ZOL2601 ASSIGNMENT 2 – SEMESTER 1 2026
COMPLETE ANSWERS – DISTINCTION GUARANTEED
Evolution Theory / Animal Physiology
Detail Information
Module Code ZOL2601
Assignment 02
Semester 1 2026
,ASSIGNMENT QUESTIONS
Question 1 [8 marks]
Various factors influence the amount of gas that can dissolve in water. Name and briefly
describe the direction of influence of the four main such factors discussed in the
learning material.
Question 2 [6 marks]
Describe the role of skin in respiration.
Question 3 [8 marks]
Draw a fully labelled diagram (that you draw yourself) illustrating differences in oxygen
dissociation curves of blood of mammals of various sizes. Explain the differences.
Question 4 [12 marks]
4.1. Use Henry's Law to calculate the quantity of oxygen in a large bucket of fresh water
(volume of 200 l) at two different altitudes, namely 100 metres and 2,500 metres above
sea level (m.a.s.l). Assume the partial pressure of O₂ at 100 metres m.a.s.l. to be 157
mmHg and at 2,500 m.a.s.l. to be 117 mmHg respectively and a temperature of 15°C
for both scenarios. (8)
4.2. How long will it take a rainbow trout (Oncorhynchus mykiss) of 600g to consume all
the oxygen in the bucket for each of the scenarios, if it consumes oxygen at a rate of
100 ml/kg of fish per hour? Assume the amount of oxygen is not replenished during the
experiment. (4)
Question 5 [8 marks]
Discuss airflow through bird lungs, and the benefits of structural adaptations unique to
bird respiration. You may include a diagram to aid your discussion.
Question 6 [8 marks]
Make use of a simple, annotated line diagram that you draw yourself to (1) illustrate the
E. Newton Harvey principle.
Question 7 [5 marks]
[Question text not visible in search results - complete based on standard curriculum]
, COMPREHENSIVE ANSWERS
QUESTION 1: Factors Affecting Gas Solubility in Water [8 marks]
Various factors influence the amount of gas that can dissolve in water. Name and
briefly describe the direction of influence of the four main such factors discussed
in the learning material.
Direction of
Factor Explanation
Influence
Gases with stronger intermolecular forces with water molecu
1. Nature of the Varies by gas are more soluble. For example, carbon dioxide is more solub
gas and solvent type in water than helium because it can form hydrogen bonds w
water molecules .
Gases are generally more soluble in cold water than in ho
water. As temperature decreases, the kinetic energy of gas
Inverse
2. Temperature molecules decreases, making them less likely to escape from
relationship
the solution. For example, oxygen is more soluble in cold wa
which is why aquatic life is more abundant in colder regions
Gases are more soluble in water when the partial pressure
3. Pressure of the gas is higher. Higher pressure forces more gas molecu
Direct
the gas above into the solution, creating a dynamic equilibrium between
relationship
the solution dissolved and undissolved gas. This relationship is quantifie
by Henry's Law .
4. Presence of Inverse Some solutes can affect gas solubility by changing chemica
other solutes relationship equilibrium or physical properties. Adding salt to water lowe
oxygen solubility because it reduces the amount of water
COMPLETE ANSWERS – DISTINCTION GUARANTEED
Evolution Theory / Animal Physiology
Detail Information
Module Code ZOL2601
Assignment 02
Semester 1 2026
,ASSIGNMENT QUESTIONS
Question 1 [8 marks]
Various factors influence the amount of gas that can dissolve in water. Name and briefly
describe the direction of influence of the four main such factors discussed in the
learning material.
Question 2 [6 marks]
Describe the role of skin in respiration.
Question 3 [8 marks]
Draw a fully labelled diagram (that you draw yourself) illustrating differences in oxygen
dissociation curves of blood of mammals of various sizes. Explain the differences.
Question 4 [12 marks]
4.1. Use Henry's Law to calculate the quantity of oxygen in a large bucket of fresh water
(volume of 200 l) at two different altitudes, namely 100 metres and 2,500 metres above
sea level (m.a.s.l). Assume the partial pressure of O₂ at 100 metres m.a.s.l. to be 157
mmHg and at 2,500 m.a.s.l. to be 117 mmHg respectively and a temperature of 15°C
for both scenarios. (8)
4.2. How long will it take a rainbow trout (Oncorhynchus mykiss) of 600g to consume all
the oxygen in the bucket for each of the scenarios, if it consumes oxygen at a rate of
100 ml/kg of fish per hour? Assume the amount of oxygen is not replenished during the
experiment. (4)
Question 5 [8 marks]
Discuss airflow through bird lungs, and the benefits of structural adaptations unique to
bird respiration. You may include a diagram to aid your discussion.
Question 6 [8 marks]
Make use of a simple, annotated line diagram that you draw yourself to (1) illustrate the
E. Newton Harvey principle.
Question 7 [5 marks]
[Question text not visible in search results - complete based on standard curriculum]
, COMPREHENSIVE ANSWERS
QUESTION 1: Factors Affecting Gas Solubility in Water [8 marks]
Various factors influence the amount of gas that can dissolve in water. Name and
briefly describe the direction of influence of the four main such factors discussed
in the learning material.
Direction of
Factor Explanation
Influence
Gases with stronger intermolecular forces with water molecu
1. Nature of the Varies by gas are more soluble. For example, carbon dioxide is more solub
gas and solvent type in water than helium because it can form hydrogen bonds w
water molecules .
Gases are generally more soluble in cold water than in ho
water. As temperature decreases, the kinetic energy of gas
Inverse
2. Temperature molecules decreases, making them less likely to escape from
relationship
the solution. For example, oxygen is more soluble in cold wa
which is why aquatic life is more abundant in colder regions
Gases are more soluble in water when the partial pressure
3. Pressure of the gas is higher. Higher pressure forces more gas molecu
Direct
the gas above into the solution, creating a dynamic equilibrium between
relationship
the solution dissolved and undissolved gas. This relationship is quantifie
by Henry's Law .
4. Presence of Inverse Some solutes can affect gas solubility by changing chemica
other solutes relationship equilibrium or physical properties. Adding salt to water lowe
oxygen solubility because it reduces the amount of water
