Study of interactions between organisms and their environments. Ecology

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

Abiotic Factors Nonliving factors in an environment Examples: Radiation Light Heat (temperature) Wind (air currents) or Water currents in aquatic environments Water (moisture) Soil (mineral concentration) Fire

Organization of Life Organisms (species) Populations Communities Ecosystems Biosphere

Levels of Organization

Feeding Relationships Autotrophs – can capture energy from sunlight Heterotrophs – rely on other organisms for their food and energy Herbivores – eat plants Carnivores – eat animals Omnivores – eat plant and animals Decomposers – break down organic matter Sunlight is the main source of energy.

Trophic Relationships Autotrophs 1 st level consumers (herbivores) 2 nd level consumers 3 rd level consumers 4 th level consumers (top predators)

Feeding Relationships 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 Trophic level – each step in a food chain or food web

Food Web

Ecology Pyramids Energy pyramid – shows the relative amount of energy available at each trophic level

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

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

RULE OF 10 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 or lost as heat

Etymology Ecology: eco- (Gk. OIKOS, house) + -logy (the study of) Abiotic: a- (without) + -biotic (life) Biosphere: bio- (life) + -sphere (L. SPHERA, globe)