Transcript EVOLUTION
Q3 WK5 D1 EVOLUTION • Evolution: • The genetic change in a species over a long, long time • The following scientists came up with possible hypotheses: • Jean Baptiste de Lamarck • Charles Darwin • Alfred Russell Wallace Jean Baptiste de Lamarck 1744-1829 • 1st to hypothesize about species modification (evolution) • His hypothesis was that evolution occurred by inheritance of “acquired traits” Individuals pass on to their offspring characteristics that they acquired (gained) during their lifetime. Ex. Giraffes & water birds CHARLES DARWIN 1809-1882 • Darwin agreed with Lamarck about species modification however disagreed with the method. • Darwin believed that individuals in a species came with varied characteristics and the environment “selected” the characteristic that was most suited (beneficial) and those individuals survived & passed on their genes. Variation = a range in type of a characteristic from random mutations in DNA (not created by experience) Selection = when an individual is able to survive and reproduce based on their specific type of characteristic Darwin’s hypothesis became known as: Evolution by Natural Selection Attach into science notebook HOW DID DARWIN COME UP WITH HIS HYPOTHESIS??? Darwin’s Voyage (1831) on the HMS Beagle • Five year voyage around the world • Galapagos Islands Darwin’s Evidence • He found fossils of extinct species resembling living species in the same area • Galapagos finches differed slightly in appearance but resembled those on the South American mainland • Darwin observed 14 different finch species • They differed mainly in beaks and feeding habitats Four Galapagos finches and what they eat Could a new species arise form an ancestral form by the gradual accumulation of adaptation to a different environment? Darwin’s Observations Scelidotherium Megatherium Small Ground Finch Galapagos Land Iguana Toxodon Evolution By Way of Natural Selection • The species inhabiting Earth today descended from an ancestral species = evolution • Natural selection is the mechanism for this evolution • Individuals with certain inherited characteristics are better able to produce more surviving offspring than individuals lacking these characteristics due to their environment • The result is an evolutionary adaptation Deer & Cactus Picture • Attach into sci. ntbk Natural Selection of cacti 1. What is the main difference between the cactus on the left and on the right? 2. Why would a deer be more likely to eat the cactus on the left than on the right? 3. What effect does the deer's behavior have on the survival and reproduction of these two cacti? 4. Do you think that evolution by natural selection is occurring in this cactus population? (Assume there is actually a large population of cacti, some look like each type of cacti shown above) Why or why not? For each of the terms, write the definition as given in your notes and write your interpretation of the definition Check & attach into sci. ntbk 10 Examples of Natural Selection Article The Origin of Species by Means of Natural Selection • Published on November 24, 1859 • Narrowly beating Alfred Wallace who was about to publish the same hypothesis. • Focused biologists’ attention on the great diversity of organisms• Their origins and relationships, similarities and differences, geographic distribution, and adaptations to their surroundings