Biology - ecosystems Flashcards
individual
single organism
population
group of organisms of same species that live within the same area
community
collection of all the different populations that live together in the same ecosystem
habitat
area where organisms live
ecosystem
describes the way that the living and non-living components of environment interact
biotic factors
- competition for resources
- infectious disease
- predation
- food supply
abiotic factors
- light intensity
- pH of water/soil
- temperature
- availability of water
- availability of oxygen
- pollution of air/water
what do plants require to survive
- light
- space
- water
- mineral ions from soil
what do animals need to survive
- territory
- food
- water
- mates
what is interspecific competition
individuals compete with those of another species
what is intraspecific competition
individuals compete with those of same species, ‘survival of fittest’
predator-prey cycles
- typical cycle, peaks and troughs of population numbers generally follow each other
- more prey means more predators can feed, survive and reproduce leading to an increase in predator numbers
- cycles take a while to sync up because it takes time for populations to respond to species
parasitic relationships
- parasite organisms that ‘feed’ off a host without giving anything back to the host
- this means that only the parasite benefits, whereas the host is harmed
- example is animal fleas
mutualistic relationships
- organism lives on a host organism, but in return there is an exchange of resources
- both organisms benefit from relationship
- e.g. hermit crabs who place sea anemones on their shells for protection
biomass
mass of living organism
biomass pyramid
used to represent biomass of food chain as a biomass pyramid
what are tropic levels
levels within food chain
what are producers
usually, photosynthetic plants
- plants absorb light energy from Sun using chlorophyll
- these are then stored in carbohydrates, fats, proteins - creating plant’s biomass
what are primary consumers
herbivores which eat plants
what are secondary consumers
carnivores which eat primary consumers
what are tertiary consumers
often not present due to the loss of biomass through each stage of the food chain
what happens to biomass through the trophic levels
decreases (not always as numbers of organisms increase as you move up too)
how is energy lost in different stages of trophic levels
- energy lost during photosynthesis - photosynthetic plants use only about 1% of Sun’s light energy during photosynthesis, with remainder lost by reflection/transpiration
- energy lost through respiration - conserving heat and movement
- energy lost through waste - some of biomass is inedible or indigestible
what are the 4 main processes of the carbon cycle
- photosynthesis
- respiration
- decomposition
- combustion
carbon cycle: photosynthesis
sugars formed from process, which are converted to starch or cellulose, or used to make fats and proteins
only process which removes carbon dioxide from the environment
carbon cycle: respiration
process releases carbon dioxide as a waste product into environment
carbon cycle: decomposition
when organisms die or produce waste, decomposers break down complex organic molecules and return elements to the soil
(decomposers are also known as detritus feeders)
carbon cycle: combustion
C + O2 –> CO2
when plant or animal matter are burnt this releases carbon dioxide
mass deforestation and burning increases the amount of CO2 returned to atmosphere, whilst reducing the amount removed through photosynthesis
water cycle
- transpiration: loss of water vapour from plants through stomata to atmosphere
- evaporation: from surface of sea, rivers and other bodies of water creating water vapour in the atmosphere
- condensation: water vapour from evaporation condenses to form clouds
