Ecology Test October Flashcards
What is a community?
- a group of interdependent species of plants, animals and microorganisms
- all of the populations of different species put together
What is interdependence
- each species depends on another in various ways
- one species removed, can have knock-on effect on community
Describe the examples of interdependence
- animals dispersing seeds of plants to new places
- using holes in trees for shelter
- transferring pollen from one plant to another
What is competition?
- organisms depending on the same resource and competing for it
What is an ecosystem?
- interaction of a community of living organisms (biotic) and non living (abiotic) parts of their environment
Give examples of competition in plants and animals
plants - light, space, mineral ions from soil, water
animals - mates, food, territory
Describe what a stable community is like
- population sizes of prey and predators rise and fall in cycles
- predators increase = more competition for food
- some die from lack of food = more prey
- more prey = more predators
What is a population?
- all the individual organisms of one species in an ecosystem
- ecosystem contains number of populations
What is an abiotic factor?
physical condition of an environment
List all of the abiotic factors
- light intensity
- temperature
- moisture level
- soil pH + mineral content
- wind intensity and direction
- CO2 levels
- O2 levels
How does temperature affect an ecosystem?
- affects enzymes (denature?)
- different species = adapted to survive in different temps
- affects rate of decay
- affects rate of transpiration
How does light intensity affect an ecosystem?
- more photosynthesis = more food for animals
How do CO2 levels affect an ecosystem?
- slow photosynthesis = higher CO2 levels
- rising CO2 levels = more photosynthesis
other factors would soon limit plant growth
How do O2 levels affect an ecosystem?
- low oxygen levels can kill aquatic animals
- absorb O2 using body surface/ gills
How does moisture level, mineral content and soil pH affect an ecosystem?
- moisture needed for decay in soil
- decay releases mineral ions into soil
- different plants adapted to different soil pHs
How does humidity, wind speed, and wind direction affect an ecosystem?
- affects rate of transpiration in plants
- can limit distribution of plant species
What are some biotic factors?
- availability of food
- new predators
- new pathogens
- competition
How does the availibility of food affect an ecosystem?
- affects size of population eating it
- too many individuals = more competition = some may not survive
- food supply increases = population increases
How do new predators and pathogens affect an ecosystem?
- can kill individuals and reduce size of population
How does competition affect an ecosystem?
- 2 populations competing for same food
- one may outperform the other
- other population decreases until there is not enough to breed
What are adaptations?
- features that organisms have that enable them to survive in conditions where they normally live
- may be structural, functional, or behavioural
What are the three types of adaptations?
- structural
- functional
- behavioural
What is a structural adaptation?
- something we could see
- shape, colour, SA to volume ratio
eg sharp claws on brown bear for catching prey
What is a functional adaptation?
- processes going on inside organism
- eg reproductive system/ metabolism
eg octopuses can change colour to camoflage themselves
What is a behavioural adaptation?
- the way an organism behaves/ acts
- eg hibernation, huddling etc
What is an extremophile?
- organisms that are adapted to survive in extreme environments
- eg very hot/ cold/ high pressure environments
bacteria living in sea vents
What are producers?
- organisms with the ability to make their own food molecules
- plants and algae
What are consumers?
- organisms that get their food molecules by eating other organisms
- primary consumers eat plants or algae
- secondary & tertiary consumers eat animals
How do you find the size of a population?
- quadrat used to mark out small area
- number of individuals in quadrat counted
- repeated for large number of randomly placed quadrats
- mean by quadrat
- mean x number of times quadrat would fit into area = estimated population size
What does randomly placing quadrats do?
- removes any bias
- increases accuracy of mean count
how do you find the distibution of a population?
- tape measure used to mark transect
- quadrats placed at regular intervals along transect
- number of individuals counted in each quadrat
- bar chart showing number of individuals at each point along transect
What is a transect?
- line across the area whre the population is found
How do you position quadrats randomly?
- use random number generator
- generate coordinates
How do you investigate the effect of factor on distribution?
- make sure transect runs across areas where factor varies
- measure factor at each quadrat position + counting organism
- present data as bar chart/ table/ scatter diagram
- look for correlation
What is the carbon cycle?
- returns carbon from organisms to atomsphere as CO2 (respiration + microorganisms help decay)
- used by plants in phtosynthesis
- carbon (in form of food molecules) transferred from plants to animals during feeding
Describe the water cycle
- water evaporates
- condenses as clouds
- precipitation, water falls as rain, hail, snow, sleet
- perlocation - water gets absorbed by ground but if soil is saturated some are run off
- transpiration, water evaporates from leaves and more water is drawn up from ground by plant
What is biodiversity?
- variety of all the different species of organisms on earth or within an ecosystem
What is good biodiversity like?
- reduce dependence of one species on another for food/ shelter/ maintenance of physical environment
- if one species of prey becomes exitinct -> predators could rely on others for survival
What does pollution in different areas look like?
in water - sewage, fertiliser or toxic chemicals
in air - smoke and acidic gases
on land - landfill and toxic chemicals
How does fertiliser harm the environment?
- washed from land to rivers when it rains
- encourage growth of aquatic algae + plants
- grow rapidly = outcompete each other = some die
- bacteria decay dead plants, use dissolved oxygen to respire
- reduced oxygen level can kill aquatic animals
How do acidic gases harm the environment?
- dissolve in rain and sea
- reduce pH of water
- increased acidity dissolves shells & skeletons of coral + crabs
- could kill them
How do landfills harm the environment?
- toxic chemicals from waste leak into surrounding soil
- contamination kill plants and animals
How do humans reduce the amount of land available for other animals?
- building
- dumping waste
- quarrying
- farming
What is peat?
- remains of plants that have not decayed
- conditions are anaerobic
What is peat used for?
- cheap compost for plants
Why do local plants and insects depend on peatlands
- plants require wet and acidic conditions of peat bogs
- wetland insects depend on these plant species for food
What are the consequences of digging up peat?
- destroys habitat including plants
- if insects are unable to migrate they die
- reduces biodiversity
- remaining exposed peat decays
- burns easily -> could be set on fire
- decay + burning of peat releases large amounts of CO2
What is the land created by clearing forests used for and what are their effects?
- grow crops for biofuels
- rearing of cattle - soil erosion, waste pollutes local rivers
- grow rice - mud in rice fields become anaerobic -> disturbed = releases methane
What is the impact of human activity in global warming?
- increased levels of CO2 and methane in atmosphere
- CO2 released by burning fossil fuels + biological materials (eg wood/ peat)
- decay of peat in damaged peatlands = More CO2
- methane released by cattle + flooded rice fields
What do methane and carbon dioxide do?
- greenhouse gases
- trap heat from sun in earth’s atmosphere
- increasing mean air temperature
What does global warming cause?
- climate change
- sea level rise
- desertification
What are the biological consequences of global warming?
- loss of habitat - rise in sea level floods coastal marshes
- changes in distrubution - some animals able to live in new places + pathogens able to spread to new places
- extinctions - animals + plants unable to migrate becoming extinct
How do humans try to maintain biodiversity?
- protection and regeneration of rare habitats
- recycling to reduce landfill
- reintroduction of field margins and hedgerows
- breeding programmes for endangered species
- reduction of deforestation and CO2 emissions
How does protecting and regenerating rare habitats help maintian biodiversity?
- national parks + nature reserves
- stop habitat destruction
- food, fuelwood, farming needed
- controversial for some countries to set aside large areas
- illegal grazing/ poaching
How does recycling help maintain biodiversity?
- reduces volume of waste in landfill
- reduces amount of land needed for new landfill sites = less habitat loss
- reduces need for replacement resources
how do breeding programmes help maintain biodiversity?
- breeding captive endangered animals
- cultivating wild plants
- increases numbers of endangered animals + plants
- releasing into wild
How does the reintroduction of field margins and hedgerows help maintain biodiversity?
- single crop = less food + fewer habitats for wild plants & animals
- variety of plants = more food + wider range of habitats
- supports organisms that are not supported by the crop
How are the reduction of deforestation and CO2 emissions being handled?
- governments trying to reduce rate of clearing tropical forests
- countries reducing CO2 emissions
What factors affect the rate of decay?
- temperature
- moisture level
- oxygen level
How does temperature affect the rate of decay?
- higher temperature = higher activity of enzymes
How does moisture level affect the rate of decay?
- many biological molecules dissolve in water
- microorganisms secrete enzymes onto biological material to disgest and absorb dissolved molecules
- can’t be done in dry conditions
How does oxygen affect the rate of decay?
- no oxygen = decay stops
How do gardeners increase the rate of decay of waste and what do they use it for?
- mix waste materials in compost heap = create airspaces for oxygen
- decay releases mineral ions into compost = fertiliser
What does anaerobic decay make and where is it made?
and what is it used for
- methane gas
- made in biogas generators
- used as fuel
What happens if waste biological material enters a river?
- creates anaerobic conditions
- bacteria uses up oxygen to decay materials
- a lot = fish die from lack of oxygen for respiration
How do you investigate the effect of temperature on the rate of decay of fresh milk?
- measure pH of milk using pH meter/ universal indicator paper
- incubate milk in water bath at different temperatures
- check pH at regular intervals (24 hrs)
What does enviromental change affect and what types are there?
- affects distribution of species in ecosystem
- temperature
- water availability
- composition of atmospheric gases
- geographic
- caused by human interaction
- seasonal
What are the effects of environmental change on distribution?
- migration during winter to warmer areas (food)
- colonise new areas
- become extinct
Why is only a small percentage of biomass transferred to the next trophic level?
- animals do not eat all parts of an organism (roots and bones)
- animals do not digest and absob all food they ingest, some egested as faeces
- food molecules used in respiration, carbon dioxide and water excreted
- some food molecules broken down, cannot be immediately used for growth, urea and water are excreted
What is food security?
- having enough food to feed a human population
What are the biological factors that threaten food security?
- new pests and pathogens, causes disease in animals and crops
- environmental changes (eg famine)
- changing diets in developed countries = scarce food resources transported around the world instead of being supplied to locals
- cost of agricultural chemicals too high for small scale farmers (yield low without them)
- increasing birth rates
- conflicts arisen form in some parts of world, affects availability of water/ food
How are intensive animal farming methods designed to maximise growth?
- animals fed high protein diets
- supplemented with antibiotics
- kept indoors with warm temperature (less heat lost to environment, less food used for respiration to keep warm, more food used for growth)
- constrict/ limit movement (less food used for energy for muscle contraction, more food used for growth)
Why has the stock/ population size of many fish species declined?
over-fishing
How are fisheries managed to limit how many fish are caught?
- regulating size of nets in boats = restricts number of fish caught
- using fishing quotas, only allowed certain weight of fish per year
sufficient fish survive and reproduce, offspring adds to stock
How do fermenters work?
- conditions inside fermenter controlled
- constant temperature, can be warmed or cooled (if microorganisms generate heat during aerobic respiration
- air bubbled into fermenter to supply oxygen for aerobic respiration
- food material with mineral ions added keeps microorganisms healthy
How is mycoprotein produced?
- produced by fusarium fungus
- cultured on glucose syrup, aerobic conditions
- fermenter
- biomass harvested + purified
What is mycoprotein used for?
- meat substitute
Why are some crop plants been genetically modified?
- increase yield
- more nutritious
What is golden rice?
- rice with the gene for producig beta-carotine inserted into genome
- beta-carotine converted to vitamin A in human body
- prevents vit A deficiency diseases
Why is golden rice only allowed in a couple of countries?
- concerns with safety of GM crops
