Topic 5 completed Flashcards
define ecosystem
a community of living organisms and the non-living components in an area which is self sustaining
give an example of an ecosystem
a woodland
define habitat
the environment where a species or group of species live
define community
populations of living things interacting with each other
define population
a group of organisms of the same species living together in the same area at the same time
what are biotic factors?
living factors
what are abiotic factors?
non-living factors
what determines the abundance and distribution of organisms in a habitat?
abiotic and biotic factors of the habitat
give 3 examples of biotic factors
competition, grazing, predation
give 5 examples of abiotic factors
climate, pollution, oxygen conc., edaphic (soil) factors, solar energy
define intraspecific competition
within the same species
define interspecific competition
between different species
define niche
the role a species plays within an ecosystem/habitat
what is included in the role of a species within a habitat?
what it eats, which other species depend on it for food, what time of day the species is active, exactly where it lives, exactly where it eats
why can 2 species not fill the same niche?
they will be in direct competition, one species will out-compete the other causing one species to die out in that habitat
how does niche affect abundance of species?
if 2 species have similar niches they will be competing against each other and so will have small abundances
how does niche affect distribution of species?
a species can only survive in a habitat if they are well adapted, if they are not well suited to the abiotic and biotic factors the species will move to a habitat they are better suited to and the distribution will change
define fundamental niche
describes the abiotic factors under which the species COULD survive
define realised niche
describes where the species ACTUALLY exists in the real world (takes into account other species)
define abundance/ population size
the number of individuals in one species in a particular area
define distribution
where a species is within a particular area
what are the 2 types of sampling?
random and systematic
what is systematic sampling?
used if there is a change in abiotic factor in an area- belt or line transects
what is random sampling? and what do you measure?
compare two gridded areas by randomly placing quadrants and comparing abundance or biodiversity
how do primary and secondary succession differ?
primary is in an area that is devoid of life, secondary starts with soil and maybe some living species
describe the steps of primary succession
1- seeds or spores carried by wind begin to grow and break down the rock(pioneer species colonise)
2- a second species grows and outcompetes pioneer species (for minerals, water etc)
3- pioneer species dies creating nutrient-dense soil (which gets deeper and can retain more water) for new species
4- this occurs repeatedly until a climax community is reached
what makes pioneer species unique?
can germinate easily and can withstand harsh conditions
define succession
the change in species inhabiting an area over time
how do woodland show succession?
rocks
lichen colonise and release minerals (pioneer species)
lichens die and decompose forming soil layer
mosses can grow
larger plants move in as soil deepens
shrubs, ferns and small trees grow outcompeting the grasses to become a dominant species
diversity increases
climax community is reached
why do some areas have different climax communities?
a temperate climate with water, a mild temp. and little change between seasons will be able to support large trees
a polar climate will only be able to support herbs or shrubs not trees but this is still a climax community
what is a plagioclimax?
when succession is stopped artificially by human activities such as mowing or grazing (deflected succession)
what is biomass?
the mass of living material in an organism
what is GPP?
Gross Primary Productivity- the rate at which energy is converted into organic molecules in plants
what is NPP?
net primary productivity- the energy available for the next trophic level
what is the NPP/GPP equation?
NPP=GPP-R (respiratory loss)
on average what percentage of energy is passed to the next trophic level?
10%
what is the equation for efficiency of biomass transfer?
biomass transfered/biomass intake
what are the 2 types of organisms in a food chain?
producers and consumers
what are the positives of wind turbines?
will not increase atmospheric CO2
what is the carrying capacity?
the maximum stable population size of a species that an ecosystem can support
how are thylakoids adapted to their function?
large surface area to allow lots of light to be absorbed
what are grana?
stacks of thylakoids in a chloroplasts
what are lamellae?
bits of thylakoid membrane that keep grana apart to maintain high surface area
what are the surroundings around grana in chloroplasts?
stroma
what is a starch granule also called?
amyloplast
how is the chloroplast adapted for its function?
double membrane to keep reactants close to reaction site
lamella keep grana apart
lots of ATP synthase in thylakoid membrane
lots of photosynthetic pigment
stroma contains all enzymes, sugars, and organic acids needed for light dependent reaction
what is the word equation for photosynthesis?
carbon dioxide + water +energy-> glucose + oxygen
what are the stages of photosynthesis?
light dependant and light independent
define phosphorylation
adding phosphates
define photosphorylation
adding phosphates using light
define photolysis
spitting a molecules using light energy
define hydrolysis
spitting a molecules using water
define oxidation
loss of electrons or hydrogen ions, or gain of oxygen
define redox reaction
a reaction that involves reduction and oxidation
define reduction
gain in electrons or hydrogen ions, or loss of oxygen
how does non-cyclic light dependent photosynthesis start?
a photon hits an electron in PSii
what are the forms of the light dependant cycle in photosynthesis?
non-cyclic and cyclic
what does non-cyclic light dependent photosynthesis produce?
ATP, NADPH and oxygen
what happens in non-cyclic light dependent photosynthesis?
election excited, moves down ETC, energy used for photophosphorylation, photolysis replaces electron in PSii, electron reaches PSi and is hit again, combine with H+ and NADP to form NADPH, oxygen is released as a byproduct
what happens in cyclic light dependent photosynthesis?
photon hits PSi and electron is excited, passed down ETC, chemiosmosis occurs, ATP produced, electron rejoins PSi
what are thylakoids?
fluid-filled sacs in a chloroplast
where does the light independent stage of photosynthesis occur?
the stroma of the chloroplast
where does light dependent stage of photosynthesis occur?
thylakoid membrane in the chloroplast
what happens in the light independent stage of photosynthesis?
the Calvin cycle: rubisco fixes CO2 to RuBP (5c), forms 6c unstable intermediate, 2x GP formed, 2 ATP used and 2 NADPH used, 2x GALP produced, loses 1c to form hexose sugars etc (2 GALP for 1 glucose), ATP used to reform RuBP
what is the name of the light independent stage of photosynthesis?
The Calvin Cycle
what can be made from the carbon which is lost during the Calvin cycle?
glucose (which is used in respiration), polysaccharides, amino acids, lipids and nucleic acid
what are 5 pieces of evidence for climate change?
temperature records, dendrochronology, pollen in peat bogs, ice cores, atmospheric carbon dioxide levels
what are the issues for temperature records as evidence for climate change?
only since 1659 when they were less accurate
how do peat bogs show evidence of climate change?
pollen is preserved, pollen is specific to each species, the depth of the pollen shows when in time the plant lived, species of plant shows weather conditions
why is the pollen preserved in peat bogs?
anaerobic and acid conditions mean decomposers cannot breakdown pollen
how does dendrochronology show evidence of climate change?
warm, wet, sunny weather= lots of photosynthesis= thicker rings
where are the newer tree rings?
outside= newer
what is measured in ice cores?
carbon dioxide levels
define global warming
rapid increase in mean earth’s surface temperature over a period of time
define climate change
a significant change in weather of a region usually over a period of several decades
What are proxies?
additional pieces of information to help support evidence (of climate change)
what are the causes of anthropogenic climate change?
combustion of fossil fuels for transport, factories, and homes produce carbon dioxide
intense farming, landfill sites and extraction of fossil fuels produces methane
give 3 examples of human proxies for climate change
ship logs, newspapers, diaries
define anthropogenic
caused by humans
what radiation is absorbed by greenhouse gases in the greenhouse effect?
infrared radiation
what are the 4 greenhouse gases?
methane, carbon dioxide, water vapour, CFCs
which greenhouses gases are most damaging?
CFCs and methane
which greenhouse gas is largest in abundance?
carbon dioxide
how are the greenhouse gases involved in the greenhouse effect?
the bonds allow the atoms to vibrate to and fro in time with heat radiation
they absorb the infrared radiation reflected by the earth
what are the 2 ways of reducing methane levels?
increase recycling (reduce landfill)
replace fossil fuels with biofuels
what are the 4 sources of carbon dioxide?
volcanic eruptions
deforestation
burning fossil fuels
decomposers respiring
what are the 4 ways of reducing carbon dioxide levels?
use renewable energy instead of fossil fuels
increase public transport
increase reforestation
reduce disturbance of carbon stores such as peat bogs
what does IPCC stand for?
Intergovernmental Panel on Climate Change
what is the IPCC?
a group of scientists that extrapolates data on greenhouse gases to create possible scenarios
what are the limitations of extrapolated data?
don’t know which scenario is most likely- don’t know about future technologies, cannot predict global climate patterns, don’t know that actions of future humans
how is climate change affecting weather pattens?
weather is becoming more frequent and more severe
how is climate change affecting weather distribution?
areas which have never had hurricanes (Dubai) may get hurricanes and are not prepared
what are the 6 effects of climate change?
changing rainfall patterns, seasonal cycle changes, rate of enzyme activity changes, life cycle changes, changes of distribution of species, time of pollination changes
how is climate change affecting rate of enzyme activity?
as temperature increases the rate will increase, until the enzymes denature due to kinetic energy causing the molecules to vibrate and the bonds break- active site changes shape
how is climate change affecting life cycles and development?
cold water fish- eggs cannot develop at high temperatures
cyanobacteria can produce toxins, as more bacteria grows (in warmer water) risk of harmful algal blooms increases
how is climate change affecting the distribution of some species?
alpine plants are moving further up mountains as it is cooler
many animal species including European butterfly species are moving north towards the pole
how is climate change affecting pollination?
the timing of the seasons is changing- the bees are pollinating earlier and the plants are flowering later
why might some species be unable to migrate northwards?
plants may be unable to move, animals may be on an island, animals may have physical barriers or be in bodies of water which don’t flow north
what are the 4 benefits of reforestation?
takes in more CO2 via photosynthesis
increases/ forms a carbon sink
increases biodiversity
provides more oxygen via photosynthesis
what are biofuels?
fuels made from biomass (material that is or was recently living)
what are the 2 issues with biofuels?
deforestation of rainforest for space to grow biofuels (loss of biodiversity)
ethical issues- using space to grow plants for burning but people are starving
what are the positives of biofuels?
no net increase in atmospheric CO2
what are the positives of wind turbines?
will not increase atmospheric CO2
how can scientific conclusions on climate change vary depending in who is reaching them?
a scientist who works for an oil company may find that fossil fuels are having less of an impact than a scientist working for a conservation company
what are the 5 questions to ask when deciding how good the evidence is?
does the statement address all the evidence?
is the data reliable?
is there plenty of evidence?
does statistical analysis find the data statistically significant?
is the source of the data biased?
define evolution
a change in allele frequency
what 2 things need to happen for evolution to occur?
gene mutation and natural selection
define natural selection
the process by which organisms that are better adapted to their environment survive, reproduce, and pass on their advantageous alleles, causing advantageous characteristics to increase in frequency within a population.
what are the 3 causes of genetic variation?
mutation, meiosis, random fertilisation during sexual reproduction
what are the stages of natural selection?
1-Natural mutations in DNA cause genetic variation in the population
2-A selection pressure such as predation, disease, competition changes
3-An allele becomes favourable as this gives a characteristic which increases chance of survival under new selection pressure
4- individuals with favourable allele more likely to survive and reproduce
5- over time frequency of the advantageous allele increases
define speciation
the development of a new species from pre-existing species over time
what has to happen in order for speciation to occur?
isolation to reduce gene flow
what are the 2 types of speciation?
allopatric and sympatric
explain allopatric speciation
1- a species become geographically separated (no gene flow)
2- the 2 groups have different selection pressures
3- different advantageous alleles
4- different changes in allele frequency
5-differences in gene pools
6-populations become genetically distinct
7- will have become reproductively isolated
explain sympatric speciation
a random change in alleles occurs which results in 2 groups becoming reproductively isolated
- seasonal changes (individuals develop different flowering or mating seasons)
- mechanical changes (changes genitalia prevent successful mating)
- behavioural changes (changes in mating call)
is allopatric or sympatric speciation due to geographical isolation?
allopatric
what is geonomics?
science that uses DNA technology to determine the base sequence of an organism’s genome and the function of its genes
what does geonomics allow?
comparisons to be made between organisms DNA
how does geonomics give evidence for evolution?
closely related species have diverged more recently and so will have more similar DNA as less time has passed for changes to occur
what is proteomics?
the study of proteins- size, shape and amino acid sequence
how does proteomics give evidence for evolution?
closely related organisms have similar DNA sequences and so similar amino acid sequences. more closely related organisms diverged more recently and so have similar DNA and proteins
what are the 3 ways scientists share and discuss ideas?
conferences, peer review, scientific journals
what are scientific journals?
academic magazines used to share new ideas, theories, experiments, evidence and conclusions. This allows any data collected to be replicated and make sure the data is reliable
what is peer review?
before publishing scientists in the same area of science read and review the work. They check the work is valid and supports the conclusion
what are conferences?
meetings that scientists attend to discuss each others work. some scientists may present their work as a poster presentation or lecture. they are easy ways for the latest theories and evidence to be shared and discussed
what is the equation for Q10?
rate at higher temperature/ rate at lower temperature (have to have difference of 10 degrees)
what does a Q10 of 3 mean?
rate has tripled with increase of 10 degrees
what does a Q10 of 2 mean?
rate has doubled with increase of 10 degrees
what does a Q10 of 1 mean?
rate is not affected by change in temperature
what does a Q10 of 0.5 mean?
rate has halved with increase of 10 degrees
