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).
(a) Tall – Tt will have tall plants because of the presence of T which is dominant gene and t is recessive gene.
(b) Dwarf plants: It is dwarf due to the presence of both the recessive genes.
(c) Tall plants: These plants are tall due to the presence of both the dominant genes.
(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]
Does the occurrence of diversity of animals on earth suggest their diverse ancestry also? Discuss this point in the light of evolution.
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?
Define variation in relation to a species. Why is variation beneficial to the species? [Delhi]
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]
State whether the following statement is true or false :
The sex of an infant is not a case of inheritance of characteristics.
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 ?
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
Will geographical isolation be a major factor in the speciation of an organism that reproduces asexually ? Give reason for your answer.
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.
A woman has only daughters. Analyse the situation genetically and provide 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.
In evolutionary terms, can we say which among bacteria, spiders, fish and chimpanzees have a ‘better body design’ why or why not ?
During which stage can the chromosomes be seen clearly? Write the features of the eukaryotic and prokaryotic chromosomes.
Who provided the evidence of DNA as the genetic material? Write the names of the components of the DNA molecule.