What are the advantages of sexual reproduction over asexual reproduction?
Reproduction is a process to produce a young one similar to their parents genetically or morphologically. There are two modes of reproduction:- asexual or sexual reproduction.
Sexual reproduction is the process of forming a diploid cell zygote from one haploid male gamete or one haploid female gamete. In this two parents are involved, and when a offspring is formed than variation occurs and variation is the key factor of the evolution. If there is no variation, population cannot respond to the changing environment and may face an risk of being extinct from the environment.
Asexual reproduction is the process of making two or more daughter cells from one parent cell, i.e, only one parent is involved. So, there is no variation occurs as in sexual reproduction occurs. It is dynamic, static where no evolution occurs in their morphological characters, where each offspring is genetically or morphologically identical to each other.
The long term survival period happens in sexual reproduction than asexual because of the variation. When genetic variation occurs, it helps the organism to survive in the drastic environmental changes.
Why is variation beneficial to the species but not necessarily for the individual?
Draw a labelled diagram of the longitudinal section of a flower.
What are the functions performed by the testis in human beings?
Why does menstruation occur?
How will an organism be benefited if it reproduces through spores?
Can you think of reasons why more complex organisms cannot give rise to new individuals through regeneration?
Asexual reproduction takes place through budding in
(a) amoeba.
(b) yeast.
(c) plasmodium.
(d) leishmania.
How does the embryo get nourishment inside the mother’s body?
What is the importance of DNA copying in reproduction?
How does reproduction help in providing stability to populations of species?
Did Döbereiner’s triads also exist in the columns of Newlands’ Octaves? Compare and find out.
What is a good source of energy?
Why is diffusion insufficient to meet the oxygen requirements of multi-cellular organisms like humans?
What are trophic levels? Give an example of a food chain and state the different trophic levels in it.
What changes can you make in your habits to become more environment-friendly?
What is the difference between a reflex action and walking?
If a trait A exists in 10% of a population of an asexually reproducing species and a trait B exists in 60% of the same population, which trait is likely to have arisen earlier?
Why should a magnesium ribbon be cleared before burning in air?
Define the principal focus of a concave mirror.
You have been provided with three test tubes. One of them contains distilled water and the other two contain an acidic solution and a basic solution, respectively. If you are given only red litmus paper, how will you identify the contents of each test tube?
Describe the structure and functioning of nephrons.
How is the amount of urine produced regulated?
The device used for producing electric current is called a
(a) generator.
(b) galvanometer.
(c) ammeter.
(d) motor.
How has the traditional use of wind and water energy been modified for our convenience?
Which gas is produced when dilute hydrochloric acid is added to a reactive metal? Write the chemical reaction when iron reacts with dilute H2SO4.
The change in focal length of an eye lens is caused by the action of the
(a) pupil. (b) retina.
(c) ciliary muscles. (d) iris.
Translate the following statements into chemical equations and then balance them.
(a) Hydrogen gas combines with nitrogen to form ammonia.
(b) Hydrogen sulphide gas burns in air to give water and sulpur dioxide.
(c) Barium chloride reacts with aluminium sulphate to give aluminium chloride and a precipitate of barium sulphate.
(d) Potassium metal reacts with water to give potassium hydroxide and hydrogen gas.
Write the balanced equation for the following chemical reactions.
1. Hydrogen + Chlorine → Hydrogen chloride
2. Barium chloride + Aluminium sulphate → Barium sulphate + Aluminium chloride
3. Sodium + Water → Sodium hydroxide + Hydrogen
The phenomenon of electromagnetic induction is
(a) the process of charging a body.
(b) the process of generating magnetic field due to a current passing through a coil.
(c) producing induced current in a coil due to relative motion between a magnet and the coil.
(d) the process of rotating a coil of an electric motor.
Two conducting wires of the same material and of equal lengths and equal diameters are first connected in series and then parallel in a circuit across the same potential difference. The ratio of heat produced in series and parallel combinations would be –
(a) 1:2 (b) 2:1 (c) 1:4 (d) 4:1