BiOB160 Study Guide Exam 1
BiOB160 Study Guide Exam 1 BIOB 160N - 00
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This 10 page Study Guide was uploaded by Paige Hamrock on Tuesday September 20, 2016. The Study Guide belongs to BIOB 160N - 00 at University of Montana taught by Scott R. Miller (P), Harry Arthur Woods in Fall 2016. Since its upload, it has received 80 views. For similar materials see Principles of Living Systems in Biology at University of Montana.
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Date Created: 09/20/16
BioB160 Study Guide Exam 1 Lecture Notes - There are many types of dogs, including; retrievers, treeing, pest control, herding, truffle(scent), helper, and companionship dogs. - Despite the differences we see in dogs, they have many similar traits, such as; floppy ears, raised tails, pleasant temperature, barking, and good diet. - Biologists have studied whether dogs have domesticated from wolves, coyotes, or some other animal. They use phylogenetic trees to find answers to not only this question, but many questions in evolution. Research has shown that dogs were descended from wolves. - There are many hypotheses as to how, when, and where this domestication happened. - There are 3 conditions required for change by selection: 1. Must be phenotypic differences between individuals within a population 2. Must be at least some genetic component adding to an individuals phenotype(h^2>0:heritability) and 3. Component of fitness must be correlated to phenotypic variation(survivorship, reproductivity NOT strength fitness). - Russian Fox Farm Experiment: selectively bred foxes that were okay around humans, bred for one behavior. - Charles Darwins father objected to his trip on the HMS Beagle. - Darwins voyage set off in 1831, was supposed to sail for two years, but ended up being 5 years. - Peter and Rosemary Grant studied the Galapagos finches for about 30 years. Main species studied was the medium ground finch. - Galapagos finches: beaks are important tools for the birds and the size and shape affects what seeds they eat(bigger beaks=bigger seeds, smaller beaks=smaller seeds). - Struggle for existence: individuals with some phenotypes perform better than others with other phenotypes. - Evolution occurs only if the heritability of the trait is greater than 0- that is, some of the variation in the original population is due to variation in the genes. If so, then the average beak depth of the next generation will shift in the direction in which selection occurred. This shift is called the response to selection. - Afact in science is an observation that has been repeatedly confirmed and for all practical purposes is accepted as “true”. Truth in science however is NEVER final - Alaw is a descriptive generalization about how some aspect of the natural world behaves under stated circumstances. - Ahypothesis is a tentative statement about how the natural world leading to deductions that can be tested. - Strong inferences consists of applying the following: 1. Devising alternative hypotheses 2. Devising a crucial experiment, with alternative possible outcomes, each of which will, as nearly as possible, exclude one or more of the hypotheses and 3. carrying out the experiment so as to get a clean result. - Atheory in science is a well substantiated explanation of some aspect of the natural world that can incorporate facts, laws, inferences, and tested hypotheses. - Darwins two major achievements: 1. recognize relationships among living things: descent with modification fives rise to homology 2. propose a mechanism for diversification(natural selection). - Homologies are similarities among structures that arises by descent from a common ancestor. Ex. bones in the forelimbs of many different vertebrates. - Analogous traits are traits that are similar because of convergent evolution, NOT because the trait was inherited from some common ancestor. Ex. two types of succulents. - Another kind of homology is during embryonic development, developmental fate of gill arches in a human embryo which become parts of the jaw, ear, and throat. - Alleles are different versions of the same genes, mutations are the ultimate source of new alleles. - Allele frequencies are measured at the level of populations. Populations are defined as groups that(mostly) interbreed with one another. - Evolution is changes in allele frequencies in populations. - Conditions for the Hardy Weinberg Equilibrium are 1. no mutations 2. Random mating 3. No natural selection 4. Extremely large population size(no drift) 5. No gene flow. - There are 3 processes that can alter allele frequencies in populations; 1. Natural Selection 2. Genetic Drift 3. Gene Flow. - Speciation is the origin of new species, is a focal point of evolutionary theory. Can take place with or without genetic separation. - The biological species concept states that a species is a group of populations whose members have the potential to interbreed in nature and produce fertile, viable offspring. - Reproductive isolation is the existence of biological factors(barriers) that impede two species from producing fertile, viable offspring. - Hybrids are the offspring of crosses between different species - For the biological species concept, it CANNOT be applied to fossils or asexual organisms and it emphasizes absence of gene flow, however, gene flow can occur between distinct species. - The morphological species concept defines a species by structural features, it applies to sexual and asexual species but relic on subjective criteria. - Pre zygotic barriers: habitat isolation, temporal isolation, behavioral isolation, mechanical isolation, and gametic isolation. - Post zygotic barriers: reduced hybrid viability, reduced hybrid fertility, and hybrid breakdown. - Speciation can occur in two ways: allopatric and sympatric. - Allopatric speciation, gene flow is interrupted or reduced when a population is divided into geographically isolated subpopulations. - Regions with many geographic barriers typically have more species that do regions with fewer barriers. - In sympatric speciation, speciation takes place in geographically overlapping populations. Can occur if gene flow is reduced by factors including: polyploidy, sexual selection, habitat differentiation. - When hybrids are less fit that parent species, reinforcement of reproductive barriers may occur through strong selection. Over time, hybridization decreases. - Porto-Earth formed about 4.6 billion years ago. At first, the entire thing was hot, molten mass, completely inhospitable to life. - Our solar system formed about 5 billion years ago from giant dust clouds in space. - Radiometric dating uses unstable elements that occur naturally in the Earths crust - Each radioactive element has what is called a “half-life” which is the amount of time it takes half of the atoms in a sample to decay. - The oldest known fossils of living organisms are 3.5 billion years old. They come from a rock formation called the apex chert in WesternAustralia. - Oxygen accumulated about 2.4 billion years ago. Around the time of the photosynthesis evolution. - There are about 35 recognized animal phyla, diversified around 600 million years ago. - Dinosaurs diversified about 235 million years ago. - Non-avian dinosaurs went extinct about 65 million years ago. - The lineages leading to chimps and humans diverged about 7-8 million years ago. - The first anatomically modern humans appear about 200,000 years ago. - WWI occurred 100 years ago. - We are members of a group called primates(chimps, gorillas, bonobos, humans, orangutans). Humans and chimps are most closely related. - Using mitochondrial DNA, current analyses estimates that the most recent common ancestor lived at some point between 99,000 and 234,000 years ago in EastAfrica. - There are many kinds of ecology, global, landscape, ecosystem, community, population, and organismal. - Macro patterns: belt of rainforests along the equator, major deserts are at 30 degrees N and 30 degrees South, deserts usually on west sides of the continents, temperate and variable beyond 30 degrees North or South, very cold beyond 60 degrees North or South. - Why do we have these macro patterns on Earth? 1. The sun delivers differential amounts of energy onto different parts of the Earth 2. Water has astonishing properties 3. Differences in the temperatures of fluids(air and water) drive convective flows in those fluids 4. Rising air cools (PV=nRT; the ideal gas law) 5. Cool air does not hold as much water and hot air. - The Earth is a giant heat engine heated by the sun. - Intensity of sunlight varies across Earths surface. - Hydrogen bonding leads to structural organization. Liquid water is much more structured than other liquids. - Water is the only common substance on Earth to exist in solid, liquid, and gas phases. - Five emergent properties of hydrogen bonding of water; 1. very strong internal cohesion 2. strong surface tension 3. high heat capacity; high thermal mass 4. solid less dense than liquid and 5. great solvent. - Water can absorb or give off a given amount of heat but changes temperature much less than other materials. Moderating and stabilizing influence. Since Earth’s surface is mostly water, this greatly moderates temperature fluctuation. Since we are mainly water, we are also greatly buffered against external temperature fluctuations. - Hot air is less dense and rises (hot air balloon). Cold, salty seawater is denser than warmer, fresher seawater. Vocabulary/Definitions Evolution: the process of change that has transformed life on Earth from its earliest beginnings to the diversity of organisms living today. Descent with modification. Biology: the scientific study of life. Emergent Properties: new properties that arise with each step upward in the hierarchy of life, owing to the arrangement and interactions of parts as complexity increases. Eukaryotic Cell: contains membrane-enclosed organelles. Prokaryotic Cell: lacks a nucleus or other membrane-enclosed organelles. DNA: genetic material is chromosomes. Genes: a discrete unit of hereditary information consisting of a specific nucleotide sequence in DNA. Genome: the entire “library” of genetic instructions that an organism inherits. Feedback Regulation: the output, or product of a process regulates that very process. Bacteria andArchaea: are prokaryotic Eukarya: organisms with eukaryotic cells. Natural Selection: a process in which individuals that have certain inherited traits tend to survive and reproduce at higher rates than other individuals because of those traits. Science: a way of knowing-an approach to understanding the natural world. Inquiry: a search for information and explanations of natural phenomena. Data: recorded observations. Inductive Reasoning: a type of logic in which generalizations are based on a large number of specific observations. Hypothesis: a tentative answer to a well framed question. Deductive Reasoning: a type of logic in which specific results are predicted from a general premise. Experiment: involves manipulation of one factor in a system in order to see the effects of changing it. Variables: factors that vary in an experiment. Controlled Experiment: one that is designed to compare an experimental group with a control group. Independent Variable: the factor manipulated by the researchers. Dependent Variable: a factor that is measured in the experiment. Theory: much broader in scope than a hypothesis, generates new hypotheses, and is supported by a large body of evidence. Fossils: the remains or traces of organisms from the past. Strata: layers of rock. Paleontology: the study of fossils. Adaptations: inherited characteristics of organisms that enhance their survival and reproduction in specific environments. Artificial Selection: the selective breeding of domesticated plants and animals to encourage the occurrence of desirable traits. Homology: similarity resulting from common ancestry. Homologous Structures: represent variations on a structural theme that was present in their common ancestor. Vestigial Structures: remnants of features that served a function in the organisms ancestors. Evolutionary Tree: a diagram that reflects evolutionary relationships among groups of organisms. Convergent Evolution: the independent evolution of similar features in different lineages. Analogous: share similar function, but not common ancestry. Biogeography: the scientific study of the geographic distribution of species. Microevolution: evolutionary change below the species level; change in the allele frequencies in a population over generations. Genetic Variation: differences among individuals in the composition of their genes or other DNA sequences. Gene Pool: the aggregate of all copies of every type of allele at all loci in every individual in a population. Hardy-Weinberg Equilibrium: the state of a population in which frequencies of alleles and genotypes remain constant from generation to generation. Genetic Drift: a process in which chance events cause unpredictable fluctuations in allele frequencies from one generation to the next. Most pronounced in small populations. Founder Effect: genetic drift that occurs when a few individuals become isolated from a larger population and form a new population whose gene pool composition is not reflective of that of the original population. Gene Flow: the transfer of alleles into or out of a population due to the movements of fertile individuals or their gametes. Relative Fitness: the contribution an individual makes to the gene pool of the next generation relative to the contributions of other individuals. Directional Selection: occurs when conditions favor individuals exhibiting one extreme of a phenotypic range, thereby shifting a populations frequency curve for the phenotypic character in one direction or the other. Disruptive Selection: occurs when conditions favor individuals at both extremes of a phenotypic range over individuals with intermediate phenotypes. Stabilizing Selection: acts against both extreme phenotypes and favors intermediate variants. Sexual Selection: a form of natural selection in which individuals with certain inherited characteristics are more likely than other individuals to obtain mates. Speciation: the process by which one species splits into two or more species. Macroevolution: the broad pattern of evolution above the species level. Biological Species Concept: primary definition of species. Species: a group of populations whose members have the potential to interbreed in nature and produce viable, fertile offspring, but do not produce these offspring with members of other such groups. Reproductive Isolation: the existence of biological factors(barriers) that impede members of two species from interbreeding and producing viable, fertile offspring. Hybrids: offspring that result from an interspecific mating. Pre zygotic Barriers: “before the zygote” block fertilization from occurring. Post zygotic Barriers: “after the zygote” may contribute to reproductive isolation after the hybrid zygote is formed. Morphological Species Concept: distinguishes a species by body shape and other structural features. Ecological Species Concept: defines a species in terms of its ecological niche, the sum of how members of the species interact with the nonliving and living parts of their environment. Phylogenetic Species Concept: defines a species as the smallest group of individuals that share a common ancestor, forming one branch on the tree of life. Allopatric Speciation: gene flow is interrupted when a population is divided into geographically isolated subpopulations. Sympatric Speciation: speciation occurs in populations that live in the same geographic area. Polyploidy: a chromosomal alteration in which the organism possesses more than two complete chromosome sets. The result of an accident of cell division. Autopolyploid: an individual that has more than two chromosome sets that are all derived from a single species. Allopolyploid: a fertile polyploid. Hybrid Zone: a region in which members of different species meet and mate, producing at least some offspring of mixed ancestry. Reinforcement: a process in which natural selection strengthens pre zygotic barriers to reproduction, thus reducing the chances of hybrid formation. Likely to only if hybrid offspring are less fit than members of the parent species. Radiometric Dating: based on the decay of radioactive isotopes. Amethod for determining the absolute age of rocks and fossils, based on the half-life of radioactive isotopes. Half-Life: the time required for 50% of the parent isotope to decay. Geological Record: a standard time scale that divides Earths history into four eons and further subdivisions. Endosymbiont Theory: posits that mitochondria and plastids were formerly small prokaryotes that began living within larger cells. Cambrian Explosion: when many present-day phyla of animals first appeared in the fossil record. Mass Extinction: large numbers of species become extinct worldwide. Adaptive Radiations: periods of evolutionary change in which groups of organisms form many new species whose adaptations allow them to fill different ecological roles. Practice Questions 1. The DNAof dogs indicates that: They likely evolved several times independently from populations of wolves. 2. During the drought in the 1970s, the main environmental event selecting on beak size of Galapagos finches was: Shifts in food resources available to birds; in particular, well into the drought, most remaining seeds were hard and large. 3. Which of the following best describes the idea of ‘strong inference’? Its the process of developing multiple competing hypotheses about some phenomenon, then devising a test or series of tests that distinguishes unambiguously among them. 4. The term ‘heritability’describes: Traits in which at least some of the variation in phenotypes is due to variation in the genes. 5. If a population of snails has only two alleles (S^a and S^b) at a gene locus, and the frequency of S^a is 0.8, whats the frequency of the genotype S^aS^a if the population is in Hardy- Weinberg equilibrium? 0.64 6. What are the three requirements for a population to evolve by natural selection? Phenotypic variation in a trait, heritability of that trait, differential survival or reproduction based on that trait. 7. In the context of speciation, what is ‘reinforcement’?Aprocess by which pre-zygotic barriers evolve to be stronger because hybrids between two populations have low fitness. 8. What is allopatric speciation? Speciation that occurs when two populations are separated for a period of time by some kind of geographic barrier. 9. Why is the climate drier on the leeward side of mountain ranges that are subjected to prevailing winds (in this US, the leeward side is to the east)? Air masses pushed by prevailing winds rise up the windward side, which cools the air and causes the moisture to precipitate out; when that air moves down the leeward side and warms up, its dry. 10. Why do CO2 levels in the Earths atmosphere fluctuate on an annual cycle? The are influenced by annual cycles of photosynthesis and decay on land masses. 11. About how long ago were dogs domesticated from their wild relatives? About 30,000 years ago. 12. What has the Russian fox farm experiment shown? That selecting for tameness can drive rapid evolution of domesticates foxes; these foxes show many other traits of dogs: raised tales, floppy ears, and the ability to bark. 13. What does it mean to say that a trait shows ‘phenotypic plasticity’? That the trait varies depending on which environment the organism is in. 14. How could it be that a population experiences strong selection on a particular trait yet the trait does not evolve? The trait is not heritable. 15. When a scientist develops a hypothesis about some natural phenomenon, what is the thing she derives from that hypothesis that actually gets tested most directly? Aprediction. 16. What are analogous traits? Traits in two different species that are similar by convergent evolution, not because the species share a common ancestor that also had those traits. 17. In the Origin of Species, Darwin talks a lot about ‘descent with modification’. What did he mean by this phrase? Similarities among individuals or species reflect that they descended from common ancestors living in the past. 18. Which of the following pairs of traits are homologous? Fur on a dog and on a cat. 19. Which are the most closely related to amphibians? Mammals. 20. If a population of snails has only two alleles (S^x and S^y) at a gene locus, and the frequency of S^x is 0.8, whats the frequency of the genotype S^yS^y if the population is in Hardy-Weinberg equilibrium? 0.04 21. Apopulation has 700 individuals, 65 of genotypeAA, 320 of genotypeAa, and 295 of genotype aa. What is the frequency of theAallele in the population? 0.35 22. What is genetic drift? Changes in allele frequencies, usually in small populations, as a result of chance events affecting which organisms live and reproduce. 23. Which of the following is the best description of the biological species concept? Species are identified as groups of potentially interbreeding populations. 24. What is the main difference between pre and post-zygotic barriers to hybridization? Pre- zygotic barriers are barriers that operate before fertilization and post-zygotic barriers are those that operate after fertilization. 25. What the key property of water that faces it so many of its strange behaviors? Hydrogen bonding. 26. What two phenomena are driven by differences in densities of fluids (air and or water)? Hadley cells and major ocean currents. 27. What is climograph? Aplot of mean annual rainfall versus mean annual temperature for different places. Major biomes of the world are clearly differentiated by just these two environmental variables. 28. Why do major deserts tend to occur on the west sides of continental land masses? Because the west sides of continents tend to have cold ocean currents going by them. These cold waters five off less water vapor by evaporation, and so the air masses blowing over the continents are quite dry. 29. Whats the current approximate level of CO2 in the Earths atmosphere? 400 parts per million. 30. How much higher are levels of CO2 now than they were during the last few ice ages? About double. 31. In the context of Earths atmosphere, whats the best description of the ‘greenhouse effect’? The tendency of atmospheric carbon dioxide to absorb outgoing infrared radiation and to reradiate it back toward Earth. 32. What is the main cause of rising levels of atmospheric CO2? Combustion of hydrocarbons. 33. Why do higher levels of atmospheric CO2 acidify the worlds oceans? Atmospheric CO2 readily dissolves into the oceans, where it undergoes a hydration reaction that releases protons. 34. If a large proportion of the variation in a trait is due to the effects of genes, the trait is said to have: high heritability 35. In dogs and cats, is the common trait of having two nostrils homologous or analogous? Homologous. 36. If there are 500 plants in a population, how many total copies of C in that population? 1000 37. Drosophila persimilis breeds in early morning, while closely related Drosophila pseudoobscura breeds in the afternoon. What kinds of barrier to hybridization does this difference in timing represent? Pre zygotic.
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