Chapter 5How Ecosystems Work

Energy from the sun enters an ecosystem when a plant uses sunlight to make sugar molecules

Energy Flow

This process in which sunlight, carbon dioxide, and water are used by plants, algae and bacteria to make carbohydrates, oxygen, and water

6CO2 + 12H2O C6H12O6 + 6O2 + 6H2O

Photosynthesis

Organisms use carbohydrates to carry out daily activities such as movement, growth, and reproduction

Energy Flow

Organisms that makes its own food

Also known as: Autotrophs- are at the base of

the food chain Ex. Plants, algae, and some bacteria

Producer

Organisms that get their energy from eating other organisms

Also known as: Heterotrophs

Consumers

Also known as herbivores; these organisms eat autotrophsEx. Insects, fish, rabbits, cows

Primary Consumers

Known as carnivores; these organisms eat herbivoresEx. Chameleon, fish, rats

Secondary Consumers

a carnivore which eats a carnivore which eats a herbivoreEx. Snake, fish, seal

Tertiary Consumer

eat tertiary consumers; have no natural enemies

Hawks and a shark

Quaternary Consumer

eat both plant and animal (primary consumers and secondary consumers) Ex. Bears, pigs, and humans

Omnivore

Decomposers eat dead plants and animals to help break down complex compounds into simpler ones.

fungi, bacteria,

Decomposers

By a process called cellular respiration

C6H12O6 + 6O2 = 6CO2 + 6H2O + energy (ATP)

-during cellular respiration cells absorb oxygen and use it to release energy from food occurs within the mitochondria of the cell

*So how do organisms use the energy they get?

A way to visualize this loss of energy from one trophic level is through an:

energy pyramid- with the lowest trophic level on the bottom (pg. 131)

Energy Transfer

Also visualize the transfer of energy through food chains and food webs

also helps us determine which organisms in an ecosystem depend on other organisms to survive

Energy Transfer

a sequence in which energy is transferred from one organism to the next as each organism eats another

Food Chain

shows many feeding relationships that are possible in an ecosystem

Food Web

Decreased amount of energy at each trophic level results in fewer organisms at the higher trophic levels and also limits the number of trophic levels

Only 10% of the energy is available at each level

Energy loss

3 Main Cycles

Carbon Cycle Nitrogen Cycle Phosphorus Cycle

Cycling of Materials

Essential for proteins fats and carbohydrates Carbon enters ecosystem by way of plants; convert

carbon dioxide into carbohydrates Consumers eat the producers and get carbon from

the carbohydrates Some of the carbon is then released back into the

air as carbon dioxide Cycle (pg. 132)

Carbon Cycle

Needed to build proteins 78% of gases in atmosphere Must be altered or fixed from the atmosphere Nitrogen-fixing bacteria accomplish this task Excess nitrogen is released into the soil Animals get nitrogen by eating plants Cycle (pg. 134)

Nitrogen Cycle

Needed for bones and teeth Plants get it from soil and water; absorb through

roots Animals get it by eating plants or from herbivores Added to soil and water by decomposition Some washes off the land into the ocean Some comes from the erosion of rocks Some from fertilizers Cycle (pg. 135)

Phosphorus Cycle

A gradual process of change and replacement of the types of species in a community

can take hundreds or thousands of years

each new community that arises often makes it harder for the previous community to survive or the new community will not survive at all

Ecological Succession

Succession that occurs on a surface where no ecosystem has existed before; such as on rocks, cliffs, newly formed islands, sand dunes,

occurs in areas where there is no soil

Primary Succession

Occurs on a surface where an ecosystem has previously existed

occurs in ecosystems that have been disturbed by humans, animals, or by natural processes (fires, volcano’s, etc.)

occurs faster than primary succession

Secondary Succession

Plants that will colonize the area and begin the process of ecological succession

make the new area habitable for other species

Pioneer Species

Over time, pioneer species and other species will continue to grow and inhabit the disturbed ecosystem

Eventually it will form a final and stable community:

Climax community

Succession

Occurs when farmland is abandoned First pioneer species take over (grasses and

weeds) taller grasses and perennial plants grow in the

area (eventually killing the pioneer plants) over time the taller plants are taken over by

taller growing trees Finally, the land returns to the community that

existed before the farmers cleared it for farmland

Old Field Succession