Abeka 7th Grade Science, Section 13.3 Review

Define autotroph and heterotroph.

An autotroph is an organism that can make its own food. A heterotroph is an organism that cannot produce its own food.

A strangler fig puts out aerial roots that allow it to grow attached to another tree. As the fig grows, it takes nutrients from the host tree and eventually kills it. What type of symbiosis is this?

parasitism

Contract scavengers, decomposers, and detritivores.

Scavengers are carnivores that seek and feed on the carcasses of dead animals instead of hunting live animals. Decomposers feed on detritus and break it into nutrients that are returned to the soil. Detritivores are larger organisms, like earthworms, ants, and shrimp, that consume detritus but cannot convert it into nutrients for the soil.

What does an organism's trophic level describe?

its feeding relationship with other organisms

What is an energy pyramid?

a diagram that shows how energy is passed from one trophic level to the next

Define predation.

one organism hunting another for food

Define neutralism.

organisms sharing only indirect contact

How do a food chain and a food web differ?

A food chain shows only one type of organism at each trophic level; a food web shows all feeding relationships in an ecosystem.

Define symbiosis.

an organism living in close association with other organisms