Study of interactions between organisms and their environments.

Biosphere – life-supporting layer of EarthBiotic factors – all living organisms in a

biosphere

Nonliving factors in an environmentExamples:

Air currentsTemperatureMoistureLightSoil

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

KangarooHabitat: woodlands, grassy plainsNiche: primary consumer

Producers– Autotrophs capture energy from sunlight

Consumers– Heterotrophs rely on other organisms for energyHerbivores – eat only plantsCarnivores – eat animalsOmnivores – eat living plants and animalsDetritivores -eat dead plants and animals

Producer—autotroph which captures energy from sunlight Primary consumer (herbivores, detritivores)—gets

energy from eating producersexamples—deer, pill bugs

Secondary consumer (carnivores, omnivores, detritivores)— get most or all energy from eating primary consumersexamples—fox, raccoon, catfish

Tertiary consumers (carnivores, detritivores)—get most or all energy from eating secondary consumersexamples—eagles, vultures

Quaternary consumer—top level (apex) predators that eat all consumers but have no natural predatorsexamples—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 WebQuaternary consumers1 2 3

4

Mutualism—both species benefit from the

relationshipExamples—rhino & oxpecker, E. coli & human gut

Commensalism—one organism benefits and the other is neither helped nor harmedExamples—clownfish & sea anemones, spanish

moss growing on trees

Parasitism—one organism benefits and the other is harmedExamples—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 1st level predator

The other 90% is used up in life processes or released as heat