Organisms and the Relationships

Focus Question

What relationships among organisms
might exist for a bird who built its nest in a tree in the jungle?

New Vocabulary

abiotic factor

biome

biosphere
biotic factor

biological community

commensalism

ecology

ecosystem

habitat
niche

mutualism

limiting factor

parasitism

population

predation
symbiosis

tolerance

Review Vocabulary

species: group of organisms that can interbreed
and produce viable offspring; group of organisms
with a distinct evolutionary history

Ecology

• Organisms depend on other organisms and

nonliving factors in their environment for
survival.

• Ecology is the scientific discipline in which the

relationships among living organisms and the
interaction the organisms have with their
environments are studied.

Ecology

• Ecologists observe, experiment, and model

using a variety of tools and methods.

• A model allows scientists to visualize or

simulate a process or system.

• Scientists use physical models, mathematical

models, and computer models.

The Biosphere

• The biosphere is the portion of the Earth

that supports life.

• It includes landmasses, freshwater,

saltwater, lower portions of the atmosphere,
and areas beneath the Earth’s surface.

The Biosphere

Biotic Factors
• Biotic factors are living factors in an organism’s

environment.

• Interactions among organisms are necessary for

the survival of species in the same geographic
location.

Abiotic Factors
• Abiotic factors are the nonliving factors in an

organism’s environment.

• Organisms adapt to survive in the abiotic factors

present in their natural environment.