Ecology : PopulationsEcology : Populations

Compare Exponential & Linear Population Growth

1. Exponential:

a. The population multiplies by the same number every week/month/year.

b. If a population has a constant birth rate through time and is never limited by food or disease

c. Occurs when number of organisms increases rapidly

d. Produces J-shaped curve on graph

***Unlimited Resources allow for this type of growth***

2. Linear:

a. The population adds the same number every week/month/year.

b. Shows slow steady growth

c. Birth & death rates are equal

d. Produces straight line on graph**Limited Resources cause this type of growth**

Limits to growthLimits to growth

• Limiting factors- a factor that causes population growth to decrease– Density independent: Usually are abiotic in nature; Any factor in the

environment that does NOT depend on the members in a population per unit area. Drought, Human disturbances

– Density dependent: Are usually biotic in nature; Any factor in the environment that depends on the number of members in a population per unit area. Competition, Predation,Parasitism, Disease

Describe Carrying Capacity

Carrying Capacity

1. The number of organism that an environment can support

2. Limits the population

3. Affected by: temperature, food supply, reproduction, hunting

Describe Factors that affect population size

1. Predation:

a. Predators limit number of prey

b. Pick out the sick, old, young

2. Competition:

a. Compete for resources

b. Water, food, living space, mates

3. Environmental changes:

a. pollution, thermal warming, unfit water, disease, all effect the population number

Write this below your graphs on Write this below your graphs on IN: 44IN: 44

• 4. Immigration- movement of organisms

into an area.

• 5. Emmigration- movement of organisms

out of an area.

Ex. Animals leave b/c they reach maturity,

Food shortage.

4. May cause species to become threatened or endangered

a. Threatened - when population declines rapidly

b. b. Endangered - when numbers are so low that extinction is possible in near future

c. Extinction - disappearance of species

Siberian tiger

Manatee

Bald Eagle

Use of Resources

A. Compare types of resources• Natural resource - part of natural

environment– EX: soil, water, crops, oil, gas, wildlife

• Renewable - replaced or recycled by natural processes (Biodegradable)

– EX: plants, animals, crops, soil

• Nonrenewable - available in limited amounts

– EX: fossil fuels, metals

Cover CropsLegumes, grasses, and othercover crops recycle soil nutrients,reduce fertilizer need, andprevent weed growth.

Controlled GrazingBy managing graze periods and herddensities, farmers can improve nutrientcycling, increase the effectiveness ofprecipitation, and increase the carryingcapacity of pastures.

Biological Pest ControlThe use of predators and parasitesto control destructive insectsminimizes pesticide use as well ascrop damage

Contour PlowingContour plowing reduces soil erosion from land runoff. On hilly areas, plowing is done across the hill rather than straight up and down.

Crop RotationDifferent crops use and replenish different nutrients. By rotating crops, the loss of important plant nutrientsis decreased.

A B C

Yr. 1

Yr. 2

Yr. 3

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corn

corn

corn

alfalfa

alfalfa

alfalfa

oats

oats

alfalfa (plowed in)

Ways to Sustain Agriculture-natural resources

Insects

BacteriaFungi

Plants

Protists Other Animals

54.4%

4.2%

18%

3.4%0.3%

19.7%

Section 6-3

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Species Diversity

C. Identify major sources of air, water, and land pollution

1. Pollution - contamination of any part of environment

2. Air pollutiona. Caused most by burning fossil fuelsb. Particulates - solid soot particles, form smogc. Can cause cancer, respiratory difficulties

3. Acid raina. Water mixes with carbon dioxide to form

carbonic acidb. Damages plants, affects fish, contaminates

waterc. More in cities and industrialized areas

Emissions to AtmosphereNitrogen oxidesSulfur dioxide

Chemical TransformationNitric acid

Sulfuric acid

PrecipitationAcid rain, fog,snow, and mist

Dry Fallout

Condensation

particulates, gases

Industry Transportation Ore smelting Power generation

Section 6-2

Figure 6-12 The Formation of Acid Rain

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4. Ozone depletiona. Ozone layer - high in stratosphere; protects

Earth from U.V.b. Depletion allows lethal doses of UV rays to

reach earthc. Caused by CFC’s(chlorofluorocarbons),

styrofoam products, some aerosol sprays

5. Greenhouse effect causes global warminga. Natural process that traps heat in atmosphereb. Atmospheric gases (CO2, methane) prevent

heat from escaping into spacec. Process where heat is retained by gases in the

environmentd. Thought to be caused by combination of

different pollutants( car exhaust, etc)

*Due to excess pollution and forest destruction the carbon cycle cannot remove the gases fast enough!

Sunlight

Some heat escapesinto space

Greenhousegases trapsome heat

Atmosphere

Earth’s surface

Section 4-1

The Greenhouse Effect

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Sunlight

Some heatescapesinto space

Greenhousegases trapsome heat

Atmosphere

Earth’s surface

Sunlight

Most direct sunlight

Sunlight

Sunlight

Sunlight

90°N North Pole

66.5°N

23.5°N

0°

23.5°S

66.5°S

90°S South Pole

Arctic circle

Tropic of Cancer

Equator

Tropic of Capricorn

Arctic circle

Section 4-1

Figures 4-1 and 4-2 Heating of the Earth’s Surface and Some Factors That Affect Climate

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Greenhouse Effect Different Latitudes

6. Water pollutiona. Sewage, industrial wastes, fertilizer runoffb. Contaminates groundwater (soil doesn't filter

out contaminants)

7. Land pollutiona. Trash is burned or buried instead of being

recycledb. Biodegradable - wastes broken down

naturallyc. Nonbiodegradable - stay in environment for

100's to 1000's of years

Fish-Eating BirdsMagnification ofDDT Concentration

10,000,000

100,000

10,000

1,000,000

1

1000

LargeFish

Small Fish

Zooplankton

Producers

Water

Section 6-3

Figure 6-16 Biological Magnification of DDT

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DDT-A chemical banned in the 1970’s

HumanActivities

that have changed the biosphere include

may have once caused often relies on the methods of thehave resulted in

which increased

Food supply Pesticide use Monocultureuse

Hunting andgathering Agriculture

Industrial growth

Urbandevelopment

Extinctions oflarge animals

Greenrevolution

High standardof living

Increasedpollution

Section 6-1

Concept Map

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1. Examine the list of natural resources shown below. Then, classify each

natural resource as either renewable or nonrenewable.a. Woodb. Fossil fuelsc. Aluminumd. Woole. Gold

2. Describe the impact that the loss of nonrenewable resources would have on the environment.

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• Rank the following items in order of their importance to you. Then, next to each item, write down how much you would be willing to pay for it.

• 1. Fresh, clean drinking water• 2. Clean air to breathe• 3. An endangered plant containing a substance that can cure cancer• 4. Gas for your family car

Section 6-4

Interest Grabber continued

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• Remember the importance of the Water, Carbon and Nitrogen Cycles to ensure a healthy environment.

Condensation

Seepage

Runoff

Precipitation

TranspirationEvaporation

RootUptake

Section 3-3Fig 3-11 The Water Cycle

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All living things requirewater to survive. Wheredoes it all come from?

It moves between the ocean,atmosphere, and land.

This figure shows how water molecules can change forms and beused through evaporation (change from liquid to gas) and transpiration(by evaporating from the leaves of plants).

CO2 inAtmosphere

CO2 in Ocean

Section 3-3

Figure 3-13 The Carbon Cycle

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Carbon is especially importantto living systems because it isthe key ingredient in all livingorganisms.

Carbon is foundin the oceans, in the air, andin certain types of rocks.

This figure shows how theseprocesses move carbon throughthe biosphere.

N2 in Atmosphere

NH3

NO3-

and NO2-

Section 3-3

Figure 3-14 The Nitrogen Cycle

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All organisms re-quire nitrogen tomake amino acids,which in turn, areused to build proteins.

This figure shows how the different forms of nitrogen cycle throughThe biosphere.

Nitrogen Cycle

Is driven primarily by the activities of unicellular organisms in the soil and oceans.

1. Nitrogen is in the atmosphere all the time.2. Bacteria change the nitrogen into nitrates, which is a kind of natural fertilizer taken in by the roots of plants and trees and used to build plant protein.3. Animals then eat the plants with protein in them4. Animal and plant waste then releases protein into the soil through decomposition.5. Finally, more kinds of bacteria break down plant protein to a form that releases nitrogen back into the atmosphere.