4. ECOLOGY & THE ENVIRONMENT Flashcards
4.1 ecology is the study of
ecosystems
4.1 an ecosystem is..
an easily described system/area where organisms interact with their physical environment
4.1 what are habitats
the places where specific organisms live
4.1 in ecology a community is formed of
the populations of all the species present in an ecosystem at a particular time
4.1 a population is
the total number of individuals of one species in a particular habitat at a particular time
4.2 ecologists measure the size of a population in a habitat using a
quadrat
4.2 most of the time for a quadrat we use a …cm X ..cm square
50cm X 50cm
0.25m^2
4.2 to measure the population you
place a quadrat on the ground
count the number individuals of your species inside the square
4.2 when individuals are on the edge to make sure data is consistent you..
only count those on the top and left edges only
4.2 if it is difficult to count your species (grass) you can..
estimate the percentage of the quadrat area covered by the species
4.2 to find out the population of a species in a habitat you would
calculate area
measure quadrat
repeat 10X for reliability
average num in quadrat
how many quads fit in total area
multiply amount fit by averg num
4.2 how do you make sure your data is valid
use random sampling
4.2 how do you take a random sample
make right angle by 10mX10m axis
generate random coordinates
OR randomly throw over shoulder
4.3B what is biodiversity
it’s the range and variety of different species or organisms on earth or within an ecosystem
4.4B to make the grid you randomly generate numbers between … for what
1-10 for coordinates
4.4B what is a transect
a sample continuously or at regular intervals along the line
4.4B pick 2 …. areas to display the different habitats
contrasting
4.4B use …. sampling to take repeated measurements and compare the average results
random
4.4B use a transect to pass through a range of
abiotic conditions
(e.g. light-shade)
4.4B what is placed at regular intervals along the transect
a quadrat
4.4B what is the quadrat used for
to measure the number / % cover of the species
4.5 what are some abiotic factors
light intensity, temperature, moisture levels, wind intensity, carbon dioxide levels & oxygen levels
4.5 what are some biotic factors
availability of food, new predators, new pathogens and competition
4.5 how does light intensity affect the community
its needed for photosynthesis
4.5 how does temperature affect the community
affects rate of photosynthesis in plants
4.5 how does moisture affect the community
plants and animals require water to survive
4.6 the arrows in a food chain represent
the direction that the energy and biomass is moving
4.6 the stages in a food chain/web are called the
trophic levels
4.6 the origin of a food chain/web is a
producer
4.6 the first animal is called the
primary consumer
4.6 the second animal is called the
secondary consumer
4.6 the third animal is called the
tertiary consumer
4.6 what is rarely drawn in food chains/webs
decomposers
4.7 a food web is more complex because
it shows links between many species
4.7 we can use …. to represent the relative amounts of organisms at each trophic level
ecological pyramids
4.7 pyramids of number are drawn to show
the number of each organism counted in the ecosystem
4.7 pyramids of biomass are drawn to show
the total mass of the organisms in each trophic level
(i.e. the mass of an individual x the number of individuals)
4.9 the units for energy in the food we eat are
kilojoules
4.9 the energy available at a trophic level in a particular area is
kilojoules per square metre per year
( kJ / m2 / year )
4.9 why are pyramids of energy drawn
to show the total energy available in each trophic level per square metre per year
4.9 we draw pyramids of ….
energy
4.9 only …% of the suns energy is used in photosynthesis
1-5%
4.9 in the first consumer …% of energy is ‘lost’
90%
4.9 in the secondary consumer …% of energy is ‘lost’
90%
4.9 100kg of grass would go to …kg of rabbit
10kg
4.9 10kg of rabbit would go to …kg of fox
(from the original 100kg of grass)
1kg
4.11B bacteria and fungi are called decomposers because
they break down the dead remains and release the chemicals for the plants to use again
4.11B step1. the nitrogen fixing bacteria absorb … and reduce it to …
nitrogen
ammonia
4.11B step1. the process of reducing nitrogen to ammonia is called
nitrogen fixation
4.11B step2. ammonia is converted to nitrites & nitrates by
nitrifying bacteria
4.11B step2. the process of converting ammonia to nitrites&nitrates is called
nitrification
4.11B nitrogen fixation is when
you reduce nitrogen to ammonia
4.11B nitrification is when
you convert ammonia to nitrites and nitrates
4.11B step3. plant roots can only absorb
nitrates
4.11B step3. the nitrates are combined with carbohydrates to form
amino acids
(then made to proteins and nucleotides)
4.11B step3. the proteins and nucleotides made from amino acids join to make
DNA and RNA
4.11B step4. animals … plants
eat
4.11B step4. animals … the proteins and DNA in plants
digest
4.11B step4. the proteins & DNA absorbed by the animal is used to … new proteins and DNA (a….)
synthesise new proteins and DNA (assimilation)
4.11B step5. when a plant or animal dies its tissues are
decomposed
4.11B step5. when they are decomposed by bacteria and fungi it is
saprotrophic feeding
4.11B step6. molecules containing nitrogen are broken down by bacteria&fungi and … is released into the soil
ammonia
4.11B step7. some nitrates are converted to .. by ..
N2 by denitrifying bacteria
4.11B step7. the process of nitrates being converted to N2 is called
denitrification
4.11B the four processes of the nitrogen cycle
decomposition, nitrification, denitrification and nitrogen fixation
4.11B the bacteria involved in decomposition
decomposing bacteria
4.11B the bacteria involved in nitrification
nitrifying bacteria
4.11B the bacteria involved in denitrification
denitrifying bacteria
4.11B the bacteria involved in nitrogen fixation
nitrogen-fixing bacteria
(found in soil and root nodules of plants)
4.11B description of decomposition
protein in dead plants and animals is broken down
ammonia is released into the soil
4.11B description of nitrification
ammonia is converted to nitrites,
and nitrites are converted into nitrates
4.11B description of denitrification
nitrates are converted to nitrogen gas (denitrification reduces the amount of nitrate in the soil and therefore makes the soil less fertile)
4.11B description of nitrogen fixation
nitrogen gas is converted to ammonia in bacteria which is used to make proteins, when the bacteria die their proteins decompose, releasing ammonia back into the soil
4.11B some nitrogen fixing bacteria live small structures -
nodules on the roots of legume plants
4.11B in the nodules there is a mutualistic relationship because
the bacteria receive glucose from the plant while the plant absorbs ammonia from the bacteria in the nodule
4.11B when the bacteria decompose they make the soil much
much more fertile releasing ammonia which can be converted into nitrates
4.11B what cycle do I need to know
the nitrogen cycle
4.11B how do I remember nitrogen fixing
grab the nitrogen from the air and pull down to fix it
4.11B what are the three types of bacteria you need to know in the nitrogen cycle
nitrogen fixing, nitrifying and denitrifying
4.11B what are the roles you need to know in the nitrogen cycle
nitrogen fixing bacteria, decomposers, nitrifying bacteria and denitrifying bacteria
