Chapter 59 Ecosystem Ecology

Compare and contrast food chain and food web

A food chain only follows just one path as animals find food. (A hawk eats a snake, which has eaten a frog, which has eaten a grasshopper, which has eaten grass) A food web shows the many different paths plants and animals are connected (A hawk might also eat a mouse, a squirrel, a frog or some other animal. The snake may eat a beetle, a caterpillar, or some other animal) A food web is several food chains connected together

explain how nutrients cycle through an ecosystem

Carbon cycle Nitrogen- nitrogen cycle Global Phosphorus Water cycle See question 17 for description

Know the basic outlines of the global phosphorus, carbon, nitrogen, and water cycles. How are human activities affecting each of these cycles

Nitrogen- nitrogen cycle 1) nitrogen fixation- nitrogen gas is converted into ammonia (NH3). Used to produce fertilizer as well. 2) nitrification- ammonia (NH3) or ammonium (NH4+) converted to nitrate (NO3-). Nitrate is commonly used by plants. This conversion is by soil bacteria. 3) assimilation- plants & animals incorporate ammonia and nitrate 4) ammonification- conversion of organic nitrogen to ammonia and ammonium 5) denitrification- reduction of nitrate to gaseous nitrogen Phosphorus- Most phosphates originate as salts in ocean sediments or in rocks. Over time, geological uplift brings these sediments to the surface, and weathering releases the phosphate ions. Plants can then absorb these phosphates from the soil and use it in cellular processes. Phosphate taken up by plants may then be passed on to animals when the plant is consumed by herbivore that, in turn, may be consumed by carnivores. After death, the animal or plant decays, and the phosphates are returned to the soil by way of bacterial decomposition. Runoff from the land may carry leached phosphate back to the ocean, where it eventually enters sediments and is reincorporated into rock. carbon cycle- carbon is absorbed by plants and soil, carbon is released from microbial respiration and decomposition as well as plant respiration water cycle (hydrological cycle)- little of the water is chemically changed, its a physical process made up of evaporation and precipitation Human activity increases CO2 levels, nitrogen levels, and phosphorus levels via greenhouse gasses and burning fossil fuels

describe how energy flows from producers to consumers and decomposers in a food web

Primary producers convert energy from the environment into a usable chemical form (using photosynthesis) Primary consumers obtain their needed energy by consuming the energy stored in the cells and tissues of primary producers. Secondary consumers eat primary consumers Decomposers break down organic material distributed by other organisms into the environment

Describe the general structure of a biogeochemical cycles (figure 59.15). What are the boxes and what are the arrows?

The boxes represent abiotic and biotic factors, the arrows represent the direction in which the energy cycles through the cycle

define the concept of "ecosystem" and contrast this with "community"

a community is the populations of different species together When the abiotic factors, or non-living things in an environment are added it in is then considered an ecosystem

What is a "biogeochemical cycle" and how is it different than a geochemical cycle?

a geochemical cycle is the pathway that chemical elements take in the surface and crust of the Earth a biogeochemical cycle or substance turnover or cycling of substances is a pathway by which a chemical substance moves through biotic and abiotic compartments of Earth.

What is biomagnification and why is this phenomenon discussed in this section of the book? How does this relate to patterns of energy transfer in an ecosystem

biomagnification- tendency of certain chemicals to concentrate in higher trophic levels in food chains The substances become increasingly concentrated in tissues or internal organs as they move up the chain

what are the principle elements of life?

carbon, oxygen, hydrogen, and nitrogen

How is matter and energy are tied together in biogeochemical cycles?

chemical element or a molecule moves through both biotic ("bio-") and abiotic ("geo-") compartments of an ecosystem and producers rely on these nutrients to provide energy

describe how human activities are altering these local and global nutrient cycles and what effects these changes are having on the biosphere.

due to greenhouse gas emissions, levels of CO2 have risen and with risen CO2 levels there is a decrease in herbivory (Stiling and Drake)

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

detrivore

heterotrophs that obtain nutrients by consuming detritus (waste)

Note the importance of decomposition nutrient cycling. How might rates of decomposition be affected by temperature? What conditions would promote or reduce the build-up of nutrients and organic matter in soil?

increased temp means increased rate of decomposition. climate, soil type, vegetation, and soil organisms impact the nutrient build-up

Understand how energy moves through an ecosystem and why the efficiency of energy transfer is, on average, about 10%. What are sources of energy loss and inefficiency in an ecosystem?

moves from primary producer-> primary consumer -> secondary consumer -> decomposer A source of energy loss is that each organism must consume some of the energy to maintain their survival. (Vertebrates tend to have lower production efficiencies than invertebrates, due to sustaining their metabolisms)

Compare and contrast production and trophic level transfer efficiency.

net primary productivity: energy that remains in the primary producers after accounting for the organisms' respiration and heat loss trophic level transfer efficiency: energy transfer efficiency between two successive trophic levels

Know the role of autotrophs as primary producers and generators of organic matter in an ecosystem.

produces complex organic compounds from simple substances present in its surroundings, generally using energy from light in which primary consumers consume

describe the possible mechanisms that promote or limit productivity in an ecosystem

terrestrial- water, temperature, and nutrient availability aquatic- light and nutrient availability

bottom-up control

the limitation placed by resources allowing growth such as food source, habitat, or space

What is the relationship of sunlight, water, nutrients and temperature to global patterns of production on land and in the sea?

they are factors that can limit primary production aquatic- nutrient availability and light terrestrial- nutrient availability, water, and temperature