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Spontaneous Generation – living things could come from nonliving things PowerPoint Presentation
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Spontaneous Generation – living things could come from nonliving things

Spontaneous Generation – living things could come from nonliving things

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Spontaneous Generation – living things could come from nonliving things

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  1. Spontaneous Generation – living things could come from nonliving things • Biogenesis – all living things come from other living things

  2. Observation • Tiny wormlike maggots turned into sturdy oval cases, from which flies eventually emerge • Francesco Redi – questioned the belief that flies were generated spontaneously from rotting meat • Experimental Group – jars with nets over them that contained meat inside • Netting allowed air to enter but not flies • Control Group – uncovered jars with meat inside • Result – maggots swarmed over the meat in the open jars while the experimental remained maggot free

  3. Control Experimental A: Independent Variable - cork Experimental B: Independent Variable - net

  4. Hypothesis – microorganisms form not from air but from other microorganisms Spallanzani • Experiment – boiled broth in a flask to kill all microorganisms in it • Experimental Group – boiled then sealed flask • Control Group – boiled then left open • Result – sealed flask remained clear and free of microorganisms; open flasks became cloudy *Disagreed – heated the flasks too long, killing the “vital force” in the air inside the flask

  5. Louis Pasteur – Made a goose-neck flask that prevented solid particles from entering but allowed air – remained clear for up to a year – he broke the neck off & the broth became cloudy

  6. Fossil – trace of a long dead organism • Found in sedimentary rock – deposited by wind & water • Develop from hard body parts • Overtime hard minerals replace the tissue leaving rocklike structures • Mold – imprint in the rock in the shape of the organism • Cast – mold has been filled with hard minerals making a rocklike model

  7. Distribution of Fossils • Law of Superposition – successive layers of rock or soil were deposited on top of one another by wind or water • Lowest stratum (rock layer) is the oldest • Relative age – using law of superposition to figure out the age of one fossil compared to another

  8. Evolution is biological change over time • A species is a group of organisms that can reproduce and have fertile offspring.

  9. 10.2 Darwin’s Observations Naturalist – collect specimens and keep careful records of observations • Lamarck: Similar species descended from a common ancestor • Acquired Trait – trait not determined by genes but by experience or behavior • Believed acquired traits could be passed down

  10. 10.2 Darwin’s Observations Charles Darwin • H.M.S. Beagle • 5-year mapping and collecting expedition to South America and South Pacific

  11. 10.2 Darwin’s Observations • Variation is a difference in a physical trait. • Galápagos tortoises that live in areas with tall plants have long necks and legs. • Galápagos finches that live in areas with hard-shelled nuts have strong beaks.

  12. 10.2 Darwin’s Observations • An adaptation is a feature that allow an organism to better survive in its environment. • Adaptations can lead to genetic change in a population. • The change in genetic makeup of the population is evolution

  13. 10.2 Darwin’s Observations Darwin’s Theories • Descent with Modification – newer forms appearing in the fossil record are actually the modified descendants of older species • Natural Selection – Organisms with favorable traits survive, reproduce, and pass the variations to the next generation

  14. 10.2 Darwin’s Observations neck feathers crop tail feathers 10.3 Theory of Natural Selection 10.4 Evidence of Evolution • Artificial selection is the process by which humans select traits through breeding.

  15. 10.3 Theory of Natural Selection 10.4 Evidence of Evolution • Island species most closely resemble nearest mainland species • Populations can show variation from one island to another • Biogeography - Study of the distribution of organisms around the world. • The study of geography provides evidence of evolution.

  16. Larva Adultbarnacle Adult crab 10.3 Theory of Natural Selection 10.4 Evidence of Evolution • Identical larvae = different adult body forms • Similarites in Biochemistry: DNA, RNA, ATP • Embryos of Vertebrates and gill slits • Embryology provides evidence of evolution.

  17. Molefoot Batwing Human hand 10.3 Theory of Natural Selection 10.4 Evidence of Evolution • Homologous structures are similar in structure but different in function • Anatomy provides evidence of evolution.

  18. 10.4 Evidence of Evolution Human hand Mole foot Bat wing Fly wing 10.3 Theory of Natural Selection • Analogous structures – similar function but different structure

  19. 10.3 Theory of Natural Selection 10.4 Evidence of Evolution Vestigial structures are remnants of organs or structures that had a function in an early ancestor but no longer have a function • Ostrich wings are examples of vestigial structures

  20. 10.4 Evidence of Evolution

  21. 11.2 Natural Selection in Populations Natural selection can change the distribution of a trait in one of three ways. • Normal Distribution – Frequency is highest near the mean value (average) and decreases toward each extreme end of the range.

  22. 10.3 Theory of Natural Selection 11.2 Natural Selection in Populations • Stabilizing selection favors the intermediate (average) phenotype rather than either extremes.

  23. 10.3 Theory of Natural Selection 11.2 Natural Selection in Populations • Directional selection favors phenotypes at one extreme.

  24. 10.3 Theory of Natural Selection 11.2 Natural Selection in Populations • Disruptive selection favors both extreme phenotypes.

  25. 10.3 Theory of Natural Selection 11.6 Patterns in Evolution • Convergent evolution – Change toward similar characteristics in unrelated species. • Different species adapt to similar environments. • Ex: Aquatic organisms

  26. kit fox red fox ancestor 10.3 Theory of Natural Selection 11.6 Patterns in Evolution • Divergent evolution – 2 or more related populations become more dissimilar. • Response to different environments

  27. 10.3 Theory of Natural Selection 11.6 Patterns in Evolution Coevolution – change of 2 or more species in close association with each • occur in beneficial and competitive relationships.

  28. 10.3 Theory of Natural Selection 11.6 Patterns in Evolution Species can become extinct. • Extinction is the elimination of a species from Earth.

  29. 10.3 Theory of Natural Selection 11.6 Patterns in Evolution • destroy many species at global level • thought to be caused by catastrophic events • at least five mass extinctions in last 600 million years • Mass extinctions are rare

  30. 10.4 Evidence of Evolution 11.6 Patterns in Evolution • Adaptive radiation – The diversification of one ancestral species into many species. • descendent species usually adapted to wide range ofenvironments

  31. Punctuated Equilibrium • A repeating pattern in the history of life • Reflected in the fossil record • Shows bursts of evolutionary activity that are followed by long periods of stability.