4. Talk to a doctor. Find out how twinning occurs. Look for any twins in your neighbourhood, or among your friends. Find out if the twins are identical or non-identical. Also find out why identical twins are always of the same sex? If you know of any story about twins, write it in your own words.
Answer:
After talking to a doctor in my neighbourhood I learnt that twinning occurs through two different processes and results in two types of twins: identical (monozygotic) and non-identical (dizygotic).
Identical Twins: Identical twins result when a single fertilized egg that splits into two embryos. This happens in the early stages of the development process, usually within the first few days of fertilisation. Identical twins come from the same egg and hence are of the same sex.
Non-identical Twins: Non-identical twins result from the fertilization of two separate eggs by two different sperm cells. Therefore, they are akin to siblings born at different times and can be of the same or different sex.
I know of a pair of twins in my neighbourhood. They are non-identical and of the opposite sex.
Identical twins are always of the same sex because the sex depends on the chromosomes contributed by the parents. Identical twins have the same set of chromosomes because both embryos result from the same fertilised egg. Hence, they are of the same sex.
I can tell you a funny story about twins. In my brother’s college there were a pair of identical twins. They were indistinguishable and often mistaken for the other person. One day there was an exam and one of the brothers was not prepared. He still did his best and passed the exam. Meanwhile unknown to him, the other brother also had an exam and it so happens that he passed with the exact same score. Identical twins and identical scores! What a coincidence!
“Talk to a doctor. Find out how twinning occurs. Look for any twins in your neighbourhood, or among your friends. Find out if the twins are identical or non-identical. Also find out why identical twins are always of the same sex? If you know of any story about twins, write it in your own words.” – Solved.
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Solution to Extended Learning Problem 1
Solution to Extended Learning Problem 2
Solution to Extended Learning Problem 3
Solution to Extended Learning Problem 4
Solution to Activity 6.1
Solution to Activity 6.2
Solution to Activity 6.3
Solutions to Chapter 6 Reproduction in Animals
