NAMEENERGY SOURCE EXAMPLE ProducerMakes own foodGrass, Trees ConsumerEating Other Organisms Mice, Humans, Starfish HerbivoreProducersCows, Deer CarnivoreOther Consumers Lions, Hawks OmnivoreProducers and Consumers Bears, Pigs, Humans DecomposerDead OrganismsFungi, Bacteria

Primary Energy Source The rate at which organic material is produced by photosynthetic organisms in an ecosystem is called primary productivity Organisms that first capture solar energy, the producers, include plants, some kinds of bacteria, and algae. Consumers are those organisms that consume plants or other organisms to obtain the energy necessary to build their molecules

Autotrophs are organisms that use Energy from sunlight or Inorganic substances to make Organic compounds. Like plants use sunlight to Make glucose.

Heterotrophs are organisms that Must get energy from food instead Of directly from sunlight. We are heterotrophs because We can’t make our own food In our cells. Instead we use cellular respiration To “burn” fuel in our bodies.

Directly or indirectly, almost all of the Energy in living systems needed for Metabolism comes from the sun.

Cellular respiration is the Process of breaking down food To yield energy. This is essentially photosynthesis In reverse. 6CO 2 + 6H 2 O + Light C 6 H 12 O 6 + 6O 2

Trophic Levels Ecologists study how energy moves through an ecosystem by assigning organisms in that ecosystem to a specific level, called a trophic level, in a graphic organizer based on the organism’s source of energy. Energy moves from one trophic level to another

Trophic Levels

Trophic Levels: First Level The lowest trophic level of any ecosystem is occupied by the producers, such as plants, algae, and bacteria Producers use the energy of the sun to build energy-rich carbohydrates

Trophic Levels: Second Level At the second trophic level are herbivores, animals that eat plants or other primary producers. They are the primary consumers A herbivore must be able to break down a plant’s molecules into usable compounds Most herbivores rely on microorganisms, such as bacteria and protists, in their gut to help digest cellulose

Trophic Levels: Third Level At the third trophic level are secondary consumers, animals that eat herbivores. These animals are called carnivores Some animals, such as bears, are both herbivores and carnivores; they are called omnivores Dentrivores are organisms that obtain their energy from the organic wastes and dead bodies that are produced at all trophic levels

Bacteria and fungi are known as decomposers because they cause decay Decomposition of bodies and wastes releases nutrients back into the environment to be recycled by other organisms

A food chain is a sequence in Which energy is transferred From one organism to the Next as each organism Eats another.

A food web shows many of the Feeding relationships in An ecosystem. In most ecosystems, energy does not follow simple straight paths because animals often feed at several trophic levels. This creates an interconnected group of food chains called a food web

Energy Transfer During every transfer of energy within an ecosystem, energy is lost as heat. Thus, the amount of useful energy available to do work decreases as energy passes through an ecosystem The loss of useful energy limits the number of trophic levels an ecosystem can support

To better determine the amount of energy present in trophic levels, ecologists measure biomass Biomass is the dry weight of tissue and other organic matter found in a specific ecosystem Each higher level on the pyramid contains only 10% of the biomass found in the trophic level below it

The Pyramid of Energy An energy pyramid is a diagram in which each trophic level is represented by a block, and the blocks are stacked on top of one another, with the lowest trophic level on the bottom

Energy Transfer Through Trophic Levels

Water moves between the Earth’s surface and The Atmosphere is a process Called the Water Cycle.

Carbon flows through Ecosystems when plants make Food and consumers eat produces And then decomposers start the Process over again. But humans have a huge impact The this due to our burning Of fossil fuels.

The Carbon Cycle

All organisms need Nitrogen. The good news is that it is All around us in huge quantities. The bad news is that almost all Organisms can’t use it from the Air. So we get it from nitrogen- Fixing bacteria that allows it To be used by plants.

Succession is a regular Pattern of changes over Time in the types of species In a community. The community that eventually Forms if the land is left Undisturbed is called Climax community.

Succession that occurs on a Surface where an ecosystem Has previously existed is called Secondary Succession. Pioneers are the first organisms To colonize any newly available Area and start the process Of succession.

Natural fires caused by Lightning are a necessary part Of secondary succession in Some communities. National forest rangers Sometimes allow natural fires To burn unless they threaten Human life or property.

Succession that occurs on Surfaces where no Ecosystem existed before is Called Primary Succession. Primary succession is much Slower than secondary Succession because it begins Where there is no soil.