organisms and their environment Flashcards
principal source of energy input to biological systems
sun
describe flow of energy through living organisms
light energy from the sun - chemical energy in organisms - eventual transfer to environment
food chain
shows transfer of energy from one organism to the next, beginning with a producer
food web
network of interconnected food chains
producer
an organism that makes its own organic nutrients, usually using energy from sunlight, through photosynthesis
consumer
an organism that gets its energy by feeding on other organisms
herbivore
animal that gets its energy by eating plants
carnivore
animal that gets its energy by eating other animals
decomposer
an organism that gets its energy from dead or waste organic material
advantages of using pyramid of biomass instead of pyramid of numbers to represent a food chain
provide a better idea of quantity of plant/animal material at each level of a food chain, therefore a better way of representing interdependence within the food chain
trophic level
position of an organism in a food chain, web, ecological pyramid
advantages of using pyramid of energy instead of p.o.n + p.o.b to represent a food chain
more accurate representation of energy flow as shows energy loss
trophic levels
producer - primary consumer - secondary consumer - tertiary consumer - quaternary consumer
why is energy transfer between trophic levels inefficient
only 10% of energy gets transferred to the next level as energy is lost or used by the organism
why do food chains have less than 5 trophic levels
only 10% of energy is transferred to next level as energy is lost as some parts undigestible + respiration + movement so very less energy is transferred to 4th level which is not enough to sustain another level
why is it more efficient for humans to eat crop plants than livestock that fed on crops
- if humans eat crops, there’s more energy available to them
- if humans eat livestock, there’s less energy as the cows lost energy
ways energy is lost
- excretion
- movement
- heat
- undigested waste
- some parts are undigestible (cellulose parts)
processes in carbon cycle that produce CO2
- respiration
- combustion
processes in carbon cycle that remove CO2
- photosynthesis
describe carbon cycle
photosynthesis - respiration - feeding - decomposition - fossil fuel formation - combustion
describe nitrogen cycle
production of amino acids + proteins - feeding + digestion of proteins - deamination - decomposition of plants + animals into ammonium ions - nitrification - denitrification - nitrogen fixation- absorption
nitrification
ammonium ions - nitrate ions
(nitrifying bacteria)
denitrification
nitrate ions - nitrogen gas
(denitrifying bacteria)
nitrogen fixation
nitrogen gas - nitrate ions
(lightning + bacteria)
population
group of organisms of one species living in one area at the same time
community
all the populations of different species in an ecosystem
ecosystem
a unit containing the community of organisms and their environment interacting together
factors affecting rate of population growth of an organism
- food supply
- competition
- predation
- disease
phases of sigmoid growth curve
- lag phase
- exponential (log) phase
- stationary phase
- death phase
lag phase
- organisms are adapting to the environment before being able to reproduce
- very few organisms so reproduction is not producing many offspring
exponential phase
- food supply is abundant + birth rate is rapid + death rate is low
- growth rate is exponential + only limited by no. of new individuals produced
stationary phase
- growth rate slows as resources become limited
- population reaches its carrying capacity
- death rate = birth rate
death phase
- death rate > birth rate as food supply is short + metabolic waste builds up to toxic levels
