Chapter 8 review

3. any physical hazard to life caused by having too much or too little of things needed for life
8. bacteria that can change nitrogen into compounds can be found in ______ nodules on plants
10. the year is divided into __________ one of earth's cycles
11. when the population of a species is so small that the species may soon become extinct
13. ___________ is released into the air during decomposition
17. plant and animal species that originally live in an ecosystem are called ____________
19. the water cycle includes precipitation, transpiration, __________, and condensation
20. whenever an ecosystem receives less water than it needs

1. during respiration organisms use ________ molecules and oxygen to produce energy
2. people and animals breathe in oxygen and breath out carbon dioxide during _______________
4. the largest manmade stress
5. Man honors God by using his _________ wisely
6. __________ get nitrogen compounds by eating other animals or plants
7. the gradual changes in the populations of organisms in an ecosystem are called _____________
9. species that are not native to an ecosystem and can cause harm
12. whenever an ecosystem receives more water than it can store or use
14. when the last known member of a species dies, the species is considered ____________
15. plants release water vapor into the air through ___________
16. __________ is important for living things to grow and function normally
18. a regular pattern of change