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level: Climate Change and Evolution

Questions and Answers List

level questions: Climate Change and Evolution

QuestionAnswer
define climatethe average weather conditions over a long period of time
define climate changethe long term shift or change in average weather patterns in a place over time
define anthropogenicman made GHG emissions
define weatherthe term used to describe daily conditions
define global warmingthe gradual increase in the average temperature of the Earth's atmosphere and surface
evidence for climate changepollen in peat bogs CO2 emissions and temperature levels records dendrochronology
Results of climate changereduction 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 bogsvery 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 recordstemperature 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 gasesCO2, water vapour, methane, N2O they absorb heat energy and reflect it back to the earth
greenhouse effectthe 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
evolutionthe change in allele frequency of a population over time as a result of natural selection
natural selectionthe 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 mutationchange 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 pressureexternal agents which affect an organism's ability to survive in a given environment
speciationthe 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 flowthe transfer of alleles between organisms
two types of speciationallopatric and sympatric
allopatric speciationpopulation is isolated by geographical features prevents them from breeding they are reproductively isolated
reproductive isolationthe inability of a species to breed successfully with related species due to geographical, behavioural, physiological or genetic barriers/differences
sympatric speciationsame 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 isolationspecies occupy different areas of the habitat
temporal isolationspecies reproduce at different times but within the same area
behavioural isolationspecies do not respond to the courtship behaviour but are found in the same area
physical incompatibilityspecies can co-exist but physical reasons stop them from mating
hybrid inviabilityoffspring is produced but they don't survive
hybrid sterilityoffspring 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 reaction5 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
Q10the 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 shrimp5 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