Ecology Flashcards
what does every food chain start with
a producer, mostly plants, sometimes algae
why are producers important in food chains
because they synthesise complex molecules
- they are the source of all biomass in a community
what is biomass
complex molecules such as glucose
what happens to biomass
it passes down the food chain to other organisms
what are primary consumers
organisms that eat producers
what is the secondary consumers
the animal that eats a primary consumer
what is a tertiary consumer
the animal that eats a secondary consumer
what are predators
consumers that kill and eat other animals
what are prey
the animal that is eaten
what happens if you increase the number of prey in one area
- prey population increases
- predators have more prey to kill and eat
- more prey will be eaten and population of prey falls
- predator have less prey to kill and eat, so population of predators fall
- because predator population has fallen, more prey can survive and reproduce
what is random sampling used to do
to compare the numbers of organisms in different areas
how to do random sampling
- using a quadrat, place it on the ground then count the number of organisms inside the quadrat
what types of organisms can random sampling be used for
plants or slow moving animals
how to carry out random sampling
- quadrats placed at random locations across the area
- one way to do this is to use random numbers to select different locations
- count the number of each organism in the quadrat
- keep doing this until awe have sampled a large number of random locations
why is it important that we place the quadrat a large number of times
to make valid results more likely. if we placed the quadrat once, it wouldnt give us a sample that represents the whole area
total population size equation
total population size = (total area/ area sampled) x number of organisms of that species counted in that sample
how to carry out sampling along a transect
- Place the transect so it runs across the habitat we are looking at
- Place the first quadrat at the start of the transect
- Count the different plants in the quadrat
- Move the quadrat closer inland by a set distance
- keep doing his u til you move further inland
- move the tape along and repeat the whole process
what is a transect
a line such as a tape measure or a piece of rope
when would we use sampling along a transect
to see how the numbers of organisms change across a habitat
sampling organisms practical method
- Start by estimating the total population of daisies in a field using RANDOM SAMPLING
- Place two tape measures at right angles (they should be 20m in length)
- Get two bags filled with numbers from 1 to 20
- (students work in groups of 3) have one student remove a number and whatever number they get, they move to that point on the tape measure, repeat this w another students
- Get the third student to place the quadrat where the other students numbers meet
- record the number of daisies in the first quadrat
- Repeat this process 9 more times for a total of 10 samples
how to improve accuracy of results
increase the number of quadrat throws to cover a larger percentage of an area
how to measure the effect of a factor on the distribution of species
- use a transect line
- Record the number of daises at the start of the transect and record the light intensity
- move the quadrat 1m down tape measure and repeat the measurements, do this all the way down the tape measure
how does the carbon cycle start
with co2 in the atmosphere
how does carbon taken into the carbon cycle
by photosynthesis
how does co2 return back to the atmosphere
by aerobic respiration
How does the carbon cycle work
- plants and algae take in co2 from the atmosphere in photosynthesis
- plants and algae respire, so some of the co2 is released back into the atmosphere - Animals eat plants, so the carbon from the plants become part if the carbs, fats and proteins in the cells of animals
- animals respire, co2 released back to atmosphere - animals release waste products such as faeces, and eventually they all die, and there is carbon in waste products and dead remains
- the waste products and dead remains are then broken down by decomposing microorganisms such as bacteria and fungi
- When decomposers carry out respiration, the carbon in the waste and dead remains returns to the atmosphere as co2
why are decomposers important
they cycle materials through an ecosystem and they release mineral ions into the soil
- they release co2 back into atmosphere
what happens if there is a lack of oxygen for decomposers
they cannot function effectively, so the carbon in dead remains, can slowly be converted into fossil fuels
describe stages of the water cycle
- energy from the sun causes the water to evaporate from the surface of the sea
- The 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 (incl rain and snow)
- once the water hits the ground, some evaporates back into the atmosphere as water vapour, some of it passes through rocks and forms aquifiers, and alot of the water forms rivers or streams
what do all forms of precipitation contain
fresh water
what is fresh water
water that does not contain salt
what role do living organisms play in the water cycle
- plants take up water in their roots, the water moved up the xylem and passes out of leave’s through stomata as water vapour
- animals take in water by food and drink, and they release water in their urine and faeces when they exhale
what do decomposers do
- return carbon back into the atmosphere
- return mineral ions back to the soil
what are the optimum conditions for decomposers to work
- decomposition takes place faster at warmer temperatures, this is because the decomposers use enzymes to break down plant material
- moist, many of the chemical reactions in decay require water
- good supply of oxygen so they can carry out aerobic respiration
why do gardeners mix their compost regularly
- to allow more oxygen to pass through the centre
- to break large clumps
- to increase the surface area for decomposers to act on
what happens if decomposers dont have oxygen
- decomposers carry out anaerobic decay
- anaerobic decay produces methane, this is called biogas
why does sour milk taste acidic
because bacteria use enzymes to produce acidic molecules
how to investigate the effect of temperature on the decay of milk
- Label a test tube ‘lipase’ and using a pippete, place 5cm3 of lipase solution into the test tube
- label another test tube milk and add 5 drops of cresol red, 5cm3 of milk and 7cm3 of sodium carbonate solution into the milk test tube
- at this point, the solution should be purple - place a thermometer unto the test tube containing the milk
- Place both test tubes into a beaker of water at our first chosen temperature
- start at 20 degrees - wait until the temperature of the solutions is the same as the water in the beakers
- use a pipette to transfer 1cm3 of lipase to the test tube containing milk and stir it
- at the same time we start a timer
- at this point lipase will start to break down fat molecules in the milk, releasing fatty acids and causing the milk to become acidic - Stop timing and record results
- repeat ay a range of different temperatures
why do we use lipase in the decay practical
because decay is quite slow
why shoukd the solution be purple after adding sodium carbonate
because sodium carbonate is alkaline and cresol red is purple in alkaline conditions
what happens to cresol red in acidic conditions
it changes from red to yellow
what do we do when the milk solution turns yellow
stop timing and record results
what is the independent variable in decay practical
temperature
what is the dependent variable in the decay practical
the time taken for the milk solution to turn yellow
what are the control variables of the decay practical
the volumes of the solution
why is it important that we use a clean test tube for the milk in each experiment
because any traces of lipase from the previous experiment will trigger the reaction before we are ready
examples of environmental changes
seasonal, geographic, or caused by human interaction
examples of environmental changes that affect distribution
temperature,availability of water, composition of atmospheric gases
what is biodiversity
the variety of all the different species of organisms on earth
why is biodiversity really important for exosystems
species depend on each other for food and shelter
- species help maintain the environment (eg decomposers break down remains of dead organisms)
what does a high level of biodiversity mean
there are lots of different species and this will make an ecosystem more stable
- lots of different species mean that an ecosystem is less dependent on one species, so if the population of a species falls, it is less likely to affect the whole ecosystem
how does deforestation affect biodiversity
- destroys the habitats of organisms effectively killing them
what is deforeststation
the cutting down of trees to provide land
why is deforestation used
- used for rice fields
- used for grazing cattle
- land could be used to grow crops which are then used to make biofuels
problems with increasing human population
- humans are using more of the earths resources
- humans are producing more waste, leading to pollution
how can waste lead to water pollution
- humans produce a large amount if sewage and this contains urine and faeces
- in some cases, untreated sewage us accidentally released unto rivers or streams
- rivers can also be polluted with fertilisers from farms
- both of these can cause dissolved oxygen levels to fall, and this could kill aquatic organisms
how to toxic chemicals cause pollution
- they can be released into rivers from factories, killing animals in rivers
how does waste from human activity pollute the air
- burning coal in power stations can produce acidic gases, which can cause acid rain
- combustion of fossil fuels release carbon dioxide which contribute to the greenhouse effect and leads to global warming
- air pollution can kill plants and animals which reduces biodiversity
how does waste contribute to land pollution
- millions of tons of waste are dumped into landfills
- landfills destroy the habitats of plants and animals
- toxic chemicals can also leach out of landfills and pollute the soil
what do humans use land for
buildings incl houses factories airports etc
- quarries
- farms
- landfills
what do peat bogs and peat lands contain
large amounts of dead plant material
- large amounts of trapped carbon, since conditions mean decay is very slow
what is peat used for
to produce cheap compost for gardens and farms
- burned to release energy
what does the destruction if peat bogs lead to
- reduced area of the habitat
- reducing biodiversity
environmental impacts of peat
once peat has been extracted and used for compost, it begins to decay, this releases large amounts of co2 into atmosphere
- burning peat releases co2
- these contribute to climate change
why might some farmers not want to give up compost with pest in it
- it is expensive
- it could increase the prices of food
human activities that increase the earths climate
- burning fossil fuels
- farming
- rice fields
what do greenhouse gases do
trap heat in the atmosphere
what is peer review
when scientific research is checked by other scientists to help detect false claims and to make sure the research is valid
effects of global warming on living organisms
- loss of habitat
- melting ice caps
- rising sea levels
- animals such as insects and birds may gradually extend their range north to cooler conditions
- change in animals migration patterns
- spring plants may flower earlier due to warmer conditions
- we may be able to grow crops in parts of the uk
how to reduce the negative effects of humans on biodiversity
- Breeding programmes for endangered species
- wetlands can be reflooded or protected
- Farmers can leave a strip of land around fields where wild plants and animals can live (field margins)
- farmers can grow hedgerows around fields for lots of species and plants to live in
- governments around the world trying to reduce deforestation and carbon emissions, also trying to use renewable energy
- recycling
what are herbivores
animals that eat plants or algae
what are carnivores
secondary consumers which eat herbivores
what are tropic levels
positions on a food chain
what are producers on the trophic level
level 1
what are apex predators
a consumer that kills and eats other animals but have no predators themselves (carnivores with no predators)
how do decomposers break down matter
they secrete enzymes into the environment and the enzymes digest the dead material, and the small soluble food molecules then diffuse back into the decomposer
why is dry biomass better than wet biomass
the moisture content of organisms can vary widely and produce inaccurate results
why does the amount of biomass decrease as you go up the trophic levels
- because biomass is the living tissue of an organism
- not all of the material that is eaten is absorbed, for example animals cannot break down cellulose
- some of the biomass that is absorbed is converted into waste products of metabolism and is released
- large amounts of biomass is used for respirations
how to calculate the efficiency of biomass transfer
efficiency = gain in biomass / total biomass intake x 100
what is food security
having enough food to feed a population
why is food security important
more people live in cities and few people grow their own food
what are the 6 biological threats to food security
- Birth rate increasing - as the population grows, the amount of food available will have to increase to feed the whole population
- Tastes changing - we now expect to eat a whole range of different foods throughout the year and many of these foods cannot be grown in the uk
- New pests and pathogens - they can eat food crops, pathogens cause infectious disease
- Environmental change - unpredictable weather can affect the growth of crops
- Resources - the resources farmers use to grow crops are becoming more expensive
- Conflicts - during period of war, farming can be disrupted and imports of food may not be possible
approximately how much biomass is transferred every level
10%
how to increase efficiency of food production (factory farming methods)
- by restricting energy transfer from food to animals in the environment
- this can be done by limiting their movement and controlling the temperature of their surroundings
- feeding animals a higher protein diet to increase growth
advantages of factory farming
- more efficient as less biomass is wasted by the animals in respiration
- we can also control the food that animals eat so that it contains all the nutrients they need and less food is wasted
- in the case of chickens, eggs can be more easily harvested if the chickens are kept indoors
- Chickens are also fed a high protein diet, they produce more eggs
- Temperature is controlled, less biomass wasted
disadvantages of factory farming
- crowded conditions could cause infectious disease to spread more easily
- animals in factory farms are often treated with antibiotics, this could increase the risk of antibiotic resistant bacteria
- crowded conditions may make the animals more stressed and make them more likely to fight
- ethical objections - people believe animals should be raised in natural conditions and be able to engage in normal behaviour
why is it important to maintain fish stocks
or else certain species may disappear altogether in some areas
what will happen if fish stocks in an area fall below a certain level
there are not enough mature fish to breed, commercial fishing will not be possible
ways we can increase the number of fish
- the fishing industry set strict quotas on the numbers of fish that can be caught for each species
- the net size should be large enough so that smaller immature fish are not caught so that these fish can develop into adults and reproduce
how is mycoprotein made
produced by a fungus fusarium
- fusarium is grown on glucose syrup in a fermenter
- in aerobic conditions, the fungus converts glucose syrup into mycoprotein
- this is harvested and purified before being made into products
advantages of mycoprotein
- suitable for vegetarians
- we can grow very large amounts of mycoprotein in a small amount of space, making it an efficient protein source
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 of the different species that live in the same habitat
meaning of ecosystem
the biotic and abiotic parts of an environment and how they interact
what do plants compete with each other for
light
space
water
mineral ions in soil
what do animals compete with each other for
- food
- water
- mating partners
- territory
what is interdependence
all of the different species in a community depending on each other for food, shelter etc
what is a stable community
one in which the populations of organisms are in balance with each other and the abiotic resources
biotic factors
- availability of food
- arrival of a new predator
- competition between species
- new pathogens
abiotic factors
- light intensity
- temperature
- water
- pH and mineral content of soil
- wind intensity and direction
- carbon dioxide and oxygen levels
what are structural adaptations
adaptations of body shape or structure
Camel adaptations
- camels have a hump on their back which is a store of fat
- fat is a thermal insulator - by storing the fat in one place, this allows heat loss from the other parts of the camels bod, reduces water loss from sweat
- thick coat on the upper surface of their body to insulate the top of the camel from sun
- mouth is leathery so can chew thorny plants
- long lashes to keep sand out of eyes
what are functional adaptations
adaptations to the body functions of organisms
examples of functional adaptations
- camels produce concentrated piss eww and dry faces to reduce water loss
- camels can tolerate large changes in body temp, allows them to cope with the intense heat of the desert
what are behavioural adaptations
adaptations to the animals lifestyle or behaviour
examples of behavioural adaptations
- kangaroo rats are nocturnal, this helps them avoid heat from the day time
- during the day, they live in burrows underground, keeping them cool and protecting them from predators
other structural adaptations
- attic fox has thick fur to provide insulation and reduce heat loss to the air
- artic fox had fur on its soles, reduces heat loss
- small ears to reduce surface area to reduce heat loss
Plant adaptation
- waxy cuticle to reduce water loss
- cacti have small leaves
- cacti have extensive and shallow roots so they can catch as much water as possible after rainfall
what are extremeophiles
organisms that are adapted to live in very extreme conditions
examples of extremophiles
bacteria live in deep sea vents with extremely high temperatures and pressure
- can also live in extreme concentrations of salt
what happens if conditions become too hot for decomposers
enzyme will denature
uses of biogas
biogas generators used to provide fuels for home
how is methane released
- produced by bacteria in paddy fields which are used to grow rice
- released by cows when they pass wind
what is a tertiary consumer
a carnivore that eats other carnivores
What percentage of the light energy that falls on producers is absorbed and used for photosynthesis
1%
how much biomass passes from one level to the other
10%
disadvantage of free range chickens
a lot of the biomass that these chickens eat is being used in respiration, providing energy for movement
- because they’re outdoors where it can be cold, energy’s also needed to keep their body temperature constant
- less biomass available for chickens to grow and produce eggs
why are number of fish dropping
trawlers use huge fishing nets to catch tons of fish at a time
what is vitamin a needed for
effective vision
