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Evolution

Evolution. BIG Ideas in Biology. 10. Evolution is the result of many random processes selecting for the survival and reproduction of a population. THEORY. DISCLAIMER!!!!. Quick Reminder…Just Listen Don’t Write: Theory VS. Law Theory : well tested, proven hypothesis… Law :

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Evolution

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  1. Evolution

  2. BIG Ideas in Biology 10. Evolution is the result of many random processes selecting for the survival and reproduction of a population

  3. THEORY

  4. DISCLAIMER!!!! Quick Reminder…Just Listen Don’t Write: Theory VS. Law • Theory: • well tested, proven hypothesis… • Law: • a theory that can withstand years and years of testing and is still true… • THEORY OF EVOLUTION • Countless other THEORIES about the beginning of life…HOWEVER…in BIOLOGY I we EXPLORE the THEORY of EVOLUTION

  5. Evolution=How we came into existence • How we related to those in the past • Driving force of evolution = natural selection

  6. Natural Selection“Survival of the Fittest”!!! • Theory that organisms with certain favorable traits are better able to successfully survive and thus pass these favorable traits onto their offspring when they reproduce • Example: White hares and Brown hares live in the arctic. White hare population is much higher…

  7. Natural Selection

  8. BIG Ideas in Biology 9. DNA segments contain information for the production of proteins necessary for growth and function in cells

  9. Trait ****REMEMBER HOW HEREDITY WORKS!!!**** Protein

  10. Allele Normal smile • Alternative form of a gene for each variation of a trait • Ex: S or s = type of smile Goofy smile Ss ss SS

  11. Genotype • Genetic makeup (genes) of an organism determined by a pair of alleles • Ex: Mrs. Red and her son both have ss genotype for their big goofy smile Normal smile Goofy smile Ss ss SS

  12. Phenotype Trait • Observable characteristics (trait) • Ex: Big Goofy Smile, blue eyes, brown hair

  13. Gene Pool • Total genes (alelles) in a population at any one time What process affects the alelles in the gene pool? Natural selection!!!!

  14. Making of Fittest – Natural Selection and Adaptation 10: 24

  15. Mutation: Changes in DNA Sequence • Another driving force but it is RANDOM • Mutations which alter DNA, alter Proteins then Traits • Most mutations are evolutionary NEUTRAL Trait DNA Unit

  16. Foundation to the Theory • Geology and Earth’s History • Earth is almost 5 billion years old!!! • Young Earth was like Mars and Venus • Life forms ~ 3.8 bya Ex 1st Life: Bacteria & Blue-Green Algae

  17. Endosymbiotic Theory: Theory that cell parts (organelles) originated as separate organisms Break it down: • Endo – Inside • Symbiotic – Close interaction between two species Chloroplast found in plant cells

  18. EndosymbioticThoery Chloroplast found in plant cells Looks like algae that lives alone…

  19. Endosymbiotic Theory Cell Transport Unit

  20. Whose Theory? • Charles Darwin • 5 year voyage on H.M.S. Beagle • December 1831

  21. Charles Darwin • Galapagos Islands: • Finches

  22. Darwin thought… • “Well…IF these finches descended from a common stock THEN natural species can descend from a common stock…similar to all of the FINCHES” • In simpler terms: present day species descended from ancestral species • Life is connected like a FAMILY TREE hypothesis

  23. Phylogenic/genetic Tree:Based on Evidence of Evolution TREE OF LIFE!!!!!

  24. Bio BIG Idea #1

  25. Evidence For Evolution • Adaptations • Fossils • Comparative Anatomy • Comparative Embryology • Comparative Biochemistry • Biogeography

  26. 1. Adaptations • Features suited to a particular environment that allow the organism to survive Ex: Eastern Africa-increase body surface Inuit-excess body fat

  27. 2. Fossil Evidence • Once living remains of organisms • Limited by: • Type of material preserved • Bone, shell, impressions, amber • Incomplete record • Easily disrupted

  28. FOSSILS Environments in every area have changed drastically • Seashell fossils in PA • PA is NOT a beach…

  29. 3. Comparative Anatomy • Homologous Structures: • Similar features • Common ancestor • DIFFERENT FUNCTION

  30. 3. Comparative Anatomy • Analogous Structures: • Look similar but are different • Different ancestor • SAME FUNCTION

  31. Homologous vs. Analogous

  32. Vestigial Structures • Vestigial Structures: • Serves NO function • Useful to ancestors…not useful for modern organism

  33. Comparative Embryology- ALL Vertebrates have a common ancestor

  34. Percent of Amino Acids That Are Identical to the Amino Acids in a Human Hemoglobin Polypeptide Species 100% Human Rhesus monkey 95% Mouse 87% Chicken 69% Frog 54% 14% Figure 22.16 Lamprey 5.Comparative Biochemistry • Similar DNA sequences… • …similar genes… • ….code for similar traits! • In closely related species

  35. 6. Biogeography Geological theory: (plate tectonics) Continental masses were one land mass that explains closely related species have common ancestors on now separated continents

  36. Other Evolution Info: • Speciation: process by which new distinct species evolve • Occurs when 1 population is isolated from another population (geography/reproduction)

  37. DIVERGENT EVOLUTION- two or more species originate from same species and become increasingly different over time

  38. CONVERGENT EVOLUTION – development of similar structures in organisms that do not share recent common ancestor Adaptation to Environment

  39. a)divergent b)convergent

  40. Gradual Evolution vs. Punctuated Evolution

  41. CWCW CRCR CRCR CRCR CRCR Only 2 of 10 plants leave offspring Only 5 of 10 plants leave offspring CRCR CRCW CRCR CRCW CRCR CRCR CWCW CRCR CWCW CRCR CRCW CRCW CRCR CRCR CRCR CWCW CRCR CRCW CRCR CRCR CRCR CRCR CRCW CRCW CRCW Generation 2 p = 0.5 q = 0.5 Generation 3 p = 1.0 q = 0.0 Generation 1 p (frequency of CR) = 0.7 q (frequency of CW) = 0.3 Figure 23.7 Genetic Drift • Describes how allele frequencies can fluctuate unpredictably from one generation to the next • Tends to reduce genetic variation

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