Review the key concepts, formulae, and examples before starting your quiz.
🔑Concepts
Sexual reproduction is a biological process that involves the fusion of male and female gametes to produce a new individual, ensuring genetic variation.
The male reproductive organs include a pair of testes, two sperm ducts, and a penis. The testes produce the male gametes called sperms, which are single-celled and have a head, middle piece, and a tail for movement.
The female reproductive organs consist of a pair of ovaries, oviducts (fallopian tubes), and the uterus. Ovaries produce the female gamete called the ovum (egg).
Fertilization is the process of the fusion of the sperm nucleus with the egg nucleus. This results in the formation of a single-celled .
Internal fertilization occurs inside the female body (e.g., humans, cows, hens), while external fertilization occurs outside the female body, usually in water (e.g., frogs, fish).
The divides repeatedly to form an . The embryo gets embedded in the wall of the uterus for further development.
The stage of the embryo in which all the body parts can be identified is called the .
Animals are categorized as (give birth to young ones directly) or (lay eggs).
Metamorphosis is the transformation of the larva into an adult through drastic changes (e.g., ).
📐Formulae
💡Examples
Problem 1:
During an experiment, a student observes that a single cell divides into two, then four, then eight cells. If the division occurs every minutes, how many cells will be present after minutes starting from a single ?
Solution:
After minutes, there will be cells.
Explanation:
The undergoes mitotic division. The number of cells follows the geometric progression , where is the number of division cycles. At , cells ; at , cells ; at , cells ; and at , cells .
Problem 2:
Differentiate between the number of eggs produced in internal vs. external fertilization.
Solution:
External Fertilization Internal Fertilization.
Explanation:
In external fertilization (like in frogs), hundreds of eggs are laid because the chances of fertilization and survival are low due to environmental factors and predators. In internal fertilization, usually one or few eggs are produced as the environment is protected.