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Phylogenetics: Evolution
This document discusses evidence that supports the theory of evolution through natural selection. It provides examples of homologous structures that indicate common ancestry, such as the bones in the human arm and horse leg. Modern examples, like the evolution of pesticide resistance in insects and antibiotic resistance in bacteria, illustrate evolution in action. The document also explains how the fossil record, analogous structures, vestigial structures, and comparisons of macromolecules across species serve as lines of evidence for evolution through natural selection over generations.
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Phylogenetics: Evolution
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- 2. Fossil- remains orimprints of once-living organisms found in layers of rock Fossil record- historical timeline based on fossils found in Earth’s crust CONNECTING: * Fossils are hard to form & find (esp. on land) * There are blank places in our record * Disturbances in the strata/rock record 1858: 1st almost complete dino skeleton found
- 3. HOW DO FOSSILSFORM? Petrified Fossil: fossil completely turns to stone 1. Organism dies in right place: sediments cover (lake bottom, mud flats) 2. Soft parts decay or are eaten 3. Sediments layer; pressure causes sediments to fuse together, encasing organism like a shell 4. Ground water with minerals seeps around the bones; minerals left in bone spaces & may replace whole bone 5. Rock layer needs uplifted & layers above eroded for fossil to be DISCOVERED
- 4. Scientists use logic& carbon dating to sequence & draw connections among fossil findings all over the world What do scientists do? Compare skeletal structure of fossils and animals alive today Date the fossils Put into logical order as new fossils are found Compare DNA and other macromolecules in animals alive today
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- 6. http://www.ucmp.berkeley.edu/fo srec/McKinney.html Which rocks are oldest? Mostrecent? Which fossils would be oldest? Most recent? A: Most recent rocks- Those on top & those cutting through others
- 7. SIMILAR STRUCTURE? =TWO REASONS: Homologous structures same structure, different function; evolved from common ancestor human arm, horse leg, bird wing Analogous structures performs same function; evolved from different origins (independently) WINGS: birds, bats, butterflies ADVANCE
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- 12. Evidence of CommonAncestor
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- 15. Vistigial Structures: structuresthat have lost their ancestral use in a species but have been retained through evolution
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- 18. Macromolecules • Compare aminoacid or DNA sequences between species • Counting the number of mutations • More differences = Further apart in evolution
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- 20. A HISTORY LESSON: CharlesDarwin: 1809- 1882, naturalist who voyaged on the HMS Beagle as a young man & is know as the founder of the idea of natural selection later in life… …really a THINKER, who put together the ideas of many contemporaries.
- 21. He collected plantand animal samples, esp. off the coast of Ecuador in the Galapagos Islands http://upload.wikimedia.org/wikipedia/commons/4/42/Voyage_of_the_Beagle.jpg VIDEO: Galapag os Island 3 min
- 22. •Noticed that plantsand animals on the islands looked similar to those in Ecuador with minor variations (differences) •This got him to thinking The beaks were suited to what the birds ate on each island! : www.biology- online.org/2/11_natural_selection.htm
- 23. •traits- specific characteristicsthat can be passed from parent to offspring through genes •An example: •Selective breeding- humans select desired traits in plant/animal and breed it for more (150+ breeds of dogs)
- 24. •Thomas Malthus wroteAn Essay on the Principle of Population: an essay that said humans had the potential to reproduce too fast for the food supply •Said that human populations are LIMITED to choices humans make & available resources/disease
- 25. •Darwin thought then,that populations of all species were limited: •LIMITING FACTORS: •Starvation •Disease •Competition •Predation •So, only a limited number survive to reproduce What was special about the survivors?
- 26. •Offspring inherit traitsto survive in the environment •Darwin thought species could evolve over time ***MOST geologists at that time thought the Earth wasn’t old enough for that What was special about the survivors? VIDEO: Evolution Adaptation 2 min
- 27. •Charles Lyell ageologist, wrote Principles of Geology; said Earth was formed by natural processes over a LONG period of time •Darwin struggled with ideas for 20 yrs •Alfred Russell Wallace 1858 a naturalist, writing to Darwin; shared the same ideas •1859 Darwin published his ideas: On the Origin of Species by Means of Natural Selection
- 28. Common ancestors •New formsare modified forms of older ones DARWIN’S THEORY: Descent with Modification
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- 30. Natural Selection •Some traitsare better suited to the environment than others. •Competition for resources leads to Natural Selection of fittest traits. DARWIN’S THEORY: Modification by Natural Selection
- 31. • Natural Selectionprocess by which individuals are better adapted to survive and reproduce than others & pass along those genes to offspring • Theory lacked some evidence, but later scientists filled in the holes 1. Overproduction: producing more potential babies than will survive 2. Inherited variation: each individual is slightly different, not exactly like parent 3. Struggle to survive: some will die, disease, competition, predators, but ALL won’t 4. Successful reproduction: those most adapted to environment will have offspring with traits like them VIDEO 1 Evolution of organic life 2min VIDEO 2 Natural Selection 2 min
- 32. CC VIDEO: #14Natural Selection (12 min)
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- 35. In any population… Thereis genetic variation. An adaptation is any characteristic that increases fitness. Fitness is the ability to survive and reproduce.
- 36. A heritable characteristicis influenced by genes and passed from parents to offspring. Heritable adaptive characteristics become more common in a population over many generations. This process is called evolution by natural selection.
- 37. Populations have normalvariation caused by mutations in an allele. The allele with the mutation is inherited. Over time, more individuals have the allele with the mutation Therefore, populations change over time.
- 38. Evolution A change inthe allele frequency in a population
- 39. Natural Selection If a traitincreases reproductive success AND is inherited, then more offspring will have the trait. Populations adapt to their environment as more individuals have that trait. Individuals do not adapt.
- 40. Evolution • Mutations andSexual Reproduction Genetic Variation • Random changes in allele frequencyGenetic Drift • Movement of allelesMigration • Some organisms survive and reproduce better than others Natural Selection
- 41. Genetic Variation Genetic Recombinationin sexual reproduction
- 42. GeneticDrift Random changes inallele frequency
- 43. GeneticDrift Physical separation Genetic separation A population is split and two genetically different populations form.
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- 46. •Speciation formation ofa new species; species become so different, they can’t mate any longer •Separation new adaptation can’t mate when go back to original population SEPARATORS: Canyon Mountain range Lake humans Textbook: HoltScience&Technology6thGrade CC VIDEO: Speciation of Ligers & Men (12 min)
- 47. Rates of Speciation PunctuatedSpeciation • Sudden shift (change) • Fossils suggest this is more common Gradual Speciation • Stable rate
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- 52. •Tusk-less elephants areproving beneficial against poachers & are living to reproduce offspring without tusks as well EXAMPLES: African Elephant http://www.wildlife-pictures- online.com/elephant_epkp4.html HSW- LINK (elephant evoln) 4 min
- 53. •During Industrial Revolution, sootcovered the trees in Europe. White moths stood out & were eaten; black moths reproduced & white moths almost gone EXAMPLES: Peppered moth http://sisu.typepad.com/sisu/pepperedm othslichen.jpg www.amentsoc.org/about/news/0111/ http://radaractive.blogspot.com/2009/07/in-regards-to-canards- natural-selection.html
- 54. •Pesticide resistance: resistant individuals live to reproduce& pass on resistant genes. Insects produce LOTS of offspring EXAMPLES: http://www.grapes.msu.edu/images/pesticResist. gif www.grapes.msu.edu/pesticideResist.htm
- 55. •Super viruses •Same flushots not work each year •Antibiotic resistance EXAMPLES: virusBacteria: staph www.healthheap.com/tag/bacteria http://health.howstuffworks.com/medicine/mo dern/light-virus.htm
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- 57. Flu Virus Resistanceto Antiviral Drugs
- 58. Each year, the fluvaccine protects against only a few strains. Flu Vaccines and Evolution
- 59. Vaccines help usmake antibodies and build immunity to diseases.
- 60. Our immune systemhas evolved to build antibodies against any disease.
- 61. Evidence of Evolution • Fossil Record •Homologous Structures • Analogous Structures • Vestigal Structures • Macromolecules • Modern examples