| define climate | the average weather conditions over a long period of time |
| define climate change | the long term shift or change in average weather patterns in a place over time |
| define anthropogenic | man made GHG emissions |
| define weather | the term used to describe daily conditions |
| define global warming | the gradual increase in the average temperature of the Earth's atmosphere and surface |
| evidence for climate change | pollen in peat bogs
CO2 emissions and temperature levels records
dendrochronology |
| Results of climate change | reduction in species
more flooding, storms and droughts
ice caps melting
sea levels and temperatures rising |
| what are peat bogs? | partially decomposed organic matter
has anaerobic and acidic conditions that prevent bacteria decomposing the organic matter |
| pollen in peat bogs | very resistant to decay
they are varied and unique
are only produced when the plant is matured
their abundance in each layer of the peat bog can be used to analyse climate change
their DNA can be analysed to see what conditions the plant they came from grew in |
| CO2 emissions and temperature level records | temperature level records as far back as 1850
CO2 records can be obtained as far back as 10 - 15 million years ago
these are both important factor and contributors to climate change |
| what is dendrochronology? | study of trees
the width of tree rings can be studied to determine climate change |
| the greenhouse gases | CO2, water vapour, methane, N2O
they absorb heat energy and reflect it back to the earth |
| greenhouse effect | the sun emits heat energy through radiation
most of the radiation is absorbed by the earth whilst the rest is reflected back into space
short wavelength UV radiation passes through the earth's atmosphere and is reflected from the surface
the reflected rays are of a longer wavelength (infrared radiation) and are trapped by GHGs
this leads to an increase in the temperature of the Earth's surface and atmosphere |
| why do models for climate change have limitations? | there is not enough knowledge about the initial conditions of the climate system |
| what are the effects of climate change on plants and animals? | change in distribution of species
change in development of organisms
change in the life cycles of species |
| how does climate change affect the distribution of species? | species will have to migrate to cooler places
this will cause competition in that area
eventually leads to extinction due to lack of food and space |
| how does climate change affect species development? | the sex of some species is determined by the temperature
an increase in temperature may effect the sex ratio of these species
this leads to extinction because the sex ratio is imbalanced |
| how does climate change affect life cycles? | increased temperature increases enzyme activity
so more enzyme-substrate complexes are formed
increasing the rate of reaction
however at temperatures above the optimum rate of reaction decreases as enzymes denature |
| evolution | the change in allele frequency of a population over time as a result of natural selection |
| natural selection | the process where organisms are better adapted to an environment to survive and reproduce
advantageous alleles are passed down to the offspring
leads to evolution |
| gene mutation | change in bases sequence on DNA
could cause a change in amino acid
this may lead to a different protein structure |
| how can evolution come about through gene mutation and natural selection? | selection pressure changes
alleles change in some of the species
the allele is advantageous for them to survive in the environment
they can pass down the allele to their offspring
those without the allele die
as time goes on the frequency of the advantageous allele increase in the species |
| selection pressure | external agents which affect an organism's ability to survive in a given environment |
| speciation | the evolution of new species from existing ones
occurs when there is a lack of gene flow between two populations of species resulting in each population evolving differently |
| gene flow | the transfer of alleles between organisms |
| two types of speciation | allopatric and sympatric |
| allopatric speciation | population is isolated by geographical features
prevents them from breeding
they are reproductively isolated |
| reproductive isolation | the inability of a species to breed successfully with related species due to geographical, behavioural, physiological or genetic barriers/differences |
| sympatric speciation | same species found in the same location/habitat
evolve differently due to other factors
so can no longer produce fertile offspring |
| what can sympatric speciation occur from? | ecological isolation
temporal isolation
behavioural isolation
physical incompatibility
hybrid inviability
hybrid sterility |
| ecological isolation | species occupy different areas of the habitat |
| temporal isolation | species reproduce at different times but within the same area |
| behavioural isolation | species do not respond to the courtship behaviour but are found in the same area |
| physical incompatibility | species can co-exist but physical reasons stop them from mating |
| hybrid inviability | offspring is produced but they don't survive |
| hybrid sterility | offspring can survive to the reproductive age but do not reproduce |
| investigate photosynthesis using isolated chloroplasts (the Hill Reaction) | grind leaves with ice cold sucrose solution in a mortar and pestle
strain the liquid into a cooled centrifuge tube and centrifuge for 5 mins at medium speed
pour the supernatant into another cooled centrifuge tube and centrifuge for 10 mins at high speed
decant and discard the supernatant
add ice cold sucrose solution and ice cold pH 7 buffer solution to the left over sediment and mix gently
pour equal volumes of the mixture into test tubes A, B and C, also add the same volume of DCPIP to test tube D only
boil tube C over a Bunsen burner then cool it under a tap
add some DCPIP to test tubes A, B and C
leave tubes A, C and D under a lamp and place B in a cupboard
observe until all the colour in tube A has disappeared |
| what does the Hill Reaction prove? | isolated chloroplasts can still produce oxygen in the presence of light providing evidence for the light dependent reaction |
| investigate the effect of temperature on the initial rate of an enzyme-catalysed reaction | 5 different temperatures of water baths between 10°C - 50°C
put some hydrogen peroxide into a conical flask
put the conical flask in the water bath to acclimatise for 2 minutes
add some yeast to the conical flask and immediately bung up the conical flask
take readings from the gas syringe every 30 seconds for about 3 mins
repeat this at each temperature 3 times |
| Q10 | the temperature coefficient
measures the rate of change of a reaction when the temperature is increased by 10°C
Q10 = rate at higher temperature / rate at lower temperature |
| investigate the effect of temperature on brine shrimp | 5 different temperatures of water baths between 10°C -30°C
add some sea salt to the water in a beaker and stir till it has all dissolved
pour out some eggs onto some paper
dip some paper in the saltwater to pick up about 40 eggs
re dip the wet paper with attached eggs into the saltwater solution
place each beaker into the water baths for 24 hours or more
count how many eggs hatched out of the 40 eggs
repeat to get means |
