Life Sciences Grade 12 Term 3 Assignment Evolution Questions and Answers:
This section provides comprehensive questions and answers for the Life Sciences Grade 12 Term 3 Assignment. The topics covered include:
- The Code of Life
- Meiosis
- Reproduction
- Genetics
- Responding to the Environment: Humans
- Endocrine System and Homeostasis
- Response to the Environment: Plants
- Evolution
Life Sciences Grade 12 Term 3 Assignment Memorandum 2024
Below you will find the 2024 Life Sciences Grade 12 Term 3 Assignment questions and the answer guide (just to give learners direction):
Questions and answers:
Seahorses: Unique Reproductive Strategy
Scenario:
Seahorses are fascinating creatures where the male undergoes pregnancy and gives birth to young seahorses. The male seahorse has a pouch on its stomach where the eggs, deposited by the female, are fertilised and cared for until they hatch. The male provides oxygen and nutrients to the developing embryos through the pouch, a role analogous to the placenta in humans.
3What type of fertilisation does the seahorse have? (1)
Answer: The seahorse exhibits internal fertilisation.
Explanation: This means that the fertilisation of the eggs occurs within the male seahorse’s body. After the female deposits her eggs into the male’s pouch, the sperm from the male fertilises the eggs inside this pouch, rather than outside in the external environment.
Explain your answer to QUESTION 3.1. (1)
Answer: The seahorse undergoes internal fertilisation because the eggs are directly deposited into the male’s pouch by the female, where the sperm fertilises them within the male’s body.
Elaboration: Unlike external fertilisation, where eggs and sperm meet outside the body (as seen in many aquatic species like fish), seahorses have a specialised reproductive strategy. The female seahorse transfers her eggs directly into the male’s brood pouch. This internal environment provides protection and optimal conditions for the fertilisation process, ensuring that the sperm effectively fertilises the eggs within the secure confines of the pouch.
Why is the seahorse reproductive strategy considered to be ovovivipary? (2)
Answer: The seahorse’s reproductive strategy is classified as ovovivipary because the embryos develop inside eggs that remain within the male’s pouch until they hatch, with the young being born live.
Elaboration: Ovoviviparous organisms are those where the embryos develop inside eggs that stay within the parent’s body until they are ready to hatch. In the case of seahorses, the male carries the eggs in his pouch, where they are fertilised and develop into embryos. During their development, the embryos receive nutrients and oxygen through the walls of the pouch, similar to how a placenta functions in mammals, although the actual nourishment comes from the egg yolk rather than directly from the male. Once the embryos are fully developed, they hatch inside the pouch, and the male gives birth to live young, making this process a clear example of ovoviviparity.