Topic 5: Biomass and NPP stuff Flashcards
Describe what is meant by the term succession (2)
-Change in communities over time
Deduce the effect of succession on the level of carbon dioxide in the atmosphere (3)
-The energy lost in respiration stops increasing
-Accumulation of biomass continues
-Therefore, with succession more carbon dioxide is fixed
-This reduces the amount of carbon dioxide in the atmosphere
Net Primary Productivity (NPP) is a measure of the increase in biomass of a plant.
Explain why respiration affects the production of biomass.
-NPP = GPP-R
-Organic molecules/glucose - are used in respiration to provide energy
-More glucose used in respiration, the less is available for the production of biomass
Explain what happened to the bare rock to allow the growth of trees (3)
-Bare rock was colonised by pioneer species
-These pioneer species break up the rock
-Dead plants add humus/organic matter as they decompose
-Eventually trees will be able to grow as the soil becomes deeper
Explain why the value for GPP is lower than the light energy available to the ecosystem (3)
-Not all light falls on the leaves
-Some of the light is reflected
-Some of the light misses the chloroplasts and passes through the leaf
-Some of the light is the wrong wavelength and is not absorbed by the chlorophyll
Suggest one abiotic factor that might affect the abundance of Epilobium Latifolium and describe how this factor could be measured (3)
-Light, soil PH, water content, mineral content, temperature
-Light can be measured using a light meter, temp can be measured using a thermometer etc
-Reading should be taken at the height of plant, soil sample around roots
-Take several readings to get an average
Devise a procedure to measure the rate of recovery of the peat bog (4)
-Use quadrats for sampling
-Determine co-ordinates for random sampling
-Record percentage of the plant in each quadrat
-Several quadrats/samples measured and mean is calculated
-Sample at regular time intervals
-Calculate rate of change
Devise an investigation to compare species richness of the plants growing under the trees in a deciduous woodland with that of a coniferous woodland (5)
-Random sampling in each woodland using suitable method of generating co-ordinates
-Use of quadrat to sample at least 10 times in each woodland
-Count the number of different species in each quadrat
-Take measures to ensure validity of investigation
-For each woodland, calculate the total number of species present
-Use statistical tests to compare the data from the two woodlands e.g. Mean and standard deviation
Devise an investigation to determine the effect of grazing on the distribution of hairy vetch plants (4)
-Random sampling in grazed and non-grazed sand dune hollows
-Measure number of plants
-At least 10 quadrats in each area to calculate mean values
-Record abiotic data at each site
-Use statistical tests such as t test to compare distribution
Suggest why NPP values would be of use to a farmer who wanted to use this land for cattle (3)
-Cattle are primary consumers
-Therefore, they gain energy available as NPP
-Farmer is ensuring there is enough NPP available for his cattle
-Availability of NPP would affect growth rate of cattle
-Farmer can change to a more efficient crop
Explain what is meant by the term net primary productivity (2)
Rate of energy incorporated into biomass, there are losses of NPP in respiration
Reasons for why there might be high GPP in a sea
-More photosynthesis
-high nutrient levels in the sea
-Optimum temperatures
-High light intensity
-Less respiration
