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EVOLUTION: CHANGE OVER TIME. In Biology…evolution refers to:. Changes in SPECIES over time A species is a group of similar organisms that can breed and produce fertile offspring. CHARLES DARWIN. Proposed the theory of evolution

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EVOLUTION: CHANGE OVER TIME


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    1. EVOLUTION:CHANGE OVER TIME

    2. In Biology…evolution refers to: • Changes in SPECIES over time • A species is a group of similar organisms that can breed and produce fertile offspring.

    3. CHARLES DARWIN • Proposed the theory of evolution • He made observations on his voyage around the world…collecting evidence to develop his theory. • On the Origin of Species (Book—1859)

    4. IMPORTANT OBSERVATIONS • Noticed a great diversity among a number of species. • Plants and animals were suited to the environment in which they lived. • Different species lived in similar ecosystems.

    5. FOSSIL RECORD • A fossil is the preserved remains of ancient organisms. • Some looked like modern animals • Some looked different than any modern organisms

    6. The Galapagos Islands • Very close to one another…but their climates differed greatly- • Low elevation: very dry, hot, sparsely vegetated • Higher elevation: a lot of rainfall, more diverse plant life

    7. The Galapagos Islands

    8. Galapagos Tortoises Saddleback Domed

    9. FITNESS • Organisms compete to survive and reproduce • Organisms best suited to their environments are most likely to succeed

    10. FITNESS is attributed to: • Adaptations • Any inherited trait that increases an organism’s chance of survival

    11. NATURAL SELECTION • SURVIVAL OF THE FITTEST— • Those that are able to survive will be able to reproduce and pass on their adaptations to the next generation

    12. NATURAL SELECTION (4 Principles) • VARIATION EXISTS WITHIN POPULATIONS

    13. NATURAL SELECTION (4 Principles) 2. ORGANISMS COMPETE FOR LIMITED NATURAL RESOURCES

    14. NATURAL SELECTION (4 Principles) 3. ORGANISMS PRODUCE MORE OFFSPRING THAN CAN SURVIVE

    15. NATURAL SELECTION (4 Principles) 4. INDIVIDUALS WITH VARIATIONS SUITABLE FOR THEIR HABITAT SURVIVE AND REPRODUCE

    16. FINCHES

    17. TWO WAYS EVOLUTION MAY OCCUR • GRADUALISM • Occurs over a long period of time • PUNCTUATEDEQUILIBRIUM • Occurs in spurts • Caused by: • Random change in DNA • Sudden environmental changes

    18. CONTINUITY OF LIFE FORMS OVER TIME

    19. TWO FORMS OF EVOLUTION • MACROEVOLUTION • changes that occur on the tree of life • MICROEVOLUTION • Changes that occur within a population • (group of individuals of the same species living in the same area)

    20. Genetic variation is caused by changes in genetic frequency—there are 5 forces of genetic change: 1. Natural Selection 2. Mutations 3. Gene flow 4. Genetic drift 5. Nonrandom mating

    21. MUTATIONS • Change in DNA sequence • Deletion • Inversion • Translocation • Duplication …however…

    22. MUTATIONS • To affect evolution, mutations must be passed on from one generation to the next… • Only mutations in gametes can be passed on… • …to affect evolution!

    23. GENE FLOW • Genes from one population are introduced into the gene pool of another • GENE POOL: combined genetic info of all members • Basically affected by migration

    24. GENETIC DRIFT • Changing the allele frequency • Some individuals may have more offspring than others

    25. BOTTLENECK EFFECT • A form of genetic drift • Sudden and severe decrease in a population size that results from natural disaster, predation, or habitat reduction.

    26. Bottleneck Effect

    27. FOUNDER’S EFFECT • A form of genetic drift • occurs when a new isolated population is founded by a small number of individuals possessing limited genetic variation (relative to the larger population from which they have migrated)

    28. Founder’s Effect http://upload.wikimedia.org/wikipedia/commons/2/24/Founder_effect-anim.gif

    29. NONRANDOM MATING • Not all individuals have the opportunity to contribute their genes to the next generation (decreasing their allele frequency) • Courtship rituals, pecking orders, breeding territories

    30. MECHANISMS OF CHANGE MUTATIONS GENE FLOW (MIGRATION) GENETIC DRIFT NATURAL SELECTION

    31. NATURAL SELECTION

    32. Peppered Moths

    33. Number of current classified species = • 2.1 million • Organisms that are not capable of breeding with each other belong to a different species

    34. What causes new species to form? • The evolutionary process called SPECIATION forms new species. • New species evolve in 3 ways….

    35. 1. GEOGRAPHIC ISOLATION • A population is divided by a barrier • Two geographically isolated populations can no longer reach each other to breed • Natural selection on each side causes the populations to become genetically different

    36. 1. GEOGRAPHIC ISOLATION

    37. 2. PARAPATRIC SPECIATION • Two neighboring populations • One hot and dry • One cooler and wet • Natural selection favors different adaptations in area • Causing genetic differences • At the boundary—individuals breed and make hybrids…

    38. 2. PARAPATRIC SPECIATION

    39. 3. BEHAVIORAL ISOLATION • Differences among individuals cause them to choose different mates. • Continual, nonrandom mating causes individuals to become genetically different.

    40. 3. BEHAVIORAL ISOLATION

    41. EXTINCTION • The death of all individuals within a species. • No longer able to survive changing environmental conditions -or- • No longer able to compete

    42. EVIDENCE OF EVOLUTION

    43. FIELD OF PALENTOLOGY • Fossils are “dead remains” that prove organisms existed • Give information about the age of organism (dating) • PROBLEMS?? • Still missing links • Haven’t found all remains

    44. FIELD OF BIOGEOGRAPHY • Geographic distribution of organisms • Grouped according to the needs of habitats, resources • Similar organisms will arise in the same geographic location

    45. Rhea (South America) Emu (Australia) Ostrich (Africa)

    46. FIELD OF BIOCHEMISTRY • All living things have DNA • Organisms that show close relationships have similar protein and DNA structures

    47. BIOCHEMISTRY

    48. BIOCHEMISTRY