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DARWINS THEORY of NATURAL SELECTION (Survival of the Fittest) Slide 2 HOW DID DARWIN EXPLAIN THE DIFFERENCES BETWEEN SPECIES ON THE GALAPAGOS ISLANDS AND ON MAINLAND SOUTH AMERICA? HOW DOES NATURAL SELECTION LEAD TO EVOLUTION? HOW DO NEW SPECIES FORM? In this section you will want to find the answers for: Slide 3 Slide 4 In 1831, Charles Darwin set sail on the HMS Beagle for a 5 year trip around the world Darwin collected and studied numerous marine organisms during this famous voyage... Slide 5 Observations he made on the Beagle expedition also provided him with the ideas that he later used to formulate his theory of evolution and natural selection. Slide 6 Group of similar organisms that can mate and produce offspring VOCABULARY a well tested concept (idea) that explains a wide range of observations SCIENTIFIC THEORY : SPECIES: What is the difference between an idea, theory and fact? Slide 7 DARWINS THEORY : Species gradually change over many generations and become better adapted to new conditions Slide 8 Slide 9 THE GALAPOGOS ISALNDS ARE A GROUP OF VOLCANIC ISLANDS Slide 10 HOW DID DARWIN THINK PLANTS... Slide 11 ...AND ANIMALS ORIGINALLY CAME TO GALAPAGOS ISLAND? Slide 12 Ancestors of todays plants & animals on the islands were brought from the mainland by wind, currents, or on floating debris... Slide 13 ONCE THEY REACHED ILSANDS, THEY REPRODUCED & OFFSPRING BECAME DIFFERENT FROM MAINLAND RELATIVES DUE TO RESOURCES AVAILABLE. Mainland Turtle Island Turtles Slide 14 THIS BRINGS US TO DARWINS THEORY OF NATURAL SELECTION Slide 15 Natural Selection Individuals that are better adapted to their environment are more likely to survive. Slide 16 WHAT ARE FACTORS THAT AFFECT SURVIVAL? Differences in species (variations) SURVIVAL OF THE FITTEST Competition for resources Over production of same species Slide 17 SO. HOW DOES THIS APPLY TO THE GALAPAGOS ISLANDS? Slide 18 Organisms that were on the Islands first had NO competition for resources (food, shelter, H2O) because no other species was there. Slide 19 Darwin studied finches found on these islands. This played an important role in his recognition of the evolutionary process. Slide 20 by studying the finches - Darwin showed how species are related to other species Slide 21 ...And over long periods of time natural selection can lead to evolution. HOW? VARIATIONS IN ORGANISMS GRADUALLY ACCUMULATE WHILE UNFAVORABLE ONES DISAPPEAR. Slide 22 As you can see in the next photos, Darwin's finches share similar size color, and habits - the difference is size and shape of their beak. Slide 23 The F I N C H E S Slide 24 WARBLER FINCHES Slide 25 Slide 26 Slide 27 Slide 28 Slide 29 Slide 30 Slide 31 Lava Finch Galapagos Volcanoes Slide 32 Slide 33 WHAT ARE SOME OTHER WAYS NEW SPECIES COULD HAVE FORMED? CONTINENTAL DRIFT Slide 34 SEPARATION by: RIVERS Slide 35 SURVIVAL of the FITTEST Slide 36 How is each organism suited to play a certain role in a certain habitat? ADAPTATIONS: inherited features that let organisms survive & produce young Slide 37 Slide 38 Camouflage: Adaptations that allow organisms to blend in w/environment. Slide 39 Whats right w/these pics? Slide 40 Slide 41 Slide 42 Whats the problem here? Slide 43 Whats wrong w/this pic? Slide 44 MIMICRY ANOTHER ADAPTATION SEEN IN ANIMALS AND PLANTS: Slide 45 KING SNAKE Slide 46 CORAL SNAKE Slide 47 WHICH IS WHICH? CORAL KING Slide 48 Slide 49 CRITICAL THINKING WHAT MAKES AN IDEA A THEORY? HOW IS A THEORY DIFFERENT FROM A FACT? UPON WHAT FACTS DID DARWIN BASE HIS THEORY OF EVOLUTION?


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