Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Ecology – study of relationships among organisms and between organisms and the nonliving environment

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Levels of ecological organization Population ecology = investigates the quantitative dynamics of how individuals within a species interact Community ecology = focuses on interactions among species Ecosystem ecology = studies living and nonliving components of systems to reveal patterns -Nutrient and energy flows

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Population ecology - quantitative dynamics of how individuals within a species interact 1. Population Size 2. Population density = # individuals/unit area -High densities -easier to find mates, -increased competition, -vulnerability to predation -Low densities -harder to find mates, -plentiful resources and space

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings 3. Population distribution (dispersion) arrangement of organisms within an area -Random -Uniform -Clumped –

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings 4. Age Structure Diagrams show the relative numbers of organisms of each age within a population – used to predict growth, stability, or decline

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings 5. Crude birth/death rates = rates per 1000 individuals Survivorship curves = the likelihood of death varies with age -Type I: More deaths at older ages -Type II: Equal number of deaths at all ages -Type III: More deaths at young ages

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Four factors of population change Natality Mortality Immigration Emigration Growth Rate Formula: -(Crude birth rate + immigration rate) - (Crude death rate + emigration rate) = Growth rate

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Exponential population growth Steady growth rates cause exponential population growth Increase by fixed % Graphed as a J-shaped curve Generally not sustainable

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Limiting factors restrain growth Limiting factors = physical, chemical and biological characteristics that restrain population growth -Water, space, food, predators, and disease Environmental resistance = All limiting factors taken together

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Logistic Growth Curve

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Carrying capacity (K) = the maximum population size of a species that its environment can sustain Limiting factors slow and stop exponential growth – resulting in S shaped curve

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Perfect logistic curves aren’t often found

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings 2 Types of Limiting Factors Density-dependent factors = affected by population density - Increased risk of predation and competition for mates occurs with increased density Density-independent factors = not affected by population density -floods, fires, and landslides

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Biotic potential (r) = the ability of an organism to produce offspring K-selected species = long gestation, few offspring -Have a low biotic potential -Stabilize at or near carrying capacity -Good competitors - parental care r-selected species = animals which reproduce quickly -Have a high biotic potential -Little parental care

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings K-selected vs. r-selected species

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Population changes affect communities As population in one species declines, other species may appear Human development now displaces other species and threatens biodiversity -As Monteverde dried out, species from lower, drier habitats appeared -But, species from the cloud-forest habitats disappeared

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Challenges to protecting biodiversity Social and economic factors affect species and communities -Nature is viewed as an obstacle to development -Nature is viewed as only a source of resources -Human population growth pressures biodiversity

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Preserving biodiversity Natural parks and protected areas help preserve biodiversity -Often, they are underfunded -Ecotourism brings jobs and money to developing areas

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings QUESTION: Review Which of the following is NOT a part of the process of natural selection? a) Organisms struggle to survive b)Organisms limit the number of young they produce c) Individuals vary in their genetic characteristics d)Some individuals are better suited to their environment than others

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings QUESTION: Review Disruptive selection would result in which of the following? a)Dogs with black coats evolving whiter coats in colder areas b)Red and white flowers interbreeding, producing pink flowers c)Fish evolving bigger eyes as the water gets muddier d)A population of birds, some with thicker beaks that eat seeds and others with thinner beaks that eat insects

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings QUESTION: Review Biological diversity includes all of the following, except: a)Species diversity b)Genetic diversity c)Population diversity d)Community diversity e)All of these are included in the concept of biodiversity

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings QUESTION: Review Sympatric speciation would occur in.... a) One population that mates in May, and another that mates in June b) Two populations separated by the Mississippi River c) Two populations separated by a glacier d) Two populations separated by the Rocky Mountains

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings QUESTION: Review Which of these species is least vulnerable to extinction? a) A species with a population size of 50 individuals b) A species distributed throughout the United States c) A species that eats only river snails d) A species that lives on mountaintops

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings QUESTION: Review An ecosystem is defined as: a) The total living things on Earth b) Members of the same population that can interbreed c) Interacting species in an area d) Species and the nonliving material they interact with

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings QUESTION: Viewpoints Should we care whether a species goes extinct? a)Yes, because all life is important and valuable b)Yes, because we are causing this wave of extinction, so we should fix it c)We should not, because it’s natural d)I don’t care; it really does not affect me

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings QUESTION: Viewpoints Do you think humans are subject to limiting factors and, ultimately, a fixed carrying capacity? a)Yes, although we have raised the carrying capacity, there are limits to the number of humans the Earth can support b)Yes, but technology will keep raising the carrying capacity, so it’s not much of a problem c)No, humans are no longer constrained by environmental limits, due to our technology and ability to manipulate the environment d)I don’t care; it really does not affect me

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings QUESTION: Interpreting Graphs and Data Which of the following graphs shows a population that will have fewer individuals in the future? (a)(c)(b)(d)

Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings QUESTION: Interpreting Graphs and Data What does this graph show? a)The effects of carrying capacity on population growth b)A population that keeps growing c)The effects of exponential growth d)The effects of increasing carrying capacity