Topic 5 On the wild side Flashcards
What is the main reason that carbon dioxide acts as a greenhouse gas? (1)
-Absorbs infrared radiation reflected by the surface of the Earth.
Explain how studying pollen grains in peat bogs can provide evidence of climate change. (4)
-Pollen is preserved in peat bogs.
-Plant species can be identified from pollen.
-Climate affects type of plants growing.
-Depth of peat correlates with period of time since pollen was produced.
-Changes in pollen over time indicates changes in climate.
Explain the effects of a temperature increase from 20 °C to 30 °C on the initial rate of activity of catalase in the yeast cells. (3)
20 °C produces 80mm^3 of oxygen.
30 °C produces 240mm^3 of oxygen.
-Between 20 °C and 30 °C there is more kinetic energy available.
-Therefore there will be more frequent successful collisions between enzyme and substrate.
-Meaning more enzyme substrate complexes will be formed.
-Q10 value indicates activity triples with this temperature rise.
Leaf rust affects crops and is a disease caused by a species of fungus, and it spreads through crops when humidity is high.
Discuss the possible impact of climate change on the effects of leaf rust on the yield of wheat crops. (4)
-Climate change may result in an increased temperature/increased humidity/drought/change in rainfall pattern.
-Increase in temperature could increase growth of leaf rust.
-Increased humidity could increase spread of leaf rust.
-A period of drought could reduce spread of leaf rust.
-Decrease in yield of crops if spread of leaf rust is increased.
Explain why anthropogenic emissions of greenhouse gases are affecting the climate. (3)
-Burning fossil fuels release carbon dioxide, increasing the levels of carbon dioxide in the atmosphere.
-Carbon dioxide is a greenhouse gas.
-Therefore more infrared radiation trapped in atmosphere.
-Causing a mean increase in surface/atmospheric temperature to increase.
Define the term ecosystem. (1)
-Organisms and non living components/abiotic factors.
Explain why the value for GPP is lower than the light energy available to the ecosystem. (3)
-Not all light falls on plants.
-Some of the light is reflected from surface of leaf.
-Some of the light misses the chloroplast and passes through the leaf.
-Some of the light is the wrong wavelength so it isn’t absorbed by chlorophyll.
Describe the role of photosynthesis in the carbon cycle. (1)
-Carbon dioxide is reduced to form organic molecules.
Net primary productivity (NPP) is a measure of the increase in biomass of a plant.
Explain why respiration affects the production of biomass. (2)
- GPP-NPP=R
-Organic molecules/glucose are used in respiration to provide energy.
-Because the more organic molecules are used in respiration, less is available for production of biomass.
It’s thought that burning wood chips is more beneficial to the environment as in the long term it does not add carbon dioxide to the atmosphere.
Explain why burning wood chips does not increase carbon dioxide to the atmosphere in the long term. (4)
-Carbon dioxide produced by burning wood chips replaces the carbon dioxide absorbed by trees.
-Trees absorb carbon dioxide from atmosphere for photosynthesis.
-New trees are grown to replace those that are cut down.
-No net increase in carbon dioxide.
Describe how different species of cichlid fish have evolved in lakes and rivers in Africa. (5)
-Random mutations lead to variation.
-Due to different selection pressures in different habitats.
-For example mouth shape or food eaten may change depending on the habitat the fish lives in, this change allows the fish to survive.
-The fish that survives pass on the beneficial/advantageous allele to its offspring.
-There is reduced gene flow between populations.
-Sympatric speciation of fish in same lake/allopatric speciation of fish in different lakes.
Explain how two species of African elephant could evolve from a common ancestor. (3)
-Two populations are geographically isolated from each other.
-Therefore reduced gene flow between the two populations.
-Which leads to allopatric speciation.
-Different selection pressures leading to natural selection.
Explain how reforestation of tropical rainforests can be used to minimise climate change. (3)
-New trees are planted.
-More carbon dioxide taken in by photosynthesis then released by respiration.
-Therefore reducing carbon dioxide in atmosphere.
-Which slows rate of global warming.
Forests are important habitats.
Many forests are exploited by humans.
Describe how forests can be managed as a sustainable resource. (2)
-Cut down older trees.
-Replace trees that have been cut down.
-Replace with seedlings.
Explain the impact of cutting down trees on climate change. (4)
-Less photosynthesis.
-Less carbon dioxide will be fixed/more carbon dioxide remains in atmosphere.
-Because carbon dioxide is a greenhouse gas.
-More heat energy trapped in atmosphere.
-More energy in atmosphere increases atmospheric temperature.
