Janine Fischer, Annie Goodstein, Elise Echeverria, Gabri Posard Population Ecology Janine Fischer, Annie Goodstein, Elise Echeverria, Gabri Posard

What is population ecology? the study of populations in relation to the environment

52.1 Dynamic biological processes influence population density, dispersion and demography population: group of individuals of a single species living in the same general area that rely on the same resources and are influenced by the same environmental factors

the number of individuals per unit area or volume Density the number of individuals per unit area or volume

Ways to determine density: Count all the individuals within the boundaries of the population Count the # of individuals in several plots within the boundary and take-average mark-recapture method: capture animals mark release set traps again count captured tagged and untagged animals to find ratio to determine population size

Ways density Fluctuates

Dispersion the pattern of spacing among individuals within the boundaries of the population

3 types of dispersion Environmental differences and social interactions contribute to variation in population ecology

Demography: study of the vital statistics of populations and how they change over time

Life Tables age-specific summaries of the survival pattern of a population cohort: group of individuals of the same age that are followed from birth to death in a life table difficult to construct for wild animals and available for only a limited number of species survivorship curve: a plot of the proportion or numbers in a cohort still alive at each age

Reproductive rates demographer focus on females in sexually reproducing species reproductive table: fertility schedule;an age specific summary of the reproductive rates in a population table tallies # of female offspring for each age group Reproductive output= proportion of females ate a given age breeding x number of female offspring from those breeding females

3 variables of life histories.. Life History: traits that affect organisms’ schedule of reproduction/ survival 3 variables of life histories..

2. How much baby makin’ happens Variables affecting organism’s life history 1. what age sex begins 2. How much baby makin’ happens 3. How many babies you get

Types of reproduction Big-Bang reproduction (semelparity): one shot reproduction Repeated Reproduction (iteroparity): multiple opportunities in life for baby makin’

Trade-offs Always a trade off between reproduction and survival ex: Female Deers reproducing having a higher mortality rate Mammals having 1 or 2 offspring adds to fitness of species Large number of offspring may be advantageous if few survive

52.3 Exponential Growth Model Growth in an Idealized and Unlimited Environment

Change in pop size = births - deaths Idealized situation Predicts birth and death rates

52.4 Logistic Growth Model More realistic Per capita rate of increase declines as carrying capacity is reached

Logistic Growth Model S shaped curve Works for populations of small animals that are grown in a constant environment Discounts many factors in the natural world

Logistic Growth Model Pop size = N Rate of Increase = rmax K = carrying capacity Per capita growth rate = (K-N) rmax (K-N) K K Population Growth Rate = rmax (K - N) K

52.5 Population Regulation Population Dynamics: complex interaction between biotic and abiotic factors that leads to variation in population size Stability and Fluctuation Metapopulation: divided population of species linked by immigration and emmigration

a population can either be density dependent or independent density dependent: birth and death rate do change with changes in the population density density independent: birth and death rate do not change with changes in the population density

What causes changes in the birth and death rates? competition for resources example: crowding in plants

Territoriality Health example: disease in cities v. rural areas

Predation Toxic Waste

Intrinsic (physiological factors) example: stress

Human Population People make more people Zero population growth= birth rate and death rate cancel eachother out Humans uniquely can control growth don’t have 100 kids

Age structure age structure: number of individuals at certain age Show’s social conditions & predicts the future

Human Global Takeover Earth carrying capacity can only hold 10-15 billion people Ecological footprint: a measure of human demand on the Earth’s ecosystem Ecological Capacity: based on a country’s resource base when they’ll run out of nonrenewable resources

The end. Jeoparty time

jeopardylabs.com/play/population-ecology16