I. Ecology

A. the study of the interactions organisms have

with each other and with their environment.

B. word “ecology” by Earnst Haeckel in 1866

from the Greek “oikos” meaning “house economy”

C. Interactions happen in the biosphere

a. Thin layer of Earth where life exists

(5 mi below ocean to 3.5 mi above surface)

b. Divided into 3 regions:

1. Lithosphere-land

(rocks, sand, soil)

2. hydrosphere-water (oceans, lakes, rivers, clouds, underground)

3. atmosphere-layer of air surrounding Earth

II. Levels of organization in the biosphere

(species population community ecosystem biome biosphere)

A. Species

1. organisms that look alike and can reproduce

2. live in a specific environment called a habitat

3. biodiversity – the variety of species in an ecosystem

B. Population - group of the same species living in the

same place at the same time

C. Community - all of the populations living in an area

D. Ecosystem - all of the communities in an area plus the

abiotic factors of the environment.

1. biotic factors – living things in an ecosystem

2. abiotic factors – nonliving things in an ecosystem

Ex) temperature, rainfall, nutrients, etc

E. Biome – very large area with unique ecosystem because of

unique climate (temperature & precipitation)

III. Population Interactions

A. The maximum number of organisms that an area can

support is called the ecosystem’s “carrying capacity”

B. The carrying capacity is determined by limiting factors

1. Density-Dependent Limiting Factors

Things that affect large, dense populations more

than smaller, less dense populations.

Ex: food, space, disease

2. Density-Independent Limiting Factors

Things that affect populations regardless of their

size or density.

Ex: floods, fire, drought

Carrying Capacity

~80 Deer

C. Limiting factors cause populations to interact in several ways:

1. territories - establishment of own area

2. predator/prey-one organism kills another

3. symbiosis - two organism living closely

a. parasitism-one organism feeds off another without

killing it (one benefits, one is harmed)

b. mutualism-both organisms benefit

c. commensalism-one organism benefits, other is

unaffected

V. Ecosystems

1. each organism in an ecosystem has a specific niche

a. the role/job of an organism in an ecosystem.

b. how it deals with the biotic and abiotic

forces in its habitat.

c. what it eats, what it feeds, where it lives, how it

reproduces, etc.

2. Ecosystem are all about energy flow

a. all energy on Earth originates from the sun

b. an ecosystem is made of many trophic levels

Step in Food

Chain

Name of Trophic

Level How it Feeds

Other Terms to Describe this Trophic

Level

1st producer

Autotroph

(energy from sun) Plants

2nd Primary Consumer Heterotroph

(eats P’s) Herbivores

Organisms that are

PC’s + any other

Consumer are

Omnivores

3rd

Secondary

Consumer

Heterotroph

(eats PC’s) Carnivores

4th Tertiary Consumer Heterotroph

(eats SC’s) Carnivores

5th Quaternary

Consumer

Heterotroph

(eats TC’s) Carnivores

Final Decomposers Heterotroph

(eats dead things) Fungi & Bacteria

Return the stored

energy & nutrients

back to the PC’s

c. several ways to show energy flow in an ecosystem:

1) food chains=simple order of who-eats-who

*overly simplified

*unstable

2) food pyramids=show how the energy in each

trophic level decreases.

*10% Rule – only 10% of the energy passes

along to the next trophic level.

Producers

(Autotrophs)

Primary

Consumers

(Heterotrophs)

Secondary

Consumers

(Heterotrophs)

Tertiary

Consumers

(Heterotrophs)

3) Food webs=network of food chains showing all

feeding relationships in an ecosystem.

*more realistic than a food chain

*show ecosystem stability

d. Not only energy flows through an ecosystem.

Pollution also gets passed along from one level to the next

and gets stronger as it collects in the organism at the top of

the food chain. This process is called

biological magnification or

bioaccumulation.

Examples of Bioaccumulation:

1. DDT - bald eagles nearly went extinct because the fish

it ate had eaten bugs killed by DDT pesticides. The

eagles’ eggs had shells that were too thin to survive

because of the pollution passed along the food chain.

2. PCB’s-chemical used to make electrical

insulators and wood sealants

-carcinogenic

-build up in fat

3. Heavy metals

*lead-from batteries, old paint, water pipes

-birth defects, brain damage

-“Mad Hatter’s” disease

(tremors, nerve damage, insanity)

-build up in fish fat

*mercury-from mines and paper mills

-brain damage, deformities

-also builds up in fish fat

VI. Natural Ecosystem Change

A. most ecosystems change over time in a predictable

sequence called ecological succession.

B. Communities and niches appear and disappear.

C. Steps in land succession:

1. pioneer species

-the first organisms to colonize bare rock

-mosses, insects, lichens

secrete enzymes that

break rock into sand

*weathering and lichens turn rock into soil

2. Intermediate Species

grasses and shrubs - build soil more

fast-growing trees

3. Climax community (oak and maple trees)

-not replaced by another

community unless the

area is disturbed by fire, flood,

logging, etc.

Different areas of the world have different abiotic factors

(temperatures, rainfall, etc.) so they develop different

climax communities.

An area with a unique climax

community is called a biome.

Ex) rain forest, desert,

tundra, savanna, etc.

D. Primary vs. Secondary Succession

E. Steps in Lake Succession:

1. Oligotrophic lake

-clear, cold water with

lots of oxygen

-sandy bottom

without weeds

-few nutrients

-salmon, trout

-Lake Michigan

2. Mesotrophic lake

-starting to fill in

with debris

-warmer, murkier,

weeds, lower oxygen

-bass, bluegill

-Muskegon Lake

3. Eutrophic lake

-very much filled in

with debris

-warm, muddy, shallow,

no oxygen

-frogs, snakes, carp

-Muskegon Marsh

*people speed up the eutrophication (aging) of lakes

by putting excess nutrients into the water from

lawn fertilizers and sewage.

VII. Ecosystem Disruption

A. Each part of an ecosystem is

necessary and interdependent

B. Several things can cause an

ecosystem to become unstable

and potentially collapse:

1. Stochastic Events – natural disruptions such as

storms and earthquakes

2. Removal of a Species – “The Lesson of the Kaibab”

3. Pollution – the wrong substances in the wrong

place in the wrong quantity

a. point-source pollution=from a single

identifiable place (factories, dumps, etc)

b. nonpoint-source pollution=from many places

(parking lot runoff, lawn fertilizers, etc)

4. Habitat Fragmentation – breaking one large area into

several small areas.

a. interrupts territories

b. interrupts migrations

c. increases edge area

5. Invasive Species – nonnative organisms that disrupt

established ecosystem energy flow.

Examples of Invasive Species of the Great Lakes:

Zebra Mussels & Quagga Mussels

Sea Lamprey

So, how’d they get here???

Emerald Ash Borer

Eurasian Watermilfoil & Curly-Leaf Pondweed

Round Goby

And the famous………

Asian Carp

Management plans for invasive species typically involve 4 steps:

1. Prevention

How are we trying to keep it from spreading to

other areas?

2. Detection

How do we know that it is in an ecosystem?

3. Control & Management

How are we trying to get rid of it?

4. Restoration & Rehabilitation of the Ecosystem

How are we trying to fix an ecosystem once the

invasive population is reduced or eliminated?

VIII. Cycles of Matter

A. Water Cycle

B. Carbon Cycle

IX. Fossil Fuels – carbon from the remains of organisms

that lived long ago.

A. Types of Fossil Fuels:

1. Coal-compacted plant remains from ancient

swamps.

-burned to heat water to spin turbines to

make electricity.

2. Petroleum-liquid formed from remains of

microorganisms in ancient seas.

-made into gasoline, grease, oil, plastics

3. Natural Gas-gas formed along with petroleum

-cleaner burning

B. Problems with fossil fuels

1. nonrenewable-can’t make more

2. hazardous to extract & transport

3. puts carbon (CO2) into atmosphere that is

supposed to be locked up underground.

X. Our Atmosphere

A. Greenhouse Effect-natural process of Earth’s

atmosphere trapping sun’s energy to keep warm.

B. PROBLEM: burning fossil fuels thickens the CO2 layer

around Earth and too much heat is trapped in,

resulting in “Global Warming”.