Chapter 2 Unit Review1. A. II b. III c. VII d. I e. VI g. IV2. The study of ecology reveals interconnectedness at many levels. Each organism is connected to other organisms and also abiotic elements of the environment. Organisms are connected to each other in food chains and food webs; organisms and abiotic factors are connected in the cycle of nutrients through ecosystems. Earth is connected to the Sun, which is the earth’s primary source of energy, and organisms are connected as they pass the energy through tropic levels. Populations increase and decrease in connected ways, as in predator-prey cycles. Some organisms are connected in symbiotic relationships.3. A. Populations b. Populations c. Ecosystem, d. Community4. Light, temperature, water, space, wind...5. A rotting log community and the abiotic factors that affect it; the bacteria and other organisms in a dog’s mouth plus the saliva, tissues, and other conditions in the mouth; the trees and other plants and animals and other organisms plus the soil, rocks and other abiotic factors in a forest; kelp shellfish, sea otters, and other organisms plus the abiotic factors found in a shallow costal marine kelp forest; all the organisms and all the abiotic factors on Earth (the biosphere)6. Producers are at the first trophic level. They capture energy from the sun and make it and nutrients available to the primary consumers, the animals and other organisms in the second trophic level.7. A8. D9. A. Note series 1 = pH 8 series 2 = pH 6 and series 3 = pH 4 B. pH 6.0 c. to test the effect of the pH, it must be the only factor that changes. The other conditions such as temperature should remain constant d. To ensure the results are valid, the type of mould used, the way the bread is incubated, and the amount of mould the bread is incubated with should all be
kept constant e. Time, light, and amount of moisture might effect the growth of bread mould f. Following the same procedure with no mould would be an appropriate control10. B11. D12. Category of Consumer Description Examples Herbivore Eat only producers Carnivore Eat only other consumers Decomposer Eat dead or decaying organic materials breaking it down so that the nutrients are recycled Scavenger Eat consumers recently killed by another consumer Omnivore Eat both producers and other consumers13. C14. Organisms in the second trophic level eat producers such as plants and algae. Organisms in the third trophic level eat herbivores15. A change in the amount of water or humidity causes a change in the number and type of plants. Temperature changes affect types of plants as well as number of insects. Availability of light affects plants. When ocean currents and upwelling change, plankton and krill become less abundant in some area’s while more in others. All of these changes lead to changes in higher trophic levels.16. Answers will vary17. A. Community b. Tree c. Hawk at the fifth trophic level18. Energy Biomass Numbers19. C20. If the given food chain alone is considered, spraying to kill beetles would reduce the size of the hawk population. Beetles might be the food supply for mice, voles, etc. That are the prey of hawks. Reducing the number of beetles would reduce the food supply for mice and voles too; the mice and vole
population would therefore decrease. A reduction in the food supply of hawks would cause a reductionin the hawk population.