Phylogenetics: Evolution
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PHylogenetics: Evolution
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Phylogenetics: Evolution
- 2. Fossil- remains or imprints 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 FOSSILS FORM? 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
- 6. http://www.ucmp.berkeley.edu/fo srec/McKinney.html Which rocks are oldest? Most recent? 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
- 12. Evidence of Common Ancestor
- 15. Vistigial Structures: structures that have lost their ancestral use in a species but have been retained through evolution
- 18. Macromolecules • Compare amino acid or DNA sequences between species • Counting the number of mutations • More differences = Further apart in evolution
- 19. CHARLES DARWIN
- 20. A HISTORY LESSON: Charles Darwin: 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 plant and 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 plants and 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 characteristics that 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 wrote An 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 traits to 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 a geologist, 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 forms are modified forms of older ones DARWIN’S THEORY: Descent with Modification
- 30. Natural Selection •Some traits are 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 Selection process 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: #14 Natural Selection (12 min)
- 35. In any population… There is genetic variation. An adaptation is any characteristic that increases fitness. Fitness is the ability to survive and reproduce.
- 36. A heritable characteristic is 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 normal variation 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 in the allele frequency in a population
- 39. Natural Selection If a trait increases 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 and Sexual 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 Recombination in sexual reproduction
- 42. GeneticDrift Random changes in allele frequency
- 43. GeneticDrift Physical separation Genetic separation A population is split and two genetically different populations form.
- 46. •Speciation formation of a 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 Punctuated Speciation • Sudden shift (change) • Fossils suggest this is more common Gradual Speciation • Stable rate
- 52. •Tusk-less elephants are proving 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, soot covered 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 flu shots not work each year •Antibiotic resistance EXAMPLES: virusBacteria: staph www.healthheap.com/tag/bacteria http://health.howstuffworks.com/medicine/mo dern/light-virus.htm
- 57. Flu Virus Resistance to Antiviral Drugs
- 58. Each year, the flu vaccine protects against only a few strains. Flu Vaccines and Evolution
- 59. Vaccines help us make antibodies and build immunity to diseases.
- 60. Our immune system has evolved to build antibodies against any disease.
- 61. Evidence of Evolution • Fossil Record • Homologous Structures • Analogous Structures • Vestigal Structures • Macromolecules • Modern examples