ECO: “home”OLOGY: “study of”

…the scientific study of the interactions among organisms and between organisms and their environments.

34.1 The biosphere is the global ecosystem.

Biotic Factors - “Living factors”

• include all living organisms (plants, animals, microbes)

Abiotic Factors - “Non-living factors”

• include all nonliving physical and chemical conditions (light, air, water, temperature, minerals, soil, climatic aspects)

The 5 Levels of Ecology

Biosphere

Ecosystems

Communities

Populations

Organisms

Individual organisms

The smallest unit of ecological study

Populations

A group of individual organisms of the same species living together in a specific area

Communities

All of the organisms of all species that inhabit a particular area

Ecosystems

Includes all of the biotic and abiotic factors in an area

Biosphere

Includes all of the ecosystems in the world

Habitats

specific environments in which organisms live

Niche• unique living

arrangement of an organism defined by its habitat, food sources, time of day it is most active, and other factors

Symbiosis• “Sym—biosis” = “Together—Living”• Definition:

–Symbiosis is a close ecological relationship between the individuals of two (or more) different species.

Who Benefits?

• Sometimes a symbiotic relationship benefits both species, sometimes one species benefits at the other's expense, and in some cases neither species benefits.

Types of Interactions

• Commensalism, Mutualism, Interspecific Competition, Predation, and Parasitism are all examples of symbiotic relationships.

Type of Interaction

Effect on Species 1

Effect on Species 2

Neutral relationship 0 0

Commensalism + 0

Mutualism + +Interspecific Competition - -

Predation + -

Parasitism + -

Table of Interactions

Neutral Relationship

• Neither species benefits from the interaction

Commensalism

• One species benefits, the other is unaffected

Mutualism

• Both species benefit from the interaction

Interspecific Competition

• Neither species benefits from the interaction

Predation

• One species (predator) directly harms the other (prey)

Parasitism

• One species benefits (parasite), the other is harmed (host).