Practise IB Biology HL D4.2 by analysing ecosystem data, making resource-management decisions and predicting change during primary succession.
106 questions in this syllabus scope, with question parts counted together.
117 papers analysed · Tagging incomplete
Laboratory-scale mesocosms were built to investigate the effect of very small contaminants (nanoparticles) on ramshorn snails (Planorbarius corneus).
Outline the requirements for sustainability within a sealed mesocosm.
Satellite imagery has been used for many years in the Amazon rainforest to monitor deforestation. Annual deforestation can be calculated using data from several satellites that have varying levels of accuracy. The graph shows the area of the Amazon rainforest that was deforested each year from 2001 to 2019, calculated using satellite images.
The Amazon rainforest currently releases very large amounts of water vapour into the atmosphere through transpiration. Suggest one consequence of this.
In fruit flies (Drosophila melanogaster), the allele for brown body (B) is dominant to black body (b) and the allele for long wings (L) is dominant to short wings (I). A dihybrid cross was made between a fruit fly heterozygous for both traits and a black, short-winged fruit fly, as shown in the image.
The expected and observed ratios of offspring of the cross are given.
Fruit flies are sometimes kept in enclosed glass mesocosms to study their population dynamics, genetics and interactions with the abiotic environment.
Explain the advantages of using mesocosms in these studies.
Feeding relationships between organisms on rocky shores along the Pacific Coast of North America were studied. The food web shows the proportions of the total energy consumed by the two carnivorous species, a starfish (Pisaster ochraceus) and a small gastropod (Thais emarginata).
Pisaster is considered a keystone species. Explain the effects of Pisaster on this community.
Outline the concept of maximum sustainable yield in the conservation of fish stocks.
Discuss the risks and benefits associated with the use of phosphate fertilizers in agriculture.
Increased leaching of nitrogen fertilizers disrupts the stability of aquatic ecosystems such as lakes. What change is expected if nitrogen leaches into a lake over time?
Wilting of surface plants
Increased biochemical oxygen demand (BOD)
Weakened mollusc shells
Bioaccumulation of pollutants at higher trophic levels
Discuss the use of DDT (dichlorodiphenyltrichloroethane) in the control of the malarial parasite.
Plastic has accumulated in marine environments and is now causing problems for wildlife. Some marine birds have become entangled in plastic debris and some have been harmed by ingesting it. The table shows the extent of the problem worldwide in different groups of birds.
Describe how ingested plastics can cause problems to marine birds.
The graph shows the change in forest area in Greater Mekong countries in Southeast Asia between 1973 and 2009. This was mainly due to deforestation.
The EDGE of Existence programme measures Evolutionary Distinctness (ED) and Globally Endangered status (GE).
Outline one method of restoration of natural processes in ecosystems by rewilding.
A retreating glacier leaves an environment of lifeless glacial deposits, including sands and gravels. Retreating glaciers often offer suitable sites for primary succession.
State one abiotic factor that will determine the type of ecosystem in a succession.
Surtsey, a volcanic island approximately 32 km from the south coast of Iceland, is a new island formed by volcanic eruptions that took place from 1963 to 1967. It has been legally protected since its formation and is free from human interference.
What changes are likely to have been observed since the formation of Surtsey?
Cyclical succession as the climax community changes
Secondary succession when animal species arrived
Arrested succession due to the drainage of wetlands
Primary succession including an increase in size of plants
No public sample questions are available for this syllabus point yet.
No public sample questions are available for this syllabus point yet.
Laboratory-scale mesocosms were built to investigate the effect of very small contaminants (nanoparticles) on ramshorn snails (Planorbarius corneus).
Suggest one advantage of using a mesocosm in this type of research.
Outline the requirements for sustainability within a sealed mesocosm.
