Presentation on theme: "(Survival of the Fittest)"— Presentation transcript:
1 (Survival of the Fittest) DARWIN’S THEORY ofNATURALSELECTION(Survival of the Fittest)
2 HOW DOES NATURAL SELECTION LEAD TO EVOLUTION? In this section you will want to find the answers for: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?
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...
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.
6 Group of similar organisms that can mate and produce offspring VOCABULARYSCIENTIFIC THEORY:a well tested concept (idea) that explains a wide range of observationsWhat is the difference between an idea, theory and fact?SPECIES:Group of similar organisms that can mate and produce offspring
7 DARWIN’S THEORY:Species gradually change over many generations and become better adapted to new conditions
11 ...AND ANIMALS ORIGINALLY CAME TO GALAPAGOS ISLAND?
12 Ancestors of today’s plants & animals on the islands were brought from the mainland by wind, currents, or on floating debris...
13 FROM MAINLAND RELATIVES DUE TO RESOURCES AVAILABLE. ONCE THEY REACHED ILSANDS, THEY REPRODUCED & OFFSPRING BECAME DIFFERENTFROM MAINLAND RELATIVES DUE TO RESOURCES AVAILABLE.Island TurtlesMainland Turtle
14 THIS BRINGS US TO DARWIN’S THEORY OF NATURAL SELECTION
15 Natural SelectionIndividuals that are better adapted to their environment are more likely to survive.
16 SURVIVAL OF THE FITTEST WHAT ARE FACTORS THAT AFFECT SURVIVAL?Differences in species (variations)Over production of same speciesCompetition for resources
17 HOW DOES THIS APPLY TO THE GALAPAGOS ISLANDS? SO….HOW DOES THIS APPLY TO THE GALAPAGOS ISLANDS?
18 Organisms that were on the Islands first had NO competition for resources (food, shelter, H2O) because no other species was there.
19 Darwin studied finches found on these islands Darwin studied finches found on these islands. This played an important role in his recognition of the evolutionary process.
20 by studying the finches - Darwin showed how species are related to other species
21 over long periods of time natural selection can lead to evolution. ...Andover long periods of time natural selection can lead to evolution.VARIATIONS IN ORGANISMS GRADUALLY ACCUMULATE WHILE UNFAVORABLE ONES DISAPPEAR.HOW?
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.