Ecology Flashcards
what is an ecosystem?
the interaction of a community of living organisms (biotic) with the non-living (abiotic) parts of their environment
what is a habitat?
the place where an organism lives
what is a population?
all the organisms of one species living in a habitat
what is a community?
populations of different species living in a habitat
what do plants compete for?
- light
- space
- water
- mineral ions
what do animals compete for?
- space
- food
- water
- mates
what is interdependence?
each species depends on other species for food, shelter, pollination, seed dispersal etc
what do organisms need to survive and reproduce?
organisms require a supply of materials from their surroundings and from the other living organisms there
what are the abiotic factors in 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
what are the biotic factors in a community?
- availability of food
- new predators arriving
- new pathogens
- one species outcompeting another so the numbers are no longer sufficient to breed
what type of adaptations do organisms have?
- structural eg. artic fox=white fur, whale=thick layer of blubber (fat)+low SA:V ratio, camel=thin layer of fat+large SA:V ratio
- behavioural eg. swallow (bird)=migrate
- functional eg. desert animals=conserve water= very little sweat+small amounts of concentrated urine, brown bear=hibernate=low metabolism=saves energy
what are organisms that live in extreme conditions called?
extremophiles eg. bacteria in deep sea vents
what is a food chain?
a way of representing feeding relationship in a community
what does a food chain show?
- producers –> eaten by primary consumers –> eaten by secondary consumers –> eaten by tertiary consumers
- consumers that kill and eat other animals are predators, and those eaten are prey
what is the relationship between predator and prey numbers?
In a stable community the numbers of predators and
prey rise and fall in cycles
the water cycle
- energy from sun=evaporates water=water vapour+transpiration
- water vapour rises=high up=cools+condenses=clouds
- water falls down as precipitation eg rain, snow, hail=provides freshwater for plants+animals
- drains into sea
- repeat
the carbon cycle
- CO2 removed from atmosphere by photosynthesis=glucose= C turned into carbs/fats/proteins=make bodies of plant+algae
- CO2 returned when plants+algae respire
- plants+algae eaten=C becomes part of fat/protein
- C moves through food chain
- animals respire=C returned to atmosphere
- plants+algae+animals die=detritus feeders+microorganisms eat them=they respire=CO2 returned atmosphere
- combustion of wood/fossil fuels=release CO2
what factors affect the rate of decay?
- temp - warm temp=enzymes that work aid in decomposition work quicker
- enzymes will denature if it’s too hot
- cold=slows down/stop rate of decomposition
- oxygen availability - O2 needed for respiration=needed to survive
- not enough O2=anaerobic decomposition=slow+releases methane
- water availability - moist environment=faster=decomposers need water to survive=
how is biogas made?
by anaerobic decay
- made up of methane
- sludge waste eg. sewage works, sugar factories=large-scale biogas
- x be stored as a liquid=used straight away eg. cooking, heating, power a turbine, lighting
where is biogas made?
- made in a digester/genetor=kept at constant temp= x respiring microorganisms being present
- batch generator=makes it in small batches=manually loaded up in waste=left to digest+cleared away at the end of each session
- continuous generator=constantly making=waste continuously fed in=produced on steady rate=large-scale projects
how do gardeners benefit from decomposition?
- they try to provide optimum conditions for rapid
decay of waste biological material - compost produced is used as a
natural fertiliser for growing garden plants or crops
what are examples of environmental changes?
- temperature eg. distribution of plants+animals change between wet and dry seasons
- availability of water eg. distribution of bird species in germany changes due to rise in temp
- composition of atmospheric gases eg. distribution of species changes due to air pollution
How are the changes caused?
- seasonal
- geographic
- caused by human
interaction
what is biodiversity?
variety of all the different species of organisms on
earth, or within an ecosystem
why is biodiversity important?
- great biodiversity=stability of ecosystems by reducing
the dependence of one species on another for food, shelter and maintenance of the physical environment - future of the human species on Earth relies on us maintaining
a good level of biodiversity but human activities are reducing
biodiversity and only recently have measures been taken to try to stop this
why do we have more waste?
- rapid growth in population and an increase in the standard
of living=more resources are used=more waste is produced
what factors affect pollution?
- water, from sewage, fertiliser or toxic chemicals eg. pesticides=pollute rivers+oceans=affect plant+animal relying on them to survive
- air, from smoke and acidic gases=pollute air eg SO2=acid rain
- land, from landfill sites (household waste)/toxic chemicals/farming eg. herbicides+burying nuclear waste=pollute soil=x grow crops
Pollution kills plants and animals which can reduce biodiversity.
how do we use land?
- building
- quarrying
- farming
- dumping waste
=less land for other animals+plants
what does the destruction of peat bogs lead to?
- x enough O2 for plants in peat x fully decay=CO2 stored in peat
- drained=farmland or used as fuel or sold to gardeners as compost
- when drained=contact with air=microorganisms decompose it+respire=use O2+release CO2
- when burned=CO2 released
- destroying peat bogs=x habitats for animals/plants= reduces biodiversity
what does peat release?
CO2
what is deforestation used for?
- provide land for cattle and rice fields
- grow crops for biofuels
what are the disadvantages of deforestation?
- less trees=less CO2 used for photosynthesis=more in atmosphere as trees decay+microorganisms eat them=release CO2 from respiration
- CO2 released when trees are burnt
- trees=habitat for animals/plants=tress cut down=less biodiversity=risk of extinction
what are the consequences of global warming?
- higher temp=sea water expands+ice melts=sea level up=flooding=loss of habitats
- higher temp=rainfall patterns change=distribution of animals+plants will change eg. animals living in hot temp widely distributed
- changes in migration patterns eg birds migrate further north as nothern areas are getting warmer
- some species unable to survive with temp change=extinct=less biodiversity
how can we maintain biodiversity?
- breeding programmes for endangered species=x extinction
- protection and regeneration of rare habitats eg. coral reefs=protect ecosystem+biodiversity
- reintroduction of field margins and hedgerows in agricultural areas=habitat for wider variety of species
where farmers grow only one type of crop - reduction of deforestation and carbon dioxide emissions by governments=reduce global warming
- recycling resources rather than dumping waste in landfill=reduces waste=reduces land used in landfill=ecosystems x destroyed
what are issues with maintaining biodiversity?
- costs money eg gov pay farmers to a subsidy to reintroduce hedgerows or to keep watch the programmes are being followed –> money prioritised for other things
- affects locals eg. reducing deforestation=people working in tree-felling unemployed=local economy affected
- protecting food security=pests eg. fox, locust=killed to protect crops/livestock=more food=food chain+biodiversity affected
what are trophic levels?
different stages of a food chain
Level 1: producers
Level 2: primary consumers
Level 3: secondary consumers.
Level 4: tertiary
consumers
what are apex predators?
carnivores with no predators
- top of food chain=highest trophic level
what do decomposers do?
- break down dead plant and animal matter by secreting
enzymes=small soluble food molecules=diffuse into microorganism
what do pyramids of biomass show?
- represent the relative
amount of biomass in each level of a food chain (how much the organisms weigh) - trophic level 1 is at the
bottom of the pyramid
how is biomass transferred?
- 1% of light transferred for photosynthesis=glucose=makes biological molecules=plant’s biomass=stores energy
- when organisms eat each other=10% of biomass transferred at each level in a food chain
why is biomass lost?
- not all the ingested material is absorbed= what isn’t absorbed=egested as faeces
- some absorbed material is lost as waste eg. lots of glucose from respiration=used to keep warm+movement=x making more biomass=CO2+H2O released & urea+water in urine
biomass efficiency equation
(biomass in next level/biomass in previous level)x100
what is food security?
having enough food to feed a population
what factors affect food security?
- the increasing birth rate has threatened food security in some
countries - changing diets in developed countries=scarce food resources
are transported - new pests and pathogens that affect farming
- environmental changes that affect food production eg. widespread famine in some countries=x rain
- the cost of agricultural inputs eg. price of seeds=too expensive to produce food=less people producing food=less food
- conflicts=affect the availability of water or food
how can farming techniques be improved?
- reducing energy transfer from animals to environment=limiting movement+keeping them in a temp-controlled environment=more energy for growth=more food for same resources
- livestock+fish=factory farmed=kept in cages/small pens
- feeding animals high-protein=increase growth
pros and cons of farming techniques
pros
- effective
- less resources used=saves money
- more food=less food insecurity
cons
- disease can be spread easily=animals kept so close
- animals live in unnatural+uncomfortable conditions=cruel
- money saved=used to maintain temp or buy pens/cages
what are the effects of fish stocks declining?
- less fish to eat
- ocean’s food chain affected
- some fish may disappear
how can we fish sustainably?
- fishing quotas=limits number+size of fish caught in certain areas=prevents species being over-fished
- net size=limits on mesh size of net (big holes)=reduces amount of unwanted/discarded fish=bigger mesh size=unwanted fish escape
- younger fish escape=can reach breeding age
how is biotechnology used?
mycoprotein
- a protein-rich food suitable for vegetarians eg. Quorn
- fungus, fusarium=grown on glucose syrup, in
aerobic conditions
- biomass is harvested and purified=produce mycoprotein
bacteria producing human insulin
- plasmid removed from bacterium
- insulin gene cut out from chromosome with a restriction enzyme=leaves sticky ends (unpaired bases)
- plasmid cut open with same restriction enzyme=leaves same sticky ends
- plasmid+human insulin gene sticky ends joined by ligase=recombinant DNA
- recombinant DNA inserted into bacterium
- modified bacterium grown in a vat in controlled conditions
- lots of bacteria that produce insulin=insulin harvested+purified
GM crops=more food or food with an improved nutritional value such as golden rice
pros and cons of biotechnology
pros
- GM crops=can be resistant to pests/grow better in droughts=better crop yields
- GM crops=more nutritional value=golden rice=chemical that’s converted into vitamin A in the body
cons
- fear that countries are dependent on GM crop companies
- poor soil=crops failing=even GM crop x survive
- people go hungry because they can’t afford food, x because there isn’t food=tackle poverty first
