BIOLOGY M.C.Q [1M]

4. Natural selection

Explanation:

Any factor, which can disturb the frequency of alleles in a population is likely to affect the Hardy-Weinberg equilibrium.

The alleles in a population can be altered by mutation, migration, genetic drift, recombination, and natural selection.

2. Directional as it pushes the mean of the character in one direction.

4. Haldane

Explanation:

J.B.S. Haldane was born in England but migrated to India in July 1957 and settled in Bhubaneswar, Orissa. He was a biologist, biochemist, and geneticist. He along with Oparin, a Russian scientist gave similar views regarding the origin of life.

The Oparin-Haldane theory is also called chemical theory. According to this theory, life originated upon our earth spontaneously from non-living matter.

4. Loss of tail.

4. Pliocene

Explanation:

The Pliocene epoch extends from 5.332 million to 2.588 million years before present. Man evolved in this era.

1. Genetic equilibrium

Explanation:

Hardy Weinberg law is applicable to genetic equilibrium. The Hardy-Weinberg equilibrium is a principle stating that the genetic variation in a population will remain constant from one generation to the next in the absence of disturbing factors.

When mating is random in a large population with no disruptive circumstances, the law predicts that both genotype and allele frequencies will remain constant because they are in equilibrium.

1. 800 to 1300cc

Explanation:

Homo erectus is an extinct species of hominin that lived throughout most of the Pleistocene. The brain capacity of Homo erectus was 800 to 1300cc.

1. Life

Explanation:

How life actually originated we do not know but we do know that it started with accumulation of biomolecules produced in reducing atmosphere. The biomolecules later on gave rise to aggregates of biomolecules.

First nucleoproteins were most probably produced on clay surfaces. That was the important first sign of life because it meant a transition from an aggregate of biomolecule to a self replicating entity, an important characteristic of living organisms.

1. Banding pattern in chromosomes number 3 and 6.

1. 2pq.

4. Convergent evolution.

2. Natural selection acting on favourable variations.

3. Gorilla

1. Theory of special creation.

Explanation:

According to special creation theory, all the different forms of life that occur today on planet earth, have been created by God, the almighty. This idea is found in the ancient scriptures of almost every religion. According to Hindu mythology, Lord Brahma, the God of Creation, created the living world in accordance to his wish.

According to the Christian belief, God created this universe, plants, animals and human beings in about six natural days. The Sikh mythology says that all forms of life including human beings came into being with a single word of God. Special creation theory believes that the things have not undergone any significant change since their creation.

4. Adaptive radiation

Explanation:

In evolutionary biology, adaptive radiation is a process in which organisms diversify rapidly into a multitude of new forms, particularly when a change in the environment makes new resources available, creates new challenges and opens environmental niches. Thus, option D is correct.

Adaptive convergence is a form of evolution in which two unrelated (or distantly related) species evolve very similar forms due to similar selective pressures. Thus, option C is wrong.

Genetic drift or allelic drift is the change in the frequency of a gene variant (allele) in a population due to random sampling. Thus, option B is wrong.

Speciation is the evolutionary process by which new biological species arise. Thus, option A is wrong.

1. Convergent

Explanation:

Convergent evolution is the process whereby organisms not closely related (not monophyletic), independently evolve similar traits as a result of having to adapt to similar environments or ecological niches.

Wings of mosquito, bats, birds are examples of convergent evolution as these organisms not closely related (not monophyletic), independently evolve similar traits as a result of having to adapt to similar environments. Thus, option A is correct.

Divergent evolution is the accumulation of differences between groups, which can lead to the formation of new species, usually a result of diffusion of the same species to different and isolated environments which blocks the gene flow among the distinct populations allowing differentiated fixation of characteristics through genetic drift and natural selection.

Parallel evolution is the evolution of geographically separated groups in such a way that they show morphological resemblances. Adaptation is the evolutionary process whereby a population becomes better suited to its habitat.

3. Fossils.

Paleontological evidences for evolution refer to the fossils. Fossils provide direct and solid evidence in favour of organic evolution thrugh ages. Fossils are studied for knowing about extinct organisms. Birbal Sahni Institute of Palaeobotany is situated at Lucknow. Birbal Sahni is called ‘Father of Indian Palaeobotany’. Age of fossils is determined by Uranium-Lead method (U²³⁸) or Potassium-Argon method or Radioactive Carbon dating (C¹⁴). ESR (electronspin - resonance method) is the most accurate method of dating of fossils.

1. Fossils.

1. Discontinuous variations.

1. Protobiont

Explanation:

First cells produced were simple aggregates of organic compounds, called protobionts, which are thought to be precursors of prokaryotes.

1. They share a common ancestor.

1. Mesozoic

1. The arm of a human, wing of a bird.

2. Development of similar characteristics in different groups of organisms of different ancestry.

1. Chimpanzee

4. Sexually reproducing population.

Explanation:

In evolutionary biology, adaptive radiation is a process in which organisms diversify rapidly into a multitude of new forms, particularly when a change in the environment makes new resources available, creates new challenges and opens environmental niches.

Adaptive radiation occurs in sexually reproducing population to create multitude new forms and not in predator free area, small and isolated populations and flightless and asexually reproducing populations.

4. Sidney Fox and Oparin

Explanation:

Coacervates were non-living colloidal aggregates of proteins and polysaccharides but did not have the ability to reproduce nor they developed a covering membrane of lipids.

Oparin and Sydney Fox held that large organic molecules synthesized abiotically on the primitive earth.

These molecules later came together spontaneously and due to intermolecular attraction formed large colloidal aggregates called coacervates.

3. Nitrogen

Explanation:

The atmosphere of earth is a layer of gases surrounding the planet and it is retained by the earth's gravity. The atmosphere protects life on earth by absorbing ultraviolet solar radiation, warming the surface through heat retention and reducing temperature extremes between day and night.

The gases in earth's atmosphere include: nitrogen-78%, oxygen-21%, argon-0.9%, carbon dioxide-0.03%. Water vapour and other gases exist in small amounts as well.

Nitrogen dilutes oxygen and prevents rapid burning at the earth's surface. Living things need it to make proteins. Nitrogen cannot be used directly from the air. The nitrogen cycle is nature's way of supplying the needed nitrogen for living things.

4. Non-evolving

Explanation:

The Hardy-Weinberg principle assumes that the allele and genotype frequencies in a large population will remain constant from generation to generation in the absence of evolutionary influences like mate choice, mutation, selection, genetic drift, gene flow, and meiotic drive.

Hardy-Weinberg Equations:

p² + 2pq + q² = 1

p + q = 1

{p = frequency of the dominant allele in a population}

{q = frequency of the recessive allele in a population}

4. Melanization of peppered moth in industrial areas.

4. Convergent evolution.

Organs having different origin but similar function are called analogous. Wings of butterfly and of birds look alike. They are not anatomically similar structures though they perform similar functions. Hence, analogous structures are a result of convergent evolution-different structures evolving for the same function and hence having similarity.

2. Pleistocene

Explanation:

The first Homo sapiens have evolved in the Pleistocene Epoch.

This time period began about 2.6 million years ago and lasted till 1,700 years ago. By the end of this period, the Homo sapiens were present all over the world.

1. Trilobites

Explanation:

Trilobites were the dominant species during the Cambrian Period, 540 to 490 million years ago. They are a fossil group of extinct marine arthropods that form the class Trilobita.

They finally disappeared in the mass extinction at the end of the Permian about 250 million years ago. 

3. Biogenetic law.

3. 96

Explanation:

The gene is autosomal recessive lethal, the heterozygous individuals carrying one copy of the affected allele and one of wild type allele will serve as carriers.

If the genotype of homozygous individuals for the recessive lethal gene is qq and that of homozygous individuals for wild-type gene is pp then the genotype of heterozygous individuals will be pq.

According to the question, the frequency of a recessive lethal allele is (q = 0.4). Frequency of wild-type allele : p = 1 - q,i.e.,1 - 0.4 = 0.6

Hardy Weinberg law states that the sum of all genotype frequencies is represented as the binomial expansion of the square of the sum of p and q. This sum is equal to one. ( p + q )² = p² + 2pq + q² = 1.

Hence, the frequency of carrier genotype in total population (2pq) = 2 × 0.6 × 0.4 = 0.48.

And the number of carriers in the population of 200 is = 0.48 × 200 = 96.

2. 1.00

Explanation:

p² + 2pq + q² = 1 is the Hardy-Weinberg principle and according to this principle the equilibrium is established between frequencies of allele in random mating population and these gene frequency remain constant from generation to generation.

Here, p represents the frequency of the "A" allele and q is the frequency of the "a" allele in the population.

Thus, p² represents the frequency of the homozygous dominant AA, q² represents the frequency of the homozygous recessive aa, and 2pq represents the frequency of the heterozygous Aa.

Further, it also states that the sum of the allele frequencies for all the alleles at the locus should be 1, so p + q = 1.

According to the question, the genotype frequency of A_¹​ allele = q = 0. Since p + q = 1; thus the frequency of A₂​ allele or p will be p = 1 - q_; p = 1 - 0 = 1.

Thus, the abundance of A₂​ allele will be 1.

2. 32%

Explanation:

According to the Hardy Weinberg law, the allele and genotype frequencies in a population remain constant in the absence of factors responsible for evolution. It states that the sum of all genotype frequencies can be represented as the binomial expansion of the square of the sum of p and q.

This sum is equal to one : ( p + q )² = p² + 2pq + q² = 1.

"p" is the frequency of the dominant allele, and "q" is the frequency of the recessive allele. The "2pq" in the equation shows the frequency of heterozygotes in the population.

According to question, if it is a recessive disease then "p" is the frequency of normal dominant allele, "q" will be the frequency of disesease causing recessive allele and "2pq" will be the frequency of carrier individual.

In the question the frequency of disease causing recessive allele is given i.e q = 80% or o.8.

If p + q = 1 then, p = q - 1 => 1 - 0.8 = 0.2 or 20%.

Thus, the frequency of carrier will be = 2 × p × q => 2 × 0.8 × 0.2 = 0.32 or 32%.

1. Convergent evolution

Explanation:

Convergent evolution occurs in an unrelated group of organisms. It is the development of similar functional structures but in unrelated groups.

The process of evolution of different species in a given geographical area starting from a point and literally radiating to other areas of geography is called adaptive radiation. Natural selection is the basis of evolution.

2. Wallace

4. Amphibian

Explanation:

Amphibians are absent in Galapagos islands as they could not leave the mainland and travel to the island by crossing saline water.

2. 1600

Explanation:

Atmosphere is the layer of air enveloping the earth at the height of around 1600 km and it consists of many gases. The major components of the atmosphere are nitrogen, oxygen and water vapour. The minor components are argon and carbon dioxide, the trace components include inert gases like methane.

The atmosphere protects us from meteors and harmful solar radiation and warms the earth's surface by heat retention. Earth's atmosphere has primary five layers, referred to as spheres. From the lowest to the highest layer, they are the troposphere, stratosphere, mesosphere, thermosphere and exosphere.

These five distinct layers have been identified using thermal characteristics, chemical composition, movement and density.

1. Biogenesis theory

Explanation:

Biogenesis means life comes from pre existing life, as in modern earth. Now life comes from pre-existing life only but life actually evolved from non living components abiogenetically.

4. All human races can interbreed and produce fertile offspring.

Explanation:

Human races are subdivisions of a single species, therefore they are capable of interbreeding.

4. Proterozoic

Explanation:

Proterozoic era is the time when life came on earth and there were evidences of life on earth, this includes the formation of cellular structures and less complex organisms.

2. Mutation

4. Insects

Explanation:

The first animals to evolve flight were insects. The earliest fossil insects with wings are dragonfly-like animals from the Carboniferous, but there are some very fragmentary insect remains from Devonian rocks in Scotland.

The fossils tell that the flight first evolved in insects approximately 410 million years ago.

4. All of the above

Explanation:

The Hardy–Weinberg principle states that allele and genotype frequencies in a population will remain constant from generation to generation in the absence of other evolutionary influences.

It operates in the absence of mutation, natural selection, and recombination.

1. Hominidae

Explanation:

The Hominidae (also known as great apes) form a taxonomic family of primates, including four genera:

1. Chimpanzees
2. Gorillas
3. Humans
4. Orangutans

4. 5,00,000 years ago

Explanation:

Oldest hominid belongs to the genus Ardipithecus of family Australopithecine, which lived in Eastern Africa more than 5 mya.