Grade 12 Life Sciences: Term 2 Study Guide (Paper 1)
This guide focuses on the core themes of the CAPS curriculum for Term 2:
Reproduction in Vertebrates, Human Reproduction, and Responding to the
Environment (Humans).
1. Reproduction in Vertebrates
Evolutionary trends in reproduction ensure a higher survival rate of offspring in different
environments.
Key Concepts
• Fertilisation: Can be External fertilisation (outside the body, usually in water)
or Internal fertilisation (inside the female body).
• Developmental Strategies:
o Ovipary: Eggs are laid outside the body (e.g., birds).
o Ovovivipary: Eggs hatch inside the body; young are born live but
nourished by egg yolk (e.g., some sharks/snakes).
o Vivipary: Young develop inside the uterus and are nourished via a
placenta (e.g., humans).
• Amniotic Egg: Contains membranes (amnion, chorion, allantois, yolk sac) to
protect the embryo from desiccation on land.
• Precocial vs. Altricial: Precocial young are mobile and independent at birth;
Altricial young are helpless and require parental care.
Practice Problem 1 An organism produces a small number of eggs. The embryos
develop inside the mother’s uterus, receiving nutrients from her blood. 1.1 Identify the
reproductive strategy described. 1.2 Explain one advantage of this strategy for survival.
Solution 1 1.1 Vivipary 1.2 Development occurs inside the mother’s body, providing
maximum protection from predators and environmental fluctuations (e.g., temperature).
This increases the chances of offspring survival despite the low number of eggs.
2. Human Reproduction
This section covers the anatomy and the hormonal control of the Menstrual Cycle.
This guide focuses on the core themes of the CAPS curriculum for Term 2:
Reproduction in Vertebrates, Human Reproduction, and Responding to the
Environment (Humans).
1. Reproduction in Vertebrates
Evolutionary trends in reproduction ensure a higher survival rate of offspring in different
environments.
Key Concepts
• Fertilisation: Can be External fertilisation (outside the body, usually in water)
or Internal fertilisation (inside the female body).
• Developmental Strategies:
o Ovipary: Eggs are laid outside the body (e.g., birds).
o Ovovivipary: Eggs hatch inside the body; young are born live but
nourished by egg yolk (e.g., some sharks/snakes).
o Vivipary: Young develop inside the uterus and are nourished via a
placenta (e.g., humans).
• Amniotic Egg: Contains membranes (amnion, chorion, allantois, yolk sac) to
protect the embryo from desiccation on land.
• Precocial vs. Altricial: Precocial young are mobile and independent at birth;
Altricial young are helpless and require parental care.
Practice Problem 1 An organism produces a small number of eggs. The embryos
develop inside the mother’s uterus, receiving nutrients from her blood. 1.1 Identify the
reproductive strategy described. 1.2 Explain one advantage of this strategy for survival.
Solution 1 1.1 Vivipary 1.2 Development occurs inside the mother’s body, providing
maximum protection from predators and environmental fluctuations (e.g., temperature).
This increases the chances of offspring survival despite the low number of eggs.
2. Human Reproduction
This section covers the anatomy and the hormonal control of the Menstrual Cycle.
