Reproduction, Genes and Asexual Reproduction (13.5 intro, 13.5.1) — "Our Home: Earth, a Unique Life Sustaining Planet"

1. 13 marks

   Why does the chapter say reproduction is essential for the continuity of life?

   Hint. The consequence of NOT reproducing is stated directly and simply.

   ✦ 'If plants and animals didn't reproduce, life would eventually disappear from Earth. Reproduction ensures that each type of organism continues to exist, maintaining the continuity of life.' This is because, without reproduction, individual organisms would eventually die without being replaced, so every type of organism would go extinct over time.

2. 23 marks

   Explain what genes are, using the chapter's own 'instruction manual' comparison.

   Hint. The comparison describes genes as something stored inside a very specific location.

   ✦ Genes, or genetic material, are stored inside every cell of a living being, and the chapter compares them to 'a detailed instruction manual inside each cell.' Some instructions tell the cell how to make blood, while others guide the formation of bones, muscles, or skin — since together, these instructions ensure that a calf grows into a cow, or a kitten grows into a cat, resembling its parents.

3. 33 marks

   Beyond simply producing more of the same kind of organism, what else does reproduction make possible, according to the chapter, and what two examples does it give?

   Hint. Small changes passed between generations can eventually change what a species is capable of surviving.

   ✦ Reproduction also allows for small changes in the instructions passed down from parents to offspring, which can sometimes help a plant or animal survive better in a new environment. The chapter's examples: camels developed humps over time to store fat and survive in deserts, and some bacteria have become resistant to antibiotics, since that resistance helps them persist despite treatment designed to kill them.

4. 43 marks

   Explain the fundamental difference between asexual and sexual reproduction, in terms of how many parents are involved and what the offspring look like.

   Hint. One process needs only one parent and produces exact copies; the other needs two and produces a mix.

   ✦ In asexual reproduction, a single parent produces new individuals that are exact copies of itself, in terms of the instructions inside the cell. In sexual reproduction, instructions from two parents combine to create offspring that are not exactly like either parent — offspring share some traits with both parents, but also have differences, since this mixing helps keep useful features while allowing new ones to appear.

5. 52 marks

   Define vegetative propagation, and name the three types of plant part the chapter uses as examples in Activity 13.3.

   Hint. The activity uses three different parts of a plant, each demonstrated with a different everyday example.

   ✦ Vegetative propagation is a kind of asexual reproduction in which any part of a plant — leaf, stem, or root — is planted in soil and can grow into a new plant. Activity 13.3's examples work since each one is a plant part — a stem cutting of a money plant, the 'eyes' of a sprouted potato, and a piece of ginger — capable of growing roots and shoots on its own.

6. 63 marks

   Ever heard of... name three organisms besides plants that reproduce asexually, and describe HOW each one does it.

   Hint. Each organism uses a genuinely different asexual method — division, fragmentation, or budding.

   ✦ Any three of: bacteria and amoebae, single-celled organisms that divide into two identical individuals; algae, multicellular organisms that can regrow from small cut parts; Hydra, a simple animal that grows tiny buds on its body that break off and grow into new individuals; or Planaria, a flatworm that can regrow from just a small fragment of its body, which is why scientists study it to understand regeneration in animals.

7. 72 marks

   Why might a student wonder how bamboo and sugarcane grow into new plants despite never seeing their seeds?

   Hint. The chapter poses this exact question as a lead-in to a concept covered earlier in this same section.

   ✦ Bamboo and sugarcane, like the money plant, potato and ginger in Activity 13.3, can reproduce through vegetative propagation — growing new plants from parts like stem cuttings — rather than only through seeds, which is why a student might never observe their seeds even though the plants clearly keep spreading and multiplying.

Solutions written by the tuition.in editorial team and checked against NCERT Curiosity — Textbook of Science for Grade 8, Chapter 13 (hecu113.pdf), Reprint 2026-27, pages 210-228. Questions are referenced from the NCERT textbook for identification.