Ecology

What is Ecology?

Ecology is the study of the interactions of

organisms with one another and with their

physical environment.

Biosphere - part of the Earth in which life

exists.

Includes land, air, and water as well as life.

Living organisms are NOT distributed

uniformly throughout the biosphere.

The biosphere is large… …So ecologists work with smaller units

called ecosystems.

Ecosystem - consists of an area’s physical

features and living organisms.

System- a set of interacting or interdependent components that form an integrated whole

Abiotic factors - physical features

Ex. elevation, humidity, rainfall

(SWATS: soil, water, air, temp, sunlight)

Biotic factors - living organisms

Ex. snails, worms, plants, insects

Members of Ecosystems are

Related Community - all the populations of

organisms living in a given area. Ecosystems rarely function independently of one

another because they are connected by both living

and non living features.

Ecological Succession Ecological succession - an existing

community of organisms is replaced by a different community over time. Can occur where no living community

existed before (like a volcano arising from the sea).

Can also occur following a dramatic change (like a forest fire).

Succession leads to a collection of organisms called a climax community.

Biomes Biome - an environment that has a characteristic climax

community.

Terrestrial- associated with a land environment 1) Tropical

a. Tropical Rain Forest

2) Grassland

a. Tropical Grassland

b. Temperate Grassland

3) Desert

4) Temperate

a. Temperate Deciduous Forest

b. Temperate Rain Forest

5) Taiga

6) Tundra

Aquatic- associated with a water environment Freshwater- (rivers, streams, ponds, lakes, wetlands)

Estuaries

Marine (intertidal zone, coastal ocean, open ocean)

Habitat- an area that provides an

organisms with its basic needs for survival

Endemic species- a species found in its

originating location and is generally

restricted to that geographic area

Non-native species – species introduced

into an area outside of their rang by

accidental or deliberate human activity

-can also be called: introduced, invasive,

alien, nonindigenous, or exotic

Energy flow through

ecosystems

Of all the sun’s energy the reaches the Earth’s

surface, only about 0.1% is used by living things.

Energy cannot be recycled or used again!

For this reason, we refer to the movement of

energy through an ecosystem as a flow, not a

cycle.

Biochemical conversion- the changing of organic

matter into other chemical forms such as fuels

Bioenergetics- the study of energy flow (energy

transformations) into and within a living system

Energy flows through

ecosystems

The sun is the ultimate source of energy for living things.

Producers - organisms that make their own food via photosynthesis.

Consumers - organisms that get their energy directly or indirectly from producers. Primary consumers - also called herbivores;

plant eating animals. Secondary consumers - animals that eat

primary consumers.

Energy flows through

ecosystems

Trophic level - each step in a series of organisms eating other organisms. At each higher trophic level, less and less of

the energy originally captured by the producers is available. This is because the energy obtained from

digested food is used to maintain metabolism.

Only about 10% of the energy from one trophic level can be used by the animals at the next trophic level!

Energy Flows Through

Ecosystems

Herbivores - organisms that eat only plants.

Carnivores - organisms that eat only animals.

Omnivores - organisms that eat plants and animals.

Decomposers - organisms that obtain energy from

non-living organic matter

Energy

Pyramid

Ecosystem relationships

Food chain -

simplest feeding

relationship linking

animals and

plants in the

biosphere.

Usually contains 3-5

total organisms.

Ecosystem relationships

Food web -

complex

relationship formed

by interconnecting

and overlapping

food chains.

Biotic Interactions in an

Ecosystem Competition- finite amount of resources to

compete over

Predation- one species uses another as food

Symbiosis-a close and usually obligatory

association of two organisms of different species

that live together, often to their mutual benefit

Commensalism –one organism benefits without

affecting the other

Parasitism –one organism benefits (the parasite), at

the expense of the other (host)

Mutualism – each organism benefits

Nutrients are recycled through

an ecosystem

nutrients are recycled and used again

and again.

Biogeochemical cycle - nutrients use

these processes to move through the

biosphere.

Ex. Water, carbon, nitrogen, oxygen cycles

Nutrients are Recycled

Through an Ecosystem - Water

Cycle

Water cycle - movement of water between the atmosphere and Earth. Consists of alternating cycles of

evaporation and condensation.

Evaporation moves water molecules into the air while precipitation returns it to Earth.

Some water sinks into the ground (groundwater) while some runs along the surface of the ground until it enters a river or stream.

Nutrients are Recycled Through an

Ecosystem – Carbon Cycle

Carbon- required

for all organic

compounds

Carbon Cycle-

movement of

Carbon through

the biosphere

Nutrients are Recycled Through

an Ecosystem –Oxygen Cycle

Oxygen

Cycle-

movement

of Oxygen

through the

biosphere

Nutrients are Recycled

Through an Ecosystem -

Nitrogen Cycle

Nitrogen - element required by living

organisms to build proteins.

Nitrogen cycle - movement of nitrogen

through biosphere.

Most can’t be used directly by living

organisms - it must be converted into more

usable forms.

Nutrient limitation

The rate at which producers can capture

energy is limited by the amount of

available nutrients.

Limiting factor - the nutrient that is in short

supply that limits an organism’s growth.