How do Organisms Reproduce?
This chapter explains why reproduction is essential for the continuation of species, and covers both asexual reproduction (in simple organisms) and sexual reproduction, including the human reproductive system.
Reproduction is the biological process by which living organisms produce new individuals of their own kind, ensuring continuity of the species across generations, even though it is not essential for an individual organism's own survival.
Asexual reproduction involves a single parent and includes: fission (e.g. Amoeba splitting into two), budding (e.g. Hydra and yeast), fragmentation (e.g. Spirogyra), regeneration (e.g. Planaria), and vegetative propagation (e.g. potato, rose cuttings) in plants.
Q. Why is variation beneficial for a species, but harmful mutations can also occur?
Variation created during reproduction increases the chance that at least some individuals will survive drastic environmental changes, aiding the survival of the species. However, sexual reproduction also allows more variation, which includes occasional harmful changes, though these are usually eliminated by natural selection over generations.
In human females, one egg matures and is released from the ovary every month, a process called ovulation. If the egg is not fertilised, it along with the thickened uterine lining is shed as menstruation.
Q. What are the functions of the male reproductive system?
The testes produce sperm and the hormone testosterone, which brings about changes during puberty. Sperm travel through the vas deferens, mix with secretions from glands to form semen, and are delivered through the urethra during copulation.
Which part of the flower develops into the fruit after fertilisation?
Correct answer: (C) Ovary
The fusion of a male gamete and a female gamete is called _______.
Fertilisation
All methods of contraception also prevent sexually transmitted diseases.
False — only barrier methods like condoms help prevent the spread of sexually transmitted diseases (STDs) in addition to preventing pregnancy; other methods like oral pills or IUDs prevent pregnancy but do not protect against STDs.