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 origin of life and organic evolution neo darwinism mechanism of evolution other theories of evolution

Potential danger to population greatly reduced in number is :

  1. Hardy-Weinberg disequilibrium

  2. Reduced gene flow

  3. Tendency towards assortative mating

  4. Loss of genetic variability
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

  • Reductions in population size and absence of gene flow can lead to reductions in genetic variability, reproductive fitness, and a limited ability to adapt to environmental change increasing the risk of extinction. 
  • Island populations are typically small and isolated, and as a result, inbreeding and reduced genetic diversity elevate their extinction risk.
So, the correct answer is 'Loss of genetic variability'

Multiple choice zoology origin of life and organic evolution neo darwinism mechanism of evolution other theories of evolution

A prezygotic isolating mechanism prevents successful

  1. gamete production

  2. fertilization

  3. zygote development

  4. reproduction of hybrids
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
Species are kept distinct from one another by prezygotic and postzygotic barriers. These barriers keep organisms of different species from mating to produce fertile offspring, acting before and after the formation of a zygote, respectively. These barriers maintain the reproductive isolation of species.
So, the correct answer is 'zygote development'

Multiple choice zoology origin of life and organic evolution neo darwinism mechanism of evolution other theories of evolution

Wild duck and pintail duck produce fertile offsprings only in captivity but seldom do so in natural habitats because of

  1. Postreproductive isolation

  2. Mechanical isolation

  3. Genetic drift

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

Ethological isolation is defined as the failure of individuals of species with recent common ancestry (i.e., related species or semispecies) to produce hybrid offspring because differences in their behaviour prevent successful mating taking place.
The mallard or wild duck (Anas platyrhynchos) is a dabbling duck which breeds throughout the temperate and subtropical Americas, Europe, Asia, and North Africa, and has been introduced to New Zealand, Australia, Peru, Brazil, Uruguay, Argentina, Chile, the Falkland Islands and South Africa.
The pintail or northern pintail is a duck with wide geographic distribution that breeds in the northern areas of Europe, Asia and North America. It is migratory and winters south of its breeding range to the equator.
Ethological isolation stops their breeding in the natural habitats, whereas they breed in captivity.

Multiple choice zoology origin of life and organic evolution neo darwinism mechanism of evolution other theories of evolution

Select the correct statement.

  1. Heritable variation allows for evolution.

  2. Adaptive radiation allows for mutation.

  3. Crossing-over allows for mitosis.

  4. Translocation allows for DNA replication.

  5. Cellular differentiation allows for meiosis.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Heritable variations serve as raw material for natural selection and accumulation of selected heritable variations over generations leads to evolution. Diversification of ancestral line into different forms is referred to as adaptive radiation. Crossing over occurs during meiosis. Translocation is the step of elongation of peptide chain during translation. Cellular differentiation leads to tissue formation; meiosis is a type of cell division. Thus, the correct answer is option A.

Multiple choice zoology origin of life and organic evolution neo darwinism mechanism of evolution other theories of evolution

A very important factor of a new species in evolution is 

  1. Extensive inbreeding

  2. Extensive outbreeding

  3. Reproductive isolation

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

A subpopulation becomes reproductively isolated from its parental population. It is the formation of species without geographical isolation and these species are called sympatric speciation.

So, the correct answer is 'Reproductive Isolation'

Multiple choice zoology origin of life and organic evolution neo darwinism mechanism of evolution other theories of evolution

Choose the correct answers from the alternatives given.
Natural selection is best defined as occurring when the environment causes

  1. differential mortality

  2. assortative mating

  3. a reduced gene pool

  4. differential success in reproduction
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The organism that is better adapted to the environment and hence, can produce more of its type is selected. Its population eventually grows and the other one is wiped out. Over long periods, this can even give rise to speciation i.e. formation of new species.

Hence, the correct answer is 'differential success in reproduction'

Multiple choice bio-chemistry digestion digestive glands liver pancreas

In Escherichia coli, how many codons code for the standard amino-acids?

  1. $64$
  2. $60$
  3. $61$
  4. $20$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

There are 64 total codons. Of these, 61 code for the 20 standard amino acids, while the remaining 3 are stop codons that do not code for any amino acid.

Multiple choice botany taxonomy and systematic botany taxonomy and systematics systematics of living world kingdom plantae plant taxonomy classification of biodiversity

Reason for diversity in living being is 

  1. Mutation

  2. Long term evolutionary change

  3. Genetic recombination

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

Mutation is the sudden change in the genetic composition of the living organism which is inherited from one generation to the other. Due to random changes in the genetic pool, it acts as a source of variation.

In order, to adjust the changing conditions with evolution, the organism undergoes changes in the genome which are inherited by generations and act as a source of diversity.
Genetic recombination is the production of offspring with combinations of traits that differ from those found in either parent. It leads to change in the genetic pool and act as a source of variation.
So, the correct answer is option D.

Multiple choice botany taxonomy and systematic botany taxonomy and systematics systematics of living world kingdom plantae plant taxonomy classification of biodiversity

The evolutionary history of a group of organism is termed as

  1. Taxonomy

  2. Systematics

  3. Phylogeny

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

  • The process of developing an evolutionary history of organisms is called phylogeny. The unit of data used here is the character or trait. 
  • Systematics deals with the evolutionary relationships between the organisms
  • Taxonomy deals with classifying and naming organisms.
  • Hierarchy is an arrangement of sequence in an increasing or decreasing order.
So the correct option is Phylogeny.

Multiple choice botany taxonomy and systematic botany taxonomy and systematics systematics of living world kingdom plantae plant taxonomy classification of biodiversity

A mutant strain of Neurospora which fails to grow on a minimal medium unless supplemented with a nutrient is called

  1. Auxotroph

  2. Autotroph

  3. Heterotroph

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

An auxotroph is a mutant organism that requires a specific nutrient for growth that the wild-type strain can synthesize on its own.

Multiple choice zoology evolution of life darwin's theory of evolution process of evolution lamarckism

A scientist kept 69 generations of Drosophila in darkness even after that the flies had normal eyes, which law is  disproved in this case? 

  1. Synthetic theory

  2. Natural selection

  3. Germplasm theory

  4. Acquired characters are inherited
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Lamarckism or theory of use and disuse has been disproved in this case. It states that animals acquired characteristics after using certain physical traits constantly.

Multiple choice zoology evolution of life darwin's theory of evolution process of evolution lamarckism

Which of the following explained evolution in most acceptable form?

  1. Lamarck, Darwin, Hugo de Vries

  2. Anaximander, Darwin, Malthus

  3. F. Redi, Richter, Cuvier

  4. Lamarck, Hardy Weinberg, Darwin
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The modern synthesis of evolution combines Darwin's natural selection, Lamarck's early observations (though modified), and Hugo de Vries's mutation theory, providing the most comprehensive framework.

Multiple choice zoology evolution of life darwin's theory of evolution process of evolution lamarckism

The phenotypic determination by genetic variation in a population refers to the degree of

  1. Fitness

  2. Heritability

  3. Limited environmental resources

  4. Overproduction of offspring

  5. Phenotypic variation
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The observed phenotypic variations of a trait in a population which is caused by genetic variation are called as heritability. It shows the extent to which a trait is determined genetically. Fitness refers to the ability of survival and production of fertile offspring. Limited environmental resources lead to the struggle for existence, not phenotypic variations. Overproduction of offspring represents the biotic potential of species.  

Therefore, the correct answer is option B.

Multiple choice zoology evolution of life darwin's theory of evolution process of evolution lamarckism

In order to increase its population through natural selection, an allele should have one of the following features.

  1. Individuals with the allele are better able to find food.

  2. Individuals with the allele are better able to resist disease.

  3. Individuals with the allele have an increased ability to find and retain mates.

  4. Individuals with the allele produce more offspring that reach adulthood.

  5. Individuals with the allele have a longer lifespan than those without it.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

A trait is favored by natural selection when it imparts reproductive fitness to the population. Reproductive fitness refers to ability of organisms to pass traits to offspring. This makes option D correct as individual with allele that enable it to produce fertile and viable offspring is favored by natural selection.