Ecosystems Flashcards
Habitat
The place where an organism lives
Population
All the organisms of one species in a habitat
Community
All the different species in a habitat
Ecosystem
All the organisms living in a particular area and all the non-living conditions
how much energy is lost from each trophic level?
90%
how is energy lost from each trophic level?
- some parts of the food aren’t eaten
- some parts are excreted
- some is used for respiration
- some is lost as heat
nitrogen fixation
the process of turning nitrogen gas in air into nitrogen compounds in the soil which plants can use
two main ways that nitrogen fixing happens:
- lightning
- nitrogen-fixing bacteria in roots and soil
the four bacteria involved in the nitrogen cycle:
- decomposers
- nitrifying bacteria
- nitrogen-fixing bacteria
- denitrifying bacteria
what is the role of the decomposers?
to break down proteins and urea and turn them into ammonia
what is the role of the nitrifying bacteria?
turn ammonia in decaying matter into nitrates
what is the role of nitrogen-fixing bacteria?
turn atmospheric N2 into nitrogen compounds that plants can use
what is the role of denitrifying bacteria?
turn nitrates back into N2 gas
how is carbon monoxide produced?
when fossil fuels are burnt without enough air supply
how is sulfur dioxide produced?
by burning fossil fuels
what is eutrophication?
- nitrates are leached into rivers and lakes
- algae grow really fast
- plants can’t photosynthesise
- microorganims feed on dead plants
- less oxygen in water
- organisms that need oxygen die
leaching
- trees take up nutrients from the soil
- the leaves return the nutrients when they die
- when trees are removed, nutrients get leached away but don’t get replaced
water cycle
- trees prevent floods
- transpiration from trees also releases some rainwater back into the atmosphere
- deforestation makes local climates drier
soil erosion
- tree roots hold soil together
- when trees are removed, the soil can be easily washed away
the balance of C02 and O2
- forests take up CO2 and store it. They release it when they die
- when they are cut down and burnt, the CO2 is released
- there is also less oxygen as less photosynthesis takes place
