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 1st level consumers (herbivores) 2nd level consumers 3rd level consumers 4th 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 1st 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)