Evolution: Principles, Mechanisms, and Consequences (Chapters 14-17) - Prof. Catherine A. , Exams of Mathematics

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Bio Notes Chapters 14-17 Chapter 14 Principles of Evolution  Evolution: explains the similarities among living things, accounts for  Scientific theory is a well-substantiated explanation of some aspect of the natural world that contains facts, laws, and tested hypothesis.  Evolution and Religion: evolution deals with the NATURAL world while religion deals with SPIRITUAL experiences. o Evolution is not a belief system o Many world religions around the world that do not have conflict with evolution.  Evolution is a change over time in the characteristics of POPULATIONS. o Occurs in POPULATIONS (all the individuals of a species in one area)  Buffon, Cuvier, Lamarck, Lyell were all influences of Darwin o All men that studied when fossils were beginning to be discovered and they were finding that different kinds of organisms could be found in different layers of sedimentary rocks (the different deeper positions fossils were older vs. the higher up organisms). o Fossils  footprints, bones, eggs, skin impressions can be fossilized evidence.  Hutton and Lyle: UNIFORMITARIANSIM  the earth developed gradually through natural processes over long periods of time and the processes are still at work.  Lamarck (1801): Inheritance of acquired Characteristics  first proposed mechanism for evolution. Gaining one characteristic in one generation can be passed on to offspring. Attempted to explain how evolution can take place but wasn’t very valid during his time period.  Charles Darwin (1858): propose NATURAL SELECTION. Most important and widely accepted theory of how evolution takes place. o Five year voyage on the BEAGLE down coast of S. America o Galapagos Islands: Turtles (with long necks) and Finches (with long beaks) were different on different islands. o Breeding of Horses: Artificial selection  training and breeding of a certain brand of horses. o Read an essay “Essay on Population” by Thomas Malthus and published “On the Origin of Species”  Alfred Wallace: would sell exotic collections from exploring the Amazon and Asia o Idea of Natural Selection at the SAME TIME Darwin did, just in a different place.  Evidence that shows that Evolution has occurred: o Fossils  whale fossils with fully formed hind legs, fossil bone of inner ear on a terrestrial carnivore o BiogeographyLearning about where organisms live and their similar ancestry: Hawaiian honey creeper bird shared a finch-like ancestor 2,000 miles away o Comparative Anatomy  things we see how populations have changed over time  Homologous Structures are SIMILAR with a common ancestry origin (similar bone structures of fore arms of mammals but have different uses)  Analogous Structures are similar in function and resemble each other bc of CONVERGENT EVOLUTION (wings in different groups such as birds and insects)  Vestigial Structures are present but not current purpose (hind limb in a whale, in some snakes and salamanders, tail bones in humans, wisdom teeth) o Biochemical and Genetic Analysis   Compare DNA sequences between organisms and measure the amount of differences.  Used Protein Similarities in the amino acid sequences  Universally shared biochemical processes such as glycolysis  How Natural Selection Works 4 Postulates about populations: o 1. Variation between members of a population o 2. Traits are inherited due to a genetic basis o 3. Unequal survival and reproduction (not all offspring survive/are produced) 1 o 4. Reproductive success is not random but due to some inherited and favorable characteristic.  What evidence shows that populations evolve from natural selection o Artificial selection, humans have been using this forever o Fruit Fly Experiment: starvation resistance characteristic is passed on to offspring o Human Diseases that are resistant to drugs (Multi-drug resistant TB, XDR TB, and MRSA) o Pesticide resistant insects o Guppie populations in Trinidad (threats of predation) Chapter 15: How Organisms Evolve  Relationship between genes, populations, and evolution o Inheritance is the link between individuals and populations o Genes and environment interact to determine traits of each individual  Population Genetics  study of frequency, distribution, and inheritance of alleles in a population. o Gene pool- sum of all genes in a population o Allele Frequency- relative proportion of the different alleles in a population o Evolution: changes in allele frequencies in a gene pool over time.  Hardy-Weinberg Principe  equilibrium population (aka ideal free population) that has NO CHANGE in the allele frequencies over time. This can exist iffffff: o 1. No mutation occur o 2. No gene flow can occur o 3. The populations have to be LARGE o 4. Has to be completely RANDOM mating o 5. No natural selection, has to be equal survival for all organisms o This is only a hypothetical situation but it helps understand the FIVE MAJOR CAUSES OF EVOLUTION if these five conditions are not met.  WHAT CAUSES EVOLUTION? Four causes:  (1). Mutations germ cell mutations can be inherited, new alleles are rare can be beneficial, harmful, neutral. They cannot be control, and we cannot eliminate them from developing populations. o Clicker Question: A bacterial allele that conveys resistance to the antibiotic streptomycin is beneficial to the cell in the presence of streptomycin.  (2). Gene flow happens, we can see change in gene flow frequencies and see evolution take place.  (3). Small Populations: GENETIC DRIFT  chance events that change allele frequencies in small populations. Affects SMALLER populations more. o Population bottleneck: drastically reduces the size of a population due to chance (disease, natural disaster, over hunting, habitat destruction). A much smaller gene pool survives the event and they then mate and reproduce so the new population is made of only survivor alleles offspring. Reduces GENETIC DIVERSITY. o Founder effect: isolated colonies are founded by a small number of organisms that have deserted their original group. Ex: immigrants carry an allele for extra finger on hand when migrating. They reproduce within themselves and so the allele increases in the immigrant population than the original population.  (4). Non-random Mating: species tend to mate only within their convenient area, with those around them. Mating is not a random process in species.  Inbreeding, competition of males for mates, choosing more attractive mates (sexual selection).  (5). Natural Selection: differential reproduction  individuals bearing certain favorable alleles leave more offspring in the next generation. o Works on the phenotypes- successful phenotypes have the best ADAPTATIONS. o The environment favors these successful adaptations: abiotic (non-living) and Biotic (living) components of an environment. Ex: predators 2