Variation and its type - class-X
Description: variation and its type | |
Number of Questions: 27 | |
Created by: Blackmamba | |
Tags: biology evolution and biodiversity classical genetics botany origin of life and organic evolution genetics and evolution variation |
Which is the source of variations?
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Mutation
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Recombination
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Deletion
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All of the above
Mutations, recombinations and deletions all are the sources of genetic variation. A Mutation occurs when a DNA gene is damaged or changed in such a way as to alter the genetic message carried by that gene. Recombination involves the exchange of genetic material either between multiple chromosomes or between different regions of the same chromosome. Deletion is a mutation in which a part of a chromosome or a DNA sequence is missing.
The variations are caused by
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Internal changes
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Environment
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Hybridization
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All of the above
Variations can be defined as the difference in characters among the individuals of same species, it gets affected by internal changes, environmental changes, hybridization etc.
Which is a source of variation and genetic diversity that is shared between prokaryotes and eukaryotes?
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Random fertilization involving a unique sperm and a unique egg
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Independent assortment of each chromosome pair during metaphase I of meiosis
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Crossing-over during prophase I of meiosis
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Random mutation
The genetic material in prokaryotes is not confined into a nucleus and they do not have a nuclear membrane and the genetic material is present in the form of chromatin and cytoplasm and there is no chance of crossing over during meiosis and no fertilization but random mutations do arise in them and it results change in the genetic material.
The major/ ultimate source of variations are
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Polyploidy
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Mutations
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Chromosome aberrations
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Segregation
- Point mutation e.g. nonsense and missense mutations
- Frame-shift mutation e.g. insertion or deletion mutations
Cannibals feed on
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Carcases
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Blood
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Carnivores
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Members of own species
Discontinuous variations are :
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Essential features
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Acquired character
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Non-essential changes
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Mutations
Height in humans is
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Somatogenic variation
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Discontinuous variation
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Continuous variation
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Both B and C
A.Somatogenic variation – These are acquired variations and non inheritable in nature. Eg:phenotypic plasticiy.
B.Discontinuous variations – These are responsible for the formation of a new species and the organism, thus, formed is called mutant. Eg:Mutations.
C.Continuous variations – These are fluctuating variations and cannot give rise to new species. Eg:Human height.
So, the correct option is ‘Continuous variations’.
Primary source of allelic variation is
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Independent assortment
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Recombination
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Mutation
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Polyploidy
Primary source of allelic variation is recombination. Recombination is the natural process of breaking and rejoining DNA strands to produce new combinations of genes and, thus, generate genetic variation. This is the phenomenon that occurs during meiosis I.
Mutations are responsible for.
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Extinction of organisms
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Variations in population
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Increase in population
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Maintaining genetic continuity
Recombinations and variations in eucaryotic organisms are due to
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Mitosis and meiosis
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Fertilization and mitosis
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Meiosis and fertilisation
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Meiosis and amitosis
The process of forming new allelic combination in offspring by exchanges between genetic materials of parents is called Recombination.
Variation is a change or slight difference in condition, amount, or level, typically within certain limits appear in the progeny compared with parents.
Recombination and variations appear in sexually reproducing organisms during meiosis and fertilization.
So, the correct option is ‘Meiosis and fertilization’.
Some individuals produce lesser amounts of insulin. It is a type of
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Physiological variation
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Behavioural variation
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Morphological variation
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All the above
- Physiological variation is related to the differences in the ways individuals of the same species react to conditions in their environment because of difference in their functioning of the body. Production of insulin is an example of physiological variation.
- So, the correct option is 'Physiological variation'
Mutation, selection and genetic drift are three important forces which are responsible for evolutionary changes
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True
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False
Evolution is dependent on the natural selection , genetic drift , gene flow , mutation are the main factors responsible for evolution .
Aspects such as sedentary habit, territoriality, etc., not aiding diversification are classified as
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Reproductive isolation
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Mutational effects
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Biological barriers
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Genetic incompatibility
Which one of the following traits of the parents cannot be inherited by their children?
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Cleft chin
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Snub nose
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Scarred eyebrow
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Brown eyes
Scarred eyebrow is an acquired trait which is never passed on to the offspring because scarring does not change the genes of the reproductive cells of the parent.
Which of the following statements is correct?
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Accumulation of useful mutations through ages has led to the creation of new species of living beings.
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Genetic variability provides raw material for the operation of natural selection and reproductive isolation.
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Genetic variability is produced by gene mutations.
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All of the above.
Genetic variability is the change in the sequence of the gens due to mutations. These mutations has led to new species generation. The so evolved species are selected in the environment based on natural selection
Laboratory mice are to be classified based on genes A, B, and C, none of these are lethal genes. How many would be genetically different gametes if they are formed by genotype AaBbCc?
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$3$
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$6$
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$8$
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$9$
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$12$
Ultimate source of variation is
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Fertilization
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Mitosis
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Meiosis
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Mutations
Variation is a change or slight difference in condition, amount, or level, typically within certain limits appear in the progeny compared with parents. Variations appear in sexually reproducing organisms during meiosis and fertilization and also by mutations. So, the correct option is ‘Mutation’.
The ultimate source of continuous variations is
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Natural selection
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Sexual reproduction
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Hormonal action
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Mutations
Sexual reproduction involves gamete formation and fertilisation. During fertilisation, 1 gamete from each parent combines to form a zygote. Because of recombination and independent assortment in meiosis, each gamete contains a different set of DNA. This produces a unique combination of genes in the resulting zygote and ultimately within the organism.
Which variations are temporary and are not connected with last or next generation?
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Hereditary variations
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Environmental variations
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Discontinuous variations
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Continuous variations
In the living organisms, variation due to environment, not transmitted from generation to generation. so these are temporary, where as variations due to mutations are transmitted from generation to generation, so they are permanent.
So, the correct option is 'Environmental variations'.
In introgressive hybridization, one species is completely replaced by another in nature.
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True
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False
The most likely reason for the development of resistance against pesticides in insects damaging crops is:
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genetic recombination
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directed mutations
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acquired heritable changes
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none of these
Which of the following is not heritable?
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Point mutation
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Chromosomal mutation
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Somatic mutation
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Gene mutation
- Point mutation is a genetic mutation where a single nucleotide base is changed, inserted or deleted from a sequence of DNA or RNA. Each triplet codon corresponds to an amino acid when translated to protein. When one of these codons is changed by a point mutation, the corresponding amino acid of the protein is changed.
- Chromosomal mutation is presence or absence of one or more set of chromosomes in a cell or a structural abnormality in the normal set of chromosomes.
- Somatic mutation is the occurrence of a mutation in the somatic cells (cells other than sperm and egg) of the organism. These are frequently caused by environmental factors like exposure to UV rays or to certain chemicals.
- Gene mutation is a permanent alteration in the DNA sequence that makes up a gene. They are of two types: Hereditary mutations (inherited from parents) and Acquired mutation (occur at some time during a person's life).
There is an inbuilt tendency to variation during reproduction, because of errors in DNA copying and as a result of sexual reproduction.
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True
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False
Sexual reproduction results in more variation than the asexual reproduction. During sexual reproduction, there are chances of errors occurring during DNA copying. Crossing over also takes place during sexual reproduction. All these ultimately result in the variation. This variation helps survival in species and also supports diversity in the course of evolution.
To be evolutionary successful, the mutation must occur in
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Somatoplasm
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Germplasm
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Karyolymph/zygote
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Ergastoplasm
Total of specialized protoplasm other than germplasm in individual body or protoplasm of somatic cells is termed as somatoplasm. Germplasm is protoplasm of germ cells (egg and sperm cells) or any living tissues with the capability of generating new organisms. The germplasm is inherited from parents to offspring along with gametes; thus any mutation in germplasm is passed to progeny which is a requisite for successful mutation; option B is correct. Since somatoplasm is not passed to offspring, any mutation in it affects that individual only and is not passed to offspring which makes option A incorrect. The liquid phase of cell nucleus which harbours the nucleolus and chromatin and other structures is called as karyolymph. Similarly, the mutation in zygote affects single individual that develops from that zygote. Option C is incorrect. The granular endoplasmic reticulum that has studded ribosomes on its surface is called as ergastoplasm which is not inherited to offspring and thus is not suitable for successful mutation; option D is incorrect. Correct option B is correct.
Which type of variation is inherited?
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Somatic variation
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Germinal variation
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Both A and B
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None of the above
Which mutation/variation is not hereditary _____________.
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Genetic
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Gametic
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Somatic
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Germinal.
A sudden, inheritable, discontinuous variation due to change in chromosomes and genes is called Mutation. It is hereditary. Mutations in somatic cells are not hereditary.
So, the correct option is ‘somatic’.
Somaclonal variations can be obtained by
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Application of colchicine
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Irradiation with $\gamma$-rays
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Tissue culture
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Hybridization