AP Biology Chapter 55: Ecosystems

What percentage of energy available at one trophic level is available at the next?

10%

If the grass has 1000j, how much will the crow have? grass-grasshopper-lizard-crow

1000j-100j-10j-1j

Write the equation for photosynthesis,

6CO2 + 6H2O + light energy = C6H12O6 + 6O2

What is a limiting nutrient? What is the limiting nutrient off the shore of Long Island, New York? Sargasso Sea?

A limiting nutrient is the element that must be added for production to increase. Off the shore of Long Island, nitrogen was limiting phytoplankton growth. Sargasso has iron which limits growth of phytoplankton.

What is eutrophication? What are factors that contribute to eutrophication?

A process by which nutrients like phosporus and nitrogen become highly concentrated in a body of water, leading to increased growth of organisms such as algae or cyanobacteria. Soil rich in nutrients washed away to the water due to no trees to hold the soil intact.

Which ecosystem would tend to have a greater biomass/unit area, a prairie or a tropical rain forest? Explain.

A tropical rainforest because the rate of photosynthesis will be higher due to more light and available water.

What trophic level supports all others?

Autotrophs, primary producers

Explain the process of biological magnification. Discuss at least one example.

Biological magnification is the process of accumulated toxins becoming more concentrated in successive trophic levels of a food web. DDT use grew rapidly. Declination of types of birds.

Write the equation for cellular respiration

C6H12O6 > CO2 + H20 +ATP

What are the primary producers of the deep-sea vents?

Chemosynthetic prokaryotes

Phytoplankton growth can be increased by additional nitrates and phosphates. What are common sources of each of these?

Common sources of nitrates and phosphates are sewage and fertilizer for farms and lawns.

What are detritivores? What is their importance in chemical cycling?

Decomposers which consume their energy from detritus, non-living organic material. They convert organic materials to inorganic compounds usable by primary producers. Fungi, Prokaryotes.

Where does energy enter most ecosystems? How is it converted to chemical energy and then passed through the ecosystem? How is it lost?

Energy enters through sunlight. Autotrophs convert chemical energy and passes it through hetertrophs through food. It is lost by heat.

What effect has deforestation been shown to have on chemical cycling?

Experimental deforestation of a watershed dramatically increased the flow of water and minerals leaving the watershed.

What is contributing to the great increase in atmospheric carbon dioxide? What are potential effects of this increase?

Fossil fuels burning leading to atmospheric CO2. It would alter geographic precipitation (agricultural US much drier)

In what ways have human activities contributed to acid precipitation? What are some negative consequences of acid precipitation?

Humans burning wood and fossil fuels releases oxides of sulfur and nitrogen that react with water in the atmosphere. Affects soil chemistry and nutrient availability by lowering pH of water.

How has agriculture affected nitrogen cycling? What are some negative consequences of nutrient enrichment?

It has increased nitrogenous materials in soil. Plowing mixes soil, therefore speeding up decomposition of organic matter, releasing nitrogen that is then removed when crops are harvested. Nutrient enrichment leaks into runoff affecting water supplies.

Why in net primary production, or the amount of new biomass/unit of time, the key measurement to ecologists?

It is the key measurement to ecologists because it represents the stored chemical energy that is available to consumers in the ecosystem.

What are some factors that limit primary productivity in aquatic ecosystems?

Light limitation affects primary productivity as well as nutrient limitation, primarily of nitrogen or phosphorus. (Low in photic zone)

Describe a technique for measuring net primary production in an aquatic environment.

Looking at the differences in absorption of light to estimate photosynthesis. (Chlorophyll captures visible light, photosynthetic organisms absorb more light at visible wavelengths.)

What is primary production? Distinguish between gross primary production and net primary production.

Primary production is the amount of light energy converted to chemical energy (organic compounds) by autotrophs during a given time period. GPP is the total primary production in an ecosystem (Amount of light energy that is converted to chemical energy by photosynthesis per unit time). NPP is equal to GPP minus energy used by primary producers for respiration.

How is atmospheric ozone depleted? What are projected effects of this depletion?

The ozone is depleted by chlorofluorocarbons (CFC). The chlorine the breakdown products contain reduces to O2. Ecologists can use filters to decrease UV radiation.

What is trophic efficiency?

The percentage of production transferred from one trophic level to the next.

What is an ecosystem?

The sum of all the organisms living within its boundaries and all the abiotic factors with which they interact.

secondary consumers

carnivores that eat herbivores

tertiary consumers

carnivores that eat other carnivores

State the trophic level of each of the following: cow__________grass_______________man__________mushroom____________

cow:primary;grass:producer;man:secondary;mushroom:detritivore

Both energy and matter can be neither_____________________nor _____________________

created; destroyed (Law of conservation of Mass)

eutrophication

excessive richness of nutrients in a lake or other body of water, frequently due to runoff from the land, which causes a dense growth of plant life and death of animal life from lack of oxygen.

Chemicals such as carbon and nitrogen cycle through ecosystems. So energy ______________ through an ecosystem and matter _____________________________.

flows; cycles within and through them

primary consumers

herbivores

detritus

nonliving organic material

List three groups of organisms that are photosynthetic autotrophs.

plants, algae, photosynthetic prokaryotes

critical load

the amount of added nutrient, usually nitrogen or phosphorus, that can be absorbed by plants without damaging ecosystem integrity.

biogeochemical cycles

the name of nutrition cycles because they involve both biotic and abiotic components

production efficiency

the percentage of energy stored in assimilated food that is not used for respiration

transpiration

the process by which moisture is carried through plants from roots to small pores on the underside of leaves, where it changes to vapor and is released to the atmosphere. Transpiration is essentially evaporation of water from plant leaves.

green world hypothesis

the proposal that terrestrial herbivores are held in check by a variety of factors, such as plant defenses, low nutrient concentration, abiotic pressures, intraspecifc and interspecifc competition

actual evapotranspiration

the quantity of water that is actually removed from a surface due to the processes of evaporation and transpiration.

primary production

the rate at which energy is converted by photosynthetic and chemosynthetic autotrophs to organic substances. The total amount of productivity in a region or system is gross primary productivity.

turnover time

the time allowed for producers to reproduce before they are eaten again

Write an equation here that shows the relationship between gross and net primary production.

NPP = GPP - R

secondary production

The amount of chemical energy in consumers' food that is converted to their own new biomass during a given time period

What is meant by the greenhouse effect? What would life on Earth be like without this effect?

The greenhouse effect is the greenhouse gases absorbing infrared radiation the Earth emits re-reflecting some of it back to Earth. The Earth would be -18C without much of the life it has now.

What are trophic levels? What is always at the first trophic level?

Trophic levels are levels of different species based on nutrition source and energy. First trophic level is autotrophs which are primary producers.

Why do people who have limited diets in overpopulated parts of the world eat low on the food chain?

Worldwide agriculture could successfully feed many more people and require less cultivated land if humans all fed more efficiently as primary consumers.