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CH 7 SEC 3 EVOLUTION OF SPECIES GOAL/PURPOSE STUDENTS KNOW THE ROLE OF GENETIC VARIATION AND EXTINCTION HAS PLAYED IN THE FORMATION OF LIFE OVER THE HISTORY OF EARTH AND HOW WE ARE TODAY! VARIETY OF SPECIES HOW MANY MILLIONS OF SPECIES EXIST? 1.5 MILLION TO??? KEY- OVER TIME, DIFFERENT ENVIRONMENTS AND GENETIC VARIATION HAVE PRODUCED, THROUGH NATURAL SELECTION, THE VARIETY OF ORGANISMS THAT EXIST TODAY. CONT’D HABITAT- IS THE SPECIFIC ENVIRONMENT THAT PROVIDES THE THINGS AN ORGANISM NEEDS TO LIVE, GROW, AND REPRODUCE KEY-A NEW SPECIES CAN FORM WHEN A GROUP OF ORGANISMS REMAINS ISOLATED FROM THE REST OF ITS SPECIES LONG ENOUGH TO EVOLVE DIFFERENT TRAITS. CONT’D GRAPHIC ISOLATION- IS WHEN SOME MEMBERS OF A SPECIES BECOME CUT OFF FROM THE REST OF THE SPECIES (SEE GALAPAGOS ISLANDS) http://video.nationalgeographic.com/video/ places/parks-and-nature-places/coastsand-islands/ecuador_galapagos/ INFERRING SPECIES RELATIONSHIPS KEY- SCIENTIST HAVE COMBINED THE EVIDENCE FROM DNA, PROTEIN STRUCTURE, FOSSILS, EARLY DEVELOPMENT AND BODY STRUCTURE TO DETERMINE THE EVOLUTIONARY RELATIONSHIPS AMONG SPECIES EXTINCTION OF A SPECIES EXTINCT- WHEN NO MEMBERS OF A SPECIES ARE ALIVE (WOOLLY MAMMOTHS) WHAT MAKES A SPECIES EXTINCT? KEY- EXTINCTION IS CAUSED BY A CHANGE IN A SPECIES ENVIRONMENT. THE MEMBERS OF THE SPECIES MAY NOT HAVE ADAPTATIONS THAT ALLOW THEM TO SURVIVE AND REPRODUCE IN THE CHANGED ENVIRONMENT EXTINCTION http://www.brainpop.com/science/ourfragil eenvironment/extinction/preview.weml THERE ARE MANY WAYS EXTINCTION CAN HAPPEN… A NEW DISEASE LOSS OF FOOD SOURCE PREDATORS KILL THEM OFF HUMAN IMPACT OVER HUNTING DESTRUCTION OF ENVIRONMENT CLIMATE CHANGE CATASTROPHIC EVENTS Cont’d Climate Change- has been the leading cause of extinction EX- an area that was once warm and moist becomes cool and dry Resulting- in plants dying and the animals that feed on those plants dying as well or becoming extinct KEY- SOME ORGANISMS IN A SPECIES MAY HAVE TRAITS THAT HELP THEM SURVIVE IN A CHANGED ENVIRONMENT. HORSESHOE CRABS HAVE SURVIVED MANY CLIMATE CHANGES HORSESHOE CRAB RECENTLY EXTINCT ANIMALS http://listverse.com/2009/07/25/10recently-extinct-animals/ http://www.youtube.com/watch?v=0Kwzg8 WmSEU http://news.discovery.com/videos/why-tellme-why-mass-extinction.html REVIEW QUESTIONS WRITE THE QUESTION AND ANSWER 1. IDENTIFY 2 FACTORS THAT ACCOUNT FOR DIVERSITY OF SPECIES. 2. HOW CAN ISOLATION LEAD TO THE FORMATION OF A NEW SPECIES? 3. WHAT CAUSES EXTINCTION?