Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Natural selection wikipedia , lookup
Punctuated equilibrium wikipedia , lookup
Hologenome theory of evolution wikipedia , lookup
Theistic evolution wikipedia , lookup
The Descent of Man, and Selection in Relation to Sex wikipedia , lookup
Saltation (biology) wikipedia , lookup
Evidence of common descent wikipedia , lookup
Genetics and the Origin of Species wikipedia , lookup
Bio NOTES: Evolution Evolution = change over time = process by which modern organisms have descended from ancient organisms HMS Beagle Charles Darwin added the most to our understanding of evolution: he sailed around the world and observed many organisms he saw that many plants and animals were very well suited to their environment Darwin learned the most at the Galapagos Islands. He saw that the characteristics Charles of many animals and plants Darwin varied noticeably among the Galapagos Islands different islands. Darwin hypothesized that each organism had adaptations that allowed them to survive on their particular island. Natural Selection = individuals best suited to their environment survive and reproduce most successfully *natural selection is also known as survival of the fittest* • Fitness, the ability to survive and reproduce in a given environment, comes as a result of adaptations. • Adaptations are inherited traits that increase an organism’s chance of survival examples: thumbs, white fur in polar bears, camouflage Only the fittest organisms pass on their traits. Because of this, a species changes over time. Members of a species have variations – we now know that these differences come from mutations in DNA! We have no control over these mutations! Polar bears wouldn’t do The environment selects which variations well in the desert will be adaptations that help with survival. Geographic Isolation Geographic isolation occurs when two populations are separated by water or landforms. This geographic separation results in the formation of new species that differ slightly depending on the environment. Adaptive Radiation -- the process in which one species evolves into diverse species that live in different ways Example: Darwin’s finches on Galapagos Islands More than a dozen species evolved from a single species of finch -- each species adapted to their environment Applications of Natural Selection Pesticide and antibiotic resistance are current issues that show natural selection at work Antibiotic Resistance • some bacteria have mutations that increase their survival • these mutations cause them to be resistant to antibiotics • they can pass these traits to future offspring • this can result in Super Bacteria or Super Bugs About 70% of hospital infection-causing bacteria are resistant to at least one type of antibiotic. Always finish Some organisms are resistant to ALL of your all known antibiotics. antibiotics! Pesticide Resistance • some insects have mutations that increase their survival • these mutations cause them to be resistant to pesticides • they can pass these traits to future offspring Evidence of Evolution: 1. Fossil Record a) Fossils: preserved remains of ancient organisms b) TWO types of Fossil Dating (fossil age determination) Relative Dating • Based on sedimentary rock layers • Determines approximate, relative age of a fossil – not the exact age Surface Rock Layers Shallow = Recent Fossil Deepest = Oldest Fossil Absolute Dating • Based on the steady decay of radioactive elements • Half-Life: Time it takes half a radioactive element to decay to a new element. • Carbon-14 has a ½ life of 5,730 years. • Determines the exact age of a fossil 2. Geographic Distribution of Living Species a) The same species of animals, living in different areas, evolved based on their surroundings. 3. Shared Anatomical Structures a) Anatomical structures: body parts, ex: arms, tails, flippers • Homologous structures: similar body structures • Vertebrate: has a backbone b) Similar Anatomical Structures, in 4-limbed vertebrates, provides evidence of evolution from a common ancestor. c) Vestigial Organs: organs or limbs which have little or no use for an organism. • Human examples: tailbone, ear muscles, wisdom teeth, appendix YOU DON’T HAVE THIS SLIDE!!!! The muscles connected to the ears of a human have lost most of their mobility. Letter c in the picture indicates the undeveloped hind legs of a baleen whale. Goose Bumps in humans are a vestigial REFLEX; a reaction to stress & cold The blind mole rat has tiny eyes completely covered by a layer of skin. WHY DOES IT HAVE EYES AT ALL?? 4. Biochemical Similarities a) Biochemical Similarities: Similarities in the Amino Acid sequence (order) of proteins. b) The CLOSER an organism’s Amino Acid sequences, the more likely they are related. Organism Amino Acid Sequence Chimpanzee Serine-Valine-Leucine-Stop Human Serine-Valine-Proline-Stop Fruit Fly Serine-Lysine-Valine-Stop 5. Embryological Similarities a) The early embryo stages of all vertebrates (with a backbone) is very similar. b) The similarities: embryonic cells develop in the same order and in similar patterns in ALL vertebrates. • Common cells & tissues develop into homologous (similar) structures. Questions: Darwin 1. Who laid the foundations of the Theory of Evolution? ______ 2. What is survival of the fittest? _________________________ natural selection 3. What is a trait that increases survival? __________________ adaptation vestigial 4. What are organs that have little or no use? ______________ 5. Embryological similarities compare the ______________ embryos of vertebrates. 6. Organisms with similarities such as biochemical, embryological, & anatomical similarities are thought to have a common __________________. ancestor 7. Which type of fossil dating uses the location of the fossil in the earth to determine the fossils age? ________________ Relative Dating 8. Which type of fossil dating determines the exact age of the fossil? _______________________ Absolute Dating 9. The half-life of an element is how long it takes the element to decay to _________ half its original amount.