The effect of light intensity on the rate of photosynthesis was measured for two species of plants, L and M.
The results are shown in the graph below.
The rate of photosynthesis of species M is
- A slower than L in low light intensities
- B slower than L in high light intensities
- C faster than L in medium light intensities
- D faster than L in high light intensities.
Which of the following describes interspecific competition?
- A Individuals of different species requiring different resources.
- B Individuals of different species requiring similar resources.
- C Individuals of the same species requiring different resources.
- D Individuals of the same species requiring similar resources.
The graph below shows information about the growth of the human population.
If the population continues to increase at the same rate as between 1975 and 2000, predict the population size in 2025
- A 8000
- B 7500
- C 8500
- D 9000
A river was sampled at five sites as shown in the diagram below.
The following tables show the results of analysing the samples at each site.
(a) (i) Using data from Table 1, describe the relationship between the number of bacteria and the oxygen level in the water.
(ii) Methylene blue is a chemical which can be used to compare oxygen levels in the water. The lower the oxygen level, the faster methylene blue changes from blue to colourless. A sample of water from each of the five sites was tested. Predict which sample would lose its blue colour fastest.
(b) Use data from Tables 1 and 2 to answer the following questions.
(i) State which of the organisms in the samples would be found in areas of high oxygen content.
(ii) Sewage in the river is a form of water pollution.
Describe the effect this pollution has on the number of different types of organisms in this river.
(c) Some species are known as indicator species.
Explain what is meant by indicator species.
