Handout for Ap Bio

-Get into the world of Fun! This handout is about population ecology, YEAH!!!-
[Chapter 53 Handout]
What is a population?
Population: Group of individuals of the same specie living in the same general area. * Why is population ecology important? * Allows for monitoring of organisms impact on environment and also helps to regulate impact. * Helps to preserve populations of organisms. * Ecologists efforts have helped to preserve endangered animals such as the BALD EAGLE
TOOLS OF ECOLOGY * Hey, how do ecologist record data taken from large populations? * Great Question! The answer is: they use manageable numbers. With a little math, some estimation and magic, ecologists can accurately calculate the approximate size of a population using the mark and recapture method!
Density
* Density influences number of individuals per unit area or volume, reflects interplay of births, deaths, immigration, and emigration * examples are number of oak trees per square kilometer in Minnesota country or Escherichia bacteria per milliliter in test tube * Ecologists use a variety of sampling techniques to estimate densities and total population sizes
Dispersion
* Dispersion is affected by environmental and social factors * Dispersion is pattern of spacing among individuals within boundaries of population * Three kinds of dispersion -Clumped -Random -Uniform
Demography
* Many factors influence a population's size, density and dispersion. * Certain vital stats. will change from generation to generation, a common tool used to compare these changes is a life table. * Life tables present the death rates of different aged members of the same population
Survivorship Curves * y-axis is logarithmic and x-axis is relative scale, species with widely varying life spans are represented on the same graph
Exponential Model * Populations of all species have the potential to expand greatly when resources are abundant. * Per Capita Rate of Increase Change in = Births + Immigrant entering - Deaths - Emigrant Leaving Population population size * Exponential Growth dN = rmaxN dT
Logistic vs. Exponential Carrying Capacity * this is symbolized by K, as maximum population size that a particular environment can sustain * this varies over space and time with abundance of limiting resources * an example would be carry capacity for bats that can be high in a habitat with abundant flying insects and roosting sites, but lower where there is abundant food but less suitable shelters
Life History Traits * are evolutionary outcomes reflected in development, physiology, and behavior of organisms * life history involves 3 main variables: when re-production began, how often organism reproduces, and how many offspring produced per reproductive episode
Density dependent population growth * Density Dependent: Birth or death rate that does NOT change. * Density Independent: Death rate increases as birth rate declines. * Mechanisms of Density-Dependent Regulation
>Competition for resources, Predation, Toxic Wastes, and Intrinsic Factors, Territorial & Disease
Immigration, Emigration, and Metapopulations * emigration and immigration influence populations * when population becomes crowded and resource competition increases, emigration increases * metapopulation is formed when immigration and emigration are important when a number of local population are linked * metapopulation helps ecologist understand population dynamics and gene flow in patchy habitats
Regional Patterns of Population Change * Two possible configurations Zero population growth = High Birth - High death rate or Zero population growth = low birth rate - low death rate * Demographic transition -Movement from high birth/death rate to low birth/death
AGE STRUCTURE -Relative number of individuals of each age in a population -EXAMPLE ON NEXT SLIDE
What does the graph explain? -Shows the percent of population between Male and Female -X-axis = percent of population= Y-axis age -demonstrates around ages that we see birth rates increase or decrease -Afghanistan: Changes/ US: Some (Baby boom!) / Italy: No
AGE STRUCTURE PYRAMID!
Limits on population size * Ecological footprint: is the aggregate land and water area needed to produce all the resources a person or group of people consume and to absorb all of their wastes * to estimate the ecological footprint of the entire population is to add up all ecologically productive land on planet and divide by population * calculation yields approximately 2 hectares (ha) per person (1 ha= 2.47) * a typical ecological footprint for a person in United States is around 10 ha * a person in US, Canada, or Norway consumes about 30 times the energy that a person in central Africa does

Questions:
1. What is the difference between density and dispersion?

2. Label the dispersion patterns shown by each pattern in the figure below. Then explain what the dispersion patterns tell us about the population and its interactions?
3. What are the three variables form the life history of a species?

4. What is the exponential model?

5. What are the two configurations of patterns of population change?

6.What are three examples of limiting resources that can limit carrying capacity?

7. Explain the importance of immigration and emigration in metapopulations?

8. Compare and contrast both density-independent and density-dependent?

9. Can the world sustain an ecological footprint that is currently the average American footprint? Explain?

10.Why do infant mortality and life expectancy vary so greatly between Afghanistan, United States, and Italy?