FREE NEET Biology Practice MCQ Test: Evolution Exercise 1 Questions Answers With Detailed Explanations [PDF]

Answer: (d)

Answer: (c)

Thorn of Bougainvillea and tendrils of Cucurbita are the examples of homologous organ. Homologous organs are those organs which are similar in their morphology, anatomy and embryology but dissimilar in their functions

Answer: (d)

Around 2.5 billion years ago, during the Precambrian, oxygen began to accumulate in the atmosphere due to the action of photosynthetic cyanobacteria.

Answer: (c)

Answer: (b)

Adaptive radiation refers to evolution of different species from a common ancestor. The mammals are adapted for different mode of life i.e. they show adaptive radiation. They can be aerial (bat), aquatic (whale and dolphins), burrowing or fossorial (rat), cursorial ( horse), scantorial (squirrel) or arboreal (monkey). The adaptive radiation, the term by Osborn, is also known as Divergent evolution.

Answer: (d)

Eyes of Octopus, bat and man are examples of analogous organs which show convergent evolution. Divergent evolution results in homologous structures. These organs have the same fundamental structure but are different in functions. Structural homology is seen in brain, heart and forelimbs of man, bat and cheetah.

Answer: (b)

Random genetic drift in a population probably results from highly genetically variable individuals. Random genetic drift refers to random fluctuations in the numbers of gene variants in a population. It takes place when the occurrence of variant forms of a gene, called alleles, increases and decreases by chance over time. These variations in the presence of alleles are measured as changes in allele frequencies.

Answer: (b)

Marsuvpials in Australia and placental mammals in North America show convergent evolution. These two subclasses of mammal have adapted in similar ways to a particular food supply, locomotor skill or climate.

Answer: (c)

According to Lamarckism (or Lamarckian inheritance) an organism can pass on the characteristics that it acquired during its lifetime. According to Lamarck, a giraffe has a long neck because its ancestors stretched their necks to get the food.

Answer: (d)

Answer: (d)

$p^{2} + 2pq +q^{2}$ = 1is the equation associated with Hardy-Weinberg Equilibrium. In this equation $p^{2}$ represents the frequency of individuals who are homozygous for one allele, 2pq is the frequency of heterozygous individuals, and $q^{2}$ is the frequency of individuals who are homozygous for the other allele.

Adding the cells of the table together will provides with, $p^{2} + pq + pq + q^{2} = p^{2} + 2pq + q^{2}$ .

Answer: (a)

Answer: (a)

Answer: (b)

Humans differ from most primates in that they lack a tail. The lower primates have tails, and the apes, which are believed by many to be our closest relatives, likewise are tailless.

Answer: (a)

Answer: (b)

Answer: (c)

Answer: (d)

Answer: (d)

When Charles Darwin returned from the voyage in 1836, he got a chance to read the books ‘The principles of Geology’ by Charles Lyell and ‘Essays on principles of (human) population’ by T.H. Malthus. Malthus in his book described that human population increases in geometric ratio while food increases in arithmetic ratio. This book of Malthus influenced the work of Charles Darwin most.

Answer: (b)

Stabilizing selection favours average sized individuals while eliminates small sized individuals. It reduces variation and thus, does not promote evolutionary change. But it maintains the mean value from generation to generation. In directional selection, the population changes towards one particular direction. It favours small or large sized individuals and more individuals of that type will be present in next generation. The mean size of the population changes. Disruptive selection favours both small-sized and large-sized individuals, It eliminates most of members with mean expression, so produces two peaks in the distribution of the trait that may lead to development of two different individuals. It is important in bringing about evolutionary change.