BIOL 1108 Edition 1nd Lecture 22 Outline of Last Lecture I Learning Objectives II Definitions III Animal Signs and Communication IV Linking Experience and Behavior V Survival and Reproduction VI Inclusive Fitness and Altruism VII Dispersal Outline of Current Lecture I Learning Objectives II Defining Populations III Bide IV Population Monitoring V Demography VI Life history VII Population Models VIII Population Regulation Current Lecture I Learning Objectives These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute II III IV V VI Describe how life table and survivorship curves represent populations over time Describe trade offs between survival and reproduction life history traits Relate population growth to organisms environments abiotic and biotic Defining Populations Population a group of individuals of the same species that live in the same general area i e potential of interacting o Abundance the number of individuals Density the number of individuals per unit area or volume Dispersion distribution the spacing of individuals in a population o Affected by resources Clumped Uniform Random Bide B births I immigration o Births and immigration add individuals to a population D deaths E emigration o Deaths and emigration remove individuals from a population Population Monitoring Observe what animals are doing Mark and recapture o For birds attach red and aluminum bands on their legs Demography Demography the study of vital statistics of populations and how they change over time o Ex Survival rates emigration ect o Death rate for females is less than males Life tables age specific summaries of survival o Typically of a cohort same age individuals Survivorship curves graphical representation o The proportion or numbers of a cohort alive at each age o 3 types Type 1 death rate is high once reaching a certain age Ex Humans Type 2 constant life line Ex Groundhog Type 3 most deaths when they are young but if they survive they live a long life Ex Sea turtles Life history VII VIII Traits that affect organism schedule of reproduction and survival It s about trade offs o Semelparity puts lots of energy into benefitting offspring for survival put all eggs in a basket o Iteroparity longer period of time to take care of one offspring multiple time Depends on how often an individual reproduces parental care and age of reproduction Population Models Change in population size over time B I D E Patterns of population growth o Populations grow by multiplication exponentially Logistic growth o dN dt rN 1 N K o r finite rate of increase under ideal conditions o N current population size o K carrying capacity Population Regulation What processes contributes to change in population size o Births and deaths o Dispersal immigration emigration What forces become more important as density increases o Population will fluctuate around carrying capacity o Extrinsic forces must be affecting these processes more as density increases What factors might decrease births increase mortality or increase dispersal out of an area when density increases o Limiting resources competition Places to live nesting sites territories space Food o Pathogens diseases Transmission rate increases with density o Predators and parasites Easier to detect capture prey host when density is high These are called DENSITY DEPENDENT FACTORS effect on birth rates death rates and dispersal rates changes as population density changes Because density dependent factors respond to population density they can REGULATE populations Density Independent factors effect on birth and death rates are independent of population size o Affects population size drastically o Ex Temperature precipitation storms droughts invasive species