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Evolution

Evolution. Millions of species of plants, animals, and other organisms live on Earth today….do you think they’re the same as when life first began?. No! Species Evolve…. Species: is a group of organisms that share similar characteristic and reproduce among themselves…

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Evolution

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  1. Evolution Millions of species of plants, animals, and other organisms live on Earth today….do you think they’re the same as when life first began?

  2. No! Species Evolve… • Species: is a group of organisms that share similar characteristic and reproduce among themselves… • Evolution is a change in inherited characteristics over time • Examples: • Antibiotic resistant bacteria

  3. Evolution of Horse

  4. Misconceptions about Evolution • Evolution does not tell us about how life first appeared on Earth • People did not come from monkeys • Individuals do not evolve. Only populations can evolve. • Not all changes are “good” • Changes that happen to a person in their lifetime do not always get passed on to their children • Peter’s arm was cut off in the war but all of his children were born with 2 arms • Evolution is not a ladder working towards a better species

  5. Jean BaptisteLamark Charles Darwin • Believed that characteristics, or traits, developed during a parent organism’s lifetime and are inherited by the offspring • Inheritance of acquired characteristics • Is it true? Do we get our parent’s big muscles from working out? • Proposed evolution by natural selection, a process by which the organisms best suited to their environments are most likely to survive and reproduce • He made observations in the famous Galapagos Islands • Natural Selection Two explanations:

  6. Darwin’s Observations • He observed 13 species of finches (a little bird) on the island • All 13 were similar, except for differences in 1- body size; 2-eating habits; 3- beak shape…..Why? • B/c these finches had to compete for their food…finches with beaks that could eat what was on the island, lived longer and had more babies than those without those beaks

  7. Why do the most beneficial traits survive? • Natural Selection is the theory that organisms with traits that help them survive in their environment are more likely to reproduce • “Survival of the fittest”

  8. Principals of Natural Selection • Population: a group of individuals that live and breed together • Variation: differences in the genes of a population • 1- Organisms produce more offspring than can survive • 2- Differences, or variations, occur among individuals of a species • 3- Some variations are passed to offspring • 4- Some variations are helpful; those organisms who have them survive and reproduce more • 5- Over time, the ones with the helpful variations more up more of the population

  9. Populations, Variations, & Adaptations! Evolution requires variation. If there is no variation in a population, it cannot change. • A variation is an inherited trait that makes an individual different from other members of it’s species…it could be a permanent change or a mutation. • Example: Shape of your hairline • Some populations have more variation than others; the more variation, the healthier the population • Florida Panthers have very little variation in the genes in their population and are now unable to breed.

  10. Changes to populations • Mutations: a change in the genes of an organism that can be passed on to offspring • Adaptations: a variation that makes an organism better suited to its environment • Adapt and Overcome! • Color, shape, behavior, or • chemical makeup Adaptations & Natural Selection

  11. Why? • Changes in the sources of Genes • Geographic Isolation

  12. Mechanisms for Evolution

  13. How fast does Evolution happen? • There are two theories (and both might be right): • Gradualism: Darwin’s Idea: Evolution moves slowly and changes happen a little at a time to make new species; Example: The camel…fossils show this • Punctuated Equilibrium: Evolution moves quickly when there are changes in the environment that can cause many new mutations; Example: from Raccoon to Brown Bear pg. 498; fossils also show this; bacteria

  14. How do you get a new species? • Any time you have a population that becomes separated from the main group and no longer breeds with the main group it is a new species • Ex. Deer separated by a glacier • Ex. Florida Panthers and the Cougar

  15. Prove it! • Clues from Fossils • Scientists learn about the past by studying fossils • The relative date of a fossil can be estimated from the ages of rocks in nearby layers • The fossil record has gaps which may be filled in later • Homologous structures, similar embryos, or vestigial structures SHOW evolutionary relationships • Evolutionary relationships among organisms can be inferred from DNA comparisons

  16. PROVE IT! • Embryology: studies embryos and their development • Homologous structures: many animals share similar characteristics • Human arms, bat wings, dog forelimbs, dolphin flippers all have the same bones • Vestigial structures: body parts that do not seem to have a use but may have been useful in an ancestor • Muscles around the ear • Little toe

  17. Embryology

  18. Homologous Structures

  19. Vestigial Structures

  20. Home Learning • Book pg. 499 #1-5 • FCAT Practice (Book) pgs.518-519

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