1 / 58

Campbell & reece : Chapter 22

Campbell & reece : Chapter 22. Descent with Modification: A Darwinian View of Life . 3 key observations about life. Striking ways organisms are suited to their environment Unity of living things(so many common features) Rich diversity of life. EVOLUTION. DESCENT WITH MODIFICATION.

trevor
Download Presentation

Campbell & reece : Chapter 22

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Campbell & reece:Chapter 22 Descent with Modification: A Darwinian View of Life

  2. 3 key observations about life Striking ways organisms are suited to their environment Unity of living things(so many common features) Rich diversity of life

  3. EVOLUTION DESCENT WITH MODIFICATION

  4. EVOLUTION A CHANGE in the GENETIC COMPOSITION of a POPULATION from GENERATION to GENERATION

  5. EVOLUTION • CAN BE VIEWED IN 2 WAYS • A PATTERN • OBSERVATIONS FROM NATURAL WORLD • A PROCESS • MECHANISMS THAT PRODUCED THE OBSERVED PATTERNS

  6. ARISTOTLE(384 – 322 BCE) • DID NOT BELIEVE ORGANISMS CHANGED OVER TIME (some Greeks did) • Viewed organisms as fixed: could be arranged on ladder from least complex  most complex

  7. SCALAE NATURAE

  8. CAROLUS LINNAEUS(1701 – 1778) • DEVELOPED BINOMIAL NOMENCLATURE • WITH A “NESTED” CLASSIFICATION SYSTEM

  9. LINNAEUS CLASSIFICATIONSYSTEM

  10. PALEONTOLOGY • STUDY OF FOSSILS • GEORGES CUVIER (1769 – 1832) • OLDER THE STRATUM OF SEDEMENTARY ROCK THE OLDER & MORE DISSIMILAR THE FOSSILS WERE TO CURRENT LIFE • NEW SPECIES APPEARED, SOME DISAPPEARED

  11. GEORGES CUVIER CATASTOPHISM: EVENTS IN THE PAST OCCURRED SUDDENLY & WERE CAUSED BY DIFFERENT MECHANISMS THAN SEEN NOW

  12. JAMES HUTTON(1726 – 1797) • Scottish Geologist • Explain geologic features by gradual mechanisms still going on now

  13. CHARLES LYELL(1797 – 1875) • Principle of Uniformitarianism • Mechanisms of change are constant over time

  14. Hutton & Lyell’s ideas influenced Darwin • Both indicated Earth had to be much older than previously believed • Darwin reasoned: slow & subtle processes could produce biological changes

  15. Lamarck’s Hypothesis of Evolution • 1st to propose mechanism of evolution • Parts of body used the most become larger, stronger; parts not used deteriorate • Inheritance of Acquired Traits

  16. LAMARCK(1744 – 1829) • EVOLUTION HAPPENS BECAUSE ORGANISMS INATELY WANT TO BECOME MORE COMPLEX

  17. CHARLES DARWIN(1809 -1882)

  18. VOYAGE of the BEAGLE1831 - 1836

  19. Darwin’s Observations • Plants & animals in temperate zones of SA closely resembled plants & animals of temperate regions of Europe • Fossils in SA resembled living organisms in SA

  20. GALPÁGOS

  21. Darwin’s Observations: Descent with Modification • Took note of many adaptations  saw adaptations & the origin of a new species as closely related processes

  22. Darwin’s Finches • 14 different species each clearly adapted to a specific niche • all similar to finches on mainland SA (common ancestor)

  23. Darwin’s Theory • Proposed that natural selection over long periods of time could cause an ancestral species to give rise to 2 or more descendant species

  24. Natural Selection: a process in which individuals with certain inherited traits tend to survive & reproduce at higher rates than other individuals without those traits

  25. The Origin of the Species by Means of Natural Selection • Darwin provided massive amounts of evidence that descent with modification by natural selection explains : • Unity of Life • Diversity of Life • Match between Organisms & their Environment

  26. Natural selection Artificial selection

  27. Darwin’s Reasoning Observations Inferences • There are variations of traits in populations • Individual with variations that are favorable will leave more offspring than one without those traits

  28. Darwin’s Reasoning Observation inference 2. Species produce more offspring than can survive 2. overpopulation leads to competition, those with traits that will help them survive  reproduce more  passing along favorable traits

  29. SURVIVAL of the FITTEST

  30. Over time natural selection increases the match between organisms & their environment

  31. When the environment changes natural selection may result in adaptations that give rise to a new species

  32. Natural Selection in response to invasive species Balloon vine Goldenrain Tree

  33. SOAPBERRY BUGS • SEEDS BURIED DEEPER IN PODS OF NATIVE PLANT, BALLOON VINE • BUGS THAT FEED ON INVASIVE GOLDENRAIN PODS NOW HAVE SHORTER BEAKS

  34. CONCLUSION • CHANGING THE ENVIRONMENT CAN RESULT IN EVOLUTION BY NATURAL SELECTION FOR MATCHING BEAK SIZE

  35. DRUG-RESISTANTBACTERIA • Normal for 1 out of 3 people to have Staph aureus on skin • MRSA • (methicillin-resistant staph aureus) • Can be fatal

  36. Developing drug-resistance

  37. Rise of MRSA hospital acquired infections 1993 - 2005

  38. From study done in Atlanta area in 2006

  39. Soapberry bug & MRSA both examples of • 1. natural selection does not “create” it “selects” for variants already present in population • 2. natural selection depends on time & place

  40. HOMOLOGY • SIMILARITY RESULTING FROM COMMON ANCESTORS

  41. Homologous Structures: Embryology • Similarities in early stages of development suggest common ancestry • At some point in development all vertebrates have a tail

  42. VESTIGIAL STRUCTURES • REMNANTS OF FEATURES THAT WERE IMPORTANT IN EVOLUTIONARY ANCESTOR

  43. Molecular Homologies • All life forms use DNA & RNA • Genetic code is universal • Some human genes code for exact same protein as bacterial gene • +/- have same function • Some organisms carry “vestigial genes”

  44. Evolutionary Tree • Can organize organisms with shared characteristics in nested groups • Deepest layer all living things share • Each successive smaller group have their own unique homologies

  45. Evolutionary Trees • are hypotheses that summarize our current understanding of patterns of descent

More Related