Population Flashcards
Teen population
A group of organisms of the same species
Population numbers increase because of
Birth and immigration
Population numbers decrease because of
Death and emigration
In stable population
Birth + immigration = deaths + emigration
Density dependent
Abiotic - living
Affect greater proportion of population
Density independent
Biotic - non living
Term carrying capacity
Maximum number of individuals of species that the environment can support indefinitely
Phases of population growth
LAG
LOG
STATIONARY
DEATH
Lag (yeast)
Enzymes are synthesised
Dna is replicated
Log ( yeast)
Population doubles every unit of time
Nutrients abundant
Stationary ( yeast)
Competition of nutrients means death and cell reproduction happen at the same time
Death ( yeast)
Nutrient depletion and toxin accumulation mean death rate is higher than cell reproduction
Ecosystem
An area that has a particular community of plants and animals interacting with their environment
Term community
All of the organisms of all species in an ecosystem
Term habitat
Place in the ecosystem where organisms live
Term niche
An organisms role in ecosystem
Applies particularly to their feeding role
Photoautrophs
Mainly green plants
Use light energy from the sun to fix carbon dioxide into organic molecules by photosynthesis
GPP - R= NPP
Gross and net primary productivity
Why is some energy never taken in at each trophic level
Some parts of food aren’t consumed
Some parts of food indigestible
Plants can’t use all light energy as some is the wrong wavelength
Why is some energy lost at each trophic level
Respiration
Lost as heat
Pyramid of biomass
A table of dry mass of living material at each trophic level of a food chain