Ecological

Communities

So…Where Do Living Things Get Energy?• Well, we have pointed out that the ultimate

source of energy is the SUN. • Plants take energy from the sun to perform

photosynthesis. The process of photosynthesis produces sugars and oxygen.

• The energy made by plants (sugar) is used by cells in all living things to make energy for the cell to use.

• That energy is transferred all throughout ecosystems.

How Do Organisms Get

Energy?6CO2 + 6H20 + SUN C6H12O6 + 6O2

Photosynthesis

C6H12O6 + 6O2 6CO2 + 6H20 + ENERGY

Cellular Respiration

Carbon Dioxide + Water + Sun Sugar (Glucose) + Oxygen

Sugar (Glucose) + Oxygen Carbon Dioxide + Water + Energy

An Exception to the Energy Rule• In most cases, the sun is the ultimate

source of energy. • NOT in the deep ocean. In 1977,

scientists discovered areas teaming with life that did not see sunlight. Instead of using sunlight, the organisms on the bottom of the ocean use hydrogen sulfide. It escapes out of cracks in the ocean floor.

• Organisms carry out the process of chemosynthesis (as opposed to photosynthesis) to create energy.

• More than 300 different species can be found around these deep ocean vents.

• The vents can produce water that is up to 752 degrees Fahrenheit. Just away from the vents, the water is very, very cold.

Producers• An organism that makes its

own food. • They are also referred to as

autotrophs or self-feeders.• Producers get their energy

from the sun. • Examples: grasses,

ferns,cactus, flowers, trees, algae, and some bacteria.

Consumers• Organisms that get their

energy by eating other organisms.

• Also referred to as heterotrophs.

• Consumers get energy indirectly from the sun by eating producers or other consumers.

• Examples: mice, starfish, elephants, humans, wolves, ants, bear.

Types of Consumers

Type of Consumer Energy Source ExamplesHerbivore

(Plant Eaters)Producers

(Autotrophs)Rabbit, cow, white tailed

deer, sheep

Carnivore (Meat Eaters)

Consumers(Heterotrophs)

Lions, hawks, snakes, shark, wolves, whales

Omnivore (Eat Plants& Animals)

Both producers and consumers

(Heterotrophs)

Black bear, pig, gorilla, raccoons, humans

Decomposers Break down non-living organisms and return

nutrients to soil, water, and air

Fungi and bacteria

Detrivores Consume detritus (non-living organic matter including leaf litter and dead organisms.

Millipedes, soil insects, earthworms…

Large = vultures

Energy Transfers• Each time one organism eats another, a transfer of energy

occurs. • To track that energy as it moves through an ecosystem, we

can observe food chains, food webs, and trophic levels. • Looking carefully at each of these also can tell us which

animals depend on others for survival. • The example below shows us a food chain, or a sequence in

which energy is transferred from one organism to another.• Pink arrows indicates who eats who.• Yellow arrows indicate the transfer of energy.

ShrimpCod

SealKiller Whale

Energy Transfers – Food Web

• Food Web – show the many pathways for energy to be moving within a community. **

• ** Notice – a food chain is just one part of a food web

Trophic Levels • Trophic Level – each step in the transfer of

energy in a food chain or a food web. • In the previous example, the shrimp were

the bottom trophic level, or energy level and the whales were the top trophic level.

• As you move up trophic levels, 90% of the energy is lost and less energy is available. So to acquire energy, animals at the top trophic levels eat much more.

Energy Pyramids • Producers form

the base of the pyramid and consumers are at the top.

• It shows that most energy is available at the bottom and the least at the top.

• 90% of energy is lost at each level as the organisms in that level use it to carry out life functions.

• 10% of the energy gets passed to the next level.

Producers

Primary Consumers

Secondary Consumers

Tertiary Consumers

1000 units of energy available.

10% of the previous level’s energy is available or 100 units of energy.

10% of the previous level’s energy is available, or 10

units of energy.

10% of the previous level’s energy is available, or 1

unit of energy