D4.2 Sustainability - revision quiz
This test contains a set of revision questions to use in preparation for assessed on this topic. There are several question styles and answers with explanations.
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The graph below shows data about the carbon dioxide concentration of the earth's atmosphere over the last 300 million years, from the time that life first appeared on earth.
Which of the following best explains why these changes occur?
Photosynthesis has caused changes to the Earth’s atmosphere, oceans and rock deposition.
The presence of oxygen in the atmosphere allows aerobic respiration.
Mesocosms can be used by ecologists to investigate natural systems. The mesocosm shown in the image is used to investigate the variables that could affect the growth of young fish.
Which variables could be easily and accurately controlled when using these aquatic mesocosms in experiments?
Mesocosms can allow the control of variables much more than the natural environment.
These tanks are all the same size, so naturally volume, and surface area can be easily controlled.
In setting up the tanks the concentration of salts can be accurately measured, as there is no movement of water through the tanks, this can also be controlled.
The graph below shows actual data from the Air monitoring station in Hawaii.
Why does the CO2 concentration decrease between June and October 2018?
In the summer season, there is more photosynthesis.
The mesocosm in the picture has been sealed since 1960.
What describes the energy interaction between the mesocosm and the environment?
A mesocosm needs light as a primary energy source and as it must be transparent, light can enter and, if not absorbed, leave. Heat can enter or leave depending on the outside temperature.
Which of the following best represents the way organisms transform energy in a sealed mesocosm?
In any ecosystem dependent upon light, light energy is converted by photosynthesis to chemical energy (in the form of glucose and carbohydrates) which will be respired and lost as heat.
Which of the following is true of ecosystems that have persisted for many thousands of years?
Stable ecosystems can persist as they can maintain equilibrium even though some changes may occur.
In a stable ecosystem, which of the following is correct in regard to climatic factors?
For an ecosystem to be stable, all members of the community must flourish and this can only happen when climatic factors are within their tolerance levels.
An ecosystem requires a source of energy, usually the sun.
What else is required for the ecosystem to be stable? (Two answers)
Nutrients are in finite supply and must be recycled.
There must also be genetic diversity between species and within species in the community.
In 2004, approximately 28000 square kilometers (km2) of Brazilian rainforest was deforested.
In 2017, approximately 7,000 km2 of rainforest was deforested.
What is the percentage decrease in deforestation between these two years?
The decrease is 21,000,from 28k to 7k, so the % decrease is 21000/28000 x100% = 75%
Which two of the following transfers of energy occur in a sealed mesocosm?
Energy enters as light and exits as heat.
A sealed aquatic mesocosm is created containing plants, herbivorous snails and bacteria that are decomposers. A gas sensor is put in the air above the tank to measure oxygen and carbon dioxide gases.
Which of the following changes could be expected to be detected by the sensor if the light intensity illuminating the tank was constant and the light on for 12h each day for 7 days?
The snail population would not be expected to change during seven days, and it would be likely to have enough food.
Carbon dioxide would be produced by respiration in all the organisms.
Carbon dioxide would be absorbed and used in photosynthesis by plants during daylight.
Oxygen concentrations would increase when there was light, if the amount of oxygen used in respiration was less than the oxygen production by photosynthesis.
Bacteria recycle organic compounds, but not oxygen.
What is the role of a keystone species in an ecosystem?
A keystone species is one that has a major effect on an ecosystem (and if removed, the ecosystem would change dramatically.).
What is meant by the term "sustainable harvesting"?
The rate of harvesting by humans needs to be less than the rate of replacement to ensure sustainability of the species.
Which of the following could be used as methods to determine whether human harvesting of a fish species was sustainable?
The monitoring of catch size, or estimating the population size could be used to evaluate the sustainability of harvesting. Conservation methods like controlling mesh size, or the fishing season, are good for conservation, but they will not help monitor population size.
Leaching is a cause of eutrophication of fresh water. Complete the paragraph below using the words provided.
water fertilisers evaporate leach increased BOD biodiversity dropped algae
The use of nitrogen and phosphate in fields can cause build up nutrients in bodies of as they from soils. This causes an overgrowth of whose subsequent death causes an increase in Saprophytic organisms use oxygen from the water in respiration when decomposing the dead remains. The high BOD means oxygen levels have and can lead to a loss of from aquatic ecosystems, as species that require high oxygen concentrations move away or die.
Excesses of fertilisers run off into fresh water and cause eutrophication. BOD is biological oxygen demand, a measure of oxygen availability in an aquatic system.
Bioaccumulation is the accumulation of toxic chemicals in the tissues of an organism. Bioaccumulation is most prevalent in top order carnivores like the Osprey (Pandion haliaetus)?
What is the reason for this?
Chemicals that bioaccumulate cannot be metabolised and are not (or are very slowly) excreted and so accumulate up the food chain due to predation.
Which of the following is usually involved in rewilding an ecosystem?
Rewilding is an attempt to recreate wild areas within human communities and land usage and create sustainable ecosystems. Hunting may be play a role in ecosystem stability and climax communities are conserved not rewilded.
What is meant by the term "arrested succession"?
Humans cause arrested succession by anthropogenic activities such as farming.
After a bush fire in an area, secondary succession occurs.
Which of the following changes are likely to be seen during the succession and re-growth of the community?
As a succession proceeds, primary production, diversity and recycling increase leading to more complex food webs.