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BIO120 SUMMARY FOR MIDTERM (Lecture 1-12).docx

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Spencer Barrett

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TH Lecture 1: Introduction to Evolution (May 15 2012) 1. Antibiotics 2. Human Mating (Selection of Mates)  Living organisms are highly diverse  Wildebeests + Zebras in African migration Timescale #1: Ecological Response (Single Generation) Timescale #2: Evolutionary Response (Multiple Generations)  Evolution: Mechanism of genetic change  Ecology: What the types of adaptations are  Adaptation as a verb + noun  Organisms change gradually over time + how it happens  Fossils (1700-1800) Idea of evolving organisms (Greeks)  Lamarck did not have the mechanism right  Traits are acquired during an organism’s lifetime  (1900) Mendel showed that inheritance was not blending of blood  Somatic Cells (i.e. skin, non-reproductive)  Wallace: Naturalist working in Asia + South America (How)  Lamarck believed that the stretching of necks was passed on (i.e. Muscles) The Origin of Species (Parsimony: Unwillingness to spend money)  1. All organisms descended from one species  2. Contain the same genes/molecules Microevolution: Mechanisms (Change over generations) Macroevolution: Evolution of animals, Extinction of Dinosaurs (i.e. Evolution of Mammalian Eye) H.M.S. Beagle  Note the coastlines of South America  Darwin as a companion to the Captain Gradualism  World has looked different, Mountains have come and gone)  Time required for change involved over billions of years  Multiple organisms to contend with (biotic interactions living)  Epiphytes: Organisms that grow on top of one another Dynamic World (Look at volcanic processes)  Fixity of Species (Everything created at once, remained static)  Fossils, Similar features between species  Malthus (1798): How come the Earth was not overpopulated?  Deaths, Competition to survive for generations (Natural Selection) Populations WILL EVOLVE if Darwin’s 4 postulates are TRUE  Natural Selection (Survival is not random, outcome, pattern)  Adaptations are the products of evolution  Changes in the characteristics of populations of individuals  Nature via Nurture TH Lecture 2: Darwin’s Dangerous Idea (MAY 15 2012) Read CH 4 in Why Evolution is True Darwin  Supposed to be a minister  LST species diversity  1 Port: Brazilian Tropical Forests (Biotic Interactions)  High species diversity between one another  Wind pollination common with species close together  Evolution of plants (flowering) with insects  Animal Pollination (Diversity in coevolution Plants + Animals)  Coevolution occurs with speciation of particular trees  Large trees seeds fall under canopy (no germination)  Survival of seeds is greater away from the parent  Ants build nests on Acacia (Ant-Plant Mutualism)  Thorns (hollow stems, food, deter predators)  Ants killing off other saplings with formic acid (herbicide)  Evolutionary imperative to protect themselves (water lilies) Patagonia  Abiotic interactions (non-living)  Stark landscape (Contrast to Brazil)  Lower part of South America  Physical environment poses constraints on Evolution  Darwin’s Rhea (Looked like ostriches) Flight-less birds  Spiny cushion plants (Morphological Characteristics)  Spiny (avoid predators, low to the ground, hooked seeds) Galapagos Islands  Young Volcanic Islands  Barren landscape, low species diversity  Birds brought cacti (Same in North America) TH Lecture 3: Evolution’s Raw Material (May 17 2012) Marsupials in Australia (Organisms similar yet different)  External pouches  Earliest mammals  Australia moved from Pangaea (used to be part of South America)  Did not have to compete with placentas  Opossum in North America Genetic Variation  Human Height  Histogram (Bell Shaped)  Characteristic/ Trait (# of digits invariable)  Human Intellect (Mean as a way to summarize data)  Variation as fuel of Evolution  Fisher’s Bioinformatics  Fitness = # of Children within a population  Populations with more variation = MORE FITNESS  Oceanic Islands (Adaptive Radiation) Adapting to a bare environment + Creating multiple branches  Dogs (Multiple Variation from 1 Gray Wolf species, through breeding)  Cats are much more homogeneous (less genetically variable) Mutation  Point Mutation (Change in a single nucleotide)  Plants (Chromosomal mutation)  Eye Colour of fruit flies (1910) Morgan Rates of Mutation -8  10 per nucleotide per generation for a point mutation  175 per person (7 lethal)  Fitness= Viability of an organism  Many mutations are lethal + deleterious (may not survive) Recombination (Source of Variation)  Zygote as 50% Mother/ 50% Father  Shuffling of Genes  Will yield new genetic forms  Genotype/Environment  Phenotype  Phenotype (Expressed Variation, Interacts with the Environment) Genetic Polymorphism + Quantitative Inheritance  Snow Geese (One gene mutation = Blue Colour)  Human ABO Blood Group  Eye Colour in Fruit Flies  B Allele Eastern Asia/Europe  Males and Females Phenotype is underlined by more than one gene  Colour variation of wild gladiolus  1 gene, 2 genes, 4 genes (Hard to distinguish individuals)  Continuous pattern of phenotypic variation  Harder to determine future generations  MS genetic component/geographic component (North American)  Component of gene + quantitative inheritance Effects of mutations greater with shortage of proteins  Skin evolved to absorb Vitamin D TH Lecture 4: Reproductive Diversity (May 17 2012) Sexual Reproduction  Most common form of reproduction within multicellular organisms  Hydra (Asexual Reproduction  Cloning)  Asexual reproduction within unicellular organisms  Water Fleas (Zoo Plankton) Cool Environment (Asexual) Preferable  Aphids (2001) Early in summer (asexual) genetically identical  Produce wings and use sexual reproduction  Genetic variability  Water Hyacinth (Vegetative Reproduction) + Sexual Reproduction  Edges (drier, less desirable)  Sexual Reproduction occurs during a time of uncertainty, less desirable Why Would Sex Evolve?  Asexual reproduction should spread at twice the rate (twofold rate)  Parthagenesis (Cloning via Asexual Reproduction)  Must be advantageous for evolution  Mutations are shuffled up (with recombination)  ABC form as a mutation in asexual reproduction  Range of variation in fitness (Sexual Reproduction)  Super offspring  The Red Queen Hypothesis  Escape disease related enemies (which evolve faster)  Fight evolving parasites and organisms  Microparasites Bacteria  Macroparasites Intestinal Worms  Never ending race between parasites + organisms (Surface binding proteins)  Asexual (Close to the parent)  Sexual (Away + Dispersed from offspring)  Deal with constantly changing populations  Inbreeding (Consequence of Sexual Reproduction)  Outbreeding (Individuals highly differential) Inbreeding Results in Inbreeding Depression  Reduces genetic variability (Does not change the allele frequency)  Does change the genetic frequency  Mutation (Asexual)/ Recombination + Mutation (Sexual)  Allelic frequencies remained unchanged in inbreeding but lost the heterozygotes  Alter the genotypic frequencies (loss of heterozygotes)  Measure genetic variability by # of heterozygotes  Selfing (Plants) Hermaphroditic Reproduction  Greater mutation within inbreeding  7 lethal alleles in heterozygotes  Small populations Inbreeding  Inbreeding Depression (Ramifications of sibling reproduction) Lecture 5: Natural Selection (May 22 ND 2012) Evolution Series  Review  Population sizes are so small = INBREEDING  Blending Inheritance (Variation is not preserved)  Mendel (1865) Particulate Inheritance (Polymorphic gene)  Variation preserved (as trait)  Selection (sorting out non random survival)  Evolution as a pattern not a process  Survival of the Fitter (relative)  Artificial Selection in pigeons + dogs  Cabbage (Suppression of internode length Branching out)  Trees host lichens + fungi  Pollution (destroyed the lichen + mass on trees)  Melanic Moths over 35 years (30% Dark Moths)  Evolution at Population level (Decline)  Theory (Particular advantage over other species)  Exponential change from compounding interest  Fixation (95% of population contain gene)  Natural Selection operates very quickly  Warbler Finch (delicate beak to pick up insects)  Measures of body size (weight + beak depth)  If a gene is heritable (genetic testing)  Variation of beak depth From parents (P < 0.05)  Phenotype does not look like parent (Recombinations)  Beak is heritable  Large, hard seeds which survived  Natural Selection (Change in genetic variation)  Small P value= non random selection  Drive toward larger beaks + bodies  Fluctuating selection  The Modern Synthesis (Change in allelic frequencies)  Gene: fw2.2 (Makes cell division stop in tomato plants  Yellowstone Park (Archaea 2.5 billion years ago)  Extremeoflies (500 common with humans) ND Lecture 6: Sexual Selection I (May 22 2012) Peacock Mating Habits  Treatment interruption to purge non-treatment bacteria  Sexual Dimorphism: Conspicuous Ornaments  Frigate Bird (Tropical)  Deer Antlers (Armorphism)  (-) Survival (predation)  (+) Mating Success  Natural selection increases fitness  Survival, Reproductive Diversity Anisogamy (Unequal size of gametes)  Female gametes (expensive  nutrient rich) less  Male (Low cost  More)  Parental Investment Theory (Supply + Demand)  Males (Competition)  Females (Choosing)  More mates benefit for males, less mates for females TH Lecture 7: Sexual Selection II (May 24 2012) Sexual reproducers have lesser black spots less parasites  Reduced fitness caused by inbreeding depression Mountain sheep, elks (Pre-copulatory competition # of copulations)  Male to Male Competition  Fighting over nest sights, social status, bird song  Social Status (Pacific Coast- February babies are born) Harem Mating System (Elephant seals)  Large throats bellow nostrils = Reverberating sounds  Rank of male hierarchy (8 not reproductively successful)  Polygamous system Mate guarding to ensure the passing on of one single mate (genes) Female Choice (Mariam Petrie)  Are they choosing? + What are they choosing?  Will this lead to higher fitness?  Bias toward the preferred traits  Peacock (Manipulate tail length)  Assume causality for mating  Natural tail length, Reduced tail length, Elongated tail length  Reduced= Piece of tail cut  Long= Piece added on to tail  Y= X +1X 2  Y= # of matings, X 1 Treatment (Long, Natural, Reduced), X =2Sham surgery Sham Surgery (Tails are cut + glued together)  Considered as a control (comparison group)  Elongated > Natural > Shortened (Mating Success)  Natural= Sham (Random Assignment)  Within the groups, the animals are similar  Longer Tail= More Fitness  Experimental lost 3 copulations Lecture 8: Molecular Evolution I (May 24 TH 2012) Read Page 90  Evolution at a cellular level  Construct molecular phylogenies (relatedness)  Humans (3 billion base pairs) Codes for amino acids  Humans (1.5% - 5% of junk DNA no known functions 80%)  Gene (1
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