Tag: biology

Questions Related to biology

Which of the following are the two key concepts of Darwinian theory of evolution?

biology evolution of life darwinism or theories of natural selection darwin's theory of evolution theories of evolution

  1. Genetic drift and mutation

  2. Adaptive radiation and homology

  3. Mutation and natural selection

  4. Branching descent and natural selection

Show answer
Correct Option: D
Explanation:
According to Darwin's theory of evolution, nature selects the fittest. Fitness is based on characteristics which are inherited. Therefore, there must be a genetic basis for getting selected and to evolve. Some organisms are better adapted to survive in an otherwise hostile environment. Adaptative ability is inherited. It has a genetic basis. Fitness is the end result of the ability to adapt and get selected by nature. Therefore, branching descent (inheritance) and natural selection are the two key concepts of Darwin's theory of evolution.

So, the correct answer is 'Branching descent and natural selection'.

By the statement 'survival of the fittest', Darwin meant that

biology evolution of life darwinism or theories of natural selection darwin's theory of evolution theories of evolution

  1. The strongest of all species survives

  2. The most intelligent of the species survives

  3. The cleverest of the species survives

  4. The species most adaptable to changes survives

Show answer
Correct Option: D
Explanation:
The organisms which are provided with favorable variations would survive, because they are the fittest to face their surroundings, while the unfit are eliminated. Originally it was an idea of Herbert Spencer $(1820 - 1903)$ who used the phrase 'the survival of the fittest' first time. While Darwin named it as natural selection.
So, the correct answer is 'The species most adaptable to changes survives'.

Which of the following are necessary for evolution by natural selection to take place?
(i) Offspring resemble their parents more than other individuals in the population.
(ii) Differences among individuals exist and lead to different numbers of successful offspring being produced.
(iii) Individuals adjust their development depending on the environment
(iv) Every individual possess enormous fertility.

biology evolution of life darwinism or theories of natural selection darwin's theory of evolution theories of evolution

  1. (i) and (ii)

  2. (ii) and (iv)

  3. (i), (iii) and (iv)

  4. (iii) only

Show answer
Correct Option: B
Explanation:

The theory of natural selection was proposed by Charles Darwin. It states that Natural selection is the process where organisms with favourable traits are more likely to reproduce. In doing so, they pass on these traits to the next generation. Over time this process allows organisms to adapt to their environment. Features which are necessary for evolution by natural selection to take place are 

a) Differences among individuals exist and lead to different numbers of successful offspring being produced.

b) Every individual possesses enormous fertility.
So, the correct answer is '(ii) and (iv)'

The diversity in the type of beaks of finches adapted to different feeding habits on the Galapagos Islands, as observed by Darwin, provides evidence for

biology evolution of life darwinism or theories of natural selection darwin's theory of evolution theories of evolution

  1. Intraspecific competition

  2. Interspecific competition

  3. Origin of species by natural selection

  4. Origin of species by mutation

Show answer
Correct Option: C
Explanation:
Darwin during his famous voyage, observed that finches from various Islands of Galapagos had beaks of different sizes and shapes. He observed that this was due to adaptation to different available food types. He concluded that the ancestral finches on reaching different islands occupied all empty ecological niches in absence of competition and evolved into different species. This provides evidences for origin of species by natural selection.

So, the correct answer is 'Origin of species by natural selection'.

Given: 1= Natural selection; 2= Variations and their inheritance; 3= Survival of the fittest; 4= Struggle for existence.
According to Darwinism, which of the following represents the correct sequence of events in the origin of new species?

biology evolution of life darwinism or theories of natural selection darwin's theory of evolution theories of evolution

  1. $3, 4, 1, 2$

  2. $2, 3, 1, 4$

  3. $1, 2, 3, 4$

  4. $4, 2, 3, 1$

Show answer
Correct Option: D
Explanation:

  1.  There is a struggle for existence, because of the disparity between the number of individuals produced by reproduction and the number that can survive.
  2. Individuals within a species show variation; no two individuals are exactly alike. Those with advantageous characters have a greater probability of survival, and therefore of reproducing, in the struggle for existence.
  3. Individuals produce offspring that tend to resemble their parents (the principle of inheritance). Provided that the advantageous characters that promote survival are inherited by offspring.
  4. The offspring that evolve according to the condition are fittest for survival.
  5. Those are selected by nature and weaker ones got eliminated.
So the correct option is '4,2,3,1'

Naturalist who sailed round the world in ship Beagle was :

biology evolution of life darwinism or theories of natural selection darwin's theory of evolution theories of evolution

  1. Charles Lyell

  2. Charles Darwin

  3. Alfred Wallace

  4. Lamarck

Show answer
Correct Option: B
Explanation:

  • Darwinism is an evolutionary theory proposed by Charles Robert Darwin, an English Naturalist. He believed that evolution is a gradual, rather than a sudden biological event. His theory was based on several facts, He sailed round in Beagle, his ship observations and inferences. They are 1) overproduction, 2) constancy in population, 3) struggle for existence, 4) natural selection.
  • The prodigality of production or overproduction: Every organism tends to increase its population in large proportions. For example, Paramecium divides by binary fission at the rate of three to four times a day. At this rate, the volume of all the paramecia equals to 10,000 times that of the earth at the end of the 9000th generation in the absence of any check.
  • Constancy in population: However, such an abnormal increase is not noticed in the population of any species in nature as the offspring die in large number before reaching the reproductive age. It is true that the food and the other sources do not increase in the same proportion as that of the population.
  • Struggle for existence: As the food sources are limited, severe competition exists among the members of a population. Darwin called it a struggle for existence.
  • Natural selection: The organisms with less reproductive success are not represented in future generations, however, fit they may be in the struggle for existence. This is called the Natural selection. Herbert Spencer called this phenomenon Survival of the fittest.
  • Darwinism failed to explain the mechanism by which variations occur. Thus Darwin faced the criticism "DARWINISM EXPLAINS THE SURVIVAL OF THE FITTEST BUT NOT THE ARRIVAL OF THE FITTEST".
So, the correct option is ' Charles Darwin'.

Darwin wrote "Origin of Species" in

biology evolution of life darwinism or theories of natural selection darwin's theory of evolution theories of evolution

  1. 1530

  2. 1795

  3. 1859

  4. 1895

Show answer
Correct Option: C
Explanation:

  • Darwinism is an evolutionary theory proposed by Charles Robert Darwin, an English Naturalist. He believed that evolution is a gradual, rather than a sudden biological event. His theory was based on several facts, observations and inferences. They are 
1) overproduction
2) constancy in population
3) struggle for existence
4) natural selection.
  • The prodigality of production or overproduction: Every organism tends to increase its population in large proportions. For example, Paramecium divides by binary fission at the rate of three to four times a day. At this rate, the volume of all the paramecia equals to 10,000 times that of the earth at the end of the 9000th generation in the absence of any check.
  • Constancy in population: However, such an abnormal increase is not noticed in the population of any species in nature as the offspring die in large number before reaching the reproductive age. It is true that the food and the other sources do not increase in the same proportion as that of the population.
  • Struggle for existence: As the food sources are limited, severe competition exists among the members of a population. Darwin called it a struggle for existence.
  • Natural selection: The organisms with less reproductive success are not represented in future generations, however, fit they may be in the struggle for existence. This is called the Natural selection. Herbert Spencer called this phenomenon Survival of the fittest.
  • He wrote Origin of Species including these points in 1859.
So, the correct option is '1859'.

Charles Darwin discovered the law of independent assortment.

biology evolution of life darwinism or theories of natural selection darwin's theory of evolution theories of evolution

  1. True

  2. False

Show answer
Correct Option: B
Explanation:
  • The law of independent assortment was given by Mendel. He also gave the 'Law of Dominance' and 'Principle of Segregation'.

Charles Darwin concluded that 

biology evolution of life darwinism or theories of natural selection darwin's theory of evolution theories of evolution

  1. Existing living forms share similarities to varying degree not only among themselves but also with the life forms that existed millions of years ago.

  2. These has been gradual evolution in the life forms on earth.

  3. Those organism, who are better fit in an environment leave more progeny that others. These therefore, will survive more and hence are selected by nature

  4. All the above

Show answer
Correct Option: D
Explanation:

The Darwin theory of natural selection can be concluded as :

1. The number of organisms are produced more than that can survive because of limited resources.
2. Organisms struggle for the necessities of life; there is competition for resources.
3. Individuals within a population vary in their traits; some of these traits are heritable.
4. Some variants are better adapted to survive and reproduce under local conditions than others.
5. Better-adapted individuals are more likely to survive and reproduce, thereby passing on copies of their genes to the next generation.
6. Species whose individuals are best adapted survive while others become extinct.
So, the correct option is 'All of the above'.

Darwin's theory of natural selection to explain organic evolution was based on?

biology evolution of life darwinism or theories of natural selection darwin's theory of evolution theories of evolution

  1. Inheritance of acquired character

  2. Appearance of sudden large inheritable variation

  3. Modification of organs through use and disuse

  4. Prodigality of reproduction, struggle for existence and survival of the fittest

Show answer
Correct Option: D
Explanation:

Darwin's theory of natural selection explains organic evolution as follows : 

1. The number of organisms are produced more than that can survive because of limited resources.

2. Organisms struggle for the necessities of life; there is competition for resources.
3. Individuals within a population vary in their traits; some of these traits are heritable.
4. Some variants are better adapted to survive and reproduce under local conditions than others.
5. Better-adapted individuals are more likely to survive and reproduce, thereby passing on copies of their genes to the next generation.
6. Species whose individuals are best adapted survive while others become extinct.


So, the correct option is 'Prodigality of reproduction, struggle for existence and survival of fittest'.