Energy and ecosystems Flashcards
What are producers?
Photosynthetic organisms that manufacture organic substances using light energy, water, carbon dioxide and mineral ions.
What are consumers?
Organisms that obtain their energy by consuming other organisms rather than using the energy of sunlight directly. All animals are consumers.
What are saprobionts?
(decomposers)
A group of organisms that break down the complex materials in dead organisms into simple ones. They release valuable minerals and elements in a form that can be absorbed by plants and so contribute to recycling.
What is a food chain?
A feeding relationship in which the producers are eaten by primary consumers. These is turn are eaten by secondary consumers, which are then eaten by tertiary consumers. Each stage in this chain is referred to as a trophic level. The arrows on a food chain represent the direction of energy flow.
What is a food web?
Most animals do not rely on a single food source and within a single habitat, many food chains will be linked together to form a food web.
What is biomass?
The total mass of living material in a specific area at a given time.
Measured using dry mass per given area, in a given time.
Grams per square metre (gm^-2) where an area is being sampled; grams per cubic metre (gm-3) where volume is being sampled.
How do you calculate net production of consumers?
N = I - ( F + R )
N: net production
I: chemical energy store of ingested food
F: energy lost in faeces and urine
R: energy lost in respiration.
How do you calculate net primary production?
NPP = GPP - R
NPP: net primary production
GPP: gross primary production
R: respiratory losses
