Chapter 2: Principles of Ecology

Ecology

The study of the interactions between organisms and their environment Includes both Biotic (living) and abiotic (nonliving) factors

Abiotic factors might include:

Temperature

Water availability/quality

Terrain (mountains, flat land, etc.)

Soil chemistry

Etc.

The biosphere

The portion of Earth that contains life

Stretches from the high atmosphere to the deepest ocean

“Skin of an apple”

Levels of Ecological organization

Organism=1

Population=group of same species in same area who interbreed

Community=interacting populations

Ecosystem=communities and abiotic factors

Biosphere=portion of planet that supports life

So very important!

Within populations and communities, there is competition for limited resources (i.e. food, water, shelter, etc.)

2 types of ecosystems

Terrestrial= on, under, or near land

Aquatic=in water

These ecosystems do occasionally overlap (pelicans, frogs, etc) but are in their own category and are influenced by different things.

Habitat vs. Niche

An organism’s habitat is simply where it lives

An organism’s niche is the role or position of the organism in the habitat

Symbiosis

Sym=together (think “symmetry”)

Bio=life

Means “living together”

3 types, defined by how they impact one another

Mutualism (+/+)

Both organisms are benefitted

Commensalism (+/0)

One organisms gets a benefit, the other is unaffected

Parasitism (+/-)

One organism is benefitted, the other is harmed

Usually does not kill host, because it relies on it for survival

Nutrition and Energy Flow

Terms:

Autotroph: “Auto”=Self “troph”=nourishment

A.k.a. Producer

Organism that makes its own energy (ex. Plants and some bacteria)

Heterotroph: “Hetero”=other

A.k.a. consumers

Get energy from consuming other living matter (ex. Animals, fungi)

Decomposers

Break down dead/dying matter into nutritional materials (ex. Fungi)

Types of Heterotrophs

Herbivore-only eats plants

Carnivore=“only” eats other animals

Omnivore=eats plants and animals

Scavengers=only eat dead organisms

How energy moves through an ecosystem

Diagrams

Food chain-simple diagram showing where energy goes

Producer (Autotroph)→Primary Consumer (Herbivore)→Secondary consumer (carnivore)→Decomposer

NOTE: Arrows show where the ENERGY is going, not what is eating what

Food web

More complex than food chain

Shows all possible feeding relationships

More realistic, but seldom perfect

Trophic Levels

Feeding step in energy chain

Begin with autotrophs

1st order heterotroph (herbivore)

2nd order heterotroph (carnivore)

3rd order heterotroph (carnivore or scavenger

Decomposer (everything ends with decomposers!)

Energy Pyramids

Model to show how much energy is available at each level

As energy moves on, only a small portion (10%) is available at the next stage

The rest is lost to the environment as heat (metabolism) while with the organism

Biomass-mass of living matter at each level

Cycles in Nature

1. Water cycle

2. Carbon cycle

3. Nitrogen cycle

4. Phosphorus cycle

With a partner, draw each of the cycles using your own design (do not copy the book, but use it as a reference)

One person will dictate what to draw.

The second person will draw.

Switch roles for each one.

Both should be able to answer questions about the pictures.

We’ll vote to see which ones should be posted in the room.