Ecology Flashcards
define interdependence
- all organisms in an ecosystem rely on each other for food, protection, shelter etc to survive
- very small changes to ecosystems have large consequences, which can be difficult to predict
what do plants compete for?
- light
- space
- water
- minerals from the soil.
what do animals compete for?
- food
- mates
- territory
what is interspecific competition?
competition between members of different species
what is intraspecific competition?
competition between members of the same species
what is a stable community?
Where all the species and environmental factors are in balance so that population sizes remain fairly constant over time
what are abiotic factors?
- non-living element of an ecosystem
- light intensity
- temp
- moisture levels
- soil pH
- soil mineral content
- wind intensity and direction
- CO2 levels
- O2 levels
what are bioindicator species?
presence informs on condition of habitat
what are biotic factors?
- living factors in an ecosystem
- food availability
- new predators
- new pathogens
- out-competition
what are some structural plant adaptations?
- spines to stop animals eating them
- wide and shallow roots to collect lots of water after rain
- large leaves to absorb lots of sunlight
- flowers to attract pollinators
- flytraps to gain nutrients
what are some behavioural plant adaptations?
- plant shoots grow quickly towards the light
- flytraps close
what is a physiological plant adaptation?
poisons for defence
what are some structural animal adaptations?
- sharp claws to catch prey, dig burrows and scratch trees to signal territory
- good vision and hearing - prey has eyes on side of head to spot predators, predators have eyes on front to judge distance to prey
what are some behavioural animal adaptations?
- scratching trees
- mating rituals
- working in packs
- using tools
what is a physiological animal adaptation?
venom for defence and killing
what is an extremophile?
organism living in extreme environment
what is an ecosystem?
interaction between a community of living organisms and their environment
what is a community?
2 or more populations of organisms
what is a population?
all organisms of same or closely-related species in an area
define decomposition
the breakdown of a dead organism/dead matter by decomposers
what can the rate of decay be estimated by measuring?
- changes in pH
- change in mass
- change in temperature
what factors is the rate of decay affected by?
- Temperature
- Water
- Oxygen
how does temperature affect the rate of decay?
- colder temperatures - decomposing organisms less active
- extremely high temperatures - decomposers killed
- generally higher temperature = faster decay as enzymes are more efficient and absorption is faster as diffusion is faster
how does water affect the rate of decay?
- little or no water - less decomposition - decomposers cannot survive.
- Many decomposers secrete enzymes onto decaying matter and then absorb any dissolved molecules. Without water these reactions cannot occur.
- higher moisture availability = faster decay
- water is necessary for digestion
how does oxygen affect the rate of decay?
- higher oxygen availability = faster decay
- higher rate of respiration in decomposers = more energy = grow and multiply.
what is biodiversity?
the number of different species.
Name two types of microorganism that cause decay.
fungi and bacteria
what is a producer?
plants and algae which photosynthesise - provide all the biomass for the food chain
what are primary consumers?
herbivores which eat producers
what are secondary consumers?
carnivores which eat primary consumers
what are tertiary consumers?
carnivores which eat secondary consumers
define biomass
living or recently dead tissues
how do you calculate the efficiency of biomass transfer?
% energy transfer = biomass in higher trophic level / biomass in lower trophic level x 100
what is food security reduced by?
- increase in human population
- changing diets mean scarce food resources are transported to be sold to other areas from areas which need them
- new pests and pathogens
- climate change making farming more difficult in many areas
- increased costs of farming
- armed conflicts
describe the process of random quadrat sampling
- When you have chosen a sampling area, divide it up into a grid.
- generate pairs of random coordinates on your grid using calculator.
- Count the number of different species within this quadrat using top right rule (only count plants touching the top or right side of quadrat).
- record results in table.
- repeat many times.
- repeat entire experiment.
- transfer to line graph after finding averages
describe the process of line transect sampling
- decide on factor being investigated
- place tape measure as a transect on the floor
- decide how often to take a sample (equal intervals ie. every 1 metre)
- place quadrat at these equal intervals
- decide on a counting method/rule (ie top-right rule)
- sample each quadrat for the species being investigated
- draw a line graph or kite diagram of the results with distance on the x-axis
when is random sampling used?
to estimate population size/species abundance
what do trophic level pyramids show?
- the number of organisms at each level OR
- the collective mass of the organisms at each level
when is systematic sampling used?
to see how abiotic factors affect population
how is biomass passed on?
energy passed on as chemical energy in the molecules of the organism
what is biomass?
the mass of living material in a living organism
what is biomass measured in?
g/m^2 for plants or kg/m^3 for animals
why do scientists use dry biomass?
- the amount of water in individual organisms varies a lot over a 24hr period so it would not be fair
- there is no energy in water molecules, so it doesn’t need to be included
what is dry biomass?
biomass when all of the water has been evaporated
how can biomass be ‘lost’?
- through respiration
- excretion in urine and faeces
- if the animal doesn’t eat all of the other thing
- movement
- maintaining temperature
why do farmers practice intensive farming?
they want as much biomass as possible in the animals, because the higher the mass of the animals, the more money they will make when they sell them for food
how does intensive farming maintain biomass in animals?
restricts energy transfer from food animals to the environment
what are 3 features of intensive farming?
restricted movement, heated farms, controlled diet
how does restricted movement increase biomass in intensive farming?
if the animals’ movement is restricted, they aren’t wasting energy as kinetic energy, so energy used to make more muscle mass
how do heated farms increase biomass in intensive farming?
less energy will be used to maintain body temp as thermal energy, so energy is used to make more muscle mass not increase temperature
how does a controlled diet increase biomass in intensive farming?
they are fed food high in protein not fat to build more muscle mass and high absorption food to lower the amount of waste in faeces and urine as less is produced
what are some ethical considerations of intensive farming?
- animals aren’t eating their natural varied diet
- close quarters create stress, anxiety and aggression
- close confinement causes illness
- restricted movement and heavier body mass (than they are supposed to be) causes joint issues and (arthritis)
what are some examples of decomposers?
can be small animals (snails, woodlice) or microscopic organisms (bacteria, fungi)
how do microorganisms digest dead material?
excrete digestive enzymes onto it and absorb the useful, soluble nutrients through diffusion
how does microorganism availability affect the rate of decay?
higher microorganism availability = faster decay as it is more efficient
how does pH affect the rate of decay?
- too high/low pH = slower decay
- denatures enzymes
how does the build-up of toxic substances affect the rate of decay?
- higher toxicity = slower decay
- will inhibit/kill bacteria
how is compost used?
as a natural fertiliser to replenish minerals in the soil (eg nitrates for protein)
why is it useful that decomposers can respire anaerobically?
produce methane gas which can be used for cooking and heating - can set up small scale biogas generators
