Topic 5B and 4A- Biodiversity and endemism/evolutions and stuff. Flashcards
(28 cards)
What human activities lead to the enhanced greenhouse effect, and therefore an increase in global temperature?
Cattle farming- this means high amounts of methane are released into the atmosphere.
Deforestation- this means less carbon dioxide is able to be absorbed during photosynthesis/ less carbon sinks.
Burning fossil fuels- This releases carbon dioxide into the atmosphere.
These all increase the concentration of greenhouse gases in the atmosphere, which leads to an increase in average global temperature. This is global warming.
When interpreting data, what can you NOT do when looking at relationships between greenhouse gas concentrations and average global temperature?
You cannot say this is direct causality, because other factors may come into play, such as solar activity. Additional studies would be needed to investigate the effects of the other factors of that given time.
Scientists have used data of greenhouse gases concentrations and average global temperature, and have produced extrapolated versions. Using this, they can represent the different scenarios which could occur. What are these scenarios?
Scenario 1
Scenario 2/3
Scenario 4
Scenario 1 is the situation where the concentration of greenhouse gases peak, but eventually actually decrease. This decreases after the various governments put plans into action to reduce their emissions significantly.
Scenarios 2/3 is the situation where the comcentrations of greenhouse gases continue to increase, but eventually level off and don’t increase. This occurs when steps are taken to reduce emissions.
Scenario 4 is the worst case scenario. This is where there is not enough world government intervention, and greenhouse gas concentrations do not lower subsequently and continue to increase to very high levels.
What are the limitations of computer models?
We don’t actually know how greenhouse gas emissions will change.
We don’t know how each scenario will affect global temperatures.
We don’t know what attempts will be made to manage the global temperature increase, or whether they will be successful.
How does global warming affect:
Enzyme activity
Life cycles
Development
Distribution
It affects enzyme activity by the temperature increase meaning there is more kinetic energy. This means that there is a greater proportion of molecules which have enough kinetic energy to react upon collisions, so more enzyme substrate complexes form, and more reactions occur. If the temperature becomes too high, the enzyme will denature, and the reactions will not occur.
If the enzymes involved in an organisms metabolism are working more efficiently, the organism will grow and develop quicker due to an increased rate of metabolism and therefore growth. This means that they will go through their life cycle faster. Conversely, if the temperature is too high, then enzyme activity will decrease, and so will metabolism. Growth will be slower, and the organism will progress through their life cycle slower.
If temperatures increase and an organism lives and thrives in cooler environments, these organisms will tend to become distributed more in the colder areas, either by migration to these areas, or dying out in one and breeding in another. The range of the species may increase as more areas become favourable to them for breeding .
Climate change can also affect the weather. In what way?
Changing rainfall patterns. Global warming will mean that some areas will have an increased rate of rainfall, and others will have less rainfall. This may mean that some species of plants/ animals which are dependent on rainfall may become more active and grow more if it increases, but if rainfall decreases, they may die out in an area or may have to migrate to an area with higher rainfall, therefore affecting the distribution of the species.
Seasonal changes. Global warming can change the timing of seasons. This may mean that rainfall comes earlier than expected. This has knock on affects. The timing will be off, and may mean that species migrate at different times. Predators who migrate to an area knowing that their prey will be active due to the confound which are provided by that particular season, but that seasons conditions have already occurred/ have not occurred yet, they will be migrating to find no food. This will mean that migrating species may die out in certain areas due to a lack of food due to changes in timing/ seasons.
How would you measure the affect of seedling growth rate respective to increasing temperature?
Place seedling of the same variety and age into soil and measure the initial heights of the seedlings. You should ensure that the soil has the same water content and pH for all seedlings. You should incubate the tray of all the seedlings at a variety temperatures ( like 14,16,18,20,22 degrees). You should allow the seedlings to grow for a constant amount of time, for example 4 days. You should then measure the height of all the seedlings and then calculate the changes in height. You should then repeat this and calculate the mean height change for each temperature, to minimise the chance for error. You should then divide this height change by time spent incubating. Plot a graph of results and draw conclusions from this.
How would you measure the effect on brine sheimp hatch rate respective to temperature?
Put an equal number of brine shrimp eggs ( for example, 100) into temperature controlled water baths. There should be 5 water baths (5,10,15,20,25 degrees). You should leave the brine shrimp to hatch at each of these temperatures for the same amount of time, for example 24 hours. You should then count the number of hatched eggs in each water bath. You should repeat this for each temperature at least 3 times to take an average. You should then divide the number of hatched shrimp by the number of hours incubated. You should then plot hatch rate against time and draw conclusions from the results. Control salinity/salt conc of water, oxygen conc of water, and volume of water.
How could you investigate how temperature affects the initial rate of reaction?
By investigating oxygen production from the esyme catalysed breakdown of hydrogen peroxide. Collect 5 tubes with the same concentration and volume of hydrogen peroxide. To keep pH constant, add equal volumes of a suitable buffer to the solutions. Place each test tube into a temperature controlled water bath (10,20,30,40,50 degrees) and add a tube into the water bath containing catalase. Wait 5 minutes for the enzyme and substrates to get up the temperature. Then take the tube containing the peroxide out of the water bath and add the same amount of catalase to each tube, and instantly close a bung onto the test tube. The bung will be attached to a gas syringe, and you will measure the volume of oxygen collected by the syringe in a given time like 60 seconds, measuring every 10s in regular 10 second intervals, and you will keep this time constant for each temperature. You can then plot a graph of oxygen collected against time, and take a tangent at t=0.
What is Q10?
What are these values usually for enzyme controlled reactions?
What does this mean?
It shows how rate changes with temperature.
If rate is x degrees, then Q10 is:
(x+10 degrees)/(x degrees).
This is always the measurement between one temperature and another which is 10 degrees higher or lower.
They are usually around 2 for enzyme controlled reactions.
Id Q10 is 2 this means that before the optimum, the rate of reaction doubles if temperature is increased by 10 degrees. If it is 3, it trebles when temperature increases by 10 degrees.
What evidence is there to support evolution?
Genomics- analysing organisms DNA base sequences to determine the functions of specific genes within specific organisms. These can be compared between different organisms to see how similar they are.
Proteomics is the study of proteins- the shape, size, and amino acid sequence of them. Since amino acid sequences are coded by base sequences of DNA, if the order of amino acids of a proteins is similar between organisms, they will have similar DNA.
How is evidence validated?
Scientific journals- other scientists can test the theory to see whether they obtain similar data. If the same results are replicated over and over again, the scientific community can become very sure that the work is valid.
Peer reviewing- scientists within the same field will blindly review a paper and see whether they agree that it holds goood points and whether or not they agree with the conclusion presented within it.
Conferences
How would you measure species diversity?
Youd first need to measure the species richness- the number of different species within an area. You could do this by a method of random sampling, using a suitable method depending on the type of organism in which you are sampling. For example if sampling plant species, you could use a frame quadrat, if aquatic, you could use a net. Repeat the sample in different randomly generated areas within the particular area you are studying to get a good representation of the general area.
To measure the species abundance- the number of individuals within a species- youd need to count the number of indiivduals within each species. You would do this by counting each sample, and doing repeats within differwent sampling areas to get a good representation of the areas.
For both, you would then use the data collected to estimate the total number of species, and abundance of these species in the given area.
What equation can be used to calculate species diversity?
N(N-1) / Σn(n-1)
where N is the total number of all species
where n is the total number of individuals of one species
How could you measure the genetic diverisity within a species?
You can observe the phenotypes of the species. As phenotypes are coded by alleles on genes, a differing in phenotypes among the individuals within a specials must entail a differing in alleles. Therefore, if there is a large number of different phenotypes, there is going to be a large variety of alleles, and therefore a large genetic diversity.
Additionally, the genotype of organisms within a species can be analysed. Here the sequence of base within a DNA sample from the organism is analysed. The order of bases in different alleles are slightly different, therefore meaning that there is genetic diversity between organisms. The greater the number of different alleles an organisms has in a specific allele, ther more genetically diverse the organism will be.
What is the equation for heterozygosity index?
number of heterozygotes in the population/number of individuals within the population.
What are the three types of adaptations for niches in organisms?
Behavioural- The way an organism acts to increase its chance of survival
This could be a mating ritual, or a defence mechanism like playing dead.
Anatomical- Structural features of an organisms body which increase its chance of survival.
This could be a particularly developed jaw muscle coupled with sharp teeth which can allow tough fruits/foods to be eaten.
Physiological- internal mechanisms/ processes which occur within organisms in order to increase their chances of survival.
This could be the ability to slow metabolism (torpor) to allow for hibernation to occur during winter months with low food availability. It could also be something bacteria producing antibiotics which kill other bacteria in surrounding areas, in order to make reseouces more abundant to themselves to boost the chances of survival.
How does natural selection give rise to evolution?
Random mutations within a species cause new alleles and therefore characteristics to be formed. A selection pressure makes conditions less favourable for the species survival, and a struggle for survival is created. Individuals with advantageous alleles and characteristics/selective advantage are more favourable to the new conditions are able to survive, however individuals without such advantageous alleles arent able to survive. So, the individuals with the advantageous alleles are able to survive and reproduce, passing their advantageous alleles onto their offspring. Over time, the frequency of the alleles passed down increase within the population, and new characteristics from this arise, and the species has now evolved
What is the definition of a species?
A group of similar organisms which are able to interbreed and produce fertile offspring.
What is speciation?
Why does this occur?
This is the development of a new species.
It occurs when a population becomes reproductively isolated. This is when the populations are no longer able to breed successfully. This could be due to:
Mechanical changes- This is when changes in genitalia prevent successful breeding.
Behavioural changes- This occurs when individuals may develop different mating/courtship rituals, so that the individuals are no longer attracted to one another, and will therefore not breed.
Seasonal changes- Individuals within a population may become sexually active at different times/ may have different mating seasons. Since they arent sexually active at the same time, they do not breed.
What are the conditions required to make the hardy-weinberg principles valid?
It predicts that the allele frequency wont change from one generation to the next.
It requires the following:
Large populations
Mutations no
Immigration no
Natural selection no
Emigration no
Random mating yes
There also needs to be random mating
What is the hierarchy of classification?
Domain
Kingdom
Phylum
Class
Order
Family
Genus
Species
What are the five kingdoms?
Fungi
Animalia
Prokaryota
Protoctista
Plantae
Fap remember.
What is the three domain system based upon?
What are they?
What are the three domains?
Molecular Phylogeny- This is the analysis of proteins and DNA of different organisms, where comparisons are made to see whether there are any similarities or differences.
They are superkingdoms which are above kingdoms in the taxonomic hierarchy.
Bacteria
Archaea
Eukaryota
so now this is Bae and fap. easy to remember!
