ENVIR ST 360 1st Edition Exam 1 Study Guide Lectures 1 5 Lecture 1 September 4 Levels of Study Individuals Populations Communities Ecosystems Biosphere Earth from narrowest to broadest Population 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 time o 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 multiplying o Logistic Population grows quickly then levels out over time Lecture 2 September 9 Population Controls on Size and Growth o Biotic Factors Competition Predation Parasites Mates o Abiotic Factors Light Topography Nutrients Water Climate Competition occurs only when something is limited o Two Types Intraspecific Competition Same species compete over resources Interspecific Competition Many species compete over resources o 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 is o 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 climate o Changes in resources o Changes in traits over time evolution Evolution 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 traits o p q 1 p percentage of dominant alleles q percentage of recessive alleles 2 o p 2pq q2 1 Hardy Weinberg Equation p2 percentage of homozygous dominant genotype 2pq percentage of heterozygous geneotype q2 percentage of homozygous recessive genotype Lecture 3 September 11 Null Model No Selection No Mutation No Gene Flow Random Mating Large Population Size Natural Selection Requirements Variation in traits Differences in fitness of genotypes Heritability of traits Selection 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 4 Lecture 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 exam