Energy and Ecosystems Flashcards
How can biomass be measured?
Biomass can be measured in terms of the mass of carbon or dry mass of tissue per given area. The chemical energy store in dry biomass can be estimated using calorimetry.
What is primary and secondary production measured in?
It is measured as biomass in a given area in a given time eg kJ ha–1 year–1.
What is biomass?
Biomass is the total mass of living material in a specific area at a given time.
What is the equation of net primary production?
NPP = GPP - Respiratory losses
What is the equation for the net production of consumers?
N = I - (F+R)
N is net production, I chemical energy store of ingested food, F energy lost in faeces and urine, R energy lost in respiration.
Why do most food chains only have 4 or 5 levels?
There is insufficient energy to support a large enough breeding population at trophic levels higher than this.
What is the role of mycorrhizae?
It is a fungi that increases the surface area of a plant’s root system to increase the rate of uptake of mineral ions and water. In return the mycorrhizae get glucose. It is a mutualistic relationship.
What are the 4 main stages of the nitrogen cycle?
Nitrogen fixation, ammonification, nitrification, denitrification.
Name 3 ways nitrogen fixation can occur:
Lightning, free-living nitrogen-fixing bacteria, and nitrogen-fixing bacteria in leguminous plants root nodules.
What are the two steps in nitrification?
Oxidation of ammonia ions in nitrite ion and oxidation of nitrite ions to nitrate ions,
How can a farmer increase the nitrogen in the soil?
Using inorganic or organic fertilizers. Ploughing the soil which creates aerobic conditions for nitrifying bacteria and prevents anaerobic denitrifying bacteria.
What is the group of organisms that break down the complex material in dead organisms to simple ones called?
Saprobionts.
Describe why leaching and eutrophication are bad:
As the nitrate ion concentration increases (no longer limiting factor) due to leaching algal bloom takes place at the top of the water. This prevents the photosynthesis of aquatic plants so they die. More saprobionts use oxygen for respiration. The concentration of oxygen in the water drastically reduces.
