Daniel Mathia Ecology 182R 1 20 15 Evolution Evolution is the process that formulates diversity Classification and Phylogenies Natural Selection Aristotle 384 322 B C Scala Naturare Major Great Chain Being In order of perfection White 1799 Progressive chain of being Major Carolus Linnaeus 1707 1778 Taxonomy Classifying organisms Major Binomial Nomenclature Major Example Homo Sapiens Example Oryza Sativa Genus Species Hierarchical Classification Similarities and Differences Groups within Groups Hierarchical Classification Russian Dolls Major Domain Kingdom Phylum Class Order Family Genus Species Distrustful kids prefer cheese over fried green spinach Phylogeny Major Evolutionary History of Organisms Major Phylogenetic Tree Major Describes history and shows evolutionary relationships near and Node Common ancestor at time of split Major distant relatives Major Humans Chimps Sister Groups Gorilla Chimps Humans Sister Groups Orangutan 13 mya common ancestor between Humans Chips Gorilla Clade Common ancestors between its descendants Major If you can cut off everything to the right with a single snip then its monophyletic group Natural Selection Charles Darwin Major 1809 1882 Naturalist 1831 1836 H M S Beagle Evolution by Natural Selection Major Breeding new varieties of Pigeons Major Traits evolve through natural selection Major Pigeons Darwin Adaptation Crypsis Major Natural Selection Inherited traits favored by natural selection Major Lizards coloration has adapted to the white sands environment To habitat evolved under natural selection Camflouge Genetically based or inherited Genotypes Description of the genetic basis of an individual Major Summarize Natural Selection Major Individuals in a population vary in some trait At least some variation Certain genotypes produce more surviving offspring than others Differences in survival among genotypes are due to an agent of selection Agent of Selections Predators Weather Temperature Moisture and other living things Humans Can be agents of artificial selection Major Kinds of Inherited traits on which selection Discrete One form of that gene allele is dominant determines the appearances Many traits are continuous or quantitative Quantitative traits are often distributed as a bell curve Mr Gabert Major Human Height Normal Distribution Major Body Color Discrete trait Three forms of Natural Selection Directional Stabilizing Disprutive Directional Selection Major Genotypes at one end of the distribution do worse Major Tall Page 60 PWR Directional Selection for maze running performance in rats Major Stabilizing Selection Daniel Mathia 1 22 15 Ecology 182 Average genotype does best Page 62 PWR Human Birth Weight Major Disruptive Selection Genotypes at both ends tails of distribution do best Page 64 PWR Disruptive selection may result in two categories of Two types of seed are available soft and hard individuals Overview Chapter 26 Mechainism of Evoultion Examples of Natural Selection Genetic Drift Gene Flow Mutation Change in allele frequnency overtime in a population of Group of individuals that interact of the same species Proportion of that allele in a particular population Evoultion Major organisms Population Major Allele Form of a gene Allele Frequency Blood Type Allele IA IB IO A IAIB AB IBIB B IO O Diploid Individuals 2 sets of chromosomes Evolution Allele Fixed Occurs when alleles frequencies change Natural Selection Review Individuals in a population vary in some trait At least some variation is genetically based Certain genotypes reproduce more than others Differences in reproduction are due to an agent of selection Dark Morph Pepper Moths 1848 which matched sooty surface Dark and light morphs have different alleles Agent of Selection is insectivorous insect feeding birds Dark Morphs began to decline due to pollution being reduced 1980s Artificial Selection Bacteria Evolving Antibiotics Agent of Selection Bodies 8 million people on anti retroviral drugs Large size nets select for fish that grow more slowly and are smaller as adults Random changes in allele frequency from one generation to the HIV Fish Genetic Drift Major other one Small Populations More susceptible to loss and fixation of alleles Cheetah and Prairie Chicken Both species our endangered Why does reduced genetic variation threaten populations Without genetic variation population cannot adapt when environment changes Major Can cause significant evolutionary change Transfers the alleles from one population to another Genetic Drift Gene Flow Chapter 26 Major Mutations Chapter 26 Alteration of a gene that gives rise to new allele 3 5 strand Point Mutation One nucleotide Change Rare per gene but common per genome Mutations pt 2 Rarely generate novel traits Usually change pre existing traits Usually deleterious Mutations in germ cells are ultimately the source of almost all genetic variation in a population Germ cells Reproductive cells Without mutation evolution would eventually become halt Reduce Genetic Variation Genetic Drift Increase Genetic Variation Mutation Daniel Mathia 1 27 14 Ecology 182R Not all variation is genetically based Some is environmentally based Meaning that genes are the same but their expression changes in Heights Genetics and Environmental based different environments Population Review Major Group of potentially interbreeding individuals of the same species Species Species Pt2 Group of individuals capable of interbreeding and reproductively Prime example of Biological Species Concept isolated from other species Species may consist of several populations all capable of Red Winged Blackbird interbreeding but rarely or never actually having the opportunity Some organisms never have sex to begin with Some bacteria protists fungi How do new species form They diverge from existing species But how 2 Critical process Isolation Genetic divergence and reproductive isolation They re needs to be a disturbance Species formation in 3 easy steps Allopatric Speciation Major One species is separated into two populations by a barrier Each population adapts to new habitiat diverges genetically When if the populations overlap again they no longer interbreed Allopatric Speciation Major Physical barriers arises that prevents interbreeding Thought to be the usual way to start speciation different countries Darwin Finches Allopatric Speciation Figure 27 1 Major Sympatric Speciation No physical barrier arises interbreeding between two different species same country