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Transcript
Evolution & Classification The Theory of Evolution Charles Darwin (1809-1882) Joined the crew of the HMS Beagle as a naturalist responsible for collecting specimens as the ship sailed around the world Visited the Galapagos Islands and noticed that animals varied from island to island noted both similarities and differences between the islands and other parts of the world Began working on an idea that new organisms develop from preexisting organisms over time This is the traditional definition for evolution The Theory of Evolution (2) Modern Scientists Evolution is… Heritable change in characteristics in a population from one generation to the next REMEMBER – a Theory is a well-supported explanation for some aspect of the natural world that incorporates many observations, inferences, and hypothesis Changing ideas in the 1700’s & 1800’s TRADITIONAL THOUGHT Most scientists thought that species were permanent and unchanging The earth was only several thousand years old ROLE OF GEOLOGY George Cuvier (1769-1832) Catistrophism – sudden geologic catastrophes cause mass extinctions (explains some the findings in fossils) Charles Lyell (1797-1875) Uniformitarianism – processes shaping the earth are the same as those in the past (logic for the earth being much older than thought at the time) Shifting Ideas With many in the scientific community researching species and the age of the earth, it set the stage for ideas of evolution. Jean Baptiste Lamarck Charles Darwin Alfred Russel Wallace Jean Baptiste Lamarck (1744-1829) French biologist Supported the idea that organisms change over time Theory of Inheritance of Acquired Characteristics – traits acquired during one’s lifetime are pass on to the next generation WRONG, WRONG, WRONG!!!!!! Why? Charles Darwin Published book On the Origin of Species by Means of Natural Selection Wanted to present: Large amount of evidence he compiled during his voyage that supported evolution An explanation for the variety and distribution of organisms present today as a result of naturally occurring processes Darwin (2) Coined the phrase “decent with modification” to describe the process of evolution Concluded that all species today must have descended from a common ancestor Species can change over time – if the change is great enough then a “new” species can emerge Alfred Wallace – had similar idea, however Darwin published his work first Darwin’s Voyage aboard HMS Beagle The Galapagos Islands Darwin and the Galapagos Finches Darwin’s Proposed Theory The Theory of Natural Selection This is the mechanism by which decent with modification can occur Natural Selection occurs because of… Overproduction More offspring are produced than survive to adulthood Genetic Variation Individuals within a population have different traits inherited from their parents some may survive longer/better than others as a result Struggle to Survive Individuals must compete with each other; some variations (adaptations) may increase survival and reproduction Differential Reproduction Individuals with the best adaptations are most likely to reproduce and pass on their adaptations (genes) Some misconceptions Natural Selection is not a “guiding hand” It does not produce perfection It does not provide organisms with what they “need” or “want” Natural Selection is not random Genetic variation DOES occur So, what does it all boil down to? Natural Selection is… A process that results from variation (genes) within a population About being “good enough” not necessarily the best Anything that allows an organism to survive and pass on it’s genes to the next generation Evidence for Evolution (natural selection) Fossil Record Transitional Species Biogeography Studying the location of organism around the world Anatomy Study of structure Embryology Study of development EMBRYOLOGY Branch of biology that studies the formation, early growth and development of an organism MORPHOLOGY Branch of biology that deals with the form and structure of an organism without consideration of the function The wing of a bat is more similar to the leg of a human than a wing of a bird PHYLOGENETICS The analysis of the evolutionary or ancestral relationships among organisms DNA analysis (gel electrophoresis) Chromosome # (karyotypes) Gene location Protein similarities 3 “types” of Evolution Convergent Evolution Different species evolve similar traits Divergent Evolution Descendants of a single ancestor diversify into species that each fit different parts of the environment Adaptive Radiation A new population in a new environment develops into a new species “Man-Made” Evolution Artificial Selection The selection of individuals by humans to create the next generation Horse Breeds Dog Breeds High-Yield Foods (corn, wheat etc.) Population Genetics Ch #16 What is Population Genetics? The study of evolution from one generation to the next (microevolution) caused by variation What causes the variation? Environmental factors Heredity Mutation Recombination Random paring of gametes What do Population Geneticists Study? Gene Pool Total genetic information in the population Allele Frequency Percentage of an allele in a population Phenotype Frequency Percentage of individuals with a specific trait within a population Hardy-Weinberg Equilibrium Mathematical way of calculating if allele frequencies are changing in a population Assumption can be made that if a population is NOT evolving then: No mutations are occurring No individuals enter or leave the population The population is large All mating is random Selection does not occur Is this likely to happen? Factors that change a population Mutation Production of new alleles Gene Flow Process of genes moving from one population to another Immigration = movement of individuals INTO a population Emigration = movement of individuals OUT of a population Genetic Drift Change in allele frequencies as a result of random events Sexual Selection Selecting mates based on some criteria CLASSIFICATION The grouping of objects or information based on similarities Classification of Organisms Ch #17 TAXONOMY Branch of biology concerned with the grouping and naming of organisms Taxonomist – biologist who study taxonomy ARISTOTLE’S SYSTEM Greek philosopher First to develop a classification scheme Plants Herbs, shrubs, trees Animals Land, air, water Linnaeus’ Classification System Swedish botanist (1700’s) Used physical characteristics of the organisms Classification based on the evolutionary context of a species Developed 2 name system binomial nomenclature Levels of Classification Domain Kingdom Phylum Class Order Family Genus Species The Three Domains of Life Eubacteria Single-cell prokaryotic organisms Archaea Prokaryotes that can live in extreme environments Eukarya All Eukaryotes The Six Kingdoms Eubacteria – aligns w/ Domain Bacteria(Archaea) Archaebacteria – Aligns w/ Archaea Protista – eukaryotes that are not plants, animals or fungi most unicellular Fungi – eukaryotes, heterotrophs – most multicellular Plantae – eukaryotes, autotrophs multicellular Animalia – eukaryotes,heterotrophs – develop from embryos Multicellular BINOMIAL NOMENCLATURE Genus – group of closely related species Species – group of organisms that can mate and produce viable offspring Binomial name = genus species Capitalize genus name When typed, the name should be in italics Ex. Homo sapiens BINOMIAL NOMENCLATURE (2) Linnaeus chose Latin as the language for the system Dead Language (does not change) Universal understanding Common names lead to confusion… Honey Badger Common names lead to confusion… North American Badger Common names lead to confusion… Eurasian Badger Common names lead to confusion… Stink Badger LINNAEUS AND SYSTEMATICS Systematics – classifying organisms in terms of their natural relationships Linnaeus Grouped according to visual similarities Modern Biologists Visible similarities Embryos Chromosomes Proteins DNA IDENTIFYING AN UNKNOWN ORGANISM Dichotomous Key A written form of a branch diagram that is used to identify an organism based on physical characteristics To create a dichotomous key… Design a branch diagram Transfer the diagram to written form THERE MUST ALWAYS BE 2 CHOICES FOR EVERY STATEMENT