Ecology and the Environment Flashcards
What is Nitrogen fixation?
nitrogen in atmosphere —> nitrogen in plants (DNA, proteins)
What bacteria is involved in Nitrogen fixation?
mutualistic nitrogen fixing bacteria (aerobic)
What is nitrification?
Ammonia —> Nitrites —> Nitrates
What bacteria is involved in nitrification?
nitrifying bacteria - oxidation (aerobic)
What is denitrification?
Nitrates —> Nitrogen in atmosphere (gas)
What bacteria is involved in denitrification?
denitrifying bacteria (anaerobic)
What is decomposition?
protein in dead plants and animals broken down —> ammonia in soil
How is Nitrogen transferred from animals to ammonia?
excretion
Denitrification makes the soil less…
fertile - less nitrate in soil
Where is nitrogen-fixing bacteria found?
root nodules of plants (leguminous crops)
What is a population?
total number of individuals of one species in a particular habitat at a particular time
How can you measure the population size in a habitat?
using a quadrat - random sampling
The stages in a food web or chain are called…
trophic levels
Pyramids of biomass are used to show…
total mass of each organism in each trophic level
Pyramids of energy should decrease between..
each trophic level
