Reproduction in Humans

(a) Fertilization → Implantation → Gestation → Birth

(b) Testis → Epididymis → Sperm duct → Urethra

Both A and R are true.

Explanation — Humans can live without reproducing in their own lifetime. However, it helps in the continuation of species on earth, generation after generation.

A is false and R is true.

Explanation — Budding occurs in both plants and animals. Both yeast (a fungus) and Hydra (an animal) reproduce by budding.

Both A and R are true.

Explanation — Only one egg is produced by an ovary alternatively every month.

A is false and R is true.

Explanation — Sperms are produced in testes and transported to urethra through the sperm ducts in males.

A is true and R is false.

Explanation — Growth means any type of irreversible increase in the size and weight of an individual during the process of development.

(a) Odd term: Uterus
Category: Male reproductive parts

(b) Odd term: Seminal vesicle
Category: Female reproductive parts

(c) Odd term: Vagina
Category: Male accessory glands

(d) Odd term: Bacteria
Category: Eukaryotic organisms

Testes → Sperm duct → Urethra

(a) The parts are:

• 1 → Ovary
• 2 → Fallopian tube
• 3 → Uterus
• 4 → Vagina

(b) Fallopian tubes (also called Oviduct)

Labelled diagrams of a sperm and ovum are shown below:

Sperm

Ovum

(a) A sperm and an ovum are unicellular.

(b) In males, the testes produce male gametes (sperms), and in females, the ovaries produce female gametes (eggs).

(c) Fertilisation.

(d) The fusion of male and female gametes in humans takes place in the fallopian tube.

(e) Zygote is formed by the fusion of the sperm and ovum.

• 1 → Seminal vesicle — Produce a secretion which serves as a medium for the transportation of the sperms.
• 2 → Prostate gland — Pours an alkaline secretion into the semen as it passes through the urethra.
• 3 → Testes — To produce and store sperms and to secrete the male reproductive hormone Testosterone.
• 4 → Urethra — Carries either Urine or Semen.
• 5 → Sperm duct — Carries the sperms from the Epididymis to the Urethra.

Labelled diagram showing the reproduction in amoeba is shown below:

(a) Reproduction in amoeba is asexual.

(b) Amoeba reproduces by binary fission.

(c) Two offsprings are produced from one division.

(d) During the reproduction in amoeba, the type of cell division that occurs is mitosis.

(e) E. coli also reproduces by binary fission.

Labelled diagram of the human female reproductive system is shown below:

(a) Ovary

(b) Vagina

(c) Uterus

(d) Fallopian tube

(e) Cervix

(a) Budding is a form of asexual reproduction in which a protuberance of cell grows from the parent body to form an independent individual.

(b) Budding is an asexual mode of reproduction.

(c) Budding is seen in Hydra and yeast.

(d) Below labelled diagram shown the process of budding in Hydra:

(e) The specific locomotory structures of Hydra, which reproduces by budding, are its tentacles.

Scrotum

Reason — Sperms are produced in the testes. A pair of testes lie outside the abdominal cavity in a sac called the scrotum.

Binary Fission

Reason — Binary fission is the most common method of reproduction in single-celled organisms. In Amoeba, it results in the division of the parent amoeba into two daughter amoeba.

Zygote

Reason — A zygote is a fertilised egg. The zygote is formed when the male gamete (sperm) and female gamete (egg) fuse. It's created when sperm meets an egg in one of the fallopian tubes. The zygote grows by cell division and produces an embryo.

Vagina

Reason — The uterus is a hollow, inverted pear shaped muscular organ which opens to the outside through a long, muscular tube called the vagina, situated between the rectum and the urethra.

Only 2

Reason — The foetus is the developmental stage where the body structures and organs are well-formed, and it starts resembling the parent. Gametes, zygote, and embryo do not resemble the parent in appearance.

Gestation period in humans is 820 days.

Reason — Gestation period in humans is 280 days.

The fusion of the male gamete (sperm) and the female gamete (ovum) to form a zygote is called fertilisation.

The process of fixing of the fertilized egg (embryo) to the wall of the uterus is termed implantation.

Difference between Egg and Sperms:

Difference between Sexual Reproduction and Asexual reproduction

Difference between Budding and Regeneration

Testes lie outside the body because the normal body temperature does not allow the maturation of the sperms. In such an arrangement, the testes are at a temperature which is 2-3°C lower than that of the body. This is the most suitable temperature for sperm production and development.

Semen contains a very large number of sperms because out of the millions of sperms released into the vagina, only a few of them are able to reach up to the upper parts of the oviducts. Some die on the way and are absorbed. Only a few of them reach the ovum. Thus, to increase the chances of fertilisation, a very large number of sperms should be present in the semen.

(a) Ovary — The ovaries have two main reproductive functions in the body. They produce eggs and secrete the reproductive hormones, Oestrogen and Progesterone.

(b) Testes — The two main functions of Testes are to produce and store sperms and to secrete the male reproductive hormone Testosterone.

(c) Fallopian Tubes — Fallopian Tubes transfer the egg from the ovaries to the uterus.

(d) Seminal vesicles — They produce a secretion which serves as a medium for the transportation of the sperms.

(e) Uterus — The embryo grows and develops in the Uterus.