Sealey evolution
- 1. Correction of Evolution Misconception… Evolution = humans came from monkeys
- 2. Evolution really means… • CHANGE OVER TIME! • Think about it… – Over 4.6 Billion years there have been LOTS of changes – Life as we know it has survived despite many obstacles – How? • Life ADAPTS to survive!
- 4. “Evolve” Means Earth has changed over time is to Change Over Time • The belief that life on quite old • To be considered science, this belief requires a great deal of evidence
- 5. The Development of Evolutionary Theory Naturalists have always wondered at the diversity of living things……… • Great varieties in shape, size, and ecological role • Estimated 3 million to 20 million different living species • Much of the natural world’s biodiversity has vanished through extinction 99% of all species that ever lived are now extinct.
- 6. Development of Evolutionary Theory What could cause such great diversity, and why have so many species died out? Charles Darwin offered an explanation based on careful observations.
- 7. Development of Evolutionary Theory Darwin Concluded: • Physical traits and behaviors enable organisms to survive and reproduce (called Fitness ) • Fitness results from adaptations • Darwin reasoned that adaptations result from natural selection and result in evolution Evolution is the process by which living things change and diversify over time
- 8. Development of Evolutionary Theory • These ideas were widely challenged until a tremendous amount of evidence was gathered to support evolution! • Now…The Theory of Evolution is the Cornerstone of Biology • Explore the Evolution Revolution
- 9. Anatomy and Comparative Anatomy • Vestigial Organs – Organs inherited but not used by modern organisms – Present but greatly reduced in modern organisms – Hip bone in python – Appendix in human – Tail bone (cocyx) in human
- 10. Anatomy: Homologous Structures • Similar parts of different organisms, often quite dissimilar in purpose, that developed from the same ancestral body parts. • Divergent evolution
- 11. Anatomy: Analogous Structures • Similar in purpose, but not inherited from a recent common ancestor • Environment selected for trait – Wings of birds and insects • Convergent evolution
- 13. Charles Darwin • Studied Medicine and Theology • Excelled in Geology and Biology • In 1831 Darwin joined the H.M.S. Beagle on a trip around the world to make maps • He was the ship’s naturalist.
- 14. The Voyage of the Beagle: Ports of Call Noted that populations of organisms were slightly different from place to place Each group was modified to their specific environment
- 21. Evolution Through Natural Selection • There is variation in populations caused by genetics • Many more offspring are produced than can survive. Many die through predation or starvation. • Some variations are favorable and help organisms compete to survive and reproduce. • Over time, the organisms with favorable variations become plentiful. The ones without favorable variations become rare or extinct.
- 22. Speciation • Natural Selection modifies populations. Some evolutionary changes are so great that some organisms can no longer interbreed with the original population • A new species results. • Species – An interbreeding population of organisms that can produce healthy, fertile offspring