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

Why offsprings are never found identical to their parents?

  1. Offsprings can be identical to only one of both the parents.

  2. All the offsprings are phenotypically different, but genotypically the same.

  3. Genetics do not play any role in this.

  4. They share the genes from both father and mother.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

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Multiple choice

The term pleiotrophy refers to __________.

  1. combining genes from different species

  2. technique for identification of patterns that occur in DNA

  3. impact of single gene over several traits

  4. inheritance of complex characters that are determined by two or more genes

  5. a form of interaction between nonallelic genes in which one combination of such genes has a dominant effect over other combinations
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Pleiotrophy refers to the control of several distinct and seemingly unrelated phenotypic effects (traits) by a single gene.

Multiple choice plant kingdom biology

Name the phenomenon that governs the following-

  1. Green beetels living in green bushes are not eaten by the crows
  2. All tall plants are obtained in $F _1$ generation, upon crossing pure tall and dwarf pea plant.

  3. Tails of mice were surgically removed for several generation ; still mice have tails in the following generation .

  4. Numbers of blue beetles on green bushes increase in a fur distant location than green beetles on green bushes, isolated by a river.

  5. A migrant beetle reproduces with the local population ; as a result genes of migrant beetle enter the new population.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Green beetles living in green bushes are camouflaged by their surroundings and are hence not eaten by the crows. This is a defense strategy employed by the beetles in order to escape predation. In the F1 generation crossing homozygous dominant (pure tall) and homozygous recessive (pure dwarf) plants will result in the heterozygous condition (Tt) with a phenotype of all tall plants as they will still have the dominant genotype. Removal of tails cannot be passed on from one generation to another, as it is not a heritable change and not a part of the genetic makeup of the organism. The isolation of an organism by a geographical barrier such as a river is called allopatry and hence governs the speciation of a sub-population such as blue beetles from green beetles. When a  migrant beetle reproduces with the local population the genes of migrant beetle enter the new population by the means of gene flow (also known as gene migration or allele flow) is the transfer of genetic variation from one population to another.  

So the correct answer is Green beetles living in green bushes are not eaten by the crows.

Multiple choice self pollination asexual and sexual reproduction in plants botany

Repeated self pollination over the generations produces.

  1. New varieties

  2. Elimination of weak traits

  3. Better progeny

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

Repeated self-pollination leads to inbreeding depression, where the accumulation of homozygous recessive deleterious alleles results in reduced fitness and vigor. This process is commonly used in breeding to create pure lines, but it often manifests as weak progeny.

Multiple choice commercial applications population - the increasing numbers and rising problem impact of depletion of natural resources population growth models depletion of resources

Carrying capacity is

  1. The capacity of an individual to produce young ones.

  2. Availability of resources in a given habitat to support a certain number of individuals of population, beyond which no further growth is possible.

  3. Gene frequency from one generation to next.

  4. Gene frequency in same generation.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The carrying capacity of an organism is the maximum population size of the species that the environment can sustain indefinitely beyond which there is no further growth. When the population reaches the carrying capacity then mortality becomes greater than natality.

Therefore, the correct answer is option B.

Multiple choice different stages of growth reproductive system in humans division for growth and reproduction human system biology

"Genes in somatic cells undergo mutation with time and cause senescence. This theory belongs to ________________.

  1. Error and damage theories

  2. Hormonal theory

  3. Immunological theories

  4. Programmed senescence theory
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

A. Error and damage theories - emphasize environmental assaults to living organisms that induce cumulative damage at various levels as the cause of aging.

B. Hormonal theory - hormones or reduced production of hormones might cause aging has also led some to believe that they could be an anti-aging elixir. 

C. Immunological theory - asserts that the process of human aging is, in fact, a mild and generalized form of prolonged auto-immune phenomenon.

D. Programmed senescence theory - refers to the idea that senescence in humans and other organisms is purposely caused by evolved biological mechanisms in order to obtain an evolutionary advantage.

So, the correct option is ‘Error and damage theories’.

Multiple choice zoology the paths traversed by life evidences for evolution - taxonomy, molecular biology and cytology evidences of evolution evidences of biological evolution

Type of selection operating in:

(i) Average weight of the new born - X.

(ii) Industrial melanism - Y.

(iii) Sunflower population in Sacramento valley of California - Z.

Here if X, Y and Z are representing the types of natural selection, then X, Y and Z will be:

  1. X - Directional selection, Y - Balancing selection, Z - Diversifying selection.

  2. X - Balancing selection, Y - Directional selection, Z - Diversifying selection.

  3. X - Diversifying selection, Y - Balancing selection, Z - Directional selection.

  4. X - Diversifying selection, Y - Directional selection, Z - Balancing selection.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Stabilizing selection (balancing) maintains the average (birth weight), directional selection shifts the trait (industrial melanism), and disruptive (diversifying) selection favors extremes (sunflower population).