Biology

Genetics and Evolutionary Biology

1,156 Questions

Genetics and evolutionary biology explain how traits are passed from parents to offspring and how species change over time. Key concepts include genetic drift, inbreeding, and heredity. This topic is fundamental for the biology section of many competitive tests.

Heredity and traitsGenetic variations and driftInbreeding conceptsEvolutionary mechanisms

Genetics and Evolutionary Biology Questions

Multiple choice zoology variation examples of natural selection selection natural selection

Read the following statements and select the correct option.
(i) Increase in melanised moths after industrialisation in Great Britain is a proof for natural selection.
(ii) When more individuals of a population acquire a mean character value, it is called disruption
(iii) Changes in allelic frequency in a population will lead to Hardy-Weinberg equilibrium.
(iv) Genetic drift changes the existing gene or allelic frequency in future generations.

  1. Only (ii) is correct

  2. Only (iv) is correct

  3. Both (i) and (iv) are correct

  4. Both (i) and (iii) are correct
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

When more individuals of a population acquire a mean character value, it is called stabilising selection. No change in allelic frequency in a population will lead to Hardy-Weinberg equilibrium.

So, the correct option is 'Option C'.

Multiple choice zoology variation examples of natural selection selection natural selection

Choose the correct answers from the alternatives given.
The offspring of better-adapted individuals are expected to make up a larger proportion of the next generation. The.most likely explanation is

  1. genetic drift

  2. mutation

  3. natural selection

  4. gene flow
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

As the natural selection a process in which organisms with certain inherited traits are more likely to survive and reproduce than are individuals with other traits. So correct answer is C, natural selection.

Multiple choice zoology variation examples of natural selection selection natural selection

Choose the correct statement.

  1. Phenotypic variation exists among individuals and the variation is heritable

  2. Those individuals with heritable traits better suited to the environment will survive.

  3. The black peppered moth during industrial revolution is related to natural selection.

  4. All of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Darwin's Theory of Evolution by Natural Selection. More individuals are produced each generation that can survive. Phenotypic variation exists among individuals and the variation is heritable. Those individuals with heritable traits better suited to the environment will survive. There is also a naturally occurring genetic mutation which causes some moths to have almost black wings.

So, the correct answer is "All of the above".

Multiple choice botany classical genetics variation and its type natural selection introduction to genetics

Which is the source of variations?

  1. Mutation

  2. Recombination

  3. Deletion

  4. All of the above
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

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. 

Multiple choice botany classical genetics variation and its type natural selection introduction to genetics

Which is a source of variation and genetic diversity that is shared between prokaryotes and eukaryotes?

  1. Random fertilization involving a unique sperm and a unique egg

  2. Independent assortment of each chromosome pair during metaphase I of meiosis

  3. Crossing-over during prophase I of meiosis

  4. Random mutation
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

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.

So, the correct option is 'Random mutation'

Multiple choice botany classical genetics variation and its type natural selection introduction to genetics

The major/ ultimate source of variations are

  1. Polyploidy

  2. Mutations

  3. Chromosome aberrations

  4. Segregation
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
Ultimate source of variation is MUTATION and nothing else. Mutations are mistakes that occur in DNA sequence of genome:
  • Point mutation e.g. nonsense and missense mutations
  • Frame-shift mutation e.g. insertion or deletion mutations
Any change in genetic DNA will be translated into a defect in the corresponding protein. Thus mutation is responsible for appearance of a phenotypic variation. Such a variation may help the organisms carrying the new variation to survive better. If it produces more progeny the variation will appear in more members. Variations which provide adaptive advantage get selected by nature, thus help organisms to evolve.

So, the correct answer is 'Mutations'.
Multiple choice botany classical genetics variation and its type natural selection introduction to genetics

Discontinuous variations are :

  1. Essential features

  2. Acquired character

  3. Non-essential changes

  4. Mutations
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
Discontinuous variations are where individuals fall into a number of distinct classes or categories and are based on features that cannot be measured across a complete range. You either have the characteristic or you don't. 
Discontinuous variation is controlled by alleles of a single gene or a small number of genes. As variations caused by mutations affect DNA in such a way that either organism has a certain characteristic resulting from mutation or not, it is an example of discontinuous variations.
So, the correct answer is 'Mutations'
Multiple choice botany classical genetics variation and its type natural selection introduction to genetics

Mutations are responsible for.

  1. Extinction of organisms

  2. Variations in population

  3. Increase in population

  4. Maintaining genetic continuity
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
Mutations are changes in the DNA. A single mutation can have a large effect, but in many cases, evolutionary change is based on the accumulation of many mutations. Gene flow is any movement of genes from one population to another and is an important source of genetic variation.

So, the correct answer is 'Variations in population'.
Multiple choice botany classical genetics variation and its type natural selection introduction to genetics

Aspects such as sedentary habit, territoriality, etc., not aiding diversification are classified as 

  1. Reproductive isolation

  2. Mutational effects

  3. Biological barriers

  4. Genetic incompatibility
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
Biological barriers are factors that prevent species migration, interbreeding, or free movement. What determines the barrier depends on the species and it's method of movement. For some species biological barriers are sedentary habits, physical like bodies of water, mountains, or deserts.
Mutation effects is the formation of altered protein from an altered or mutated genes.
When the species are not able to cross breed is called as genetic incompatibility
Thus, the correct answer is option C.
Multiple choice botany classical genetics variation and its type natural selection introduction to genetics

Which of the following statements is correct?

  1. Accumulation of useful mutations through ages has led to the creation of new species of living beings.

  2. Genetic variability provides raw material for the operation of natural selection and reproductive isolation.

  3. Genetic variability is produced by gene mutations.

  4. All of the above.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

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

Multiple choice botany classical genetics variation and its type natural selection introduction to genetics

Ultimate source of variation is

  1. Fertilization

  2. Mitosis

  3. Meiosis

  4. Mutations
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

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’.

Multiple choice botany classical genetics variation and its type natural selection introduction to genetics

The ultimate source of continuous variations is 

  1. Natural selection

  2. Sexual reproduction

  3. Hormonal action

  4. Mutations
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

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.

As reproduction takes place continuously throughout the generation as well as these variations are inheritable, it is the ultimate source of continuous variations.
So, the correct option is 'Sexual reproduction.'

Multiple choice botany classical genetics variation and its type natural selection introduction to genetics

Which variations are temporary and are not connected with last or next generation?

  1. Hereditary variations

  2. Environmental variations

  3. Discontinuous variations

  4. Continuous variations
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

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'.