B7: Ecology Flashcards
What do organisms compete for?
-Food
-Water
-Space
-Light
-CO2/O2
-Mate
What is interdependence?
-Organisms depending on each other for survival
-When this happens, a COMMUNITY is formed
What are abiotic factors?
The non-living factors e.g. light, temperature, moisture, soil pH, CO2 & O2 concentration
What are biotic factors?
The impact of other organisms on an ecosystem e.g. food, predators/prey and pathogens
What is the sampling practical?
-Place QUADRAT in random positions in an area (ideally 10% of an area, using a random number generator to choose locations)
-Count number of chosen organism in each, calculate mean then multiply by total area to get estimate for population
-Moving it along a TRANSECT allows you to observe changes in population density over a distance
What do food chains show?
The direction of BIOMASS transfer between organisms
What are producers?
Organisms that use sunlight to produce biomass e.g. plants, algae
What are primary consumers?
They eat producers, herbivores/omnivores
What are secondary consumers?
Prey on primary consumers, carnivores/omnivores
What are tertiary consumers?
Prey on secondary consumers, carnivores/omnivores
Where are apex predators found:
-At the top of the food chain
-They have no natural predators
What are the different levels in a food chain/web called?
Trophic levels
How is carbon recycled?
When a organism dies and decomposes, and as they excrete CO2 while alive (bacteria also do this)
What is the water cycle?
-Rain falls
-This runs into rivers, sea
-Water is evaporated
-Cycle continues
How can decomposition be used?
-To produce natural fertilisers to help crops grow
-To produce methane gas for use as a fuel
Define biodiversity
The variety of species of organisms that exist in an ecosystem
How does high biodiversity make for a stable ecosystem?
Organisms will be able to be dependent on a greater number of other species for survival
How does human development result in reduced biodiversity?
-The destruction of habitats
-Disposing of waste in safe ways in order to reduce our impact is getting harder
What is land needed for?
-Building
-Quarrying
-Farming
-Disposing of waste
Why are peat bogs being destroyed and what effect does this have on biodiversity?
-Being destroyed for compost
-Reduces biodiversity of that ecosystem, especially for microorganisms
-Burning peat also releases CO2-contributes to global warming
What is the main reason for deforestation?
To create farmland
What is the pyramid of biomass?
Indicates how much biomass is transferred between trophic levels
any % =
‘the bit’/’the lot’ x100
e.g. % absorbed = biomass at 2nd level/biomass at first level x100
Why is biomass lost at each level?
This is due to not all of it being consumed/absorbed, and organisms losing it while they are alive via excretion
