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What is Ecology?
The study of the interactions between
organisms and their environment
Interactions between organisms is
not simply who eats who but varied,
some good some bad
Organization in the Environment
 Organism
 Populations
 Communities
 Ecosystems
 Biomes
 Biosphere
 Single animal
 Group of the same
animal
 Different populations in
the same area
 Includes the abiotic
factors
 Geographic area
characterized by certain
types of plant and
animal communities
 Earth where life exists
2 parts of ecology
Biotic factors
The living part of the environment
Animals, plants, insects, humans
Abiotic factors
The non-living part of the environment
Water, soil, light, temperature
Habitat vs. Niche
Habitat – the environment in which an
organism lives
When things like deforestation, building of
roads and buildings occur, habitats are being
destroyed
Niche – organisms way of life in the
ecosystem
Includes its habitat, food, predators,
competitors and abiotic factors
Niche of the Gray Wolf
Consumers
Carnivores, eating moose,
deer, reindeer, sheep and small
animals such as birds and
snakes
Social Structure – hunt in packs
Nurture and teach their young
Important in population control
Producers
Make their own food/energy
Use the sun to go through the
process of photosynthesis
Includes plants, algae and some
bacteria
Consumers
Can’t make their own energy, get it by
eating producers or other consumers
Herbivore – eats only plants
Carnivore – eats only animals
Omnivores – eats both plants and animals
Scavenger vs. Decomposer
Scavengers eat dead animals for
energy
Examples include turkey vultures
Decomposers get energy by breaking
down the remains of dead organisms
Recyclers, bacteria and fungi
Predation
Prey – the organism that is eaten
Predator – the organism doing
the eating
Adaptations
Predator – speed or ambush prey
Prey – run away, camouflage,
poisonous, bright colors, groups
Competition
Can occur among individuals within a
population or between populations
Competition for resources, mates,
space
Symbiosis
Long term, association between
two or more species

Mutualism
Both organisms benefit
Commensalism
One organism is
benefiting and the
other is unaffected
Parasitism
One organism is
harmed and the
other is benefiting
Limiting factors
Populations cannot grow indefinitely
because the environment contains
only so much food, water, living
space and other resources
When one or more becomes scarce,
it becomes a limiting factor
Carrying Capacity
The largest population that a
given environment can support
over a long period of time
When the population gets larger
than carrying capacity, limiting
factors will cause the population
to get smaller
Food Chains and Webs
Food chains represent how energy
flows from one organism to the next
Rare in nature because animals
usually eat more than one organism
Food webs represent many pathways
that energy flows in an ecosystem
Energy Pyramids
Represents the
loss of energy
by each
organism in a
food chain or
web
Coevolution
Long term change that takes
place in two species because of
their close interactions with each
other
Herbivores evolving with the
plants they eat
Flowers and their pollinators