Producers and Energy in Ecosystems

• All living organisms need to take in energy to live and grow.
• Many different food chains interconnect, forming complex food webs in ecosystems.

Producers

• Producers, also called autotrophs, create their food from inorganic molecules like water, CO2, nitrogen, and phosphate.
• Most producers get their energy from the sun and change inorganic molecules into complex carbohydrates like sugars and starches for food, this is photosynthesis.
• Some bacteria that live deep within the ocean use chemosynthesis to produce energy, as sunlight cannot reach them.
• Producers are the base or first level in all food chains.
• There are many more producers in a food chain than consumers or decomposers.
• Only 10% of the energy from each energy level is passed on to the next energy level.
• Examples include trees, shrubs, grass, algae, lichen, seaweed, and some bacteria.
• Algae, including seaweed, are the primary producers for most aquatic ecosystems.
• In Arctic ecosystems, lichens are the primary producers.

Consumers

• Consumers, also called heterotrophs, do not produce their food but eat other organisms to obtain energy.
• In the food chain, a consumer can be at the second, third, fourth, or even higher energy levels.
• As energy goes up the food chain, only around 10% is passed up to the next level.
• Consumers fall into three groups: herbivores, carnivores, and omnivores.
• Herbivores eat only plants, carnivores eat only other animals, and omnivores eat both plants and animals.
• Consumers can include mammals, birds, fish, reptiles, amphibians, insects, fungi, and some types of bacteria.
• Examples of herbivores are rabbits, dears, cows, elephants, and sheep, and many fish; they are considered a first-level consumer.
• Carnivores include lions, tigers, snakes, sharks, spiders, and sea stars; they eat only meat and can be second, third, fourth, or higher-level consumers.
• Omnivores include bears, dogs, raccoons, insects, and people; they can be second, third, fourth, or more levels of consumers.

Decomposers

• Decomposers break down dead and decaying organic matter; they are also considered heterotrophs.
• A saprophyte is another name for decomposers, especially fungus or bacteria, that live on dead or decaying organisms.
• They break apart organic material back into elemental substances of water, CO2, nitrogen, calcium, and phosphorus.
• Decomposers do not have a predator/prey relationship.
• They do not actively hunt or trap their food but use what is already dead for their food source.
• Most decomposers are microscopic organisms.
• The two main categories are detritus feeders and scavengers.
  • Detritus feeders include earthworms, sowbugs, bacteria, fungi, and molds; they break down organic matter to be used again in the ecosystem.
  • Scavengers include buzzards, ants, and termites in the desert ecosystem; they tear apart and digest animals for energy.
• Mushrooms do not have any chlorophyll, so they cannot produce their food.

Food Chain

• Grass is eaten by the bee, who is a primary consumer and herbivore.
• The wasp, a secondary consumer, and carnivore get its energy when it eats the bee.
• Next, a frog, a third-level consumer, and a carnivore will get its energy from consuming the wasp.
• The frog is eaten by the snake, a fourth-level consumer, and a carnivore.
• The hawk, a fifth-level consumer, and carnivore will get its energy by eating the snake.
• Finally, the hawk will die someday and possibly be eaten by a buzzard, earthworms, and bacteria (decomposers).
• At each level of the food chain, only 10% of the energy gets passed up the chain to the next level.
• The amount of energy that reaches the buzzard is only.001% of the original amount of energy taken up by the grass.

All living organisms need energy to survive. Producers, or autotrophs, create their food from inorganic molecules. They form the base of food chains, with the majority using photosynthesis (or chemosynthesis) to convert energy, with only 10% of energy being transfered to the next level.