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EVOLUTION

EVOLUTION. Neanderthal Modern day human Homo neanderthalensis Homo sapiens. If evolution was condensed into 1 day…. yrs. yrs. yrs. yrs. Evolution-

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EVOLUTION

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  1. EVOLUTION Neanderthal Modern day human Homo neanderthalensis Homo sapiens

  2. If evolution was condensed into 1 day….. yrs. yrs. yrs. yrs.

  3. Evolution- The theory of evolution suggests that organisms that exist today evolved from earlier, more primitive forms over a long period of time. Evidence of Evolution- 1. Fossils- shows common ancestry among organisms ~any remains or trace of a once- living organism ~found in __________________rock*, ice, tar or amber change in organisms over time “the diversity of living things as well as their unity may be the result of evolution” sedimentary *sedimentary rock is a type of rock formed from layers of particles that settled to the bottom of a body of water, often containing fossils

  4. ~the ages of rocks have been determined by ___________________ ~lower layers of rock contain _______________life forms ~upper layers of rock contain _____________________life forms radioactive dating older, simpler newer, more complex

  5. 2. Comparative Anatomy- shows common ancestry among organisms a. homologous structures- structures in various organisms that are similar in structure and origin but have different functions in each organisms ex). whale flipper, bat wing and human arm

  6. b. vestigial structures- structures that were once functional but no longer are. ex). appendix, tailbone, wisdom teeth Discover 6/04

  7. 3. Comparative Embryology- shows common ancestry among organisms When you compare vertebrate___________ embryos, at some point in development, they all have similar appearances (gill slits, tails) w/a backbone Fish Salamander Tortoise Chick Hog Cat Rabbit Human

  8. 4. Comparative Cytology- shows common ancestry among organisms ~Cytology = _____________________ ~all living things are made of cells ~all cells have similar organelles with similar functions 5. Comparative Biochemistry- shows common ancestry among organisms ~all living things contain similar compounds _________________________________ ~the closer the relationship between organisms, the greater the similarity of their chemicals (humans can use insulin from sheep and pigs!) the study of cells enzymes hormones DNA glucose

  9. Theory of Spontaneous Generation Idea that living things could arise spontaneously from things like mud, sweat, decaying meat. Redi disproved this theory. A relatively simple sketch of Redi's experiment regarding spontaneous generation. Starting from the left, the first flask is capped, and no maggots grow within it, then in the second flask flies are kept out, but the mesh allows maggots to grow within, and finally flies are allowed into the third flask where maggots grow.

  10. THEORIES OF EVOLUTION 1. Jean Baptiste Lamarck- • Theory of use and disuse- “use it or lose it”. He theorized that if you need a structure and use it , it will become more developed over time. • Likewise, if you no longer need a structure (appendix, tail) and stop using it, it will decrease in size, become non-functional or disappear. b. Theory of Acquired Characteristics- He believed that traits acquired in a lifetime are passed on to offspring (like my acquired taste for chocolate!)

  11. August Weismann- disproved Lamarck's theory of acquired characteristics. His experiment: he removed the tails of mice, mated them and all of the offspring HAD tails! Other examples that support Weismann: dog breeds with clipped tails and ears, circumcision

  12. 3. Charles Darwin- theorized that evolution occurred as a result of Natural Selection.. The main points of his theory: a. overproduction- most species produce more offspring than can survive because of limited food and space b. competition- overproduction leads to a struggle for available food, water, space and mates c. survival of the fittest- ~variations among individuals make some better adapted or more “fit ” ~the “fit” survive because they are best adapted to the environment ~(the “fit” are not necessarily the strongest) Look at these examples of “fit” organisms: leaf fish, frog, spider, ptarmagin

  13. d. natural selection- nature “selects” organisms with optimal traits (the “fittest”) to survive and be the parents of the next generation. This next generation will inherit the favorable characteristics that enabled their parents to survive & reproduce e. speciation- when a new species arises with helpful variations/adaptationsthat have accumulated over many generations An older Darwin

  14. Survival of the fittest……this tree has adapted to grow on the side of a hill (Thatcher Park, 9/05)

  15. MODERN THEORY OF EVOLUTION a. Today’s theorists accept Darwin’s ideas of natural selection, BUT Darwin’s theory DID NOT address how variations arise in a population. For example, why do some giraffes have long necks and some have short ones? The answer is from gene mutation and random recombination of genes during _________________ The same thing goes for humans. We’re all different because of mutations and combination of genes from our different parents. fertilization

  16. b. natural selection: nature has selected the fittest organisms in the following instances: ~insects that are resistant to pesticides (are fit enough to survive and reproduce) ~bacteria that are resistant to antibiotics (are fit enough to survive and reproduce). You’ve all probably been on antibiotics and have noticed that you’ve taken different brands. That’s because the bacteria build up a resistance to the old antibiotics. c. Geographic Isolation- ~small population becomes isolated (mountain range, body of water, Pangea) ~they adapt to their new environment and become so different that they can no longer interbreed with the original population ~this inability to breed with the original population is called ________________________________ ~over time , this leads to speciation:_____________________________ ex). Darwin’s finches on the Galapagos Islands reproductive isolation the development of a new species

  17. Rate of Change- there are 2 different theories on how long it takes for evolution to occur: • 1. Gradualism- evolution occurs gradually, slowly and continuously • 2. Punctuated Equilibrium- when species have long periods of stability and then have sudden, brief intervals of major change. Gradualism PunctuatedEquilibrium

  18. The Heterotroph Hypothesis...how did life begin on earth??? • primitive inorganic materials • conditions “hot, thin soup”: • gases: -NH3 (ammonia) • -CH4 (methane) • -H2 (hydrogen) • sun and lightning provided the ENERGY needed to • SYNTHESIZE materials • small organic molecules formed (sugars, amino acids) • Stanley Miller reproduced this theory in his lab • sun, lightning and energy= • SYNTHESIS

  19. Video clip, S. Miller’s expt 15 mins ****

  20. large organic molecules were formed (proteins, carbs) Sidney Fox reproduced this theory in his lab large molecules clumped together aggregates (colonies) were now present These were heterotrophic (no CO2 available) they reproduced! these aggregates are now considered ALIVE BECAUSE THEY CAN REPRODUCE no free oxygen these heterotrophs were anaerobic heterotrophs produced CO2 during respiration/fermentation photosynthesis now possible

  21. autotrophs evolved produced oxygen aerobes evolved

  22. Quick Summary Heterotrophs CO2 given off autotrophs aerobes anaer. resp photo- synthesis O2 produced

  23. (fossils, comparisons) you cannot inherit acquired characteristics (simpler) (mutation & crossing-over) survival of the fittest

  24. Pine bush, rainforest An increase in biodiversity increases the stability of an environment

  25. evolution fossils comparative biochem homologous vestigial Darwin Lamarck speciation gradualism punctuated equil. reproductive geographic spontaneous generation Origin of life aggregate O2 photosyn They were anaerobic respiration or ferm sun, lightning, radiation

  26. Notes: The Unity and Diversity of Living Things All living things have the potential to carry out life functions. This is one fact that unites living things. But, living things are not the same. There are billions of different living things. How do we tell them apart? How do we keep them organized?

  27. Biological Diversity(don’t put in notes) Edward Wilson, 1999 The total # of kinds of plants, animals and microorganisms known to science (those which have a scientific name) is about 1.4 million. But, the actual # is estimated to be between 10 and 80 million. “We don’t know even to the nearest, the amount of diversity in the world.” Out of the 1.4 million named organisms, there are approximately 750,000 insects 242,428 plants 123,151 arthropods 46,983 fungi 19,056 fish 9,048 birds 4,000 mammals

  28. Humanity is creating a radical new environment too quickly to allow species to adjust. Species need thousands of years (maybe millions) to assemble complex genetic adaptations. Most of life is consequently at risk (of extinction)” ……this is why human impact is directly related to the environment. Now, back to notes….

  29. The Diversity of Life In order to study the billions of living organisms, scientists need to have an organized system: a classification system. Taxonomy is the branch of Biology that studies classification. Hundreds of years ago, scientists classified living organisms into 2 groups called kingdoms. Plant Animal But, they kept discovering organisms (ex. mushrooms) that didn’t fit into either kingdom. Today, we use a 5 kingdom classification system: 1. Monera 2. Protista 3. Fungi 4. Plant 5. Animal

  30. But, even these groups are too broad to have an organized system so the kingdoms are broken down into smaller & smaller groups: Kingdom Phylum Class Order Family Genus Species Broadest, largest group Smallest, most specific (hint: species~specific) How do we place organisms in the proper K,P,C,O,F,G,S? We examine them and group them according to the following:

  31. 1. evolutionary relationships (did they come from the same ancestor?) 2. the presence (eukaryotic) or absence (prokaryotic) of a nuclear membrane within the cell. 3. unicellular or multicellular? 4. type of nutrition (heterotrophic or autotrophic)

  32. Kingdom Characteristics Examples Monera Protista • most primitive kingdom • lacks a nuclear membrane • (prokaryotic) • some organelles • bacteria • blue green algae • mostly unicellular • eukaryotic a. protozoa b. algae heterotrophic paramecium ameba autotrophic spirogyra

  33. Kingdom Characteristics Examples Fungi Plants mushroom yeast bread mold athlete’s foot fungus • Eukaryotic • Multicellular • Have branched filaments called rhizoids (like roots) that secrete digestive enzymes into the surface that the fungi is on. The fungi then absorb the digested material • heterotrophic see next slide • multicellular • photosynthetic • autotrophic • Bryophytes lack vascular tissue (xylem, phloem) have no true roots, stems, leaves moss b. Tracheophytes fern water lily sycamore tree do have vascular tissue and true roots, stems, leaves

  34. sponges pores hydra jellyfish • hollow body cavity • 2 cell layers planaria tapeworm liver fluke flatworms • round worms • parasitic trichina hookworm heartworm segmented worms earthworm leech

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