Question 3.1 [11 marks]
Question 3.1.1 [2 marks]
Which population-regulating factor is illustrated by this graph?
Answer: The graph likely illustrates the predator-prey relationship as a population-regulating factor.
Question 3.1.2 [2 marks]
Is this regulating factor named in question 3.1.1 a density-dependent or a density-independent factor? Give a reason for your answer.
Answer: This regulating factor is a density-dependent factor because its effects on population sizes are influenced by the population density; as the prey population increases, the number of predators also increases, affecting the prey population further.
Question 3.1.3 [2 marks]
Define the following terms:
(a) Prey
Answer: Prey refers to organisms that are hunted and eaten by predators as a food source.
(b) Predator
Answer: A predator is an organism that hunts, captures, and feeds on other organisms (prey) for sustenance.
Question 3.1.4 [2 marks]
Based on the organisms on the graph, which is considered a scavenger?
Answer: The scavenger would typically be a species that feeds on dead or decaying organisms. The specific organism can be identified based on the graph provided.
Question 3.1.5 [2 marks]
Will the prey population increase or decrease when there are few predators? Explain your answer.
Answer: The prey population will likely increase when there are few predators because reduced predation pressure allows more individuals to survive and reproduce, leading to growth in the prey population.
Question 3.1.6 [1 mark]
Identify the dependent variable in the above graph.
Answer: The dependent variable is typically the population size of the prey or predator, depending on what is being analyzed in the graph.
Question 3.2 [17 marks]
Question 3.2.1 [7 marks]
Tabulate two major differences between logistic and geometric growth forms. Include an example of a species representing each growth form.
| Characteristic | Logistic Growth | Geometric Growth | |--------------------------|----------------------------------------|-------------------------------------------| | Growth Rate | Slows down as it approaches carrying capacity | Consistent growth rate without limits | | Population Dynamics | S-shaped curve; stabilizes at carrying capacity | J-shaped curve; can overshoot capacity | | Example Species | Elephants (populations stabilize) | Bacteria (rapid growth under optimal conditions) |
Question 3.2.2 [1 mark]
Identify the growth form in the graph above.
Answer: The growth form in the graph is likely logistic growth.
Question 3.2.3 [4 marks]
Identify phases 1 to 4 in the above graph.
Answer:
- Phase 1: Lag Phase (slow growth as the population is establishing)
- Phase 2: Exponential Growth Phase (rapid population increase)
- Phase 3: Deceleration Phase (growth rate slows as resources become limited)
- Phase 4: Carrying Capacity Phase (population stabilizes around a maximum sustainable size)
Question 3.2.4 [1 mark]
Which phase is NOT shown in the graph above?
Answer: The death phase is not shown in the graph.
Question 3.2.5 [3 marks]
Identify the phase based on the explanation provided and write only the number (1-4).
a. Population rapidly increases.
Answer: 2
b. Population number increases slowly.
Answer: 1
c. Population stays the same.
Answer: 4
Question 3.2.6 [1 mark]
Define population density.
Answer: Population density is the number of individuals of a specific species per unit area or volume, often expressed as individuals per square kilometer or per liter of water.
Question 3.3 [9 marks]
Tabulate FOUR differences between food allergies and food intolerances.
| Aspect | Food Allergy | Food Intolerance | |-------------------|------------------------------------------------|------------------------------------------------| | Immune Response| Involves an immune system response (IgE antibodies) | Not immune-related; involves digestive system issues | | Symptoms | Can be severe, including anaphylaxis | Symptoms are generally milder (e.g., bloating, cramps) | | Onset | Symptoms may develop quickly after exposure | Symptoms often occur hours or days later | | Treatment | Avoidance of allergenic foods; medical intervention may be needed | Management through dietary changes; less severe treatment |
Question 3.4 [10 marks]
Question 3.4.1 [3 marks]
Describe how acid mine drainage forms.
Answer: Acid mine drainage forms when sulfide minerals in exposed rocks react with oxygen and water, producing sulfuric acid. This acidic water leaches metals and minerals from the surrounding soil and rock, leading to contamination of nearby water bodies.
Question 3.4.2 [2 marks]
Give TWO negative effects of acid mine drainage on the environment mentioned in the extract.
Answer:
- Contaminates drinking water.
- Disrupts the growth and reproduction of aquatic animals.
Question 3.4.3 [4 marks]
Explain why it is economically better to use slag to neutralise the acidic water than lime.
Answer: Using slag is more economically favorable than lime because slag is a waste product of mining, which means it is readily available and less expensive than lime, which must be mined. Additionally, using slag reduces the need for additional mining activities, thus minimizing the environmental impact while effectively neutralizing acidic water.
Question 3.4.4 [1 mark]
Give ONE other way mining affects the quality of water.
Answer: Mining can lead to sedimentation in water bodies, which can degrade water quality by increasing turbidity and disrupting aquatic ecosystems.
1 answer