BIOLOGY M.C.Q (1 Marks)

2. Mesozoic era.

4. There should become physical basis of inheritance.

3. When the population live in different conditions.

Explanation:

Genetic variation is the naturally occurring genetic differences among individuals of the same species. This variation permits flexibility and survival of a population in the face of changing environmental circumstances.

Factors affecting the gene frequency of population:

Physical distribution of individuals affects a population.

When a population interbreeds.

Random fluctuations in the numbers of alleles in a population.

Migration is the movement from one location to another.

2. Divergent evolution.

3. Palaeozoic → Mesozoic → Coenozoic.

2. Adaptive radiation

Explanation:

Adaptive radiation is the relatively fast evolution of many species from a single common ancestor. It occurs when an organism enters a new area and different trait affect its survival.

An example of adaptive radiation is Hawaiian honeycreeper is small, passerine birds.

They are closely related to the rosefinches in the genus Carpodacus. Their great morphological diversity is the result of adaptive radiation in an insular environment.

Hence, Hawaiian honeycreeper (birds) are an example of Adaptive radiation.

3. Shrews.

2. Australopithecus

Explanation:

Ardipithecus and Australopithecus species are often referred to as australopithecines. Australopithecus species were bipedal (walked on two feet), an important hominid feature.

The Australopithecus gives rise to man-like apes. It had human-like teeth but it had more of an ape brain than a human brain.

2. 0.48

Explanation:

The Hardy-Weinberg equation is given as - p² + 2pq + q² = 1

where p is the frequency of the 'A' allele and q is the frequency of the 'a' allele in the given population.

p² represents the frequency of the homozygous genotype AA.

q² represents the frequency of the homozygous genotype aa.

2pq represents the frequency of the heterozygous genotype Aa.

So, (0.6)² + 2pq + (0.4)² = 1

0.36 + 2pq + 0.16 = 1

2pq = 0.48

Hence, the frequency of heterozygotes in a random mating population at equilibrium is 0.48.

So, the correct answer is '0.48'

1. Miller–Urey experiment.

4. All of the above

Explanation:

A primate is a mammal of the order Primates, which includes lemurs, lorises, tarsiers, monkeys, apes and humans. They exhibit menstrual cycle.

Primates arose from ancestors that lived in the trees of tropical forests. Most primate species remain at least partly arboreal.

4. Both B and C

Explanation:

According to Darwin, Marsupials were considered inferior with respect to placentals. These species thrived where there was no competition or in other words in the absence of natural selection. Marsupials existence in Australia and New Zealand gives us clue about the geological period and we get evidence that these continents were joined long ago.

As per continental drift theory around 30 to 40 million years ago, South America and Australia were joined in the Southern hemisphere and it is believed that marsupials could have migrated between these islands which proves both the continental drift and the related geological period.

1. The young ones are protected inside the mother's body and are looked after they are born leading to more chances of survival.

4. All of these.

2. Directional.

Industrial melanism is not a mean character but is acquired by most of the individuals. Hence, it is an example of directional change.

1. Cambrian

4. All of the above

Explanation:

The conditions to maintain the Hardy-Weinberg equilibrium are no mutation, no gene flow, large population size, random mating, and no natural selection.

Hardy-Weinberg equilibrium is disturbed by deviation from any of its five conditions.

Hence, Hardy-Weinberg equilibrium can be disturbed by Mutations, Non-random mating and Genetic drift.

So, the correct answer is 'All of the above'.

1. Amino acids.

1. Artificial selection.

3. Coenozoic

Explanation:

The Azoic era is the era without life which includes the origin of the earth, its cooling down and other changes to make it suitable for life forms. The Proterozoic era (2000 million yrs ago and spanned for 1500 million years), the era of early life, is marked by a build-up of oxygenic atmosphere and appearance of the first eukaryotic cell.

Mesozoic era (from 230 million years ago to 63 million yrs ago) is the era of medieval life and includes three periods namely, Cretaceous (135 million years), Jurassic (180 million years) and Triassic (225 million years). It is also known as the age of gymnosperms or age of reptiles.

The Cenozoic era is the era of modern life and is also known as the age of mammals and angiosperms. It began 63 million yrs ago and is still continuing which makes it the most recent/latest.

2. Study of traditional plantlore, plant use, etc.

3. Convergent evolution.

1. Homo neanderthalensis.

4. 2 million

Explanation:

Life on Earth has been evolving for more than 3000 million years. It continues to do so. It has been estimated that the total number of species of plants and animals living today varies from 5 to 5 million, but only 1.8 million species have so far been described. Of the total known biodiversity, about 0.5 million species represent plants and the remaining species contribute animals. 

This huge variety of living things reflects the geological, climatic and other environmental differences that occur on this planet. These species live together as ecological communities, some are producers, others are consumers. Each is dependent on the presence of many other species.

3. Jurassic

Explanation:

Jurassic is a geological period which is marked by the evolution of first bird from the theropod dinosaurs.

In the Jurassic, birds evolved from small specialized coelurosaurian theropods, and are today represented by 10,000 living species.

In modern birds, the body is typically held in a somewhat upright position, with the upper leg (femur) held parallel to the spine and with the forward force of locomotion generated at the knee.

The common features which prove the evolution of birds from the theropod dinosaurs are a furcula (wishbone), air-filled bones, brooding of the eggs, and in coelurosaurs, at least feathers.

1. Java man

Explanation:

Homo erectus made tools made of stones and bones and made fire using primitive stone tools. Java ape man or Homo erectus erectus lived in caves and knew use of fire for hunting, defence and cooking.

3. Homo habilis.

4. Development of a common set of characteristics in group of different ancestry.

Explanation:

Convergent evolution describes the independent evolution of similar features in species of different lineages.

4. Proterozoic

Explanation:

The term proterozoic comes from the Greek words proteros (meaning first) and zoon (meaning life). Although early fossils are now thought to occur in older, archean rocks, for many years the oldest evidence of life was known from proterozoic strata. The proterozoic represents the last stage of what was once called, precambrian, 3.7-billion-year-long period before the paleozoic era.

Many of these life forms developed the ability to photosynthesize. As a byproduct of photosynthesis, they created oxygen and over billions of years this oxygen transformed the Earths atmosphere. Because oxygen was toxic to some early life forms, many went extinct. Others thrived and evolved into the first multicellular organisms, which are preserved as the ediacaran fauna. Both the beginning and end of the proterozoic were marked by widespread glaciation.

About one billion years ago the dominant organisms of earth were cyanobacteria and protozoans, therefore, it was named 'proterozoic'. Proterozoic era is called as age of prokaryotic microbes. During archaezoic era, precambrian era and phaenerozoic era microbes are not dominant. So, they are not called as age of prokaryotic microbes.

1. Variation

2. rRNA