Reproduction: How Life Continues

In a china-rose (hibiscus or gudhal) plant, a pollen tube grows and continues through the style after pollen lands on the stigma. Which process is about to happen next?

A farmer plants two varieties of maize side by side, but notices that seeds form only when pollen from one variety reaches the stigma of the other. What type of pollination is this?

What determines a baby’s biological sex? So far, you have learnt that every person has two sex chromosomes. Females have XX and males have XY chromosomes. The mother always contributes an X chromosome to a baby and the father contributes either an X (Female: XX) or a Y (Male: XY) chromosome. Now, from the above information, can you predict who determines the sex of a baby?

Ravi suddenly notices that he is growing taller rapidly, his shoulders are broadening, and his voice cracks. What stage of life is he entering?

Rina’s period occurs every 28 days. Her last period was on the 5th of March. On which day is she most likely to get her next period?

A human zygote has just formed. How many chromosomes does it have?

In many animals, the young ones can walk or find food soon after birth but human babies are completely dependent for a long time. What might be some advantages and disadvantages of this for humans as a species?

A flower’s anthers are removed before it matures. Later, pollen from another plant of the same species is dusted onto its stigma and seeds are produced. Which process has been ensured here?

Arrange the following stages of sexual reproduction in plants in the correct order: (i) Pollen germination on stigma (ii) Fertilisation (iii) Pollination (iv) Formation of zygote

Why does asexual reproduction produce offspring that are genetically identical to the parent?

Explain why the menstrual cycle stops during pregnancy.

Why are flowers that bloom at night white or light in colour as compared to flowers that bloom during the day?

Why do vegetatively propagated plants tend to be more vulnerable to diseases than sexually reproduced plants?

If all flowers in a type of plant were only capable of self-pollination, how would it affect the genetic diversity over several generations? Explain.

A farmer wants to produce a large number of genetically identical plants quickly. Suggest suitable reproduction methods and explain why they are effective.

Suresh prepares slides with pollen grains in different sugar concentrations (0%, 2.5%, 5%, 7.5%, 10%) to study the germination of pollen.

A student claims, “In humans, ovulation always happens on day 14 of the menstrual cycle”. Critically examine this claim and state whether the claim is correct or not. Give at least two reasons for your answer.

Read about the ‘Seed Village Programme’ (Beej Gram Yojana) run by the Government of India. Why is it important to save indigenous seeds?

Prepare a report on IVF, its uses and drawbacks. Discuss it with your class.

Conduct a survey on crop fields. Interact with farmers on the crops grown on their farms and farm animals based on the following points —