Question 1
Write about different parts of the male reproductive system of human beings.
The male reproductive system of human beings consists of a pair of testes, sperm ducts, urethra, penis and accessory glands. Each of them is briefly described below:
- Testes — Testes are located outside the abdomen in a sac-like structure called scrotum. They are the primary reproductive organs of the male reproductive system. They produce the male gametes called sperms.
- Sperm Ducts — The sperms produced in the testes, travel through the sperm duct or vas deferens to reach the urethra.
- Accessory Glands — As the sperms pass through the sperm duct, secretions from the accessory glands are mixed with them. This mixture is called semen.
- Urethra — It is a tube through which urine and semen passes.
- Penis — Through penis, sperms are discharged and deposited into the vagina of the female body. In males, the penis is the organ used both for the discharge of the urine and the sperms.
Reproduction in Animals – Interactive Study Guide
Reproduction ensures the continuation of species. Animals reproduce sexually (fusion of gametes) or asexually (single parent, no gametes). This chapter also covers embryo development and cloning.
Sexual vs Asexual Reproduction
| Feature | Sexual | Asexual |
|---|---|---|
| Parents | Two (male + female) | One |
| Gametes | Required (sperm + egg) | Not required |
| Offspring | Genetically different (variation) | Genetically identical (clones) |
| Examples | Humans, frogs, birds | Amoeba, Hydra, yeast |
Fertilisation Types
Inside female body. Fewer eggs, better protection. Examples: humans, birds, dogs.
Outside body (in water). Many eggs, lower survival. Examples: frogs, fish, starfish.
Development Sequence
Zygote (1 cell) divides → Embryo (ball of cells, implants in uterus) → Foetus (recognisable body parts) → Birth (~9 months in humans)
Nutrition via placenta through umbilical cord.
Asexual Reproduction Types
- Budding: Bud grows from parent → detaches (Hydra, yeast)
- Binary fission: Parent splits into 2 equal parts (Amoeba, bacteria)
- Fragmentation: Body breaks into fragments, each grows (Planaria, starfish)
Cloning: Dolly the Sheep
First cloned mammal (1996). Ian Wilmut, Roslin Institute, Scotland. Nucleus from donor cell → enucleated egg → embryo → surrogate mother → Dolly (genetic copy of donor).
Self-Test Questions
- What is the difference between internal and external fertilisation?
- Differentiate between viviparous and oviparous animals with examples.
- Describe binary fission in Amoeba.
- What is IVF? Why is it called "test-tube baby"?
- How was Dolly the sheep cloned?