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Give the basic features of the mechanism of inheritance.

The basic features of inheritance are (i) Characters are controlled by genes. (ii) Each gene controls one character. (iii) There may be two or... View Article

Evolution has exhibited a greater stability of molecular structure when compared with morphological structures. Comment on the statement and justify your opinion.

Morphological structures are nothing but the structure which are apparent to our eyes.They are those biomolecules which are the integral... View Article

Give reasons why acquired characters are not inherited.

Acquired characters do not produce change in the DNA of germ cells, so they cannot be inherited. Only those characters which have a gene for them... View Article

Differentiate between inherited and acquired characters. Give one example for each type.

An acquired trait is the character developed in an individual as a result of environmental influence. Inherited traits that are inherited from... View Article

All the human races like Africans, Asians, Europeans, Americans and others might have evolved from a common ancestor. Provide a few evidences in support of this view.

All human beings have emerged from a common ancestor as they have the maximum number of common characters. All humans are a single species... View Article

Bacteria have a simpler body plan when compared with human beings. Does it mean that human beings are more evolved than bacteria? Provide a suitable explanation.

It depends on the way we evaluate evolution. If the complexity of the body is a parameter then Human are far superior to bacteria. Bacteria have... View Article

Does geographical isolation of individuals of a species lead to the formation of a new species? Provide a suitable explanation.

Yes, geographical isolation of individuals of a species does lead to formation of new species. Example: Building of dams in along rivers isolates... View Article

A woman has only daughters. Analyse the situation genetically and provide a suitable explanation.

Women have two X chromosomes and men have one X and one Y chromosome. Hence a female produces gametes which are all of the same kind and only... View Article

Give the pair of contrasting traits of the following characters in pea plant and mention which is dominant and recessive (i) yellow seed (ii) round seed

(a) Yellow - Dominant, Green - Recessive (b) Round - Dominant, Wrinkled - Recessive Dominant traits are always expressed when the connected... View Article

Does the occurrence of the diversity of animals on earth suggest their diverse ancestry also? Discuss this point in the light of evolution.

Inspite of the fact that animals have different variety of structures they don not have common ancestry. This is because common ancestry may... View Article

What are homologous structures? Give an example. Is it necessary that homologous structures always have a common ancestor?

Homologous structures are comparable in two organisms which have the same ancestors, but the functions displayed may or may not be the same. For... View Article

A very small population of a species faces a greater threat of extinction than a larger population. Provide a suitable genetic explanation.

A very small population of a species faces a greater threat of extinction than a larger population. Smaller population faces more random... View Article

In human beings, the statistical probability of getting either a male or female child is 50 : 50. Give a suitable explanation.

The sex of an infant is determined by the type of sex chromosome contributed by the male gamete. The ratio of male gamete containing x chromosome... View Article

Why do all the gametes formed in human females have an X chromosome?

Human females have two X chromosomes called sex chromosomes. During meiosis at the time of gamete formation, one X chromosome enters each gamete.... View Article

Mention three important features of fossils which help in the study of evolution.

Fossils are the remains or traces of ancient life that have been preserved by natural processes. Examples of fossil include shells, bones, stone... View Article

Do genetic combination of mothers play a significant role in determining the sex of a newborn?

No. Sex of a newborn will be determined by the chromosome donated by the father. The sex of an individual depends on the combination of sex... View Article

Some dinosaurs had feathers although they could not fly but birds have feathers that help them to fly. In the context of evolution, this means that (a) reptiles have evolved from birds (b) there is no evolutionary connection between reptiles and birds (c) feathers are homologous structures in both the organisms (d) birds have evolved from reptiles

d) Birds have evolved from reptiles Dinosaurs were reptiles, belonging to the class Reptilia, whilst birds belong to their own class, Aves.... View Article

The theory of evolution of species by natural selection was given by (a) Mendel (b) Darwin (c) Morgan (d) Lamarck

b) Darwin According to Charles Darwin, evolution is a very slow and gradual process. He concluded that evolution took place over a very long... View Article

The number of pair (s) of sex chromosomes in the zygote of humans is (a) one (b) two (c) three (d) four

a) One Chromosomes are a thread-like structure holding genetic information. It is present in the cell nuclei. A normal cell contains 23 pairs... View Article

In peas, a pure tall plant (TT) is crossed with a short plant (tt). The ratio of pure tall plants to short plants in F2 is (a) 1 : 3 (b) 3: 1 (c) 1: 1 (d) 2: 1

c) 1:1 Explanation The parents are homozygous tall (TT) and dwarf (tt), the progeny of the F1 generation will be hybrids (Tt). In the... View Article

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