Biology - Ecology Flashcards
what is a habitat
the environment in which an organism lives
what is a population
the total number of organisms of the same species living in the same geographical area
what is a community
the populations of all the different species that live in the same habitat
what does biotic mean
living organsim
what is abiotic
non -living parts of an environment
what is an ecosystem
An ecosystem is the interaction of a community of living organisms (biotic) with the non-living (abiotic) parts of their environment.
what do plants compete for
- light
- space
-water
-mineral ions in the soil
what do animals compete for
-food
-water
-mating partners
-territory
what does interdependence mean
the idea that, Within a community, each species depends on other species for food, shelter etc. If one species is removed it can affect the whole community.
what is a stable community
where all the species and environmental factors are in balance so that population sizes remain fairly constant.
what are examples of biotic factors which affect community
- availability of food
- arrival of a new predator
-competition between species
-new pathogens
what are Abiotic factors which can affect a community
- light intensity
- temperature
- moisture levels
- soil pH and mineral content
- wind intensity and direction
- carbon dioxide levels for plants
- oxygen levels for aquatic animals.
how can a change in the availability of food affect a given community
if availability of food falls then the number of organisms fall in the community will also fall
how can an arrival of a new predator
can cause the population of a prey species to fall
OR
a new predator can also affect existing predators eg if they’re competing for the same prey
how can competition affect the community
if a species is outcompeted then its population can fall so much that numbers are no longer sufficient to breed and the species may become extinct
how can a pathogens affect a community
- if infectious disease emerges and spreads it can wipe out a population of a species
how can a light intensity affect a community
- all plants need to carry out photosynthesis so if light intensity is too low then rate of photosynthesis falls and plants grow slowly = animals which feed on plants may not have enough food
how can temperature affect a community
if the temperature of environment changes then it can cause the distribution of species to change eg animals could migrate and plant species may disappear from that area
how can water affect plants
animals/plants need water to survive
but many species are adapted to deal with low levels of water
how can PH /mineral content affect plants
many plants canot grown on osil which is too acidic /alkaline
plants need certain minerals in the soil eg nitrate used to make amino acids for proteins
how can wind intensity and direction affect plants
strong winds blowing inland from sea can cause plants to lose water ( so plants growing in sand dunes are adapted to reduce water loss)
how can carbon dioxide and oxygen affect a community
carbon dioxide is needed for plants to photosynthesise if c02 fall then rate of photosynthesis also decreases
oxygen is needed for aerobic respiration , but level of dissolved oxygen in water can fall eg on hot days =. harmful to aquatic organism
how are camels structurally adapted for their surrounding
- have a hump on their back which is a store of fat =thermal insulator , by storing fat in one place = heat loss from other parts of camel body = reduces water loss from sweating
AND metabolic reactions can be used to produce water from the fat - have thick coat on upper surface of body = insulates top of camel from heat = reduces water loss from sweating
-camels mouth = leathery = chew desert plants which have thorns and these plants are usualy good source of water
- long eyelashes to keep dust out of eyes
- wide feet = prevents camel from sinking into sand
how are camels functionally adapted for their surrounding
produce concentrated urine and dry faeces = reduce water loss
- camels can tolerate large changes in their body temperature = which help them cope with heat in desert
how are animals structurally adapted for their surrounding in extreme cold
- thick fur = insulation and reduces heat loss to air
- fur on feet = reduces heat loss to ice and snow
- small ears = reduces surface area = reduces heat loss
- fur colour = white = effective camouflage, which helps to hunt prey
how are plants structurally adapted for their surrounding eg in the desert ( cactus))
- well adapted to living in dry conditions
- have very small leaves which reduce water loss
- some cacti don’t have leaves but instead spines which protect the cactus from animals
-cacti have extensive and shallow roots = which allow cacti to catch us much of water after rainfall before it evaporates /sinks in the ground - cacti can store water in their stem = they can survive many months without rain
what are extremophiles
an organism that lives in an extreme environment (e.g., high temperatures, pressure or salt concentration)
how can animals be adapted to living in cold climates
small surface area to volume ratio (animals are large) to reduce the energy transfer from the animal to its environment
mammals have lots of insulation (blubber)
some have thick fur coats for insulation
penguins huddle together to keep warm and transfer energy to each other
how can animals be adapted to living in hot/ dry climates
- kidneys produce concentrated urine to deal with the low water intake
- most animals are more active in the early morning or the night when it is cooler
- most animals are relatively small and have a large SA: V ratio to increase energy transfer to the environment
- camels sweat very little to reduce water loss
what is a producer
an organism that makes its own food from photosynthesis
what is a primary consumer
animals that eat producers
what is a predator?
consumers that kill and eat other animals
what are decomposers
a group of microorganisms that feed on waste droppings/dead organisms and release carbon dioxide, water and mineral ions as waste products
why are decomposers important for plants
they return mineral ions (eg, nitrates) to the soil, which plants use to make proteins of other chemicals in their cells
also, decay returns carbon to the atmosphere, which is used in photosynthesis
what conditions affect the rate of decay
- temperature (for the decomposers’ enzymes)
- moisture (as microorganisms grow faster in moist conditions and prevent them from drying out)
- oxygen (microorganisms need oxygen to break down food, grow and reproduce)
what is produced when bacteria decompose waste anaerobically
methane gas, which can be used as a fuel for generating electricity or for vehicles
how do plants avoid competition with their own seedlings?
they use wind to help them spread their seeds as far as possible. some produce seeds with special adaptations for flight.
what is a structural adaptation
a physical feature that helps an organism’s survival in its habitat
what is a behavioural adaptation
a behaviour or action an organism does to help their survival in their habitat
what is a functional adaptation
an adaptation of an organism’s biological processes (eg, metabolism) that helps it survive in its habitat
what conditions can extremophiles survive in
- very high concentrations of salt
- very high temperatures/ pressures
why are producers useful in food chains
- they synthesise complex molecules ( glucose ) - the producers are the source of all biomass in a community
describe the population- prey graph ( of a stable community)
- if there is a rise in the population of prey = more rabbit offspring survive = predators have more prey to kill and eat = predator population also increases
- now that there are more predators , the prey population falls = after some time the predator population falls
- now since predator population fall the prey survive and reproduce = rise to prey population = more prey for predators to eat …..
what are the ways scientists determine the number of organisms in an area
- random sampling
- sampling along transect
what is random sampling
used to compare the numbers of organisms in different areas ( using a quadrat)
how do you use a quadrat
place on the ground and then count the number of organisms inside the quadrat
how to calculate total population size
total area / area sampled x number of organisms of the species counted in sample
how can carbon enter the carbon cycle
by photosynthesis
how is carbon first started
started with carbon dioxide in the atmosphere
how is carbon dioxide returned back into the atmosphere
by aerobic respiration
what are the 2 key processes in the carbon cycle
- photosynthesis = brings carbon into the cycle
- respiration = returns carbon back into the atmosphere
describe the process of the carbon cycle
- carbon dioxide is found in the atmosphere
- plants and algae take in carbon dioxide from the atmosphere in photosynthesis
- the carbon is used to make carbohydrates, fats and proteins which make up the cells of plants and algae
- plants and algae respire so some of the carbon is released back into the atmosphere as carbon dioxide
- animals can eat plants and algae
- other animals can then eat these animals
- the carbon that was in the plants becomes part of the carbohydrates, fats and proteins in the cells of animals
- like plants, the animals respire, so some of the carbon is released back into the atmosphere as carbon dioxide
-animals release waste products eg faeces - and at some point all animals and plants die , so now there is carbon in waste products and in dead remains
- the waste products and dead remains are then broken down by decomposing microorganisms eg bacteria/fungi
- when decomposers carry out respiration , the carbon in the waste and dead remains is returned to the atmosphere as carbon dioxide
which conditions can decomposers not function effectively in
lack of oxygen
what happens if the decomposers cant function effectively
the carbon in dead remains can be slowly converted to fossil fuels
describe the water cycle
energy from the sun causes water to evaporate from the surface of sea
water vapour travels into the air and cools down
when it cools, the water vapour condenses to form clouds
the water in clouds then falls to the ground as precipitation
once water hits the ground some of it evaporates back into the atmosphere as water vapour
some of the water passes through rocks and forms aquifers
a lot of water passes into river
the water in rivers and streams eventually drains back into the sea through surface runoff
why is the water cycle important
living organisms require water and the water cycle provides organisms on land with a continuous supply of water
why is the carbon cycle important
carbon-containing molecules such as glucose are important for living organisms to grow and provide energy for vital functions within cells
what is decomposition
the breakdown of dead materials into simple organic matter
how do decomposers break down dead matter
- decomposers release enzymes which catalyse the breakdown of dead material into smaller molecules
what is transpiration
the evaporation and movement of water away from the plant’s leaves from the inside of the plant
how do plants take up water in their roots
- by water moving up the plant in the xylem and passes out of the leaves through stomata as water vapour
how do animals take up water
- through drinking and in their food
- animals release water in their urine, in their faeces and when they exhale
why is compost used
used as a natural fertiliser for growing garden plants or crops as it is rich in minerals needed for growth
what are the optimal conditions for decomposition
temperature : decomposition takes place faster at warmer temperatures (because the decomposers use enzymes to break down plant material and these enzymes work faster in warm conditions)
amount of water: decomposing microorganisms work faster if the compost is moist because many of the chemical reactions in decay require water
amount of oxygen: decomposers carry out aerobic respiration which requires a good supply of oxygen
why is compost warm anyway
because decomposers release energy when they carry out aerobic respiration
how do farmers increase oxygen intake in compost
- by mixing compost and breaking up larger clumps to increase surface area for decomposers to act on
-using a gardening fork to allow more oxygen to pass into the centre
- using compost bins with holes to allow oxygen to enter
what happens to decomposition when there is an absence of oxygen
decomposing microorganisms carry out anaerobic decay which produces a mixture of gases eg methane
what is biogas
a renewable fuel that’s produced when organic matter, such as food or animal waste, is broken down by microorganisms in the absence of oxygen
how is biogas used
small scale biogas generators can be used to provide fuels for homes
what is biodiversity
the variety of all the different species of organisms on earth, or within an ecosystem.
why is a high level of biodiversity good
ensures the stability of ecosystems by reducing the dependence of one species on another for food, shelter and the maintenance of the physical environment
what are the negative effects that human activities have on biodiversity
- deforestation to provide land
how does waste lead to water pollution
- humans produce large numbers of sewage containing urine and faeces, in some countries it is released into nearby waterways but sometimes untreated sewage is accidentally released into rivers or streams
- rivers and streams can also be polluted with fertilisers from farms , both fertilisers and untreated sewage cause dissolved oxygen levels to fall which kills aquatic organisms
how does waste from human activities lead to air pollution
- burning coals in power stations release acidic gases = cause acid rain and can release smoke
- this can kill plants and animals = reduces biodiversity
how does waste from human activities lead to land pollution
- millions of tons of waste dumped into landfills = destroy habitats for plants and animals
- toxic chemicals can leech out of landfills and pollute the soil
how do humans use land
- for buildings eg houses , factories , shops , airports
- for farms , quarries, landfills
how does the amount of land affect the biodiversity
the more land used for human activities = less land available for animals and plants = reduces biodiversity
what do peat bogs and peat lands contain
large amounts of dead plant material and large amounts of trapped carbon as conditions in peat bog slows decay
what is peat used for
to produce cheap compost for gardens and farms
or in some countries is burned to release energy eg to generate electricity
how does peat bog destruction affect biodiversity
reduces the area of this habitat and thus the variety of different plant, animal and microorganism species that live there
what is an issue of peat
- once peat is extracted and used for compost, it begins to decay as peat bogs are a store of carbon = releasing large amounts of carbon dioxide into the atmosphere = contributes to climate change
what is global warming
the gradual increase in the average surface temperature of the Earth
why is peer review good
helps to check false claims and makes sure that research published in scientific journals is valid
what is the consequence of global warming
- loss of habitat
- migration patterns of animals may change
- may be able to grow crops in england when it normally isnt supposed to grow
- in other parts of the world it may be too hot to grow crops needed
how to maintain biodiversity
- breeding programmes for endangered species
- protection and regeneration of rare habitats
- reintroduction of field margins and hedgerows in agricultural areas where farmers grow only one type of crop
- reduction of deforestation and carbon dioxide emissions by some governments
- recycling resources rather than dumping waste in landfill.
what are herbivores
animals that eat plants / algae
what are secondary consumers
carnivores that eat herbivores
what is a tertiary consumer
a consumer that eats other carnivores.
what trophic level are producers in
1
what trophic level are
secondary consumers in
3
what trophic level are primary consumers in
2
what trophic level are tertiary consumers in
4
what are apex predators
carnivores with no predators
how do Decomposers break down dead plant and animal matter
by secreting enzymes into the environment. Small soluble food molecules then diffuse into the microorganism.
what do trophic levels tell us
an organism’s position on a food chain
how do scientists work out the biomass of an organism in a food chain
- collect all of the required organisms in an area and kill them
- dry them and weigh them = gives dry biomass
why is dry biomass more useful than wet biomass
because the moisture content of organisms can vary widely and produce inaccurate results
what percentage of light energy is absorbed and used for photosynthesis by producers
1 %
why does the biomass decrease for each trophic level
- not all the ingested material is absorbed, some is egested as faeces
- some absorbed material is lost as waste, such as carbon dioxide and water in respiration and water and urea in urine.
what % of biomass passes onto each trophic level
10%
how to calculate the efficiency of biomass transfers
efficiency = gain in biomass / total biomass intake
what does food security mean
having enough food to feed a population.
what are the biological factors which threaten food security
- the increasing birth rate has threatened food security in some countries
- changing diets in developed countries means scarce food resources are transported around the world
- new pests and pathogens that affect farming
- environmental changes, e.g. global warming that affect food production, e.g. if rainfall patterns change, many countries cannot grow enough crops to feed populations = widespread famine
-modern farming methods require lots of resources eg fertilises and pesticides to increase crop yields as the population increases the resources = more expensive = may be harder to afford = and threatens the security of their food production - occurring
- conflicts that have arisen in some parts of the world which affect the availability of water or food if farming is disrupted and imports of food is not available
what are advantages of factory farming methods
- more efficient
- less biomass wasted by animals in respiration
- can control the food that animals eat, so it contains the nutrients they need so less food is wasted
how can the efficiency of food production be improved
improved by restricting energy transfer from food animals to the environment. EG BY :
limiting their movement and controlling the temperature of their surroundings. = less biomass wasted
Some animals are fed high protein foods to increase growth.
what are disadvantages of factory farming methods
- when animals are kept in crowded conditions = infectious disease spread easily
- when the animals are treated with antibiotics it could increase the risk of antibiotic-resistant bacteria
- overcrowding animals can make them more stressed and tempermental
what are the ethical objections to intensive farming
- animals should be raised in natural conditions and be able to engage in normal behaviour
- engaging in natural behaviour will increase the animals’ welfare eg by reducing stress
how do factory farms prevent infectious diseases
animals treated with antibiotics
what are issues of fish stocks falling
- once fish stocks in an area fall below a certain level, there are not enough mature fish to breed = commercial fishing will not be possible
what methods are the governments attempting to reverse fish loss
- fishing industry sets strict quotas on number of fish that can be caught for each species ( by reducing the number of fish caught, the remaining fish can breed and bring the population back to normal levels)
- net size must be large enough that smaller,immature fish are not caught = these fish can develop into adults and reproduce
why is the fungus Fusarium useful
produces mycoprotein, a protein-rich food suitable for vegetarians. The fungus is grown on glucose syrup, in aerobic conditions, and the biomass is harvested and purified.
how can GM food be used and why is it good
to produce more food
- have improved nutritional value eg golden rice
what does genetically modified bacterium produce
human insulin. When harvested and purified this is used to treat people with diabetes.
how is Golden rice be useful for people
golden rice has been genetically modified to produce all the molecules the body needs to make vitamin A = prevents hundreds of thousands of cases of blindness each year
what are advantages of mycoprotein
- suitable for vegetarians
- we can grow very large amounts of mycoprotein in a relatively small amount of space = mycroprotein a very efficient protein source
