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 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

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'.

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

In introgressive hybridization, one species is completely replaced by another in nature.

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
he movement of a gene (gene flow) from one species into the gene pool of another by the repeated backcrossing of an interspecific hybrid with one of its parent species is called Introgressive hybridization.
So the given statement is true.
Multiple choice biology variation variation and its type natural selection introduction to genetics

There is an inbuilt tendency to variation during reproduction, because of errors in DNA copying and as a result of sexual reproduction.

  1. True

  2. False
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

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.

Thus, the correct answer is option A.

Multiple choice biology variation variation and its type natural selection introduction to genetics

To be evolutionary successful, the mutation must occur in 

  1. Somatoplasm

  2. Germplasm

  3. Karyolymph/zygote

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

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. 

Multiple choice zoology applications of biotechnology cloning process of cloning gene cloning

Individuals of a clone have the

  1. Same behavior.

  2. Same height.

  3. Same genome.

  4. Same number of leaves.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
The individual produced by the asexual reproduction are considered as a clone of their own parents and have same genome because of the following reasons:
1) Fusion of gametes does not takes place in asexual reproduction so there is no chance of recombination and variation.
2) The parent cell divides to form daughter cell by mitosis due to which the offspring is genetically identical to the parent.
3) The offspring produced are clones of their parent and have same number of chromosomes.
So, the correct answer is option C.
Multiple choice zoology molecular basis of inheritance the search for genetic material dna structure and replication molecular genetics

A molecule that acts as a genetic material must fulfill the traits given, except

  1. It should provide the scope for slow changes that are required for evolution

  2. It should be able to generate its replica

  3. It should be able to express itself in the form of Mendelian characters

  4. It should be unstable structurally and chemically
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Genetic material must be stable to store information accurately over generations. If it were unstable, it could not reliably pass on traits.