 oekologie Energy and nutrients too

Ecology Scientific study of interactions between different kinds of living things and the environments in which they live. The biosphere is the living world Ecologist study living systems from single celled organisms to earth as a whole

Ecology (bet you didn’t know or mention this in History for extra credit) Linnaeus wrote the Oeconomy of Nature in 1749 –Nature was made for human benefit Adam Smith (founder of economics) was a follower of Linnaeus –Nature exists to be exploited for wealth by humans Modern economic models do not concern themselves with environmental wealth

Energy from the Sun Plants are primary producers (same as autotroph) –Produce living tissue from non-living sources –Water, CO2, energy –Remember fixation Non-plants are consumers (same as heterotroph) –Cannot make living tissue from simple non living sources –Need to consume producers to get the energy and nutrient they need

Different Heterotrophs Herbivores (eat autotrophs) Carnivores (eat other animals) Omnivores (eat both plants and animals) Parasites (obtain energy and nutrient from living hosts) Decomposers (eat dead plants or animals or their waste products)

Energy Flow in the Biosphere Flow of energy is from sunlight to tissues in primary producer to tissue of the consumers to the tissues of the decomposers Every step in this process is called a trophic level

Energy efficiency The greater the number of trophic levels between consumers and primary producers, the smaller the amount of energy that is available to the consumers compared to the energy originally captured by the primary producer Only 10% of the energy from one trophic level can be used by the next trophic level

Energy efficiency The energy chain from primary producer to herbivores to carnivores creates an ecological pyramid Three types of ecological pyramid (show decreasing amounts of energy, numbers of organisms, mass of living tissue at successive trophic levels) –Pyramid of energy –Pyramid of numbers –Pyramid of biomass –(See graphs on page 290)

Nutrients The chemical building blocks of life Remember what these are (macromolecules are made of them?) Review photosynthesis Review metabolism (anabolism and catabolism) Nutrients move from one trophic level to the next

Energy versus Nutrients Energy Flow: Sun to chemical energy to mechanical energy to heat to biosphere –Energy is conserved but not recycled Nutrient Flow: Like energy, nutrients are not destroyed as a result of use by living things –They are either parts of tissue or waste products –The are passed from one organism to another and one part of the biosphere to another –Nutrients are cycled

Nutrient cycles Passing the same nutrients over and over again through different parts of the biosphere Cycles are closed loops, something flows continuously Nutrients do not arrive from outer space, what is here is here for the most part

Three Important cycles Water cycle (see page 81) Nitrogen cycle (see page 84) Carbon cycle (see page 82) These are just examples: all nutrients have a cycle (sulfur cycle, phosphorus cycle….)

Ecosystem productivity Ecosystem is a localized section of the biosphere Productivity is measured by the rate of energy capture by the autotrophs Productivity can be limited by one nutrient (N, P, K, O for example) Nutrient limitation means one nutrient in short supply

Food Webs Food chain: sequence of organisms related to one another as predator-prey There are no food chains in nature (no straight line relationships) Food webs: the complex feeding relationships that exist in nature

Food web examples Coastal salt marsh (see page 298) Marine food web –Open ocean –Upwelling zone

Bonus Material: Major Carbon Pathways Four pathways simultaneously occur in the carbon cycle –Biological pathway Photosynthesis, respiration, death and decay –Geochemical pathway Release of CO2 to atmosphere by volcanoes and rock weathering CO2 exchange between oceans and atmosphere –Biogeochemical Burial and conversion of once living things (coal, fossil fuel) –Human pathway Clearing forest, burning, mining

Carbon data conflict Some researchers say most carbon travels in the geochemical pathway Others say most travels in the biological and biogeochemical pathway Human activity results in an increase in atmospheric carbon, without a corresponding activity to lower it CO2 in the atmosphere is a greenhouse gas, adsorbs heat and reflects it back to earth instead of letting it escape to space. This is the warming in global warming.