The Ghost Orchid (Epipogium aphyllum) is a rare plant species which lacks leaves or chlorophyll. The plant has formed a symbiotic relationship with a fungus in order to obtain the nutrition it requires. The growth of the fungus is slowed as a result of the relationship.
Which of the following rows correctly describes E.aphyllum?
| Heterotroph | Autotroph | Parasite | Saprotroph | |
| A | ✓ | X | X | ✓ |
| B | X | ✓ | X | ✓ |
| C | ✓ | X | ✓ | ✓ |
| D | ✓ | X | ✓ | X |
Which of the following statements about inorganic nutrients are true?
I, II and IV
II and III
II, III and IV
II only
The graph shows changes in percentage cover of four plant species on a sand dune ecosystem over 500 years.
Which of the following explanations cannot be supported using the information in this graph.
All four species never formed part of the same community
Beech grass became extinct after 100 years
Interspecific competition between conifer trees and shrub bunchgrass occurs leading to a decrease in shrub bunchgrass
Intraspecific competition results in a decrease in conifer trees after around 400 years
A water quality investigation was carried out after some cases of heavy metal poisoning were detected in a countryside village with a river running through it. The investigators were trying to establish if poisoning was worse on the north or the south of the river.
| North of the river | South of the river | |
| Number of cases of heavy metal poisoning | 26 | 12 |
The results from a chi-squared test were:
| Chi-squared value: | 5.2 |
| Degrees of freedom: | 1 |
Critical values table:
| Degrees of Freedom | P = 0.05 | P = 0.01 | P = 0.001 |
| 1 | 3.83 | 6.64 | 10.83 |
| 2 | 5.99 | 9.21 | 13.82 |
| 3 | 7.82 | 11.35 | 16.27 |
What conclusions can be drawn from the information above?
The χ2 value is greater than the critical value so there is an association between heavy metal poisoning and location
The χ2 value is lower than the critical value so there is no association between heavy metal poisoning and location
Poisoning from heavy metals is worse in villages
Heavy metals are found in both locations, north and south of the river
Which row of the table correctly identifies an observation of food chains and the theory used to explain that observation?
| Observation | Theory | |
| I | Food chains are short | Energy losses occur at each trophic level |
| II | Food chains have a pyramid structure | Organisms with a larger biomass provide more energy to the next trophic level |
| III | Food chains all start with a producer | Producers transfer energy most efficiently |
| IV | Energy losses occur at each trophic level | Energy is transferred to the surroundings during respiration |
I only
I and IV
II and IV
I and III
Which of the following is not true about mesocosms?
Mesocosms allow the control of environmental conditions
Mesocosms allow collection of reliable data
Continuous data can be collected from a mesocosm
It is easy to mimic natural environmental conditions in a mesocosm
