Answers to the Extraordinary Ecology Review

Hola! Welcome to the last set of review answers on this blog. Hard to believe that we're almost done. Okay, before I get all sappy, here's what you're looking for to help you study for your quiz tomorrow.

1. List three abiotic factors (sun, soil, water, temperature, precipitation, wind are just a few) and three biotic factors (animals, plants, fungi, bacteria are just a few)

2. List three things that would cause an animal to leave its normal environment: Basically any change in an abiotic factor that puts its survival in jeopardy

3. Definitions:

Organism: one of any living species
Population: more of any living species in a particular time and place/area
Community: when several populations come together in a particular area
Ecosystem: biotic and abiotic factors that are available in a particular area
Biosphere: all biotic and abiotic factors that are available on the planet

4. Relationship Definitions:

Predator/Prey: one lives, one dies
Intraspecific Competition: members of the same species vying for a resource
Interspecific Competition: members of different species vying for a resource
Mutualism: both species benefit
Commensalism: one species benefits; one species is unaffected
Parasitism: one species benefits-one species is harmed but not killed

5. What is a limiting factor and how does it affect a population's carrying capacity?

Food, Water, Shelter, Space are all limiting factors. The limiting factors keep the carrying capacity of a particular species in an area in check because if the resources are not limited, the number of organisms living in an area will increase dramatically and then decrease dramatically due to death of organisms that occur when the resources are depleted or run out.

6. What is the difference between the way energy and nutrients (matter) move through an ecosystem?

Energy flows through the ecosystem and then is lost to the universe forever, while matter is continuously recycled.

7. Carbon cycle- CO2 in atmosphere from volcanoes, fossil fuels, factories, etc. CO2 comes down from atmosphere to be used by plants in photosynthesis that are eaten by animals and breathed back into the atmosphere by cellular respiration OR phytoplankton can use CO2 in the water and when aquatic organisms die, they CAN become fossils and burned potentially as fossil fuels, but not always.

8. Water cycle- water in clouds can fall as precipitation and can condense on things as condensation. If it can't soak into the ground, it can runoff towards the nearest body of water. The water can also be taken up by plants and evaporated through transpiration back into the atmosphere. It can also be infiltrated or soaked into the ground and then percolated as it travels through the ground back towards the body of water.

9. Nitrogen Cycle: N2 in the atmosphere can come down into the soil where it can become NH3 through nitrogen fixation, NH4 through plants and animals dying or through ammonification, NO3 through nitrification. Once it is in NO3 (nitrate) form, plants and animals can use it, or if they can't or there is too much NO3, it can be changed back to N2 to return to the atmosphere through a process called denitrification.

10. Why can matter be recycled through the biosphere? Because I can make and break chemicals apart. Also, because producers will be eaten by primary consumers. The primary consumers will be eaten by the seconday consumers, and the secondary consumers by the tertiary consumers and eventually all things at all trophic levels will die and be recycled by the decomposers who will then have the producers use the nutrients in the soil to grow (through the nitrogen cycle)

11. What is a decomposer and why are they important in the environment?
A decomposer eats dead and dying matter. They are important because without them the matter would not get broken down in the ecosystem and be available to be recycled.

12. How are a food web and a food chain related?

A food chain consists of four steps. It shows you the energy and nutrient movement through the producer, primary consumer, secondary consumer, tertiary consumer. There are sometimes more than four steps but there always have to be at least four. In the Australian grassland example we used in class, you can see that there are multiple ways to get to the tertiary consumer level. Multiple food chains that are interconnected make the food WEB for the ecosystem. In other words, a food web is made up of multiple food chains within an ecosystem.

13. Define:

Herbivore: Plant eater- Brachiosaurus or Brontosaurus
Carnivore: Meat eater- Tyrannosaurus rex or velociraptor
Omnivore: Eats both plants and meat

14. What organisms play a key role in the nitrogen cycle and go through a process known as nitrogen fixation? Nitrogen fixing bacteria live in nodules (little bumps) on the roots of plants and fix or change nitrogen from N2 to NH3.

15. What are the major threats to biological diversity? The major threat to biological diversity is habitat destruction. When you take away an organism's home the likelihood that it has been given the DNA to code for all the structural, behavioral, and physiological adaptations it would need to live successfully in a new environment that is drastically different that what it is used to is not that great so it is likely to die and if species die and there are no more of them, then we lose diversity.

16. Which two biomes receive the lowest annual average rainfall?

Desert (less than 30 cm) and Tundra (30-50 cm).


17. Which climate zone includes the FEWEST biomes? Polar region-it only contains the tundra while all the rest of the biomes are either in a temperate, tropical or temperate tropical location at least of the ones given on the table.

18. Which biome shows the smallest range for average temperature listed? Tropical Dry Forest only changes 12 degrees C between wet and dry season. A close second is the tropical rain forest with a change of 14 degrees between day and night.

19. Which trophic level stores the largest amount of energy? Producers

20. If the producer level contains 1000 Kcal, how many calories would be stored in the primary consumers level? 100 because the primary consumers receive 10% of the energy that the producers have and 90% is lost as heat.

21. The total mass of producers in the ecosystem will weigh more or less than the total mass of the tertiary consumers? Why?

The mass of the producers in the ecosystem will weigh MORE because the biomass that is required of the producers is extremely great in order to support the growth and survival of all the levels on top of it. If you look at the producers (plants) and how many of them there have to be along with grasses, trees, flowers, shrubs, etc....this is WHY we are so dependent on plants, because if they weren't there, look at who in the food web ecosystem would be effected. EVERYONE.

22. When living in separate environments both organism A and organism B have stable populations. When organism A and B are put in the same environment, organism B's population severely declined. Why do you think this happened?

Competition occurred and Organism A outcompeted Organism B for resources needed for the population's survival.

23. In a food web would you expect to have more producers or more primary consumers? Why? Look at question 21.


24. What would happen to the secondary and tertiary consumers if a disease were to infect they producers? Don't say they would die.....at least not right away. If you look at the secondary and tertiary consumers....most of them don't eat the producers, BUT if the producers aren't there, then the primary consumers will eventually die, and without the primary consumers, then the secondary consumer population begins to decrease as well as the tertiary consumers. The secondary consumers will eventually die and that will leave the tertiary consumers who will continue to decrease and die.


25. The predator/prey graph would look like prey being in the environment and steadily increasing. When the predator line increases, the prey line will decrease because they are being eaten---eventually the prey will decrease to a point where there are not enough for the predators and they will start to die because they don't have anything to eat and there numbers will decrease. Without a large number of predators, the prey numbers start to increase. With prey being abundant again, the predators can eat and live and there numbers start to increase....see the cycle so you should have up and down hills for both predator and prey with the prey going first and the predators following it. Most of the time this is how the graph looks although there are sometimes where rather than the predators following the prey, the prey follows the predator.

Okay, that's it. I hope this review was helpful for you. Study hard, get sleep, eat a good breakfast and have a good day at school while taking your quiz. I'm off to make it now. Goodnight! Dr. R