2 What is Ecology? Ecology – study of the interactions among organisms and between organisms (biotic) and their abiotic environment.BioticLiving component of the environmentEx: birds, insectsAbioticNonliving or physical components of the environment Ex: light, oxygen
3 What is Ecology? Levels of Biological Organization Ecologist are most interested in the level that includes or is above an individual organism. (From elephant )Levels of biological organization: Starts with the atom, which combines to form a molecule -> cells -> tissues -> organs etc.
4 What is Ecology? Ecological Levels of Organization: Level after organism is population. Population: A group of organisms of the same species that live together in the same area at the same timeSpecies: A group of similar organisms whose members freely interbreed with one another in the wild to produce fertile offspringPopulation: group of organisms of the same species that live together in the same area at the same time
5 What is Ecology? Ecological Levels of Organization: Populations are organized into communitiesCommunity: all the populations of different species that live and interact together within an area at the same time
6 What is Ecology? Ecological Levels of Organization: Ecosystem processes collectively regulate global cycles of water, carbon, nitrogen, phosphorus and sulfur, which are essential to the survival of human and all other organismsEcosystem: A community and its physical environment
7 What is Landscape Ecology? A subdiscipline that studies ecological processes that operate over large areasLandscape –encompasses larger area and several ecosystemsBiosphere –the whole earth
8 The Energy of Life What is energy? Energy exist in different forms The capacity or ability to do workEnergy exist in different formsChemical, radiant (light), thermal (heat), mechanical, nuclear, electricalUnitsKilojoules (kJ)Kilocalories (kcal)1 kcal = kJ
9 The Energy of Life Potential vs. Kinetic Energy This is stored energy Law of conservation of energy: energy cannot be created or destroyed, but is changed from one form to another.This is stored energyThis is the energy of motionPotential energy changed into kinetic energy when the arrow is released
10 The Energy of Life Thermodynamics – Thermodynamics: The study of energy and its transformationsClosed system: does not allow sunlight inOpen system: radiant energy free to move back and forth
11 The Energy of Life 1st Law of Thermodynamics – energy can change forms, but is not created or destroyed2nd Law of Thermodynamics –“Entropy Rules!”amount of usable energy decreases as energy changes forms1st Law deals with quantity of energy,2nd Law with quality of energy.Entropy: A measure of the disorder or randomness in a system
12 The Energy of Life Photosynthesis 6 CO2 + 12 H2O + radiant energy C6H12O6 + 6 H2O + 6 O2SugarIn photosynthesis, energy from the sun is stored in plants
13 The Energy of Life Cellular Respiration C6H12O6 + 6 O2 + 6 H2O 6 CO H2O + energyIn cellular respiration stored energy is released to do work
14 The Energy of Life Case-in-Point: Life Without the Sun This picture shows a hydrothermal vent ecosystem found at the bottom of the oceanBacteria living in the tissue of the tube worm extract energy from hydrogen sulfide
15 The Flow of Energy Through Ecosystems Producers, Consumers, and DecomposersEnergy flows from ProducersTo ConsumersAnd finally to Decomposers
16 The Path of Energy Flow Food Chains – Shows the flow of energy in an ecosystem where energy from food passes from one organism to another.Starts hereEnds with decomposersNote that energy is lost as heat
17 Food Webs – How is a food web different from a food chain? A more realistic modelConsist of interlocking food chainsTakes into account different food sources for an organism
18 The Path of Energy FlowCase-in-Point: How Humans Have Affected the Antarctic Food WebBaleen whalesWhat would happen if you eliminated krill?KrillSquidFishesDuring the last 150 years (until the 1986 global ban on whaling), the hunting of whales steadily reduced the number of large baleen whales in Antarctic waters. As a result of fewer whales eating krill, more krill became available for other krill-eating animals, whose populations increased. This altered the ecosystem. Now that commercial whaling is regulated, it is hope that number of large baleen whales will increase and resume their former position of dominance in terms of krill consumption. Human-related change has thinned the ozone over Antarctica allowing more of the sun’s ultraviolet radiation to penetrate the atmosphere, which may damage the algae that forms the base of the Antarctic food web. Another human induced change is global warming. As the water warms, less pack ice is available to provide the food supply for the krill. In addition, fishermen have started to harvest krill to make fishmeal for aquaculture industries. The loss of krill effects the entire Antarctic food web including the many marine animals that depend on krill for food.Toothed whalesPenguinsSeals
19 The Path of Energy Flow Pyramid of Numbers Ecological Pyramids graphically represent the relative energy values of each trophic level.Pyramid of NumbersA pyramid of numbers shows the number of organisms at each trophic level in a given ecosystem.The organisms at the based of the food chain are the most abundant, and few organisms occupy each successive trophic level, giving the pyramid its shape.
20 Ecological Pyramids Pyramid of Biomass A pyramid of biomass illustrates the total biomass at each successive trophic levelBiomass is a quantitative estimate of the total amount of living material and indicates the amount of fixed energy at a particular time.
21 Ecological Pyramids Pyramid of Energy A pyramid of energy illustrates the energy content of the biomass of each trophic level.These pyramids always have large energy bases and get progressively smaller through succeeding trophic levels showing that most energy dissipates into the environment when going from one trophic level to the next.Pyramid of Energy
22 The Path of Energy Flow Example: Thermodynamics in Action Temperate forest: Primary producers = 1,500 g / m2Desert: Primary producers = 100 g / m2Food webs very complex, more tertiary consumers, some quaternary.Food webs very simple, very few tertiary consumers
23 The Path of Energy Flow Desert Biomass Pyramid such as . . . 13.5 kg coyote must range ~12 ha to subsist (30 acres).Desert Biomass PyramidTertiary consumers = 0.1 g / m2Tertiary consumers must range over large areas to obtain enough energy to subsist.Secondary consumers = 1.0 g / m2Primary consumers = 10 g / m2Primary producers = 100 g / m2
24 The Path of Energy Flow Temperate Forest Biomass Pyramid 13.5 kg coyote only needs ~1 ha to subsist (2.5 acres).Temperate Forest Biomass PyramidNOTE: just relative examples, not accurateTertiary consumers = 1.5 g / m2Secondary consumers = 15 g / m2Primary consumers = 150 g / m2Primary producers = 1,500 g / m2Also, possibility of quaternary consumers, like bears.
25 The Path of Energy Flow Ecosystem Productivity = Net Primary ProductivityGross Primary ProductivityPlant cellular respiration=
26 Net primary productivity (NPP) Plants respire to provide energy for their own use so that the energy in plant tissues after cellular respiration has occurred is the net primary productivity (NPP).The Net primary productivity represents the rate organic matter is actually incorporated into plant tissues for growth.Only the energy represented by NPP is available as food for an ecosystem’s consumers.
27 Gross Primary Productivity (GPP) Gross primary productivity (GPP) of an ecosystem is the rate energy is captured during photosynthesis. (Total energy)It is primary because plants occupy the first trophic level in food webs.
28 Human Impact on Net Primary Productivity Humans consume more of Earth’s resources than any other animal species.When both direct and indirect human impacts are accounted for, humans use 32% of the annual NPP of land-based ecosystems.Humans represent only 0.5% of the total biomass of all consumers and are in competition with other species’ needs for energy.Human use of so much of the world’s productivity may contribute to the loss of many species through extinction.To minimize this impact, humans must share terrestrial photosynthesis products, NPP with other organisms and control the population explosion.
29 The Path of Energy Flow Ecosystem Productivity Note that areas with more producers have a higher NPP