Ecology Accelerated Biology

Ecology o o Ecology – The scientific study of interactions among organisms and between organisms and their physical environment

Habitat vs. Niche o o Habitat – The physical area in which an organism lives. Within that habitat each organism has a niche o o Niche – The role that the individual plays in its environment

Biodiversity o o Biodiversity – The variety of organisms in a given area o o The rainforests and coral reefs are biomes of extreme biodiversity o o We estimate that there are 10 million species on earth and we have described only about 3 million o o Insects and plants are the groups of life with the most species diversity

Abiotic vs. Biotic Factors o o Biotic – Any living part of the environment with which an organism might interact o o Animals, plants, mushrooms, bacteria o o Abiotic – Any nonliving part of the environment o o Sunlight, heat, precipitation

Levels of Organization o Organism – One individual of one species o Population – All members of a single species in an area o Community – All the interacting organisms of different species living in a particular area o Ecosystem – Includes all of the organisms (biotic) and the nonliving (abiotic) environment found in a particular place o Biosphere – Consists of all life on Earth. Includes the land, water, and atmosphere

Primary Producers o o Producer – Green plants that convert light energy from the sun into chemical energy through the process of photosynthesis. Producers are autotrophs (self–feeder)

Consumers o o Consumer – Organisms that feed on producers and other consumers. Consumers are heterotrophs (other–feeder) o o Primary – First consumer in a food chain. Primary consumers are herbivores o o Secondary – Second consumer. May be an omnivore or carnivore o o Tertiary – Third consumer o o Top consumer – Final consumer in a food chain

Consumers o o Herbivore – Eats only plants o o Omnivore – Eats both plants and animals o o Carnivore – Eats only animals

Decomposers o o Decomposers – Organisms that feed on decaying matter. They recycle all of the nutrients within an ecosystem. Examples include bacteria, fungi, worms, and insects

Detritivores o o Detritivores – Scavengers that feed off dead animals, animal waste, and rotting vegetation

Food Chain vs. Food Web o o Food Chain – Series of steps in which organisms transfer energy be eating and being eaten o o Food Web – Network of feeding interaction (series of connected food chains)

Trophic Levels o o Trophic Level – Each step in a food chain or food web o o Producers always occupy the first trophic level o o Primary consumers occupy the second trophic level o o This is an herbivore o o Secondary consumers occupy the third trophic level

Ecological Pyramids o o Ecological Pyramids – Show the relative amount of energy or matter contained within each trophic level in a given food chain or food web o o Normally, about 10% of the energy available at one level is passed to the next trophic level o o Smaller numbers of organisms at higher trophic levels o o Three different types of ecological pyramids: 1. 1.Pyramid of energy 2. 2.Pyramid of biomass 3. 3.Pyramid of numbers

Ecological Pyramids

Pyramid of Energy o o Relationship showing the transfer of energy in each trophic level o o Only 1% of the sun’s energy is used by producers in the process of photosynthesis o o Each time energy is transferred form one tropic level to the next, only 10% is transferred, while the other 90% is lost to the environment in the form of heat

Pyramid of Biomass o o Relationship showing a decrease in biomass with each trophic level o o Biomass – The total amount of living tissue within a given trophic level o o Some organisms are never consumed o o Some parts of organisms aren’t consumed (teeth, bones, bark, etc.) o o Measured in grams of organic matter per unit area

Pyramid of Numbers o o Relationship showing a decrease in numbers of organisms with each trophic level o o Organisms at the bottom of the food chain will usually be more abundant because the higher trophic levels contain less energy and can support fewer organisms

10,000 phytoplankton 1000 aquatic insect larvae 100 dragonflies 10 trout 1 person

Biological Magnification o o Build–up of pollutant in organisms at higher trophic levels o o Ex) DDT in eagles and other birds o o Causes serious problems for top-level consumers, such as thin shells in eagle eggs

Biological Magnification DDT