Evolution
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Catégorie :Category: nCreator TI-Nspire
Auteur Author: RNDMPRSN
Type : Classeur 3.0.1
Page(s) : 1
Taille Size: 15.12 Ko KB
Mis en ligne Uploaded: 26/01/2025 - 20:45:05
Uploadeur Uploader: RNDMPRSN (Profil)
Téléchargements Downloads: 3
Visibilité Visibility: Archive publique
Shortlink : http://ti-pla.net/a4478550
Type : Classeur 3.0.1
Page(s) : 1
Taille Size: 15.12 Ko KB
Mis en ligne Uploaded: 26/01/2025 - 20:45:05
Uploadeur Uploader: RNDMPRSN (Profil)
Téléchargements Downloads: 3
Visibilité Visibility: Archive publique
Shortlink : http://ti-pla.net/a4478550
Description
Fichier Nspire généré sur TI-Planet.org.
Compatible OS 3.0 et ultérieurs.
<<
What is evolution? " Characterized by a change in the genetic make-up of a population over time. " Supported by multiple lines of evidence. Early Ideas " Earth is young " Earth is unchanging James Hutton (1788) ºProposed the theory of Gradualism ºEarth was formed entirely by slow-moving processes, such as erosion and sedimentation, and that these slow forces continue to shape the landscape. ºGeorge Cuvier (1796) ºPaleontology: Found that fossils were dissimilar to modern life ºTheory of Catastrophism ºMajor changes to Earths crust were due to catastrophic vs gradual changes. ºSpecies can become extinct ºSpecies can change over time Thomas Malthus (1798) ºWrote: Essay on the Principle of Population ºDescribed competition as a struggle for survival ºPopulation size can increases exponentially but it remains stable over time&why? Charles Lyell (1830) " Proposed the theory of Uniformitarianism Changes to Earth is uniform Land masses change over immeasurable time Earth is ancient Jean Baptiste Lamarck (1809) " Looked at fossil record and role of environment " Idea #1: use and disuse " Idea #2: inheritance of acquired characteristics Charles Darwin (1837) " Developed theory of natural selection " Invited to travel around the world 1831-1836 (22 years old!) made many observations of nature ºmain mission of the Beagle was to chart South American coastline Robert Fitzroy HMS Beagle Voyage of the HMS Beagle ºStopped in the Galapagos Islands " Most of the animal species on the Galapagos lived nowhere else& BUT - they resembled species living on the South American mainland. " Darwin hypothesized that the islands had been colonized by plants and animals from the mainland that had then diversified on the different islands Darwins Finches " Darwin was amazed to find out that all 14 species of birds that he found were finches& " But there is only one species of finch on the mainland! Essence of Darwins Ideas 1. Variation exists within populations 2. Competition for limited resources results in differential survival. 3. Individuals with more favorable phenotypes are more likely to survive and reproduce. 4. Evolutionary fitness is a measure of reproductive success 5. Changes in environment causes changes in selection Darwins Finches Explained& " Variation in beak sizes and shapes existed within mainland population of finches. " Changes in food availability lead to changes in competition among individuals. " Individuals that could forage for food more successfully (ideal beak phenotype) were more likely to survive and reproduce. " The other individuals either died or moved to a different environment (an island!) " Over many generations the populations diversified à SPECIATION! /Adaptive Radiation " Darwin returned to England in 1836 He wrote secret papers describing his collections & observations He completed a draft of his theory of species formation in 1844 but was reluctant to publish it. &then came a letter Alfred Russel Wallace (1858) " A young naturalist working in the East Indies " Had written a short paper with a new idea. " He asked Darwin to evaluate his ideas and pass it along for publication. November 24, 1859, Darwin published On the Origin of Species by Means of Natural Selection Natural Selection A major mechanism for evolution Recall& " Evolution is the change in the genetic make-up of a population over time. The process of natural selection? According to Darwin& 1. There is natural variation in populations. 2. Competition for limited resources results in differential survival. 3. Individuals with more favorable adaptations are likely to survive. ØMore likely to produce more offspring ØMore likely to pass traits on to the next generation 4. Selection is based on the environmental conditions Individuals are selected and populations evolve! Where does variation come from? " Mutation " random changes to DNA Beak depth " errors in mitosis & meiosis " environmental damage " Sexual Reproduction " mixing of alleles " new arrangements in every offspring " spreads variation " offspring inherit traits from parent " recombination of alleles " new combinations = new phenotypes " Fitness is the survival & reproductive success of individuals " Individuals with certain phenotypic variations leave more or less surviving offspring " Depends on abiotic and biotic factors that can be more or less stable " Affects the rate and direction of evolution Artificial Selection " Also referred to as selective breeding " Humans select traits in organisms that are desirable " Organisms with common traits are crossed " Leads to a change in the allele frequencies in a population over time. " Operates on the natural variation that exists in the population. Adaptations " Evolutionary biologists refer to an adaptation as a genetically controlled trait that evolved as a result of natural selection " Increases the fitness of an organism. " Physiologists use adaptation when they mean acclimatization " Short te
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Compatible OS 3.0 et ultérieurs.
<<
What is evolution? " Characterized by a change in the genetic make-up of a population over time. " Supported by multiple lines of evidence. Early Ideas " Earth is young " Earth is unchanging James Hutton (1788) ºProposed the theory of Gradualism ºEarth was formed entirely by slow-moving processes, such as erosion and sedimentation, and that these slow forces continue to shape the landscape. ºGeorge Cuvier (1796) ºPaleontology: Found that fossils were dissimilar to modern life ºTheory of Catastrophism ºMajor changes to Earths crust were due to catastrophic vs gradual changes. ºSpecies can become extinct ºSpecies can change over time Thomas Malthus (1798) ºWrote: Essay on the Principle of Population ºDescribed competition as a struggle for survival ºPopulation size can increases exponentially but it remains stable over time&why? Charles Lyell (1830) " Proposed the theory of Uniformitarianism Changes to Earth is uniform Land masses change over immeasurable time Earth is ancient Jean Baptiste Lamarck (1809) " Looked at fossil record and role of environment " Idea #1: use and disuse " Idea #2: inheritance of acquired characteristics Charles Darwin (1837) " Developed theory of natural selection " Invited to travel around the world 1831-1836 (22 years old!) made many observations of nature ºmain mission of the Beagle was to chart South American coastline Robert Fitzroy HMS Beagle Voyage of the HMS Beagle ºStopped in the Galapagos Islands " Most of the animal species on the Galapagos lived nowhere else& BUT - they resembled species living on the South American mainland. " Darwin hypothesized that the islands had been colonized by plants and animals from the mainland that had then diversified on the different islands Darwins Finches " Darwin was amazed to find out that all 14 species of birds that he found were finches& " But there is only one species of finch on the mainland! Essence of Darwins Ideas 1. Variation exists within populations 2. Competition for limited resources results in differential survival. 3. Individuals with more favorable phenotypes are more likely to survive and reproduce. 4. Evolutionary fitness is a measure of reproductive success 5. Changes in environment causes changes in selection Darwins Finches Explained& " Variation in beak sizes and shapes existed within mainland population of finches. " Changes in food availability lead to changes in competition among individuals. " Individuals that could forage for food more successfully (ideal beak phenotype) were more likely to survive and reproduce. " The other individuals either died or moved to a different environment (an island!) " Over many generations the populations diversified à SPECIATION! /Adaptive Radiation " Darwin returned to England in 1836 He wrote secret papers describing his collections & observations He completed a draft of his theory of species formation in 1844 but was reluctant to publish it. &then came a letter Alfred Russel Wallace (1858) " A young naturalist working in the East Indies " Had written a short paper with a new idea. " He asked Darwin to evaluate his ideas and pass it along for publication. November 24, 1859, Darwin published On the Origin of Species by Means of Natural Selection Natural Selection A major mechanism for evolution Recall& " Evolution is the change in the genetic make-up of a population over time. The process of natural selection? According to Darwin& 1. There is natural variation in populations. 2. Competition for limited resources results in differential survival. 3. Individuals with more favorable adaptations are likely to survive. ØMore likely to produce more offspring ØMore likely to pass traits on to the next generation 4. Selection is based on the environmental conditions Individuals are selected and populations evolve! Where does variation come from? " Mutation " random changes to DNA Beak depth " errors in mitosis & meiosis " environmental damage " Sexual Reproduction " mixing of alleles " new arrangements in every offspring " spreads variation " offspring inherit traits from parent " recombination of alleles " new combinations = new phenotypes " Fitness is the survival & reproductive success of individuals " Individuals with certain phenotypic variations leave more or less surviving offspring " Depends on abiotic and biotic factors that can be more or less stable " Affects the rate and direction of evolution Artificial Selection " Also referred to as selective breeding " Humans select traits in organisms that are desirable " Organisms with common traits are crossed " Leads to a change in the allele frequencies in a population over time. " Operates on the natural variation that exists in the population. Adaptations " Evolutionary biologists refer to an adaptation as a genetically controlled trait that evolved as a result of natural selection " Increases the fitness of an organism. " Physiologists use adaptation when they mean acclimatization " Short te
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