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Biology 1b Evolution and Environment GCSE CORE Key words: acquired, natural selection.

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Presentation on theme: "Biology 1b Evolution and Environment GCSE CORE Key words: acquired, natural selection."— Presentation transcript:

1 Biology 1b Evolution and Environment GCSE CORE Key words: acquired, natural selection

2 Biology 1b Evolution and Environment GCSE CORE Lets get a grip of Evolution and Natural Selection through the following interactive video; xcel/environment/evolutionact.shtml

3 Biology 1b Evolution and Environment GCSE CORE Objective What are the theories of evolution? Success Criteria By the end of the lesson I: can explain the two theories of evolution and who has created them can explain evidence that supports one of the theories can identify the evidence for evolution

4 Biology 1b Evolution and Environment GCSE CORE Who was Charles Darwin?

5 Biology 1b Evolution and Environment GCSE CORE Natural selection of Finches This is just one of the examples that got Darwin thinking about natural selection.

6 Biology 1b Evolution and Environment GCSE CORE Summary Darwin's finches He noticed that the finches (songbirds) onHe noticed that the finches (songbirds) on the different islands there were fundamentally similar to each other, but showed wide variations in their size, beaks and claws from island to island. For example, their beaks were different dependingFor example, their beaks were different depending on the local food source. Darwin concluded that, because the islands are soDarwin concluded that, because the islands are so distant from the mainland, the finches that had arrived there in the past had changed over time.

7 Biology 1b Evolution and Environment GCSE CORE Darwin’s theory of evolution The British naturalist Charles Darwin (1809–1882) later suggested a more persuasive argument for evolution. Darwin proposed that evolution took place through natural and sexual selection. Darwin developed his theory of evolution after noticing close similarities between certain fossils and the adaptations of modern day animals he saw during his round-the-world voyage on the HMS Beagle.

8 Biology 1b Evolution and Environment GCSE CORE Darwin knew that in religious Victorian society his findings would be controversial and blasphemous. He was unwilling to publish and risk his reputation. However, when Darwin learned that another British naturalist, Alfred Russel Wallace, had proposed an almost identical theory of natural selection, he published his findings. Controversial research Luckily, a handful of influential scientists were convinced by Darwin's work and spoke out in public to promote his ideas.

9 Biology 1b Evolution and Environment GCSE CORE Darwin made extensive use of specimens and fossil evidence to explain his theory of evolution, but because DNA and genes had not yet been discovered, he was unable to explain why traits varied within individuals or how they were inherited. Could Darwin explain everything? Victorian scientists found it difficult to test Darwin’s theory. For his theory to work, the Earth needed to be millions of years old, but its age was not known at that time. In addition, little was known about the process of fossilization or how to explain gaps in the fossil record.

10 Biology 1b Evolution and Environment GCSE CORE The short-necked ancestors of modern giraffes needed to reach the leaves on tall trees when food was scarce. Lamarck’s theory of evolution How would this theory explain a giraffe’s long neck? Over their lifetimes these giraffes stretched their necks; a trait which was then passed on to their offspring. Jean-Baptiste Lamarck ( ) was a French botanist who believed that species evolved because they inherited traits acquired through the over or under-use of body parts.

11 Biology 1b Evolution and Environment GCSE CORE What evidence for evolution?

12 Biology 1b Evolution and Environment GCSE CORE Theory of Evolution The theory of evolution states that all present day organisms (and many more that are now extinct) have evolved from simpler organisms over long periods of time (billions of years) DARWINs theory is that evolution takes place through natural selection LAMARCKs theory is that all organisms originated from worms and that this was caused by the inheritance of acquired characteristics

13 Biology 1b Evolution and Environment GCSE CORE Science vs religion Read page 116 and answer Why is it important for students to know about evolution? Include – evidence of evolution - the current scientific theories - final comment stating your opinion

14 Biology 1b Evolution and Environment GCSE CORE Objective What are the theories of evolution? Success Criteria By the end of the lesson I: can explain the two theories of evolution and who has created them can explain evidence that supports one of the theories can identify the evidence for evolution


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