organisms and their environment Flashcards
ecology
the study of organisms in their environment
habitat
the place where an organism lives
each species has adaptive feature that enables it to live in its specific habitat
community
all of the populations of all the different species in an ecosystem
ecosystem
a unit containing all of the organisms in a community and their environment, interacting together
niche
the role of an organism in its natural environment; the way in which it interacts with other organisms and with the non-living parts of the environment
all living organisms need
energy
all the energy in an ecosystem originates from the sun
what happens to the energy from the sun
captured by plants and used to make organic nutrients- glucose, starch, and other organic substances such as fats and proteins.
how do animals get their energy
by ingesting plants or by eating animals which have eaten plants
food chain
a diagram showing the flow of energy from one organism to the next, beginning with a producer.
food web
a network of interconnected food chains
producer
an organism that makes its own organic nutrients, generally using energy from sunlight, through photosynthesis.
they produce the energy-containing organic nutrients that all the other organisms in the food chain need.
consumers
an organism that gets its energy by feeding on other organisms
primary consumer
an animals that gets it energy from eating plants
secondary consumer
an animal that eats the primary consumer
tertiary consumer
an animal that eats the tertiary consumer
herbivores
an animal that gets it energy from eating plants
carnivores
an animal that gets energy from eating other animals
decomposer
an organism that gets its energy from dead or waste organic material.
what happens to the energy across trophic levels (along the food chain)
some energy is passed on to the next level. most is lost
how is energy lost along the food chain
when an organisms used glucose for respiration, some of the energy released from the glucose is lost as heat energy.
weh none organism eats another it rarely eats all of it. so not all if the energy is transferred
when an organism eats another the enzymes break down the molecules so that they can be absorbed, but sometimes they arent and they pass through the alimentary canal and are lost as faeces.
further along the food chain…
less energy available for each trophic level.
near the beginning of the food chain is the best way to eat without
pyramid of numbers
a diagram in which the area of the bar at each trophic level shows the relative number of organisms at that level in the food chain
usually the shape is big to small (producer is big pop.) because there is less energy available as you go up so less animals
trophic level
the position of an organism in a food chain, food web or pyramid of biomass or numbers
pyramid of biomass
a graph showing the relative quantity of biomass at each trophic level.
better than pyramid of numbers bc it gives a better representaiton of the quantity of energy at each level
pyramid of energy
a graph showing the relative quantity of energy at each trophic level
kJ/m2
how to measure energy in animals
killing, then burning it to measure how much energy how much energy is released
best way to measure energy
why are decomposer important
they help to release substances from dead organisms, the released substances can then be used by other living organisms. 2 or the substances are carbon and nitrogen
nitrogen fixation
converting inert nitrogen gas into a more reactive form, such as nitrate ions or ammonia
there are several ways to do this:
lighting
artificial fertilisers
nitrogen fixing bacteria
lightning
makes some of the nitrogen gas in the air cobined with oxygen, forming nitrogen oxides. they dissolve in rain and are washed into the soil, where they form nitrates
artificial fertilisers
nitrogen and hydrogen can be made to react in an industrial chemical process to make ammonia.
they ammonia is used to make ammonium coumpounds and nitrates, sold as fertilisers
nitrification
converting ammonium ions to nitrate ions
denitrification
converting nitrate ions to nitrogen gas
what happens to a population’s size
stays roughly the same
lag phase
the stage at the start of a population growth curve where the population remains small and grows only very slowly
log or exponential phase
the stage in a population growth curve where the population grows at its maximun rate; birth rate exceeds death rate
stationary phase
the stage in a population growth curve where the population falls; death rate exceeds birth rate .
sigmoid growth curve
an S-shaped curve showing change in the size of a population through all the phases in population growth
limiting factors in population size
food supply
disease
no. of predators
limiting factor
a factor that is in short supply, which stops an activity happening at a faster rate
age pyramid
a diagram showing the relative numbers of individuals of different stages in a population
the human population
stably increasing
