Feeding Relationships and Energy Flow in Ecosytems

Ecological principles Study of relationships between living organisms (biotic) and their environment(abiotic- sunlight,temperature, moisture,nutrients)

Species Estimated 5-100 million,1.8 million named we don’t know how many others may exist that we haven’t yet found “groups of organisms that resemble one another in appearance, behavior, chemistry, genetic make up and breed with one another to produce fertile offspring”

Levels of organization Population – interacting individuals of the same species occupying a specific area Community – populations of all species occupying a particular place, complex interacting network of plants, animals and microorganisms Ecosystem – communities interacting with each other and their non-living environment Ecosphere/Biosphere – all ecosystems

Characteristics of living things Made up of cells Characteristic DNA found in each cell Transform matter and energy to supply their needs(metabolism) Maintain constant internal balance(homeostasis) Perpetuate themselves Adaptation and evolution

Earth’s Life support systems – major components

Types of Organisms and Role in Food Chain

Terrestrial Food Chain and Nutrient Flow

Category and Type of Organism Feeds on/ Food from Examples Trophic Level  

Types of organisms Herbivores- eat plants (examples) Carnivores- eat animals (examples) Omnivores – eats plants and animals (examples) Scavengers – eats dead organisms Detritivores – Detritus Feeders- live off detritus (parts and wastes of living organisms) Decomposers- recycle organic matter in ecosystems by breaking down dead organic matter and releasing the inorganic compounds into the soil and water to be used as nutrients by producers

Category and Type of Organism Feeds on/ Food from Examples Trophic Level  

Decomposers Bacteria ,fungi Cycle nutrients by breaking down dead organic matter, releases simple inorganic compounds into the soil, taken up by producers

Category and Type of Organism Feeds on/ Food from Examples Trophic Level  

Feeding RelationShips & Trophic Levels Trophic Level- step in a food chain or food web, “feeding step/stage” 1. Producers/Autotrophs- Photosynthesizers- green plants that perform photosynthesis Chemoautotrophs- obtain carbon through chemosynthesis- the biological conversion of carbon molecules (usually CO2 or CH4 ) and nutrients into organic matter using the oxidation of inorganic molecules or methane as a source of energy 2. Primary consumers – herbivores 3. Secondary consumers – carnivores that feed on herbivores or omnivores 4. Tertiary consumers – feed on other carnivores

Consumers Producers Herbivore Omnivore Carnivore Decomposer Scavenger Category and Type of Organism Feeds on/ Food from Examples Trophic Level Producers Creates own food with energy from the sun Grass, flowers, acorns, trees First/Bottom Consumers Herbivore Producers only Deer, cows, sheep, grasshoppers Primary consumer Omnivore Producers and consumers Bears, pigs, gorillas, rats, raccoons, cockroaches, humans Primary/ secondary consumer Carnivore Consumers only Lions, hawks, snakes, sharks, spiders, alligators, whales Secondary/Tertiary consumer Decomposer Breaks down dead organisms and returns nutrients to soil, water and air Fungi and bacteria Tertiary consumer Scavenger Eats dead and decaying organisms Vultures, hyena

PhotoSynthesis 6H20 + energy + 6CO2  C6H12O6 + 6O2 Performed by green plants Plants/Producers use photosynthesis to make the sugars they need to survive. The equation for photosynthesis is: Water + Sun energy + carbon dioxide  Glucose (sugar) and oxygen 6H20 + energy + 6CO2  C6H12O6 + 6O2

Food webs and Energy flow-complex network of interconnecting food webs

Food chains-all organisms are potential food for other organisms Always start with a producer, without a producer there is no energy for the first level The arrow shows the path of energy flow This means that the arrow points to the organism doing the eating or “to the belly”

Food webs show all of the feeding relationships in the ecosystem A food web should show a variety of plants and animals and how they relate in terms of feeding relationships

Food web – grazing Plants – herbivores- carnivores- decomposers

Food web – detrital Producers – decomposers – detrivores (forests, streams, marshes)

Energy efficiency More trophic levels = greater energy loss Rarely more than 4-5 trophic levels Always very few top carnivores- not enough energy to support too many 90% of energy is used with each trophic level, 10% of original energy is still available to the next trophic level

Ecological pyramids Graphic representation of organisms, energy, biomass available in an ecosystem Ecological efficiency varies from 5-20% energy available between successive tropic levels. About 10% efficiency

Biomass The dry weight(because water is not a source of energy) of all organisms at that tropihic level. Represents the amount of stored energy Energy in biomass transfers from one level to another(5-20%) with certain amount of energy lost as heat at each transfer(80-95%)

Pyramid of numbers Graphic display estimating the number of organisms at each trophic level

Gross Primary Productivity (GPP) The rate at which an ecosystem producers capture and store a given amount of chemical energy as biomass in a given length of time Greatest – shallow waters near continent, coral reefs ,high upwelling regions of ocean Lowest – deserts, open ocean

Net primary Productivity(NPP) Rate at which producers store chemical energy by photosynthesis – rate at which producers use chemical energy by aerobic respiration Greatest – estuaries, marshes,tropical rain forest Lowest – open ocean, tundra, desert

Agricultural land Try to increase NPP and Biomass by adding water and nutrients(Nitrogen = nitrates ; phosphorous = phosphate)

Total global net productivity Land – 59%, aquatic – 49% Open ocean with low NPP but total contribution high because of vast expanse Tropical rain forest – nutrients in vegetation not soil, major contributor to NPP, only occupy 2% of land surface