these beaks lead Darwin to his theory of Evolution?

22. Why would God create so many different species to suit each island?

23. Beaks The island with the finches with chunky beaks had lots of hard nuts. Only a bird with a chunky beak could survive there. On another island there were smaller and more delicate seeds and the finch had a wee pointy beak, ideally suited for eating the nuts.

25. He concluded that Survival depends on being able to adapt

26. Creatures that don’t adapt, become extinct

27. Only the fittest survive.

28. They pass the adaptations on to future generations

29. Organisms produce more offspring than actually survive so there is a ‘survival of the fittest’ • Organisms can die from many causes: disease, starvation, and being eaten, among other things.

30. Every organism must struggle to survive • They struggle to get resources to survive and to get away from predators Not all of them make it – 99% of species we have found through fossils are extinct.

31. There is variation within a species • There are visible differences such as markings / physiological differences and less visible ones such as speed

32. Mutation Every now and then the DNA mutates. This means it changes slightly and can happen for lots of reasons. The offspring becomes a little different from its parents.

33. When something goes wrong with the transfer of DNA... • ‘Genetic Mutation’ occurs. • This can often result in a handicap or other disadvantage. But... It can also result in an advantage! • The advantage will be passed on to future generations. 16/08/2014 33

34. Unhelpful DNA Sometimes this mutation is unhelpful and the change means the life-form can’t survive as well as its parents did. It dies and so does its DNA (because it’s less likely to mate).

35. Helpful DNA If the wee mutation gives the life-form something its parents didn’t have which is really useful it is more likely to survive (and mate).

36. So, some variations allow members of a species to survive and reproduce better than others. • A faster gazelle is more likely to out run a cheetah • A brighter / sweeter flower will attract more bees

37. Organisms that survive and reproduce pass their traits to their offspring, and the helpful traits gradually appear in more and more of the population. • If there are slow and fast cheetahs • More of the fast ones will live to reproduce • So in the next generation there’ll be more fast cheetahs

38. Describe Darwin’s theory of Evolution using these terms… Struggle ‘Survival of the fittest’ Best adapted DNA Extinct Traits Mutations Variation

39. Darwin’s theory of Evolution • Based on a struggle to survive • ‘Survival of the fittest’ which means… • Life that is best adapted to the environment is more likely to live, breed and pass on its DNA • Life that does not adapt become extinct • Certain traits that give life-forms an advantage are ‘preserved’ in the gene pool because of this e.g. … • Every so often mutations happen which may prove helpful / unhelpful to the life-form • Variation in species brings advantage or disadvantage

40. An example • There are hares living in a cold, snowy, polar region. All of the hares are brown and many of them are killed and eaten by other animals each year, so more are born than survive.

41. These hares are competing for life and struggling to survive, partly by trying to avoid predators, to "not be the one who gets eaten.”

42. Each hare is a little bit different from other hares, but one time a hare is born, white, because of a mutation in the genes.

43. This variation in colour helps the albino hares to survive. Against the white snow, predators have a harder time seeing them, so more of the white hares are able to survive and therefore to reproduce. Can you see the hares? Exactly!

44. In the next generation there are more white hares, because the white hair gene is passed on. In this generation, too, more white hares survive and reproduce. They pass the trait on to their offspring, who also survive and reproduce more than do the brown hares. Gradually, there are more and more white hares in the population, until the entire population is made of white hares. 

45. It also works the other way around!

46. What can you see?

47. Peppered Moths This is one of the best known examples of Natural Selection. The peppered moth is speckled grey an white- very similar to the bark of a tree. When it lands on a tree its natural colour disguises it. Birds don’t see it so don’t eat it.

48. Peppered Moths Every now and then a black peppered moth appears (through random DNA mutation). It lands on a tree, gets spotted by a bird and gets eaten.

49. The Industrial Revolution • During the Industrial Revolution there was lots of smoke and soot in the atmosphere. Trees became covered in soot turning them ‘black’.

50. The Industrial Revolution Now the normal peppered moths were being eaten more and more, their disguise wasn’t as good any more. The mutant black ones had really useful colouring and weren’t eaten.