Nutrient Cycles Flashcards
What are saprobiotic microorganisms?
Decomposers that obtain their food from dead or decaying remains of other organisms
What are the main reasons for the increased CO2 and methane levels in the atmosphere?
- burning of fossil fuels
- deforestation
- farming
- industry
What are greenhouse gases?
Gases such as methane and carbon dioxide which in the atmosphere cause more heat energy to be trapped, so raising the temperature at the earths surface
How is carbon dioxide taken out of the atmosphere?
It is absorbed by plants when they carry out photosynthesis
How is carbon dioxide put back into the atmosphere?
By respiration and combustion of fossil fuels
Which part of the day is carbon dioxide concentration in the atmosphere at it’s highest and why?
At night as it is no longer been taken up by plants by photosynthesis and is released when organisms respire
When does respiration occur?
It is carried out constantly through the day and night
Which part of the day is carbon dioxide concentration in the atmosphere at it’s lowest and why?
During hours of daylight as plants are absorbing light energy for photosynthesis
What are the main causes of global warming?
Increasing carbon dioxide and methane concentrations
What is meant by the term global warming?
A term used to describe the increase in the average global temperature over the last centaury
What is responsible for increase in global temperature?
Human activity
What is meant by the greenhouse effect?
The trapping of the sun’s warmth in a planet’s lower atmosphere, it is the effect of greenhouse gases absorbing outgoing energy
Why is the greenhouse effect essential?
To keep the planet warm, but too much means the planet warms up
What are the main effects of global warming?
- changing climate patterns
- melting of ice caps
- increased crop yield
- survival of certain species
- rising sea levels
- changes in rainfall patterns
- storms
What are the four stages of the nitrogen cycle?
Nitrogen fixing, ammonification (by decomposers), nitrification and denitrification
Why do plants and animals require nitrogen?
To make proteins and nucleic acids (DNA and RNA) but first they need bacteria to convert the nitrogen into nitrogen compounds first
How is nitrogen removed from the atmosphere?
Nitrogen fixation
How is nitrogen put back into the atmosphere?
Denitrification
What do each stages of the nitrogen cycle involve?
Saprobiotic microorganisms
What are nitrifying bacteria?
Microorganisms that convert ammonium compounds to nitrites and nitrates
What does nitrogen fixation involve?
Where nitrogen gas from the atmosphere is converted into nitrogen-containing compounds ,such as ammonia, by nitrogen fixing bacteria
What are the two types of nitrogen fixation bacteria?
Free living and mutualistic
What do free living nitrogen fixing bacteria do?
Reduce nitrogen gas to ammonia, which they then use to make amino acids. When they die and decay, nitrogen-rich compounds are released
What do mutualistic nitrogen fixing bacteria do?
They live in root nodules such as peas and beans plants, they obtain carbohydrates from the plant and the plant acquires their amino acids from these bacteria (mutualistic relationship)
