Matter, Energy, and Food Webs Flashcards
What is the amount of biomass that is available to consumers at subsequent tropic levels?
Net primary production
What is the total amount of organic material produced by plants?
Gross primary production
What is the amount of biomass at higher graphic levels known as?
Secondary production
What is the percentage of energy transferred from one trophic level to the next, that varies between 5% and 20%, called?
Ecological efficiency
What is the original source of energy that powers ecosystems?
The sun
What law states that the total energy content of a trophic level is only one-tenth of the preceding level?
10% law
What is the measure of the total leaf area of a given plant?
Leaf Area Index
What is the gain in mass or plant tissue per unit in time known as?
Relative growth rate
What is the formula for relative growth rate?
Increase in dry mass per unit in time/
Original dry mass of plant
What is the increase in plant weight per unit of leaf area per unit time?
Net Assimilation Rate
What is the difference between productivity and production?
Productivity is a rate, whereas production is total energy
Why is the net primary production of open ocean ecosystems low in comparison to that of coastal systems?
Water reflects or absorbs much of the sun’s energy before it reaches producers.
What is the constant mass of a dried plant material?
Standing crop
What is the biological origin of coal?
Plant matter
What is the biological origin of oil?
Algae
What is the biological origin or limestone?
Tiny shells and other bits of skeletons
What three processes release carbon into the atmosphere?
Combustion, cellular respiration, and volcanic activity
What bacteria fixes atmospheric nitrogen?
Azotobacter
What bacteria converts Ammonia to Nitrite?
Nitosomonas sp.
What bacteria converts nitrite to nitrate?
Nitrobacter spp.
What bacteria releases nitrogen back into the atmosphere?
Denitrifying bacteria
What bacteria turn nitrogen back into Ammonia?
Nitrogen-fixing cyanobacteria
What three processes fix atmospheric nitrogen?
Microbial fixation, Haber Process, and lightning.
What process releases nitrogen gas into the atmosphere?
Denitrification
In what form is most nitrogen available to plants?
Nitrate (NO3)
How do animals get the Nitrogen they need?
By eating plants and herbivores
Why might farmers plough a crop of legumes into the ground rather than harvest it?
Legumes restore Nitrogen to the soil by increasing bacteria count.
What are five ways humans intervene with the Nitrogen cycle?
Haber Process, irrigation and harvesting crops, burning crops, using pesticides, crop rotation.
What are the two ways water returns to the oceans from land?
Precipitation and runoff
What are three ways humans intervene with the water cycle?
Deforestation, the building of dams, the creation of non-permeable surfaces
What is the main reservoir for water on earth?
Oceans
What are the earth’s main reservoir’s for freshwater?
Lakes, aquifers, glaciers, and rivers
What role do plants play in the hydrologic cycle?
They transpire, creating humidity.
What are two instances in the Phosphorus cycle where bacterial action is important?
Chemical waste and fertilization
What are the three forms of inorganic phosphate that make up the geological reservoir?
Rock phosphates, insoluble phosphates, and dissolved phosphates.
What must occur to make rock phosphate available to plants?
Weathering
What are two ways in which Sulfur can enter the atmosphere from natural sources?
Volcanic activity and hot springs
What are two ways in which sulfur can enter the atmosphere as a result of human activity?
Combustion of fossil fuels and smelting
What three processes make sulfur available for uptake by plants?
Decomposition of decayed matter, acid precipitation drops sulfate into the soil, conversion of hydrosulfic acid to sulfate by microorganisms.
What are two major roles of Sulfur in the biosphere?
Increases the Earth’s albedo, makes up key components in proteins
