Does geographical isolation of individual of a species lead to formation of a new species? Provide a suitable explanation.
Yes, geographical isolation of individual of a species lead to the formation of a new species.
Geographical isolation of a population leads to genetic drift and there will be no gene flow between it and the parent species. Inbreeding in small population will reproduce among themselves and generate new variations. Accumulation of those variations over several generations will lead to formation of new species.
Choose the one term from the following which includes the other three :
broccoli, wild cabbage, cauliflower, cabbage
Which of the processes, sexual reproduction or asexual reproduction, brings about maximum variations in the offsprings ?
”The sex of the children is determined by what they inherit from their father and not their mother.” Justify.
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]
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.
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]
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.
Study the following cross and showing self-pollination in Flf fill in the blank and answer the question that follows
Define the term ‘evolution’. “Evolution cannot be equated with progress”. Justify this statement. [Delhi]
Evolution has exhibited a greater stability of molecular structure when compared with morphological structures. Comment on the statement and justify your opinion.
Write the names of at least three inorganic molecules which helped in the origin of life on the earth.
Give an example of characteristics being used to determine how close two species are in evolutionary terms.
In evolutionary terms, can we say which among bacteria, spiders, fish and chimpanzees have a ‘better body design’ why or why not ?
Mendel said that the characteristics or traits of organisms are carried from one generation to the next by internal factors which occur in pairs. What is the modern name for these factors ?
Does geographical isolation of individuals of a species lead to the formation of a new species ? Provide a suitable explanation for your answer.
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 ?
Who provided the evidence of DNA as the genetic material? Write the names of the components of the DNA molecule.
Give an example of body characteristics used to determine how close two species are in terms of evolution and explain it. [All India]
If we cross pure-bred tall (dominant) pea plant with pure-bred dwarf (recessive) pea plant we will get pea plants of F1 generation. If we now self-cross the pea plant of F2 generation, then we obtain pea plants of F2 generation.
(a) What do the plants of F2 generation look like?
(b) State the ratio of tall plants to dwarf plants in F2 generation.
(c) State the type of plants not found in F2 generation but appeared in F2 generation, mentioning the reason for the same. [All India]
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 ?
(a) What do you understand by the term ‘variation’ ?
(b) Name two human traits which show variation.
(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
(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 ?
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………………………