What do you understand by the term ‘evolution’ ? State Darwin’s theory of evolution.
Evolution is the sequence of gradual changes that takes place in the primitive organisms over millions of year in which new species are produced. Darwin’s theory of evolution is known as ‘The Theory of Natural Selection’. It can be described as follows:
(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 ?
a) Name the scientist who gave the theory of origin of life on earth. What is this theory ?
(b) How are those species which are now ‘extinct’ studied ?
Will geographical isolation be a major factor in the speciation of an organism that reproduces asexually ? Why or why not ?
How are fossils formed? Describe, in brief, two methods of determining the age of fossils. [All India]
State whether the following statement is true or false :
The sex of an infant is not a case of inheritance of characteristics.
Does the occurrence of diversity of animals on earth suggest their diverse ancestry also? Discuss this point in the light of evolution.
A woman has only daughters. Analyse the situation genetically and provide a suitable explanation.
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 ?
Give an example of characteristics being used to determine how close two species am in evolutionary terms ?
What do you understand by the double helical structure of DNA? Who proposed this structure?
”The sex of the children is determined by what they inherit from their father and not their mother.” Justify.
Define variation in relation to a species. Why is variation beneficial to the species? [Delhi]
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)]
How is the equal genetic contribution of male and female parents ensured in the progeny? [Delhi]
Give an example of body characteristics used to determine how close two species are in terms of evolution and explain it. [All India]
Fill in the following blanks with suitable words :Fill in the following blanks with suitable words :
(a) Genes always work in …………………
(b) In pea plants, the gene for dwarfness is………………… whereas that for tallness is…………………
(c) Most people have………………… earlobes but some have………………… earlobes.
(d) A human gamete contains………………… chromosomes whereas a normal body cell has………………… chromosomes in it.
(e) All races of man have………………… blood groups.
(f) The………………… chromosomes for a………………… are XX whereas that for a………………… are XY.
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 ?
Does genetic combination of mother play a significant role in determining the sex of a new born baby ?
(a) What are genes ? Where are they located in our body ?(a) What are genes ? Where are they located in our body ?
(b) What is meant by dominant genes and recessive genes ? Give one example of each.
(c) Explain how, characteristics (or traits) are inherited through genes.
State one characteristic which shows that the birds are very closely related to dinosaurs.
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 ?
Choose the one term from the following which includes the other three :
broccoli, wild cabbage, cauliflower, cabbage
Why are the small numbers of surviving tigers a cause of worry from the point of view of genetics ?
Will geographical isolation be a major factor in the speciation of an organism that reproduces asexually ? Give reason for your answer.
Name the various tools of tracing evolutionary relationships which have been used for studying human evolution.
Out of bacteria, spider, fish and chimpanzee, which organism has a better body design in evolutionary terms ? Give reason for your answer.
In human beings, the statistical probability of getting either a male or female child is 50 : 50. Give a suitable explanation.
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.
Why are the small numbers of surviving tigers a cause of worry from the point of view of genetics ?
