Biology

Heredity and Evolution

Question:

Define homologous organs.

Answer:

Homologous organs are those organs, which have similar origin and basic plan of development, but may or may not differ in their functions. The forelimbs of a human, a bird and a horse are homologous organs.

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Heredity and Evolution

Q 1.

Will geographical isolation be a major factor in the speciation of an organism that reproduces asexually ? Give reason for your answer.

Q 2.

Define variation.

Q 3.

How do homologous organs provide evidence in support of evolution?

Q 4.

Define homologous organs.

Q 5.

What is meant by the term speciation? List four factors which could lead to speciation. [Delhi]

Q 6.

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

Q 7.

”The sex of the children is determined by what they inherit from their father and not their mother.” Justify.

Q 8.

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

Q 9.

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

Q 10.

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

Q 11.

How do embryological studies provide evidence for evolution?

Q 12.

State one characteristic which shows that the birds are very closely related to dinosaurs.

Q 13.

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

Q 14.

Name the various tools of tracing evolutionary relationships which have been used for studying human evolution.

Q 15.

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

Q 16.

How do Mendel’s experiments show that traits are inherited independently ?

Q 17.

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 18.

A new born child has an XY pair of chromosmes. Will it be a baby boy or a baby girl ?

Q 19.

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

Q 20.

Explain with an example, how genes control the characteristics (or traits).

Q 21.

Name the scientist who gave the theory of evolution.

Q 22.

What factors could lead to the rise of a new species ?

Q 23.

What constitutes the link between one generation and the next ?

Q 24.

The forelimbs of a frog, a bird and a man show the same basic design (or basic structure) of bones. What name is given to such organs ?

Q 25.

Choose the one term from the following which includes the other three :
broccoli, wild cabbage, cauliflower, cabbage

Q 26.

Study the following cross and showing self-pollination in Flf fill in the blank and answer the question that followsncert-exemplar-problems-class-10-science-chapter-9-heredity-evolution-1

Q 27.

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 ?

Q 28.

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

Q 29.

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

Q 30.

Write the expanded form of DNA.

Q 31.

Explain Darwin's theory of evolution.

Q 32.

What is a gene?

Q 33.

What is a sex chromosome?

Q 34.

Explain the mechanism of sex determination in humans. [All India]
Or
With the help of a flow chart explain in brief how the sex of a newborn is genetically determined in human beings. Which of the two parents, the mother or the father, is responsible for determination of sex of a child? [Foreign]

Q 35.

Give an example of body characteristics used to determine how close two species are in terms of evolution and explain it. [All India]

Q 36.

An individual cannot pass on to its progeny the experiences of its lifetime.” Justify the statement with the help of an example and also give reason for the same. [Foreign]

Q 37.

(a) What is the genotype of dwarf plants which always produced dwarf offspring ?
(b) What is the genotype of tall plants which always produced tall offspring ?
(c) What is the genotype of

  1.  dwarf plants, and
  2.  tall plants, whose parental cross always produces tall offspring ?

Q 38.

(a) What do you understand by the term ‘variation’ ?
(b) Name two human traits which show variation.

Q 39.

Where did life originate on the earth ?

Q 40.

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 41.

What do you understand by the term ‘evolution’ ? State Darwin’s theory of evolution.

Q 42.

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

Q 43.

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

Q 44.

Define a gene.

Q 45.

How is sex determined in human beings?

Q 46.

Define Genetics. What is the contribution of Mendel in the field of genetics?

Q 47.

During which stage can the chromosomes be seen clearly? Write the features of the eukaryotic and prokaryotic chromosomes.

Q 48.

The human beings who look so different from each other in terms of colour, size and looks are said to belong to the same species. Why? Justify your answer. [All India(C)]

Q 49.

What evidence do we have for the origin of life from inanimate matter? [All India]

Q 50.

Define the term ‘evolution’. “Evolution cannot be equated with progress”. Justify this statement. [Delhi]