Energy and Matter Exchange in the Biosphere Unit 1 Energy and Matter Exchange in the Biosphere

Unit Concepts Chapter 1 Chapter 2 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 2 food 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 Hypothesis Metaphor 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.

The Biosphere Earth has three basic structural zones: Lithosphere (land) Hydrosphere (water) 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 Biosphere Energy enters the biosphere by photosynthesis. For some organisms, energy enters their part of the biosphere through the process of chemosynthesis

Photosynthesis 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).

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 + 6H2O + 3H2SO4 This differs from photosynthesis in source energy and end product Banff Hot Spring is a similar example of this!

Living and Non-living Components Biotic 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 Investigations Begin 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.

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 biosphere Dynamic 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 Levels A category of living things defined by how it gains its energy; the first trophic level contains autotrophs, each high level contains heterotrophs. First Trophic level: primary producers (autotrophs)  make their own food and rely on sunlight. Second Trophic level: primary consumers  Rely on autotrophs for energy Third Trophic level: secondary consumers  Rely on primary consumers and producers for energy. Fourth Trophic level: tertiary consumer  Rely on secondary consumers.

Autotrophs an organism that uses the Sun’s energy and raw materials to make its own food; a producer. Chemoautotrophs are bacteria that obtain energy from oxidation of inorganic compounds such as ammonia. Photoautotrophs Possess chlorophyll and carry on photosynthesis.

Heterotrophs an organism incapable of making its own food, and so must feed on other organisms to gain energy. Herbivores Carnivores Omnivores Primary Consumer Secondary Consumer Tertiary Consumer

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

Limits of Energy Transfer Every time energy is transferred between the components of an ecosystem, the amount of energy available to the next trophic level is reduced. WHY? Some energy is released as thermal energy during cellular respiration. Converted to another energy molecule other than glucose Laws of Thermodynamics (Law of 10)

Thermodynamics Is the study of energy transformations. First Law of Thermodynamics: although energy can be transformed (changed) from one form to another, it cannot be created or destroyed. Second Law of Thermodynamics: during any energy transformation, some of the energy is converted into an useable form, mostly thermal energy, which cannot be passed on. Therefore, the amount of energy available in each step of a chain of transformations is always less than the amount of energy available in the previous step.

Ecological Pyramids Graphs called ecological pyramids can be used to represent energy flow in food chains and food webs. Helpful in comparing ecosystems and visualizing the relationships in ecosystems. Pyramids of Energy measure of the amount of energy available at each trophic level. About 10% of energy is incorporated into the next trophic level. Rapid loss of energy explains why there is few large carnivores. Pyramid of Numbers based on the number of organisms at each trophic level. Pyramid of Biomass dry mass of tissues in the plants or animals is measured and graphed. Biomass is a measure of stored energy content. For example: Rainforests have more biomass then the Tundra.