UnitUnit 11

Energy and Matter

Exchange in the Biosphere

Unit ConceptsUnit ConceptsChapter 1

producers (autotrophs) capture energy and store it by photosynthesis or chemosynthesis

heterotrophs and decomposers consume autotrophs and other heterotrophs

matter is cycled in the biosphere, but energy follows a one-way path

Chapter 2food chains and food webs are models that describe feeding relationships and energy transfer between organisms in trophic levels

ecological pyramids describe relationships between trophic levels quantitatively

because all organisms are connected, changes that affect one trophic level affect other trophic levels

Earth is a Closed System

A closed system is one in which matter is not exchanged with its surroundings; however, it does exchange energy with its surroundings.Life is totally dependent on incoming solar energy and the matter available on earth.

When we see the whole planet from a distance, we can see that everything on Earth is connected. There are no real boundaries. The

atmosphere that envelops Earth is continuous and free to flow

Gaia HypothesisMetaphor used to compare earth to a living body.Our brain requires oxygen and nutrients from the circulatory system, just as the need for living and non-living interactions on our planet.There needs to be a balance of all components. What affects one part affects all parts.Dynamic equilibrium describes any system in constant change in which components can adjust to the changes without disturbing the entire system.

Have you upset our dynamic equilibrium?

Some ecologist’s have evidence to suggest that the earth is facing a crisis in which the dynamic equilibrium is being upset.No consensus on the magnitude.Problem appears to be because of our activities and actions.The decision you make will, in part, determine the future direction of life on this small and fragile planet.

The BiosphereEarth has three basic structural zones:

1. Lithosphere (land)2. Hydrosphere (water)3. Atmosphere (air)

Living organisms can be found in all 3 zones, an area referred to as the biosphere (ocean depths to the lower atmosphere).

Energy Enters the BiosphereEnergy Enters the BiosphereEnergy enters the biosphere by photosynthesis. For some organisms, energy enters their part of the biosphere through the process of chemosynthesis

Photosynthesis and Cellular RespirationPhotosynthesis and Cellular Respiration

Cellular respiration and photosynthesis (and chemosynthesis) are related processes.

Photosynthetic producers capture the Sun’s energy and convert it to chemical energy (glucose).In Alberta photosynthesis is limited by the availability of water. Higher altitudes and elevations in the mountains also affect the reactions that can take place here

Chemosynthetic producers capture the chemical energy stored in chemical bonds and convert it to chemical energy (glucose).Chemosynthetic bacteria form the base of food chains in deep sea vents. They have the ability to use chemical energy in the hydrogen sulfide along with water and carbon dioxide to form carbohydrates in the following reaction:

6CO2 + 6H2 O + 3H2 SO4

This differs from photosynthesis in source energy and end productBanff Hot Spring is a similar example of this!

Vent CommunitiesVent Communities

Living and Non-living ComponentsBiotic Components the biological or living components of the biosphere.

Abiotic Components the non-living components of the biosphere. They include chemical and physical factors.

The interaction between these two group is what ecologists endeavor to understand and explain.

Ecological InvestigationsBegin at the organism level, by looking at how the individual interacts with its biotic and abiotic environment.Populations a group of individuals of the same species occupying a given area at a certain time.

Populations influence and are influenced by its immediate environment.

Community the populations of all species that occupy a habitat.Ecosystem both abiotic and biotic components.

The physical and chemical environment, as well as the community of organisms, interact with each other in the ecosystem.

The number of species in an ecosystem.Because all organism are connected, a reduction in biodiversity caused by extinction of a single species can cause a domino effect.Example: A car can only run with all of its parts.

Interconnected Ecosystem

Food Chain step-by-step sequence linking organisms that feed on each other (transfer of energy between tropic levels).Producers an autotroph; an organism that makes its own food.Consumers a heterotroph; an organism that must eat producers or other consumers to survive.

Summary: Equilibrium in the Biosphere

Living organisms are found in a limited region of earth known as the biosphereDynamic equilibrium is used to describe any system in which changes are continuously occurring but the components have the ability to adjust to these changes without disturbing the entire system.Number of species in an ecosystem is describe biological diversity.Any reduction in biodiversity (extinction) can cause a “domino effect”

Trophic LevelsTrophic LevelsA category of living things defined A category of living things defined by how it gains its energy; the first by how it gains its energy; the first trophictrophic level contains level contains autotrophsautotrophs, , each high level contains each high level contains heterotrophsheterotrophs..

1.1. First First TrophicTrophic levellevel: primary : primary producers (producers (autotrophsautotrophs) ) make make their own food and rely on sunlight.their own food and rely on sunlight.

2.2. Second Second TrophicTrophic levellevel: primary : primary consumers consumers Rely on Rely on autotrophsautotrophsfor energyfor energy

3.3. Third Third TrophicTrophic levellevel: secondary : secondary consumers consumers Rely on primary Rely on primary consumers and producers for consumers and producers for energy.energy.

4.4. Fourth Fourth TrophicTrophic levellevel: tertiary : tertiary consumer consumer Rely on secondary Rely on secondary consumers.consumers.

AutotrophsAutotrophsan organism that uses an organism that uses the Sunthe Sun’’s energy and s energy and raw materials to make its raw materials to make its own food; a own food; a producerproducer..ChemoautotrophsChemoautotrophsare bacteria that obtain are bacteria that obtain energy from oxidation of energy from oxidation of inorganic compounds inorganic compounds such as ammonia.such as ammonia.PhotoautotrophsPhotoautotrophsPossess chlorophyll and Possess chlorophyll and carry on photosynthesis.carry on photosynthesis.

HeterotrophsHeterotrophsan organism incapable of an organism incapable of making its own food, and so making its own food, and so must feed on other organisms must feed on other organisms to gain energy.to gain energy.HerbivoresHerbivoresCarnivoresCarnivoresOmnivoresOmnivores

Primary ConsumerPrimary ConsumerSecondary ConsumerSecondary ConsumerTertiary ConsumerTertiary Consumer

Fo od WebFo od Web

A representation of the feeding A representation of the feeding relationships among organisms in an relationships among organisms in an ecosystem.ecosystem.

Limits of Energy TransferLimits of Energy Transfer

Every time energy is transferred between Every time energy is transferred between the components of an ecosystem, the the components of an ecosystem, the amount of energy available to the next amount of energy available to the next trophic level is reduced.trophic level is reduced.

WHY?WHY?•• Some energy is released as thermal energy during Some energy is released as thermal energy during

cellular respiration.cellular respiration.•• Converted to another energy molecule other than Converted to another energy molecule other than

glucoseglucose•• Laws of Thermodynamics (Law of 10)Laws of Thermodynamics (Law of 10)

ThermodynamicsThermodynamicsIs the study of energy transformationsIs the study of energy transformations..

•• First Law of ThermodynamicsFirst Law of Thermodynamics: although energy can be : although energy can be transformed (changed) from one form to another, it cannot be transformed (changed) from one form to another, it cannot be created or destroyed.created or destroyed.

•• Second Law of ThermodynamicsSecond Law of Thermodynamics: during any energy : during any energy transformation, some of the energy is converted into an useable transformation, some of the energy is converted into an useable form, mostly thermal energy, which cannot be passed on.form, mostly thermal energy, which cannot be passed on.

•• Therefore, the amount of energy available in each step of a chaiTherefore, the amount of energy available in each step of a chain of n of transformations is always less than the amount of energy availabtransformations is always less than the amount of energy available le in the previous step.in the previous step.

Ecological PyramidsEcological PyramidsGraphs called ecological pyramids can be used to represent energGraphs called ecological pyramids can be used to represent energy y flow in food chains and food webs. Helpful in comparing ecosysteflow in food chains and food webs. Helpful in comparing ecosystems ms and visualizing the relationships in ecosystems.and visualizing the relationships in ecosystems.

Pyramids of EnergyPyramids of Energy measure of the amount of energy available measure of the amount of energy available at each trophic level.at each trophic level.

•• About 10% of energy is incorporated into the next trophic level.About 10% of energy is incorporated into the next trophic level.•• Rapid loss of energy explains why there is few large carnivores.Rapid loss of energy explains why there is few large carnivores.

Pyramid of NumbersPyramid of Numbers based on the number of organisms at each based on the number of organisms at each trophic level.trophic level.

Pyramid of BiomassPyramid of Biomass dry mass of tissues in the plants or animals dry mass of tissues in the plants or animals is measured and graphed.is measured and graphed.

•• Biomass is a measure of stored energy content.Biomass is a measure of stored energy content.•• For example: Rainforests have more biomass then the Tundra.For example: Rainforests have more biomass then the Tundra.