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WHAT IS EVOLUTION? A CHANGE IN A POPULATION OVER TIME I. JEAN BAPTISTE LAMARCK 1744-1829 •A FRENCH NATURALIST, IN CHARGE OF THE INVERTEBRATE FOSSILS AT THE NATURAL HISTORY MUSEUM IN PARIS IN THE EARLY 1800’S LAMARCK’S THEORY • 1. ORGANISMS WILL ALWAYS TRY TO IMPROVE & BECOME ADVANCED • 2. THE EFFORT TO IMPROVE CAUSES THE MOST USED STRUCTURES TO EVOLVE WHILE OTHER PARTS ARE WASTED AKAPRINCIPLE OF USE AND DISUSE (vestigial structures) • 3. ONCE A BODY STRUCTURE IS MODIFIED BY USE OR DISUSE THE MODIFICATION IS INHERITED AKA INHERITANCE OF AQUIRED CHARACTERISITICS Maybe Lamarck was right? Vestigial Structures Inherited from a common ancestor, but not used George Cuvier 1769-1832 French Naturalist • Studied fossils – Catastrophes caused animals to become extinct • Disagreed with Lamarck. • He believed that structure and function of animal organs was determined by the influence of their environment. • Parts could not change without affecting the entire organism. Do you agree? Darwin Returns from his Beagle trip • BECAME VERY POPULAR because of all the SPECIMENS & SAMPLES he sent back from his trip • Becomes Friends with Charles Lyell, a GEOLOGIST • Lyell stated “The Earth must be very old, since geological formations are slow & gradual.” Charles Lyell THOMAS MALTHUS 1766-1834 • CLERGYMAN WHO WROTE ABOUT ECONOMICS. • “THE HUMAN POPULATION WAS GROWING SO FAST THAT RESOURCES WOULD SOON RUN OUT, PEOPLE WOULD DIE DUE TO DISEASE, WAR & OTHER DISASTERS” THOMAS MALTHUS CONT. • How did this influence Darwin? • Darwin saw that PLANTS & ANIMALS PRODUCE more OFFSPRING then can SURVIVE as well. INFLUENCES ON DARWIN • 1. DARWIN thought geological changes could influence plant & animal adaptationCHARLES LYELL • 2. HE OBSERVED farm animals and pets selectively bred for desirable traits FARMERS. ARTIFICIAL SELECTION • Darwin suspected this also occurred in nature- “Natural Selection” • Cuvier-Environment affects adaptation Alfred Wallace 1820-1903 • Wrote to Darwin to get advice on his theory of evolution. His theory was based on Natural Selection. • Darwin freaks! This is his work of 20 years! • Fellow scientist at the Royal Society decided to let the two present their theories. • Darwin’s was accepted based on his years of accumulated evidence. IV. MAJOR COMPONENTS OF DARWIN’S NATURAL SELECTION THEORY • 1844 DARWIN WROTE HIS THEORY ON EVOLUTION-NATURAL SELECTION • THERE ARE 5 POINTS TO HIS THEORY • 1. VARIATION IN POPULATION-VARIATIONS ARE PASSED ON FROM PARENT TO OFFSPRING • 2. SOME VARIATIONS ARE FAVORABLE-IF FAVORABLE IT IMPROVES THE ORGANISMS ABILITY TO LIVE & REPRODUCE IV. MAJOR COMPONENTS OF DARWIN’S NATURAL SELECTION THEORY • 3. MORE YOUNG ARE PRODUCED THAN CAN SURVIVE-ONLY A FEW LIVE LONG ENOUGH TO REPRODUCE • 4. THOSE THAT SURVIVE & REPRODUCE HAVE FAVORABLE Traits. A LARGER & LARGER PORTION OF THE NEXT GENERATIONS WILL INHERIT THESE FAVORABLE VARIATIONS • 5. GRADUALISM-OVER A LARGE AMOUNT OF TIME, SMALL CHANGES ACCUMULATE & POPULATIONS CHANGE IDEAS ABOUT HOW LIFE IS CREATED Prior to Darwin SPONTANEOUS GENERATION • LIFE COMES FROM NON-LIVING THINGS, e.g. THE AIR • WHY DOES MEAT GET MAGGOTS? • Maggots come from MEAT REDI’S EXPERIMENT 1668 Let’s watch the animation But, first draw this experiment LOUIS PASTEUR • 1860’S people still believed in SPONTANEOUS GENERATION! • Pasteur wanted to end the debate on where life comes from • He had an ingenious experiment • He ends up proving his theory• Biogenesis, life comes from life. LOUIS PASTEUR’S EXPERIMENT