Study of interactions between organisms and their environments.

Biosphere – life-supporting layer of Earth Biotic factors – all living organisms in a biosphere

Nonliving factors in an environment Examples: Air currents Temperature Moisture Light Soil

Habitat—the natural home or environment of an animal, plant, or other organism. Niche—a position or role taken by a kind of organism within its community. Antelope Habitat: grassland, savannah, etc. Niche: primary consumer Kangaroo Habitat: woodlands, grassy plains Niche: primary consumer

Producers– Autotrophs capture energy from sunlight Consumers– Heterotrophs rely on other organisms for energy Herbivores – eat only plants Carnivores – eat animals Omnivores – eat living plants and animals Detritivores -eat dead plants and animals

Producer— autotroph which captures energy from sunlight Primary consumer (herbivores, detritivores)— gets energy from eating producers examples—deer, pill bugs Secondary consumer (carnivores, omnivores, detritivores)— get most or all energy from eating primary consumers examples—fox, raccoon, catfish Tertiary consumers (carnivores, detritivores)— get most or all energy from eating secondary consumers examples—eagles, vultures Quaternary consumer— top level (apex) predators that eat all consumers but have no natural predators examples—orcas, lions Decomposers— break down organic matter (leftovers of dead plants and animals) examples—fungi, bacteria

Food chain – a series of steps in which organisms transfer energy by eating and being eaten Food web –the feeding relationships that form a network of complex interactions (more realistic…why?) Trophic level – each step in a food chain or food web

Food Web Quaternary consumers

Mutualism— both species benefit from the relationship Examples—rhino & oxpecker, E. coli & human gut Commensalism — one organism benefits and the other is neither helped nor harmed Examples—clownfish & sea anemones, spanish moss growing on trees Parasitism — one organism benefits and the other is harmed Examples— tapeworms in your intestines, wasp larvae in caterpillar

Energy pyramid – shows the relative amount of energy available at each trophic level Sunlight is the main source of energy. Energy passes from one level to another in only one direction. Matter passes from level to level in a cycle (the circle of life).

Biomass pyramid – represents the amount of living organic matter at each trophic level

Pyramid of numbers – shows the relative number of individual organisms at each trophic level

Only 10% of energy is transferred from one trophic level to the next. Example: It takes 100 kgs of plant materials (producers) to support 10 kgs of herbivores It takes 10 kgs of herbivores to support 1 kg of 1 st level predator The other 90% is used up in life processes or released as heat