Biology

Genetics and Evolutionary Biology

1,123 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 the paths traversed by life mutational theory of evolution theories of evolution other theories of evolution

In a random mating population in equilibrium, which of the following brings about a change in a gene frequency in a non-directional manner?

  1. Mutation

  2. Random drift

  3. Selection

  4. Migration
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

In a random mating population in equilibrium, mutations bring about a change in gene frequency. Mutations are non-directional.

Hugo de Vries conducting experiments on Evening Primrose and when he self-pollinated the plants from F1 generation. He found that though the majority of plants are similar to parents, there were a few different plants which appeared at random, in which inherited characters appeared suddenly without any previous indication in the race.
On this basis, he gave the mutation theory
  • mutations appear suddenly but become operational immediately
  • mutations are inheritable
  • do not revolve around normal characteristics of species
  • same type of mutations can appear in the number of individuals of the species

Multiple choice zoology the paths traversed by life mutational theory of evolution theories of evolution other theories of evolution

The concept of sudden genetic change which breeds true in a species is represented as 

  1. Inheritance of acquired characters

  2. Natural selection

  3. Laws of inheritence

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

The concept of sudden genetic change which breeds true in a species is represented as a mutation. Any sudden or spontaneous change in character which is inheritable is known as mutation. It is defined as the changing of the structure of a gene, resulting in a variant form which may be transmitted to subsequent generations, caused by the alteration of single base units in DNA, or the deletion, insertion, or rearrangement of larger sections of genes or chromosomes. 

So, the correct answer is option D.

Multiple choice zoology the paths traversed by life mutational theory of evolution theories of evolution other theories of evolution

Gene frequency in a population remains stable, unless and until there is ___________.

  1. Random drift

  2. Random mating

  3. Selection

  4. Mutation
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
  • In biology, a mutation is the alteration of the nucleotide sequence of the genome of an organism, virus, or extrachromosomal DNA.
  •  Mutations result from errors during DNA replication or other types of damage to DNA such as may be caused by exposure to radiation or carcinogens.
  • Hence, gene frequency in a population remains stable, unless and until there is a mutation. 
  • So, the correct answer is 'Mutation'.
Multiple choice zoology the paths traversed by life mutational theory of evolution theories of evolution other theories of evolution

The concept of sudden genetic change, which breeds true in an organism is visualized as

  1. Natural selection

  2. Inheritance of acquired characters

  3. Mutation

  4. Independent assortment
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The concept of sudden genetic change, which breeds true in an organism is visualized as a mutation. Any sudden or spontaneous change in character which is inheritable is known as mutation. It is defined as the changing of the structure of a gene, resulting in a variant form which may be transmitted to subsequent generations, caused by the alteration of single base units in DNA, or the deletion, insertion, or rearrangement of larger sections of genes or chromosomes.

So, the correct answer is option C.

Multiple choice zoology the paths traversed by life mutational theory of evolution theories of evolution other theories of evolution

After observing the variations Hugo De Vries first of all described the mutation in

  1. Oenothera lamarckiana

  2. Neurospora crassa

  3. Pisum sativum

  4. Drosophila melanogaster
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Hugo de Vries studied inheritance of flower colour in Oenothera lamarckiana (evening primrose) and proposed mutation theory that says that mutations are sudden, random, and inheritable and discontinuous variations which serve as raw material for evolution. 

George Beadle and Edward Tatum gave molecular definition of a gene while working on nutritional mutants in Neurospora crassa and proposed the one gene–one enzyme hypothesis.
Mendel conducted hybridization experiments on garden pea plant, Pisum sativum and proposed “Laws of inheritance” but did not observe any mutations.
Morgan and Muller identified radioactive nature of X-rays to induce point mutations while working on sex linked inheritance in Drosophila. 
So, the correct answer is option A.

Multiple choice zoology the paths traversed by life mutational theory of evolution theories of evolution other theories of evolution

In nature, the occurrence of mutations are

  1. Mostly harmful

  2. Mostly useful

  3. Mostly neutral

  4. Mostly neutral or harmful
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Example for harmful effect of mutation: Oncogenes are harmful mutations can cause cells to become malignant and can ultimately lead to cancer. Mutations are mostly harmful and sometimes neutral (silent mutations)

So, the correct answer is 'Mostly neutral or harmful'

Multiple choice zoology the paths traversed by life mutational theory of evolution theories of evolution other theories of evolution

According to the theory of mutation by Hugo de Vries

  1. Only small mutation takes part in variation

  2. Only large mutation takes part in variation

  3. Both small and large mutation cause variation in species

  4. None of the above
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

According to Devries the evolution is very fast like horse running

movement, but not slowly like snails movement as said by Darwin.

Devries also said that there are no middle forms between the ancestor

and new species.

Multiple choice zoology the paths traversed by life mutational theory of evolution theories of evolution other theories of evolution

The major cause of evolution of genes and protein is

  1. Point mutation

  2. Chromosomal aberration

  3. Sexual reproduction

  4. Gene duplication and divergence
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Point mutation refers to the single nucleotide change in genes or single amino acid change in proteins. These changes lead to variability in population and ultimately leads to evolution. Meiosis during sexual reproduction produces new combination of already existing alleles and genes through crossing over but does not creates any new alleles. Gene duplication and divergences are rare events as compared to point mutation. Chromosomal aberrations will bring changes in entire chromosome, not individual genes and / or proteins.

Multiple choice zoology the paths traversed by life mutational theory of evolution theories of evolution other theories of evolution

Forthcoming generation will be less adaptive than the present generation due to :

  1. Genetic drift

  2. Adaption

  3. Mutation

  4. Natural selection
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

According to De Vries theory of evolution:

  • Mutation or discontinuous variation is the raw material of evolution.
  • The mutation appears suddenly and produced their effect immediately.
  • Mutants are different from the parents and there is no intermediate stage between the two.
  • The same type of mutation can appear in several individuals of a species.
  • Mutation can appear in all direction and all mutations are the inheritance
  • Useful mutations are selected by nature an lethal mutations are eliminated.

So, the correct option is 'Mutation'.

Multiple choice zoology the paths traversed by life mutational theory of evolution theories of evolution other theories of evolution

Theory of mutation by a De Vries considers that :

  1. Only small mutations take part in developing variations

  2. Only large mutations take part in developing variations.

  3. Both small and large mutations cause variations.

  4. None of the above.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Hugo de Vries after his work on Evening Primose, put forth his theory explaining the structural changes in gene structures, called mutation as the cause of variations. Only large, single step and abrupt mutation termed as saltation are capable enough to drive the process of evolution.

So, the correct option is 'Only large mutations take part in developing variations'.

Multiple choice zoology the paths traversed by life mutational theory of evolution theories of evolution other theories of evolution

To be evolutionary successful, mutation must occur in :

  1. Germplasm DNA

  2. Somatoplasm DNA

  3. Plasma protein

  4. RNA
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

  • For a mutation to be evolutionary successful, it must occur in Germplasm DNA since germline mutations are the only one that can be passed on to offspring, when either a mutated sperm or oocyte come together to form a zygote.
  • After this fertilization event occurs, germ cells divide rapidly to produce all of the cells in the body, causing this mutation to be present in every somatic and germline cell in the offspring; this is also known as a constitutional mutation.
So, the correct option is 'Germplasm DNA'.

Multiple choice zoology the paths traversed by life mutational theory of evolution theories of evolution other theories of evolution

Mark the correct set.

  Column I  Column II
1. Sewall Wright A.  Mutation
2. Hugo de Vries   B.  Natural selection
3. Darwin C.  Industrial melanism
4. Kettlewell  D.  Genetic drift
5. Hardy-Weinberg E.  Genetic equilibrium

  1. A- 2, B- 3, C- 4, D- 1, E- 5

  2. A- 1, B- 3, C- 5, D- 2, E- 4

  3. A- 3, B- 2, C- 1, D- 4, E- 5

  4. A- 1, B- 2, C- 3, D- 4, E- 5
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
Hugo de Vries, a Dutch botanist, one of the independent rediscoveries of Mendelism, put forward his views regarding the formation of new species which are due to mutations. 
In 1859, Charles Darwin set out his theory of evolution by natural selection as an explanation for adaptation and speciation. He defined natural selection as the "principle by which each slight variation if useful, is preserved".
Industrial melanism is an effect of urban pollution prominent in many species of arthropods. It is the phenomenon of an organism evolving dark pigmentation when exposed to an environment polluted by dark soot deposit and sulfuric buildup from industrial pollution. The first important experiments on the peppered moth were carried out by Bernard Kettlewell at Oxford University.
Genetic drift or allelic drift is the change in the frequency of a gene variant (allele) in a population due to random sampling. Sewall wright was the chief developer of the mathematical theory of genetic drift.
Genetic equilibrium describes the condition of an allele or genotype in a gene pool (such as a population) where the frequency does not change from generation to generation. It is also called as Hardy-Weinberg equilibrium. Therefore, the correct answer is option A.
Multiple choice zoology the paths traversed by life mutational theory of evolution theories of evolution other theories of evolution

For evolutionary success, mutation must occur in

  1. Somatic RNA

  2. Somatic DNA

  3. Germplasm DNA

  4. Germplasm RNA
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Germplasm is living hereditary assets, for example, seeds or tissues that are kept up with the end goal of creature and plant reproducing, protection, and other research employment. Germplasm accumulation is vital for the support of organic decent variety and sustenance security.

So, the correct option is 'Germplasm DNA'.

Multiple choice zoology the paths traversed by life mutational theory of evolution theories of evolution other theories of evolution

De Vires called mutants

  1. Variants

  2. Elementary species

  3. New species

  4. Sports
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
Hugo de Vries gave mutation theory in 1901 stating that evolution occurs through discontinuous variation or sudden change due to elementary species (later called mutants) which passed on to generations. Thus, the correct answer is 'elementary species.'