Chapter 55/56 Notes

Chapter 55: Ecosystems

and Restoration

Ecology

Essential Knowledge

2.a.1 – All living systems require constant input of free energy (55.2 & 55.3).

2.d.1 – All biological systems from cells and organisms to populations, communities, and ecosystems are affected by complex biotic and abiotic interactions involving exchange of matter and free energy (55.1 – 55.4)

4.a.6 – Interactions among living systems and with their environment result in the movement of matter and energy (55.1, 55.3, 55.4, 55.5).

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

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

Trophic Levels

1. Primary Producers

2. Primary Consumers

3. Secondary Consumers

4. Detritivores

Primary Producers

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

Are the source of the energy available to an ecosystem.

Primary Consumers

Organisms that feed on the producers.

Ex: Herbivores

Secondary Consumers

Organisms that feed on the Primary Consumers.

Ex: Carnivores

Detritivores

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

Ex: bacteria and fungi

Food Chain

Linear pathway of who eats who in an ecosystem.

Food Webs Network showing all the feeding

relationships in an ecosystem.

Primary Productivity

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

Primary Productivity

NPP = GPP - Rs

NPP = Net Primary Productivity

GPP = Gross Primary Productivity

Rs = Respiration

Available Energy

Daily - 1022 joules of solar radiation.

1% - captured by Ps.

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

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

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

Ex: N, P, K, Mg Light, CO2

Energy Transfers

Not 100% efficient.

Averages 10% with each tropic level change

Why? Second law of thermodynamics. Waste. Materials that can’t be digested etc.

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

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

The higher level consumers usually need a large geographical area.

Pyramids

Graphical representation of relationships in ecosystems.

Ex:

1. Productivity

2. Biomass

3. Numbers

Question

What would a numbers pyramid look like in an Indiana forest? Inverted pyramid. Few producers

(trees) and many primary consumers.

What would a Biomass pyramid look like in an Indiana forest? Pyramidal in shape.

Chemical Cycling

Matter is recycled through ecosystems.

Ex: Biogeochemical Cycles

Matter Reservoirs

1. Organic Materials

2. Inorganic Materials

Available Unavailable

Representative Biogechemical Cycles

Water

Carbon

Nitrogen

Know one or more of these cycles for various multiple choice questions and possibly a short answer question

Water cycle

Carbon cycle

Nitrogen cycle

Energy vs Matter

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

Matter - cycles in ecosystems.

Chapter 56: Conservation

Biology and Global

Change

Question ?

What is Man's influence on Ecosystems ?

Humans have had many negative impacts.

Biological Magnification

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

Ex: DDT Heavy metals -Hg, Cd, Pb

Causes

Not broken down by digestion/decomposition.

Lipophilic.

Concentrates and effects the upper levels of the food web.

DDT Example

Greenhouse Effects

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

Causes:

Warms Earth’s temperatures

Global warming

Carbon Dioxide Levels

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

Point: the levels of CO2 are rising.

Cause? Probably due to humans.

Human CO2 Increase Causes

Industrialization.

Burning of fossil fuels.

Loss of forests.

Result

Earth will heat up.

Ice caps melt and sea levels will rise.

Climate shifts.

Increased Ps (?)

Exotic Species

When transplanted species are too successful and upset the ecosystem in new areas.

Ex: Starlings Fire Ants Carp

Invasive speci

es website

Australia

Has had many problems with transplanted species

Ex: Rabbits Cacti Foxes

Cane toads

Cane Toad National Geographic Video

Summary

Identify the trophic levels of ecosystems.

Recognize the flow of energy through food chains and food webs.

Recognize the calculations used in measuring productivity.

Recognize how productivity and energy transfers can be diagramed in pyramid form.

Recognize that matter cycles in ecosystems.

Identify the concept of Biological Magnification.

Recognize several current environmental concerns.