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Transcript
Date: March 30th, 2017- period 1 Aim # 63: How does evolution occur by natural selection? Do Now: Please take out last night’s homework “Phylogenetic Tree” HW: 1)Daily Review of class notes. 2)Castle Learning due Friday 3)Quarterly Exam next Tuesday 4/4 Date: March 30th, 2017- period 5 Aim # 63: How does evolution occur by natural selection? Do Now: Please take out last night’s homework “Phylogenetic Tree” HW: 1)Daily Review of class notes. 2)Castle Learning due Friday 3)Quarterly Exam next Wednesday 4/4 Aim #63: How does evolution occur by natural selection? 1) How Does Evolution Occur? • EVOLUTION is a slow change in a species over time. • Evolution occurs by a process called NATURAL SELECTION. Read this cartoon, what do you think NATURAL SELECTION is? Lamarck’s theory of Evolution Lamarck believed that by the selective USE or DISUSE of characteristics, organisms lost or acquired certain traits that would be passed on to the offspring. 2) Charles Darwin • Considered the “father” of evolution. • Charles Darwin traveled to the Galapagos island, an uninhabited environment, where he studied evolution (Darwin’s Finches) Brain Pop: Charles Darwin ~ 4 minutes https://www.brainpop.com/science/famoussc ientists/charlesdarwin/ 3) Natural Selection • NATURAL SELECTION is the KEY to Darwin’s theory. • According to this theory, evolution is controlled by NATURE. Only the organisms that are able to SURVIVE and REPRODUCE will pass on their genes. 4) Natural Selection vs. Artificial Selection People select the desirable traits that will appear in the Offspring. Environment selects the desirable traits that will appear in the offspring. 5) Conditions that are vital to Evolution: • Overproduction • Variation • Struggle For Survival • Best Adapted To Survive • Darwin did NOT have knowledge of the genetic basis of inheritance a) Overproduction • More offspring are produced than can survive (most die young). Overproduction leads to • Organisms COMPETITION!! such as bacteria, fish, insects, and rabbits have high reproductive rates because the chance that their young will survive is minimal. b) Variation • Variation: Individuals have differences in their appearance, structure, or genes. • Source of variation: + = – Sexual Reproduction (sperm + egg) – Meiosis (Independent Assortment & Crossing Over) – Mutation (Change in DNA) • Mutations change the base sequence of DNA. • Many mutations are HARMFUL, but some can help the organism SURVIVE. c) Best Adapted To Survive • The ENVIRONMENT chooses which traits have adaptive value. • An individual that has traits favorable in a certain environment will live to reproduce and pass on those traits, others will die out. Adaptive Value • Adaptive Value: a change that produces a trait that helps an organism survive. -Example: Camouflage • If all the members of a species were the same then an environmental change would wipe out the entire species. VARIATION increases the chance that some members of a species will survive. d) Struggle For Survival • “Survival of the fittest” • Only those BEST suited will survive because of competition for finite (limited) resources (oxygen, water, food, and shelter) 6) Conditions that lead to Evolution: Activity: • You are a naturalist who traveled to the Galapagos Islands. The following are excerpts from field notes. Choose a proper heading for each of the notes • Use these choices: overproduction, survival of the fittest, competition, variation. Overproduction • Female finches found on the Galapagos Islands lay enormous numbers of eggs Competition • These finches fight for a particular species of insect that inhabits the small holes found in the tree bark Survival of the fittest • The finches with the long beaks survive and produce greater numbers of offspring with long beaks Variation • Some finches’ beaks are long, some are short. The finches with long beaks are better adapted to remove the insects from the bark. Date: March 30th, 2017- period 1 Aim # 63: How does evolution occur by natural selection? Do Now: Please take out last night’s homework “Phylogenetic Tree” HW: 1)Daily Review of class notes. 2)Castle Learning due Friday 3)Quarterly Exam next Tuesday 4/4 Date: March 30th, 2017- period 5 Aim # 63: How does evolution occur by natural selection? Do Now: Please take out last night’s homework “Phylogenetic Tree” HW: 1)Daily Review of class notes. 2)Castle Learning due Friday 3)Quarterly Exam next Wednesday 4/4 Brain Pop: Natural Selection ~3 minutes https://www.brainpop.com/science/cellularlif eandgenetics/naturalselection/ 7) Patterns Of Change Species with SHORT reproductive cycles that produce MANY offspring tend to evolve more quickly than species with LONG life spans and FEW offspring. Types: 1) Gradualism – evolution occurs steadily through time (Slow & Continuous) . 2) Punctuated Equilibrium- species stay the same for long periods of time and then change rapidly. Gradualism Punctuated Equilibrium 8) Examples of Natural Selection • Industrial Melanism • Antibiotic / Pesticide Resistance Antibiotic Resistance Ex: Punctuated Equlibrium • When bacteria are exposed to an antibiotic there is a chance that a few will have a gene that makes them resistant. • The bacteria WITHOUT the resistance will be killed, while those that are RESISTANT will survive and pass on their genes for antibiotic resistance. The antibiotic is the selecting agent Resistant Bacteria Antibiotic X 9) Why should we be concerned about antibiotic overuse? Why does evolution matter now? http://www.pbs.org/wgbh/evolution/educators/teachstuds/svideos.html https://www.youtube.com/watch?v=pc_Tx1h3qGc Pesticide Resistance Insect A- Has resistance to A Insect B- Has resistance to B Insect C- Has resistance to C • What would happen to the population if insecticide A were sprayed on the field? The pesticide selected only those flies that were resistant to pesticide A to survive. In other words, some insects had a MUTATION that allowed them to survive the presence of the insecticide. These insects were then able to reproduce and pass their mutation into the next generation. Extinction • The disappearance of an entire species (ex. Dinosaurs) • It can be caused by temperature changes, pollution, or landscape changes. Practice Question a. Identify one concept being represented in the cartoon. b. Briefly explain the concept you identified Time Permitting Supplemental Information Examples of Organisms that are Best Adapted to Survive A cryptic frog - This species has developed a coloring, texture and form that are similar to the leaves found in its environment Disruptive Coloration • Stripes and spots • Helps break up an animal's outline • Doesn't hide animals presencemisrepresents it Counter Shading-Top and Bottom Desert horned lizard on a sandy river bed San Diego Katydids Plant or Animal?... Leafy Sea Dragon • Chamaeleo pardalis, a chameleon species found in the forests of Madagascar • Chameleons can produce a wide range of colors and patterns on their skin A Von Höhnel’s chameleon turns bark-like in Kenya. •As the seasons change, the Arctic fox changes the color of its coat. •In the spring and summer, it has a dark coat, to match the brown dirt in its environment. •In the fall and winter, it turns white, to match the surrounding snow. Mimicry: monarch and viceroy Milk snake and coral snake Aggressive Mimicry • evolved devices with which they mimic the prey (or potential mate) of other (usually smaller) predators. • They use these devices as lures • The angler fish (Antennarius) displays a lure resembling a small fish Warning Coloration: warns others that they may be “unpleasant to eat” (poisonous) Poison Dart Frogs