Chapter 54 ecosystems
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Chapter 54 Ecosystems. Ecosystem. All the organisms and abiotic factors in a community. Ecosystem Studies. 1. Energy Flow – the movement of energy through trophic levels. 2. Chemical Cycling – the movement of matter from one part of the ecosystem to another. Trophic Levels.

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Chapter 54 Ecosystems

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Chapter 54 ecosystems

Chapter 54 Ecosystems


Ecosystem

Ecosystem

  • All the organisms and abiotic factors in a community.


Ecosystem studies

Ecosystem Studies

1. Energy Flow – the movement of energy through trophic levels.

2. Chemical Cycling – the movement of matter from one part of the ecosystem to another.


Trophic levels

Trophic Levels

  • Division of an ecosystem based on the source of nutrition (energy).


Trophic levels1

Trophic Levels

1. Primary Producers

2. Primary Consumers

3. Secondary Consumers

4. Detritivores


Primary producers

Primary Producers

  • Usually plants, capture energy and store it in chemical bonds.

  • Are the source of the energy available to an ecosystem.


Primary consumers

Primary Consumers

  • Organisms that feed on the producers.

  • Ex: Herbivores


Secondary consumers

Secondary Consumers

  • Organisms that feed on the Primary Consumers.

  • Ex: Carnivores


Comment

Comment

  • There may be several layers of Secondary Consumers in an ecosystem.


Detritivores

Get their energy from the organic waste produced by all levels.

Ex: bacteria and fungi

Detritivores


Food chain

Linear pathway of who eats who in an ecosystem.

Food Chain


Food webs

Network showing all the feeding relationships in an ecosystem.

Food Webs


Primary productivity

Primary Productivity

  • The rate at which light energy is captured by autotrophs or primary producers.


Primary productivity1

Primary Productivity

  • NPP = GPP - Rs

  • NPP = Net Primary Productivity

  • GPP = Gross Primary Productivity

  • Rs = Respiration


Available energy

Available Energy

  • Daily - 1022 joules of solar radiation.

  • 1% - captured by Ps.

  • About 170 billion tons of organic matter is created each year.


Primary producers1

Primary Producers

  • 50 - 90% of GPP is lost to Rs by the primary producers.

  • NPP = 10 - 50%

  • Animals - use only NPP, which limits the food webs.


Limiting factors

Limiting Factors

  • Material or nutrient that is not present in sufficient quantity for the primary producers.

  • Ex: N, P, K, Mg Light, CO2


Energy transfers

Energy Transfers

  • Not 100% efficient.

  • Why?

  • Second law of thermodynamics.

  • Waste.

  • Materials that can’t be digested etc.


Energy transfer

Energy Transfer

  • Averages 10% with each Trophic Level change.


Question

Question ?

  • Why do most ecosystems have only 3 - 4 trophic levels?

  • There isn’t enough energy passed up through the food web to support more levels.


Implications

Implications

  • There has to be fewer high level consumers in a food web.

  • The higher level consumers usually need a large geographical area.


Question1

Question

  • Which would support more humans per area?

    • Eating meat?

    • Eating plants?


Pyramids

Pyramids

  • Graphical representation of relationships in ecosystems.

  • Ex:

    1. Productivity

    2. Biomass

    3. Numbers


Chemical cycling

Chemical Cycling

  • Matter is recycled through ecosystems.

  • Ex: Biogeochemical Cycles


Matter reservoirs

Matter Reservoirs

1. Organic Materials

2. Inorganic Materials

  • Available  Unavailable


Representative cycles

Representative Cycles

  • Water

  • Carbon

  • Nitrogen

  • Know one or more of these cycles for an essay question.


Energy vs matter

Energy vs Matter

  • Energy - flows through ecosystems and is mostly lost as heat.

  • Matter - cycles in ecosystems.


Question2

Question ?

  • What is Man's influence on Ecosystems ?

  • Humans have had many negative impacts.


Hubbard brook

Hubbard Brook


Biological magnification

Biological Magnification

  • The concentration of toxins in successive levels of a food web.

  • Ex: DDT Heavy metals (Hg, Cd Pb)


Causes

Causes

  • Not broken down by digestion/decomposition.

  • Lipophilic.

  • Concentrates and effects the upper levels of the food web.


Greenhouse effects

Greenhouse Effects

  • The trapping of heat by the Earth's atmosphere. (CO2, H2O etc.).


Carbon dioxide levels

Carbon Dioxide Levels

  • Prior 1850 - 274 ppm 1958 - 316 ppm 1992 - 351 ppm

  • Point: the levels of CO2 are rising. The cause is probably due to humans.


Causes1

Causes

  • Industrialization.

  • Burning of fossil fuels.

  • Loss of forests.


Result

Result

  • Earth will heat up.

  • Ice caps melt and sea levels will rise.

  • Climate shifts.

  • Increased Ps (?)


Acid rain

Acid Rain

  • Caused by air pollution.

  • Lowers the pH of rainfall.

  • Is seriously damaging many ecosystems.


Habitat destruction

Habitat Destruction

  • Worst problem threatening most species today.


Comment1

Comment

  • Man has a major impact on the Biosphere.

  • Man needs to learn how to work with the Biosphere.


Summary

Summary

  • Know the tropic levels of ecosystems.

  • Know an example of a food chain and a food web.

  • Know how energy moves through an ecosystem.


Summary1

Summary

  • Know how matter moves through an ecosystem.

  • Know one or more examples of matter cycling.

  • Be able to discuss in detail a human impact problem on ecosystems.


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