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Starter: What does the following term mean to you? “Natural selection by survival of the fittest”

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Presentation on theme: "Starter: What does the following term mean to you? “Natural selection by survival of the fittest”"— Presentation transcript:

1 Starter: What does the following term mean to you? “Natural selection by survival of the fittest”

2 Natural Selection Learning Intentions: Natural selection/survival of the fittest occurs when more offspring are produced than the environment can sustain. Only the best adapted individuals survive to reproduce, passing on the genes that confer the selective advantage. Success Criteria: Describe and explain, with examples, how natural selection is described as survival of the fittest.

3 Starter: What does the following term mean to you? “Natural selection by survival of the fittest”

4 Survival of the fittest This means the species most adapted to their environment will survive and pass their genes onto the next generation. It takes many generations. For some species this takes millions of years (e.g humans). Other species reproduce much more quickly and evolve much faster (e.g bacteria). Twig on Glow: Survival of the fittest. Twig on Glow: Mutations and adaptations

5 Natural Selection Natural Selection occurs when more offspring are produced than the environment can sustain. Well-adapted individuals are those which have inherited characteristics such as the ability to avoid predators, compete strongly for food, or resist disease. They survive and reproduce, passing on the genes that make them successful. They are said to have a selective advantage. Natural Selection is sometimes called survival of the fittest or Darwin’s theory of evolution.

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8 Natural Selection Charles Darwin visited the Galapagos Islands and recorded his findings about the different species of finch. He found that: On each Island, the landscape and food source for the finches was different. The finches had adapted to their environment by changing their body size and beak shape so that they could eat food and survive. This resulted in 13 different species being formed over millions of years.

9 Darwin’s finches Darwin saw different beak size and shape on each island. He concluded each bird beak was best adapted for the food available on each island.

10 Darwin’s finches experiment In groups of 4 you will play the role of different finches, trying to survive and pass you genes onto the next generation.

11 Millions of years ago there was an island with two species of bird. One had a long thin beak and the other had a wide beak. The island had a variety of trees and plants.

12 Beak Adaptation Experiment Get into groups of 4 and collect the following equipment: 1 container of food, 4 paper plates, 1 stop clock, 1 big spoon, 1 small spoon, 1 forceps & 1 tooth pick. Number yourselves bird 1, bird 2, bird 3, or bird 4 in your group. You will carry out 3 feeding experiments, following the instructions on the board as you go. You will be given 30 seconds to collect as much food as you can from the feeding container, you may only use the “beak” you have been given and you must place your food on your own paper plate for counting. Each food type has the following energy values: Rice= 1KJ Small beans= 5KJ Large seeds= 7kJ Broad bean= 10KJ Use a copy of the table for your group to calculate the energy values for your group. You must have at least 40kj to survive and reproduce. If not you become extinct. If your spoon type is extinct you “become” the beak type of a survivor.

13 Rice (1KJ) Small beans (5KJ) Large seeds (7kJ) Broad bean (10KJ) Total energy consumed Bird 1 (big spoon) Bird 2 (forceps) Beak Adaptation Results Table 1 Record in the table how many of each food each bird successfully picked up with their beak from the bowl in 30 seconds.

14 Who survived? You must have at least 40kj to survive and reproduce. Which birds were best adapted to survive and pass their genes onto the next generation?

15 Mutation! A random mutation (change in the DNA) has caused two new species to develop. One has a large beak and the other a smaller thinner beak.

16 Rice (1KJ) Small beans (5KJ) Large seeds (7kJ) Broad bean (10KJ) Total energy consumed Bird 1 (big spoon) Bird 2 (small spoon) Bird 3 (forceps) Bird 4 (tooth pick) Beak Adaptation Results Table 2 Record in the table how many of each food each bird successfully picked up with their beak from the bowl in 30 seconds.

17 Who survived? You must have at least 40KJ to survive and reproduce. Which mutations were advantageous? Which birds would have survived and which would have eventually become extinct?

18 Volcano! A volcano has erupted and split the island in two. One island has formed where the beans grow. The other island has formed where the seeds grow. Half the class is on each island.

19 Rice (1KJ) Small beans (5KJ) Large seeds (7kJ) Broad bean (10KJ) Total energy consumed Bird 1 (big spoon) Bird 2 (small spoon) Bird 3 (forceps) Bird 4 (tooth pick) Beak Adaptation Results Table 3 Record in the table how many of each food each bird successfully picked up with their beak from the bowl in 30 seconds.

20 Who survived? You must have at least 40KJ to survive and reproduce. Island 1- which birds got enough energy to survive AND pass their genes on? Island 2- which birds got enough energy to survive AND pass their genes on?

21 Bird Island Evolution On the original island the _________ beak bird was best adapted to survive. Two new birds developed through random ___________. These are changes to the ________. The new species most likely to survive was _________. The birds best adapted for survival on the bean island were________ and _________. The birds best adapted for survival on the _____and _____ island were __________ and __________.

22 Natural Selection Learning Intentions: Natural selection/survival of the fittest occurs when more offspring are produced than the environment can sustain. Only the best adapted individuals survive to reproduce, passing on the genes that confer the selective advantage. Success Criteria: Describe and explain, with examples, how natural selection is described as survival of the fittest.

23 Starter: On a show me board write a short conclusion about the Darwin’s Finches experiment.

24 Natural Selection Learning Intentions: Natural selection/survival of the fittest occurs when more offspring are produced than the environment can sustain. Only the best adapted individuals survive to reproduce, passing on the genes that confer the selective advantage. Success Criteria: Describe and explain, with examples, how natural selection is described as survival of the fittest.

25 More Examples of Natural Selection: Peppered Moths Peppered Moths can be found in two colours- black and white forms.

26 In unpolluted areas, where lichen grows on trees. The white form are camouflaged. More of the black form are eaten by predators.

27 In polluted areas trees become blackened by soot and pollution. Lichen don’t grow. The black form are camouflaged. More white form are eaten by predators.

28 Peppered Moths and Natural Selection Peppered Moths can be found in two colours- _____and w_______ forms. The black form arose from a r________ mutation. In unpolluted areas, where l_______ grows on tree’s, the w_______ form are camouflaged. More of the b_____ form are eaten by predators, less can pass their g_____ onto the next generation. The next generation are mainly white form. In industrial areas, tree’s become b_______ by soot and pollution the black form are camouflaged. More w_____ form are eaten by predators, less can pass their genes onto the next generation. The next generation are mainly black form.

29 Peppered Moth Simulation http://biologycorner.com/worksheets/pep peredmoth.html http://peppermoths.weebly.com/

30 Evolutionary biologists Some scientists think that competition drives evolution. This theory is known as the Red Queen Theory.

31 The Red Queen hypothesis Red Queen refers to Alice in Lewis Carroll's Through the Looking-Glass and her explanation of the nature of Wonderland:Lewis CarrollThrough the Looking-Glass “Now, here, you see, it takes all the running you can do, to keep in the same place.” Literacy

32 The Red Queen Hypothesis The Red Queen hypothesis states that the rate of evolutionary change is dependant on the rates of change in another species. OR As one species adapts, a co-dependant species also adapts.

33 Red Queen Example As the rabbits who are fastest survive to pass on their genes, the whole rabbit population becomes faster in the next generation. The next generation of fox only the fastest are able to catch the faster rabbits. Therefore the fox population also becomes faster.

34 Are red heads becoming extinct? Read through the newspaper article. http://www.dailymail.co.uk/sciencetech/ article-476430/Redheads-extinct-100- years.html http://www.dailymail.co.uk/sciencetech/ article-476430/Redheads-extinct-100- years.html Answer the following questions… Literacy

35 1.When does the article say red hair could become extinct? 2.According to National Geographic, how much of the worlds population has red hair? 3.What do you think the writer means by “ the gene can be dormant” 4.According the article, what proportion of Scots carry the red gene? 5.Where in the world do you think the red hair mutation might have first arisen (Northern Europe/ Africa/ America/ Australia/ Asia)? Are red heads becoming extinct?

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37 Natural Selection Learning Intentions: Natural selection/survival of the fittest occurs when more offspring are produced than the environment can sustain. Only the best adapted individuals survive to reproduce, passing on the genes that confer the selective advantage. Success Criteria: Describe and explain, with examples, how natural selection is described as survival of the fittest.


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