How do embryological studies provide evidence for evolution?
The embryology of different vertebrates provide very strong evidence favoring organic evolution. The early embryos of different vertebrates show striking similarities. This indicates common origin and ancestry of different vertebrates. Thus embryological studies provide direct evidence for evolution.
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 ?
How are fossils formed? Describe, in brief, two methods of determining the age of fossils. [All India]
(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 ?
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)]
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 ? Why or why not ?
Define variation in relation to a species. Why is variation beneficial to the species? [Delhi]
Explain with examples how the following are evidences in favour of evolution in organisms. (i) Homologous organs (ii) Analogous organs (iii) Fossils [Delhi]
The gene for red hair is recessive to the gene for black hair. What will be the hair colour of a person if he inherits a gene for red hair from his mother and a gene for black hair from his father ?
Name the various tools of tracing evolutionary relationships which have been used for studying human evolution.
A woman has only daughters. Analyse the situation genetically and provide a suitable explanation.
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]
(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 ?
(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
Give the contrasting traits of the following characters in pea plant and mention which is dominant and which is recessive :
(a) Yellow seed (b) Round seed
Only variations that confer an advantage to an individual organism will survive in a population. Do you agree with this statement ? Why or why not ?
State whether the following statement is true or false :
The sex of an infant is not a case of inheritance of characteristics.
Name the first scientist who studied the inheritance of traits from one generation to the next.
Gregor Mendel’s first law of genetics states “Of a pair of contrasted characters, only one can be represented in a gamete by its internal ‘factor’.
(a) Give the modern name for this ‘factor’.
(b) State where these factors are found in gametes.
(a)What is meant by ‘heredity’ ? What are the units of heredity.
(b) State Mendel’s first law of inheritance.
(a) Why did Mendel choose pea plants for conducting his experiments on inheritance ?
(b) State Mendel’s second law of inheritance.
(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 whether the following statement is true or false :
Human beings have evolved from chimpanzees.
Fill in the following blanks with suitable words :Fill in the following blanks with suitable words :
(a) The human forelimb and bat’s forelimb are an example of……………………organs whereas an insect’s wing and a bat’s wing are an example of…………………organs.
(b) The evolution of eye is an example of evolution by…………………
(c) The scientific name of all human beings is……………………..
(d) Broccoli has evolved from……………..by the process of artificial selection.
(e) The theory of natural selection for evolution was proposed by………………………
Out of bacteria, spider, fish and chimpanzee, which organism has a better body design in evolutionary terms ? Give reason for your answer.
(a) Define ‘speciation’. Explain how speciation occurs.
(b) Will geographical isolation be a major factor in the speciation of a self-pollinating plant species ? Give reason for your answer.
Evolution has exhibited a greater stability of molecular structure when compared with morphological structures. Comment on the statement and justify your opinion.
What do you understand by the double helical structure of DNA? Who proposed this structure?
