Presentation on theme: "Darwin’s Theory of Evolution. What is a scientific theory? A well substantiated explanation of some aspect of the natural world, based on a body of facts."— Presentation transcript:
What is a scientific theory? A well substantiated explanation of some aspect of the natural world, based on a body of facts that have been repeatedly confirmed through observation and experiment.
The Puzzle of Diversity Evolution ◦ Change over time ◦ Change in the inherited characteristics of populations over successive generations.
Evolution how ◦ Mutations that result in better chance for survival Traits are passed on to offspring
The puzzle of diversity Charles Darwin ◦ Largest contributor to current understanding of evolution ◦ Voyage of the H.M.S. Beagle Collected samples of life in different parts of the world. ◦ Galapagos Islands Patterns of diversity Fossils
Are Scientific Discoveries Unique? Alfred Russel Wallace
Influences on Darwin ◦ Jean-Baptiste Lamarck (1809) Living things have changed over time ~ all species descended from other species. Species are adapted to their environment.
Jean-Baptiste Lamarck Organisms acquired or lost certain traits during their lifetime. These traits could be passed on to their offspring. 3 parts to this idea…
Tendency Towards Perfection All organisms seek perfection Acquire traits that help them flourish ◦ Birds’ desire to fly led to flight
Use and Disuse Change parts of body through use and disuse Bird tries to fly, wings develop over time ◦ Bird does not fly, wings fall off over time Tie an arm behind your back…
Inheritance of Acquired Traits Gained during an organism’s lifetime ◦ Body builders, strong heart, obesity Traits passed directly to offspring ◦ Since I run a lot, my child will see the advantage Epigenetics?
Evaluating Lamarck was wrong; so, what did he contribute? Laid the foundation for evolutionary theory First to document that organisms adapt to their environment
Influences on Darwin ◦ Charles Lyell – Principle of Geology Past events must be explained using processes that can be observed. Slow process ~ These processes are still occurring! ◦ Robert Frost once said, “In three words I can sum up everything I know about life: it goes on.”
Stop, collaborate, and listen… Could one person come up with and completely legitimize a theory on his/her own? Could Darwin have drawn the picture of Evolution all by himself? ◦ Who were four of the main contributing artists to his first proposal?
Darwin Presents His Case Publication of On the Origin of Species ◦ Inherited Variation ◦ Artificial Selection ◦ Natural Selection Struggle for existence Fitness and Adaptation Survival of the Fittest Natural Selection Descent with modification Common descent
15-3: Darwin Presents His Case Publication of On the Origin of Species ◦ Evidence Fossil record Geographic distribution Homologous body structures Vestigial organs Similarities in Embryology Strengths and Weaknesses of Evolution