How do homologous organs provide evidence in support of evolution?
The presence of homologous organs indicates that all vertebrates have a common ancestry. Similarly, all organs and systems of the vertebrates show fundamental similarities, which point towards common ancestry.
What is meant by the term speciation? List four factors which could lead to speciation. [Delhi]
Will geographical isolation be a major factor in the speciation of an organism that reproduces asexually ? Give reason for your answer.
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]
Which of the processes, sexual reproduction or asexual reproduction, brings about maximum variations in the offsprings ?
Name five varieties of vegetables which have been produced from ‘wild cabbage’ by the process of artificial selection.
Choose the one term from the following which includes the other three :
broccoli, wild cabbage, cauliflower, cabbage
”The sex of the children is determined by what they inherit from their father and not their mother.” Justify.
What type of plants were used by Mendel for conducting his experiments on inheritance ?
State one characteristic which shows that the birds are very closely related to dinosaurs.
(a) What will you get in the F1 and F2 generations in the following cross ?
Pure tall pea plant x Pure dwarf pea plant
(b) Is it an example of monohybrid cross or dihybrid cross ?
What are homologous structures? Give an example. Is it necessary that homologous structures always have a common ancestor?
Study the following cross and showing self-pollination in Flf fill in the blank and answer the question that follows
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?
Give one example each of characters that are inherited and the ones that are acquired in humans. Mention the difference between the inherited and the acquired characters. [Delhi]
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]
a) Name the scientist who gave the laws of inheritance.
(b) Name an animal in which individuals can change sex. What does this indicate ?
(a)What is meant by ‘heredity’ ? What are the units of heredity.
(b) State Mendel’s first law of inheritance.
What name is given to the sequence of gradual changes over millions of years in which new species are produced ?
Does the occurrence of diversity of animals on earth suggest their diverse ancestry also? Discuss this point in the light of evolution.
Does geographical isolation of individual of a species lead to formation of a new species? Provide a suitable explanation.
Evolution has exhibited a greater stability of molecular structure when compared with morphological structures. Comment on the statement and justify your opinion.
Give an example of body characteristics used to determine how close two species are in terms of evolution and explain it. [All India]
State the meaning of inherited traits and acquired traits. Which of the two is not passed on to the next generation? Explain with the help of an example.
(a) If a normal human cell has 46 chromosomes, how many chromosomes will be there in a human (;) sperm cell, and (ii) zygote ?
(b) What sizes of plants are produced if both parents have genes Tt ?
Write the names of at least three inorganic molecules which helped in the origin of life on the earth.