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 biodiversity, classification and conservation levels of biodiversity environmental conservation and biodiversity biodiversity on earth and in india

Which of the following ways is most likely to decrease the genetic diversity in a population?

  1. Gene mutation

  2. Genetic recombination

  3. Stabilising natural selection

  4. Immigration of individuals
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
  • Genetic diversity is the total number of genetic characteristics in the genetic makeup of a species. For example, The genetic diversity shown by the medicinal plant Rauwolfia vomitoria growing in different Himalayan ranges might be in terms of the potency and concentration of the active chemical (reserpine) that the plant produces. 
  • Genetic variation is an important force in evolution as it allows natural selection to increase or decrease the frequency of alleles already in the population.
  • Stabilizing natural selection is most likely to decrease the genetic diversity in a population because the frequency of alleles remains constant in stabilized natural selection.
  • So, the correct answer is 'Stabilising natural selection'.
Multiple choice zoology biodiversity, classification and conservation levels of biodiversity environmental conservation and biodiversity biodiversity on earth and in india

Which of the following is incorrectly matched?

  1. Alpha diversity Number of species in a given habitat

  2. Genetic diversity Variation of genes within species

  3. Beta-diversity - Diversity of habitat in the whole region

  4. Species diversity - The product of species richness and evenness
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
Genetic diversity is the total number of genetic characteristics in the genetic makeup of a species. It is distinguished from genetic variability, which describes the tendency of genetic characteristics to vary. Genetic diversity serves as a way for populations to adapt to changing environments. With more variation, it is more likely that some individuals in a population will possess variations of alleles that are suited for the environment. Those individuals are more likely to survive to produce offspring bearing that allele. The population will continue for more generations because of the success of these individuals. The academic field of population genetics includes several hypotheses and theories regarding genetic diversity. The neutral theory of evolution proposes that diversity is the result of the accumulation of neutral substitutions. Diversifying selection is the hypothesis that two subpopulations of a species live in different environments that select for different alleles at a particular locus. This may occur, for instance, if a species has a large range relative to the mobility of individuals within it. Frequency-dependent selection is the hypothesis that as alleles become more common, they become more vulnerable. This occurs in host–pathogen interactions, where a high frequency of a defensive allele among the host means that it is more likely that a pathogen will spread if it is able to overcome that allele.
So the correct option is 'genetic diversity- variation of genes within species'.
Multiple choice zoology biodiversity, classification and conservation levels of biodiversity environmental conservation and biodiversity biodiversity on earth and in india

Which evolutionary force decreases the genetic diversity of a population by increasing the proportion of smaller individuals?

  1. Mutation

  2. Gene flow

  3. Bottle neck effect

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

The bottleneck effect occurs when a population's size is drastically reduced, leading to loss of genetic diversity as only certain individuals survive and reproduce. This reduces the gene pool. Mutation increases diversity, gene flow can increase diversity by introducing new alleles, and random mating maintains Hardy-Weinberg equilibrium.

Multiple choice zoology biodiversity, classification and conservation levels of biodiversity environmental conservation and biodiversity biodiversity on earth and in india

Genetic diversity will be more common in organisms with 

  1. Parthenogenesis

  2. Sexual reproduction

  3. Asexual reproduction

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

Genetic diversity refers to the variety of genes within a species. Each species is made up of individuals, that have their own particular genetic composition. Within a species there may also be discrete populations with distinctive genes. 

Asexual reproduction results in no new gene configurations, so the offspring is genetically identical to the parent. 
Sexual reproduction results in an offspring, that receives genes from two parents. The advantage of sexual reproduction occurs when the two parents come from different populations. This way the genetic info is the combination of two parents from two separate populations. This is why young male lions are kicked out of the pride and why it is illegal to marry your cousin, as this insures genetic diversity.

Multiple choice zoology biodiversity, classification and conservation levels of biodiversity environmental conservation and biodiversity biodiversity on earth and in india

How does the genetic diversity of a modern corn field compare to the genetic diversity of a population of the pre-domesticated corn plant?

  1. Less diversity

  2. More diversity

  3. More genetic diversity, but less phenotypic variation

  4. The same amount of diversity
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The genetic diversity of a modern corn field is more diverse as it may contain genes transferred from from bacteria, to naturally protect it from pests 

For example, Bt corn
However, a pre domesticated corn plant is the one that is most suitable to be grown in a certain environment, majorly by artificial selection that is cross breeding and deriving a gene pool from an existing one that can provide a better commercial value
Example - sweet corn, a recessive trait, but is abundantly available due to taste preference and comparatively soft kernels

Multiple choice zoology biodiversity, classification and conservation levels of biodiversity environmental conservation and biodiversity biodiversity on earth and in india

Write the correct sequence of genetic diversity.

  1. Kingdom $\rightarrow$ species $\rightarrow $chromosomes$ \rightarrow $genes $\rightarrow$ nucleotides
  2. Population $\rightarrow$species $\rightarrow$ chromosomes $\rightarrow$ genes $\rightarrow$ nucleotides.
  3. Species $\rightarrow$ genes $\rightarrow$population $\rightarrow $ chromosomes$ \rightarrow $ nucleotides
  4. Kingdom $ \rightarrow$ population $\rightarrow$ species $\rightarrow$ genes $\rightarrow$ chromosome $\rightarrow$ nucleotides
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Genetic diversity is the diversity in the number and types of genes as well as chromosomes present in different species and variations in the gene and their alleles in the same species.
Population $\rightarrow $Species $\rightarrow $Chromosomes $\rightarrow $Genes $\rightarrow $Nucleotide is the correct sequence of genetic diversity.

Multiple choice zoology biodiversity, classification and conservation levels of biodiversity environmental conservation and biodiversity biodiversity on earth and in india

A species spread over a large tract with varied environmental conditions will have

  1. Higher genetic diversity

  2. Uniform gene pool

  3. Little genetic diversity

  4. Either B or C
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The variety and variability of living organisms (both plants and animals) are known as biodiversity. The variation measured by biodiversity is at the genetic, species, and ecosystem level. Gene-based diversity is known as genetic diversity. It is a way for populations to adapt to changing environments. A species spread over a large tract with varied environmental conditions will have higher genetic diversity.

So, the correct answer is 'Higher genetic diversity'.

Multiple choice zoology biodiversity, classification and conservation levels of biodiversity environmental conservation and biodiversity biodiversity on earth and in india

In India, we find mangoes with different flavours, colours, fibre content, sugar content and shelf life. The large variation is due to 

  1. Genetic diversity

  2. Species diversity

  3. Induced mutations

  4. Hybridisation
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
Genetic diversity represents the total number of genetic characteristics in the genetic makeup of a species. Whereas, the genetic variability describes the tendency of genetic characteristics to vary. This diversity lets the population adapt to changing environments. For example, In India, we find mangoes with different flavors, colors, fiber content, sugar content and shelf life. The great variation is due to the genetic diversity.
So, the correct answer is 'Genetic diversity'.
Multiple choice zoology biodiversity, classification and conservation levels of biodiversity environmental conservation and biodiversity biodiversity on earth and in india

The interbreeding individuals of a species showing continuous distribution are

  1. Endemic

  2. Deme

  3. Cline

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

In biology, a deme is a term for a local population of organisms of one species, that actively interbreed with one another and share a distinct gene pool. When demes are isolated for a very long time they can become distinct subspecies or species. The term 'deme' is mainly used in evolutionary biology and is often used as a synonym for population. In evolutionary computation a "deme" often refers to any isolated subpopulation subjected to selection as a unit rather than as individuals. 

Multiple choice zoology biodiversity, classification and conservation levels of biodiversity environmental conservation and biodiversity biodiversity on earth and in india

Cheetah populations in Africa have been increasing for the past several decades from numbers in the hundreds to numbers in the thousands.
A study was conducted in which skin tissue samples were obtained from five wild cheetahs and grafted onto five other cheetahs. An immune response regarding non-self tissue rejection was absent in the cheetahs that received the skin grafts.
Recently, a small wild population of cheetahs has become infected with a new type of infectious cancer. Scientists are concerned about the extinction of the entire species because

  1. Wild cheetah populations have lost their genetic diversity and are now equally susceptible to diseases.

  2. The immune systems of the wild cheetahs have become suppressed by stressors in their environments.

  3. Wild cheetah populations are still so small that transmission of infectious diseases will occur rapidly.

  4. Skin cancer tends to metastasize faster and be more malignant than many other forms of cancer.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

In case the species population were large, it would not face extinction in case of the rapid spread of the infectious disease, until the remedies are put in place by the scientist  to control the disease. Small population and rapid spread are the major concerns with respect to the extinction of the species

So, the correct answer is 'Wild cheetah populations are still so small that transmission of infectious diseases will occur rapidly'

Multiple choice zoology biodiversity, classification and conservation levels of biodiversity environmental conservation and biodiversity biodiversity on earth and in india

A continental population of insects has blue, red, green, and black variations. The color is controlled by the interaction of two genes, one with two alleles, the other with three alleles.
A piece of driftwood carrying two green insects and five red insects floats in the ocean for several days and washes up on a small island where the insect species did not previously live. The seven insects establish a new population on the island that increases in number significantly over several generations.
Which of the following statements correctly compares the island population with the original mainland population?

  1. Red is dominantly inherited in the island population, while on the mainland green is dominant.

  2. The island population has lower genetic diversity than the mainland population.

  3. The island population is more likely to experience competition with other insect species than the mainland population.

  4. The island population size is increasing, while the mainland population is decreasing.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

It is given that out of blue, red, green and black variations of insects, only red and green insects established a new population on the new island. Since, these four colors are controlled by two genes, new population could have either of colour of insects. It is an example of founder effect. The island population will have lower genetic diversity than the mainland population because small populations usually have less genetic diversity than large population.

Thus, the correct answer is 'The island population has lower genetic diversity than the mainland population.'

Multiple choice biology selection and evolution ethology animal behaviour natural selection

Identify the true statement:

  1. Mutations are adaptive and occur according to the changes in the environment.

  2. Genetic drift is the random fluctuations in the allele frequencies in large population.

  3. Natural selection is the difference in reproduction that causes difference in the contribution of alleles of next generation.

  4. Mutations are directional and occurs in the individuals of a population.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Natural selection is defined by differential reproductive success based on heritable traits, which leads to changes in allele frequencies over generations.

Multiple choice biology selection and evolution ethology animal behaviour natural selection

Choose the correct answers from the alternatives given.
Populations of peppered moths (Biston betularia) of England changed from 1% dark and 99% grey individuals to 99% dark and 1% light 
individuals between 1848 and 1898. The selective agent causing the change was

  1. humans

  2. birds

  3. lichens on tree bark

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

Due to Industrial melanism, refers to the evolution of dark body colours in animal species that live in habitats blackened by industrial soot. The phenomenon has been documented in numerous species that hide from predators by blending in with their backgrounds. The main predator is bird.

So the correct option is B, birds.

Multiple choice biology selection and evolution ethology animal behaviour natural selection

Choose the correct answers from the alternatives given.
Natural selection may occur when there are

  1. heritable traits

  2. differences in the adaptiveness of forms of traits to prevailing environmental conditions

  3. differences in survival and reproduction among individuals that differ in one or more traits

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

Natural selection is the process where organism with favorable traits are more likely to reproduce. In doing so, they pass on these traits to the next generation. Over time this process allows organism to adapt to their environment.

Hence, the correct answer is 'all of the above'