Introduction to EcologyEcology is the study of the interactions between organisms and the living (BIOTIC) and nonliving

(ABIOTIC) components of their environment.

BIOTIC FACTORS ABIOTIC FACTORS

predators weather (ie. wind)

prey climate (ie. temp.)

available mates available water

available food

Levels of Organization• Just like there is a hierarchy of organization among

different organisms, there is a hierarchy within the environment as well.

The Biosphere– The biosphere includes all places life exists, including three

main parts:• land• water• air (atmosphere)

– The biosphere is a thin film of life covering an otherwise lifeless planet

• If the Earth were an apple, the biosphere would be the skin of the apple.

Biomes & Ecosystems• A biome is a grouping of related ecosystems with similar

climates.

Ecosystems includes all of the organisms and the nonliving environment found in a particular place.

The environmental factors that interact in an ecosystem are divided into two classes: biotic and abiotic factors.

Biotic factor (living components of the environment)

Abiotic factors (nonliving factors of the environment)

The biotic and abiotic factors are dependent on each other.

Communities, Populations, & Organisms• A community is a group of different populations that live

together in a defined area.– ie. a pond ecosystem, the community would be all the

fishes, turtles, algae, bacteria and plants w/in the ecosystem

• A population includes groups of individuals that belong to the same species and live in the same area.

ie. all the mud turtles in the pond

• An organism is an individual within a population ie. ONE, single mud turtle in the pond

• A species survival in a given habitat is dependent on the environmental conditions and the availability of resources (limiting factors – food, energy, habitat, water, sunlight).

• Resources (limiting factors) are the energy and materials that a species needs.

• A niche is a species way of life. A niche is the role that the species plays in the environment that it lives in.

• Niche includes:1. range of conditions that the species can tolerate2. methods by which the species can obtain the needed

resources3. number of offspring4. time of reproduction5. all of the species other interactions with its environment

• The fundamental niche is the range of conditions that a species can potentially tolerate and the range of resources it can potentially use.

• The realized niche of a species is the range of resource it actually uses.

• The fundamental niche will usually contain a broader set of conditions that the realized niche.

• A species niche can change within a single generation.– ie. caterpillar to butterfly

• Generalists are species with broad niches:– The species can tolerate a

range of conditions and use a variety of resources.

• Specialists are species that have narrow niches.