Define a gene.
A gene is a small portion of the DNA, with codes for a particular polypeptide or a protein. In other words, it is the functional unit of the DNA. It is also responsible for the transmission of hereditary characters from the parents to the offspring.
Which of the processes, sexual reproduction or asexual reproduction, brings about maximum variations in the offsprings ?
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.
Name five varieties of vegetables which have been produced from ‘wild cabbage’ by the process of artificial selection.
State one characteristic which shows that the birds are very closely related to dinosaurs.
Evolution has exhibited a greater stability of molecular structure when compared with morphological structures. Comment on the statement and justify your opinion.
Will geographical isolation be a major factor in the speciation of an organism that reproduces asexually ? Give reason for your answer.
Study the following cross and showing self-pollination in Flf fill in the blank and answer the question that follows
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]
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]
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 ?
Write the names of at least three inorganic molecules which helped in the origin of life on the earth.
What type of plants were used by Mendel for conducting his experiments on inheritance ?
Out of bacteria, spider, fish and chimpanzee, which organism has a better body design in evolutionary terms ? Give reason for your answer.
Give an example of body characteristics used to determine how close two species are in terms of evolution and explain it. [All India]
What are homologous organs? Can the wing of a butterfly and the wing of a bat be regarded as homologous? Why? [All India]
In evolutionary terms, can we say which among bacteria, spiders, fish and chimpanzees have a ‘better body design’ why or why not ?
Define the term ‘evolution’. “Evolution cannot be equated with progress”. Justify this statement. [Delhi]
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 ?
Will geographical isolation be a major factor in the speciation of a self-pollinating plant species ? Why or why not ?
What is meant by the term speciation? List four factors which could lead to speciation. [Delhi]
Does the occurrence of diversity of animals on earth suggest their diverse ancestry also? Discuss this point in the light of evolution.
Can the wing of butterfly and the wing of a bat be considered homologous organs ? Why or why not ?
Who provided the evidence of DNA as the genetic material? Write the names of the components of the DNA molecule.