ENVIR ST 360 1st EditionExam # 1 Study Guide Lectures: 1-5Lecture 1 (September 4)Levels of Study: Individuals, Populations, Communities, Ecosystems, Biosphere (Earth) *from narrowest to broadestPopulation: Definition: A group of individuals of the same species living in the same place at the same time Population ecology: Study of the distribution and abundance of a given species in a specified area at a given timeo Two big questions: SIZE: Why are the populations the size they are? GROWTH: How does a population grow? 2 Types of Growth:o Exponential: Population continuously multiplyingo Logistic: Population grows quickly, then levels out over timeLecture 2 (September 9) Population: Controls on Size and Growth:o Biotic Factors: Competition, Predation, Parasites, Mateso Abiotic Factors: Light, Topography, Nutrients, Water, Climate Competition-occurs only when something is limitedo Two Types: Intraspecific Competition: Same species compete over resources Interspecific Competition: Many species compete over resourceso Competition has the greatest impact on a population when there is a limited resource for a single species Density-how tightly packed together a population iso Two types of factors that affect the population Density Dependent: Density affects the impact of the factor (Disease) Density Independent: Density does not affect the impact of the factor (Drought) What we can learn from studying populations:o Changes in climateo Changes in resourceso Changes in traits over time… evolutionEvolution Definition: Change in genetic makeup of a population over time (generational) Relative Fitness: Value of 0-1 describing the likelihood of a trait to survive and be passed down through generations 2 Equations to determine frequency of traitso p+q=1 p= percentage of dominant alleles q= percentage of recessive alleleso p2+2pq+q2=1 (Hardy-Weinberg Equation) p2= percentage of homozygous dominant genotype 2pq= percentage of heterozygous geneotype q2= percentage of homozygous recessive genotypeLecture 3 (September 11)Null Model: No Selection No Mutation No Gene Flow Random Mating Large Population SizeNatural Selection Requirements: Variation in traits Differences in fitness of genotypes Heritability of traitsSelection acts upon the phenotype, the expressed trait.Lecture 4 (September 16)How to calculate the genotype frequencies of a population Starting Point: Know what percent of the population is homozygous recessive (what percentage is expressing recessive trait) Take the square root of that decimal to find q Plug q into the p+q=1 equation and find p Plug the values of p and q into the Hardy-Weinberg equation P2= %AA, 2pq= %Aa, q2= %aa*Detailed example with flower population in Lecture Note 4Lecture 5 (September 18)Student Questions/Answers Non-evolving populations need a large population size because large populations are less likely to change genetically based on random events due to their greater genetic variability. Initial Allele frequency is the frequency of the dominant allele at generation 0. (PopG) Genetic drift is typically found in small populations when there’s really random population changes that differ greatly from the theoretical line (PopG); Gene flow is the immigration and emigration of individuals from populations. Mutation is a random event due to mismatching in genes of an individual; natural selection occurs when an individual is better adapted to its environmental conditions. Natural selection can act upon mutations. If there’s a population that has all 5 conditions of the null model, but a mutation occurs that gives individuals an advantage, the population then has potential to be evolving**Go over the practice essays and rat population activity discussed in discussion groups.**Do practice PopG activities to prepare for questions on
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