Biology

Heredity and Evolution

Question:

Define variation.

Answer:

Children do not resemble their parents completely. They possess characters obtained from both the parents. These changes in the phenotypic and genotypic characters are known as variations. Thus a given population of a species has indefinite variants.

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Heredity and Evolution

Q 1.

What is a gene?

Q 2.

A man having blood group O marries a woman having blood group B and they have a daughter. What will be the blood group of the daughter ?

Q 3.

Name the scientist who gave the theory of evolution.

Q 4.

Why are traits acquired during the lifetime of an individual not inherited ?

Q 5.

Who provided the evidence of DNA as the genetic material? Write the names of the components of the DNA molecule.

Q 6.

Describe briefly four ways in which individuals with a particular trait may increase in a population. [Foreign]

Q 7.

Which of the processes, sexual reproduction or asexual reproduction, brings about maximum variations in the offsprings ?

Q 8.

If the 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 ?

Q 9.

What type of plants were used by Mendel for conducting his experiments on inheritance ?

Q 10.

Gregor Mendel’s first law of genetics states “Of a pair of contrasted characters, only one can be represented in a gamete by its internal ‘factor’.
(a) Give the modern name for this ‘factor’.
(b) State where these factors are found in gametes.

Q 11.

(a) How do Mendel’s experiments show that traits may be dominant or recessive ?
(b) How do Mendel’s experiments show that traits are inherited independently ?

Q 12.

What are fossils ? Giving one example, explain how fossils provide evidence for evolution.

Q 13.

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

Q 14.

(a) Define ‘natural selection’.
(b) “Only variations that confer an advantage to an individual organism will survive in a population”. Do you agree with this statement ? Give reason for your answer.

Q 15.

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

Q 16.

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

Q 17.

Explain how sexual reproduction gives rise to more viable variations that asexual reproduction. How does this affect the evolution of those organisms that reproduce sexually ?

Q 18.

Define evolution. Describe the contribution of Lamarck.

Q 19.

State whether the following statement is true or false :
The sex of an infant is not a case of inheritance of characteristics.

Q 20.

Which of the following represent tall plants and which represent short plants (or dwarf plants) ?Which of the following represent tall plants and which represent short plants (or dwarf plants) ?
(a) Tt
(b) tt
(c) TT
Give reason for your choice (The symbols have their usual meaning).

Q 21.

In a human, how many chromosmes are present in :
(a) a brain cell ?
(b) a sperm in the testes ?
(c) an egg which has just been produced by the ovary ?
(d) a skin cell ?
(e) a fertilised egg ?

Q 22.

What name is given to the sequence of gradual changes over millions of years in which new species are produced ?

Q 23.

Write the names of at least three inorganic molecules which helped in the origin of life on the earth.

Q 24.

What evidence do we have for the origin of life from inanimate matter (lifeless matter) ?

Q 25.

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.

Q 26.

What are the different ways in which individuals with a particular trait may increase in a population ?

Q 27.

Can the wing of butterfly and the wing of a bat be considered homologous organs ? Why or why not ?

Q 28.

A study found that children with light-coloured eyes are likely to have parents with light-coloured eyes. On this basis, can we say anything about whether the light eye colour trait is dominant or recessive? Why or why not?

Q 29.

Explain the importance of fossils in deciding evolutionary relationships.

Q 30.

Name the plant on which Mendel performed his experiments.

Q 31.

What is a sex chromosome?

Q 32.

Define homologous organs.

Q 33.

Where are the genes located? What is the chemical nature of genes?

Q 34.

Define variation in relation to a species. Why is variation beneficial to the species? [Delhi]

Q 35.

What are fossils? What do they tell us about the process of evolution? [All India(C): All India 2011]

Q 36.

Distinguish between acquired and inherited traits by giving one example of each. Why are traits acquired during the lifetime of an individual not inherited? [Delhi(C)]

Q 37.

What constitutes the link between one generation and the next ?

Q 38.

Which of the two, sperm or ovum, decides the sex of the child ?

Q 39.

Name the famous book written by Charles Robert Darwin.

Q 40.

Name five varieties of vegetables which have been produced from ‘wild cabbage’ by the process of artificial selection.

Q 41.

What is meant by acquired and inherited traits ? Explain with one example each.

Q 42.

With the help of an example, explain how variation leads to evolution.

Q 43.

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

Q 44.

A man with blood group A marries a woman with blood O and their daughter has blood group O. Is this information enough to tell you which of the traits  blood group A or O is dominant ? Why or why not ?

Q 45.

Why are the small numbers of surviving tigers a cause of worry from the point of view of genetics ?

Q 46.

Give an example of characteristics being used to determine how close two species am in evolutionary terms ?

Q 47.

Why are human beings who look so different from each other in terms of size, colour and looks said to belong to the same species ?

Q 48.

How are the areas of study – evolution and classification inteilinked?

Q 49.

What evidence do we have for the origin of life from inanimate matter?

Q 50.

What is heredity?