| A | B |
|---|
| producers | organisms that produce their own food through photosynthesis |
| population | individuals of the same kind living in the same environment |
| food web | shows the relationship between many different food chains in a single ecosystem |
| consumers | living things that must eat to get energy |
| habitat | place in an ecosystem where each population lives |
| exotic | nonnative organism |
| competition | contest between organisms for limited resources |
| energy pyramid | shows amount of energy available to pass from one level of a food chain to the next |
| learned behaviors | behaviors that animals are taught after birth |
| decomposer | consumer that breaks down tissue of decaying organism |
| community | all the populations of organisms living together in an environment |
| ecosystem | community of organisms and their physical environment |
| threatened | likely to become endangered if not protected |
| individual | single organism in an environment |
| instinct | behavior an organism inherits |
| food chain | shows how consumers in an ecosystem are connected to one another according to what they eat |
| niche | role of a population of organisms within a particular habitat |
| endangered | having a population so small it is likely to disappear unless steps are taken to save it |
| symbiosis | long-term relationship between different kinds of organisms |
| extinct | species becomes this after the last individual in the population dies |
| An ecosystem is made up of a community and its- | environment |
| In a healthy ecosystem, population of living things are- | interdependent |
| The types and number of animals in an ecosystem are determined by the- | types and number of plants |
| What do the producers in a community do? | make food |
| In a food chain, each level of consumer eats organisms- | from the level below it |
| What percentage of energy at any level of a food chain is passed on to the next higher level? | about 10 percent |
| Different organisms can share the same resource, such as a tree, because they have different- | niches |
| A cleaner fish picks bits of food from between a shark's teeth. This relationship is an example of- | mutualism |
| Behaviors for building shelters, finding mates and hunting are usually- | instinctive |
| Which of the following is NOT a natural cause for population decline? | pesticides |
| Most declines in population of organisms today are caused by- | human activity |
