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

Within a population and due to competition between individuals, the individuals with an advantage will survive to pass their genes on to the next generation. What is this idea called?

  1. Adaptation

  2. Darwin's theory

  3. Speciation

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

Natural selection is the process where individuals with advantageous traits survive and reproduce more successfully than others in a competitive environment. These beneficial traits are then passed to offspring, becoming more common in the population over generations. Adaptation is the outcome of this process, not the process itself. Darwin's theory is broader, encompassing natural selection as the key mechanism.

Multiple choice

What is the difference between genetic drift and change due to natural selection?

  1. Genetic drift does not require the presence of variation.

  2. Genetic drift does not involve the competition between members of a species.

  3. Genetic drift never occurs in nature, natural selection does.

  4. There is no difference between these two.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The key difference is that genetic drift is random change in allele frequencies unrelated to fitness advantages, while natural selection involves differential survival based on competitive advantages. Genetic drift occurs through chance events (bottlenecks, founder effects) without requiring competition between organisms. Natural selection specifically requires competition where advantageous traits are favored.

Multiple choice

All of the following are believed to contribute to genomic diversity among various species except

  1. gene duplication

  2. gene transcription

  3. lateral gene transfer

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

Gene transcription is the process of making RNA from DNA - a routine cellular function that happens constantly and does not create genetic diversity. Gene duplication creates extra copies that can evolve new functions. Lateral gene transfer moves genes between species. Chromosomal rearrangements alter gene structure and regulation. The latter three processes increase genomic variation, while transcription merely maintains existing genetic information.

Multiple choice

Which of the following statements about gene mutation is correct?

Mutation is the permanent change in the hereditary material, i.e., changes in the structure of chromosome or DNA. These changes in the DNA modify the sequence of amino acid in the protein of genes.

  1. It is the mutation from wild type to a new type.

  2. It is a change in the structure of gene.

  3. It is the mutation caused due to intracellular factors or due to background cosmic radiation.

  4. It is the mutations in germ cells or gametes or cells of germinal.

  5. It is the permanent change in the hereditary material.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Gene mutations or point mutations are changes in the structure of gene. Since genes are DNA segments, the gene mutations include changes in the number or arrangement of nucleotides. These are also known as ‘intragenic mutations’. Gene mutations alter or modify the information conveyed by the gene. Lethal, albinos, chlorophyll deficiencies, sickle cell anaemia, etc., are caused by gene mutations.

Multiple choice

Which of the following staements characterizes induced mutation?

Mutation is the permanent change in the hereditary material, i.e., changes in the structure of chromosome or DNA. These changes in the DNA modify the sequence of amino acid in the protein of genes.

  1. Mutations occurring in the somatic cells.

  2. Mutation caused due to intracellular factors or due to background cosmic radiation.

  3. Mutations in germ cells or gametes or cells of germinal.

  4. Mutation from wild type to a new type.

  5. Mutation introduced artificially or experimentally.
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

Induced mutations are introduced artificially or experimentally. Any physical or chemical agent, which introduces mutation is called a mutagen or mutagenic agent, physical (high or low temperature and the radiations) and chemical mutagens (mustard gas, colchicines, acridine dyes, nitrous acid, etc).

Multiple choice

Which of the following statements is/are false?

a. Heredity is the continuity of features from one generation to the next. b. Heredity information is present in the gametes of the parents. c. The male ovum fuses with the female sperm to form a zygote that gradually develops into an offspring.

  1. Only a

  2. Only a and b

  3. Only b

  4. Only b and c

  5. Only c
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

This is the correct option as this statement is false. The male sperm fuses with the female ovum to form a zygote that gradually develops into an offspring.

Multiple choice

Which of the following statements is/are false?

a. The process in which new species develop from the existing species is known as speciation. b. The gene that can decide the appearance of an organism only in the presence of another identical gene is called a recessive gene. c. If a sperm carrying X chromosomes fertilises an ovum carrying X chromosome, then the child born will be a boy.

  1. Only a

  2. Only a and b

  3. Only b

  4. Only b and c

  5. Only c
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

This is the correct option as this statement is false. If a sperm carrying X chromosomes fertilises an ovum carrying X chromosome, then the child born will be a girl.

Multiple choice

Which of the following is not a character of r-selected species?

  1. small adult size

  2. long generation time

  3. a high energy allocation to reproduction

  4. maximum population growth
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

r-selected species are adapted for rapid reproduction in unstable environments. Their key characteristics include: small adult size, short generation time (NOT long), high energy allocation to reproduction, and maximum population growth rate. Long generation time is a K-selected trait - these species invest more in fewer offspring and live in stable environments.

Multiple choice

Which of the following statements is/are false? P. genetic diversity helps prevent a species from becoming extinct Q. the phenomenon in which animals with favorable adaptation reproduce more rapidly is called differential reproduction R. geographic isolation is a common mechanism contributing to speciation S. biologists estimate that 99% of all the species that have ever existed are now extinct

  1. P, R

  2. P, S

  3. Q, R

  4. none of these
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

All four statements are factually correct in evolutionary biology. Genetic diversity does provide extinction resistance by ensuring some individuals may survive environmental changes. Differential reproduction (natural selection) is the mechanism by which favorable adaptations spread. Geographic isolation is indeed a key speciation mechanism. Paleontologists do estimate that over 99% of all species that ever existed are now extinct. Since all statements are true, none are false.

Multiple choice

If two populations are merged, each with different frequencies of an allele at a locus, and randomly mating occurs immediately, how long will it take to achieve a Hardy-Weinberg equilibrium in the new population?

  1. One generation

  2. Ten generations

  3. Variable depends on allele frequencies

  4. The population will never achieve equilibrium
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

When two populations with different allele frequencies merge and begin random mating, Hardy-Weinberg equilibrium is achieved in just one generation. Random mating in the first generation immediately creates the genotype proportions predicted by HWE, based on the new combined allele frequencies. No additional generations are needed.

Multiple choice

Genetic diversity is required for natural selection to act, but natural selection can reduce or eliminate diversity. What process can restore genetic diversity to a population?

  1. Genetic drift

  2. Mutation

  3. Sexual selection

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

Natural selection reduces genetic diversity by favoring certain alleles over others. Mutation is the ultimate source of new genetic variation - it creates novel alleles that didn't exist before. Genetic drift reduces diversity (especially in small populations), and stabilizing selection specifically reduces variation by favoring intermediate phenotypes. Only mutation introduces new genetic diversity.

Multiple choice

Which of the following is not required for a population at Hardy-Weinberg equilibrium?

  1. There is no migration between populations.

  2. Natural selection is not acting on the alleles in the population.

  3. Mating is random.

  4. Multiple alleles must be present at every locus.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Hardy-Weinberg equilibrium requires five conditions: no migration, no natural selection, random mating, no mutations, and large population size. Having multiple alleles at a locus is not a requirement - the equilibrium can be maintained with just two alleles at each locus.

Multiple choice

A trait in an organism is influenced by

  1. maternal DNA only

  2. paternal DNA only

  3. both maternal and paternal DNA

  4. neither by paternal nor by maternal DNA

  5. the environment
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

A trait in an organism is influenced by both maternal and paternal DNA.