NCERT Exemplar Class 11 Biology Solutions Chapter 1 The Living World

Multiple Choice Questions:

Question:1

As we go from species to kingdom in a taxonomic hierarchy, the number of common characteristics
a. Will decrease
b. Will increase
c. Remain same
d. May increase or decrease

Answer:

Question:2

Which of the following ‘suffixes’ used for units of classification in plants indicates a taxonomic category of ‘family.’
a) -Ales
b) -Onae
c) -Aceae
d) -Ae

Answer:

Question:3

The term ‘systematics’ refers to:

a) Identification and study of organ systems
b) Identification and preservation of plants and animals
c) Diversity of kinds of organisms and their relationship
d) Study of habitats of organisms and their classification

Answer:

Question:4

Genus represents

a) An individual plant or animal
b) A collection of plants and animals
c) Group of closely related species of plants and animals
d) None of these

Answer:

Question:5

The taxonomic unit ‘Phylum’ in the classification of animals is equivalent to which hierarchical level in the classification of plants

a) Class
b) Order
c) Division
d) Family

Answer:

The answer is option (c) Division.

Explanation: As in the case of the animal kingdom, phylum comes after kingdom an in the plant kingdom, division comes after kingdom, so division is the equivalent hierarchical of phylum in the classification of the plants.

Question:6

Botanical gardens and zoological parks have

1. Collection of endemic living species only
2. Collection of exotic living species only
3. Collection of endemic and exotic living species
4. Collection of only local plants and animals

Answer:

The answer is option (c) collection of endemic and exotic living species

Explanation: You will have to either visit a botanical garden or zoological park yourself or look up on the internet to find that they have a collection of endemic and exotic living species. For example, tiger and lions are found in the zoological parks, which are the examples of endemic species, whereas giraffe is an example of an exotic species that is found in the zoological parks.

Question:7

Taxonomic key is one of the taxonomic tools in the identification and classification of plants and animals. It is used in the preparation of

1. Monographs
2. Flora
3. Both (a) and (b)
4. None of these

Answer:

The answer is option (c) Both (a) and (b).

Question:8

All living organisms are linked to one another because

1. They have common genetic material of the same type
2. They share common genetic material but to varying degrees
3. All have common cellular organization
4. All of the above

Answer:

Ans: The answer is option (b) They share common genetic material but to varying degrees.

Explanation: The entire theory of evolution is based on the fact that all the organisms have had the same ancestors and have common genetic material. The variations that came in the genetic material with the evolution had created a diversity of the organisms that we observe around us.

Question:9

Which of the following is a defining characteristic of living organisms?

1. Growth
2. Ability to make sound
3. Reproduction
4. Response to external stimuli

Answer:

The answer is option (d) Response to external stimuli

Explanation: The other character than the response to the stimuli might not be apparent for any time, but the response to the stimuli could be confirmed whenever required and thus can be considered as the defining characteristic of living organisms.

Question:10

Match the following and choose the correct option

Options

1. (i)-D, (ii)-C, (iii)-E, (iv)-B, (v)-A
2. (i)-E, (ii)-D, (iii)-B, (iv)-A, (v)-C
3. (i)-D, (ii)-E, (iii)-B, (iv)-A, (v)-C
4. (i)-E, (ii)-C, (iii)-B, (iv)-A, (v)-D

Answer:

The answer is option (a) (i)-D, (ii)-C, (iii)-E, (iv)-B, (v)-A

Explanation: The order that is followed for the taxa is Kingdom, Order, Family, Genus and then Species.

The classification for the potato is as follows: -

• Species: tuberosum
• Genus: Solanum
• Family: Solanaceae
• Order: Solanales
• Kingdom: Plantae

Very Short Answer Type Questions:

Question:1

Linnaeus is considered as Father of Taxonomy. Name two other botanists known for their contribution to the field of plant taxonomy.

Answer:

Question:2

What does ICZN stand for?

Answer:

Ans: ICZN is the abbreviation for International Code for Zoological Nomenclature.

Question:3

Couplet in taxonomy means_______.

Answer:

Couplet in taxonomy means contrasting characters.

Question:4

What is a monograph?

Answer:

A monograph provides the work on the primary research and has the information for the various taxon.

Question:5

Amoeba multiplies by mitotic cell division. Is this phenomena growth or reproduction? Explain ?

Answer:

Amoeba is known to reproduce by mitotic cell division because it divides into two new organisms and thus is it an act of reproduction rather than growth.

Question:6

Define metabolism.

Answer:

Question:7

Which is the largest botanical garden in the world? Name a few well known botanical garden in India.

Answer:

• Lloyd Botanical Garden, Darjeeling
• National Botanical Garden, Lucknow
• Indian Botanical Garden, Kolkata
• Botanical Garden of FRI, Dehradun

Short Answer Type Questions:

Question:1

A ball of snow when rolled over snow increases in mass, volume and size. Is this comparable to growth as seen in the living organisms? Why?

Answer:

Question:2

In a given habitat we have 20 plant species and 20 animal species. Should we call this ‘diversity’ or ‘biodiversity’? Justify your answer.

Answer:

Question:3

International Code of Botanical nomenclature (ICBN) has provided a code for the classification of plants. Give a hierarchy of units of classification botanists follow while classifying plants and mention different ‘suffixes’ used for the units.

Answer:

According to the International Code of Botanical nomenclature, the units of classifications and their suffixes used by the botanists are given below.

Question:4

A plant species shows several morphological variations in response to altitudinal gradient. When grown under similar conditions of growth, the morphological variations disappear, and all the variants have common morphology. What are these variants called?

Answer:

Ans: The variants that occur due to the morphology are called biotypes. The biotypes have a similar genetic structure, but they have different morphology because the abiotic factors like pH of the soil, temperature, rainfall, etc. change the morphology of the plants. This change is an abiotic factor is observed due to the difference in the altitude gradient.

Question:5

How do you prepare your own herbarium sheets? What are the different tools you carry with you while collecting plants for the preparation of an herbarium? What information should a preserved plant material on the herbarium sheet provide for taxonomical studies?

Answer:

The herbarium sheet can be prepared by following the given steps: -

1. Collection: You will need to collect the living beings of a particular species.
2. Pressing: The collected specimens of the species are kept between two sheets and then pressed hard so as to preserve them.
3. Drying: In this step, the specimen is kept for drying, which is usually done in the sun.
4. Poisoning: The specimens need to be injected with the antifungal treatment so that they can be preserved for longer.
5. Mounting: In this step, the sample of the specimen is kept over the herbarium for mounting.
6. Labelling: The information about the classification of the specimen is written on the label.

The tools that are necessary and would be required while collecting the specimen of a particular species for the herbarium include digger, sickle, polythene bags, pruning knife, vasculum, old newspaper, blotting paper, herbarium sheets, labels, glue, plant press, field notebooks, etc.

The necessary information that needs to be put on the label while putting it in a herbarium for preservation includes the name of the division that it belongs to, the family, genus and the species of the specimen.

Question:6

What is the difference between flora, fauna and vegetation? Eichhornia crassipes is called as an exotic species while Rauvolfia serpentina is an endemic species in India. What, so these terms exotic and endemic refer to?

Answer:

The term flora is used to refer to the total plant species that are sound in a particular geographical area. The fauna is the total animal species found in that area, and the vegetation is a broader term that is used for a larger area than an ecosystem of a particular area. At times, vegetation is used to refer to the plants’ species that is present all around the globe.

Endemic species: The species of any living beings that are found in a particular geographical area is referred to as the endemic species of that area. For example, Rauvolfia serpentina is an endemic species found in India.

Exotic species: The species that are not naturally found in a particular geographical area but is either present due to careful selection or breeding or has been imported to that area for any reason is referred to as the exotic species. For example, Eichhornia crassipes is not naturally found in India, and thus it is an exotic species in India.

Question:7

A plant may have different names in different regions of the country or the world. How do botanists solve this problem?

Answer:

As it is quite obvious that there are a zillion languages that are spoken all around the world and they further have more dialects, it is possible that the name of a plant species would be different for different languages. This can create a huge problem as the people cannot remember a million names for a single plant, and when it comes to remembering so many names for all the species, it is impossible. Thus, the botanists have come up with a binomial nomenclature so that the naming of all the species is unique and yet same globally. The botanical name of a plant species consists of its genus name and its species name. This ensures that the scientific name of a particular plant species is the same for the ease of research.

Question:8

Brinjal and potato belong to the same genus Solanum, but to two different species. What defines them as separate species?

Answer:

Question:9

Properties of cell organelles are not always found in the molecular constituents of cell organelles. Justify.

Answer:

Though the function of the cell organelles is different, they are usually made up of similar molecules. The molecules of the cell organelle are arranged in a certain way to form a particular cell organelle. For instance, a brick can be used to make a house or a bigger factory, even though the end products are different, the constituents of the brick remain the same. In a similar manner, the properties of the cell organelles do not depend on the molecular constituents.

Question:10

The number and kinds of organisms is not constant. How do you explain this statement?

Answer:

First talking about the number of the organisms, the population of any species of organism is not constant. The population tends to change in accordance with the conditions. If the conditions are favourable, then the population grows else the population reduces. Next, the kinds of any organisms also do not remain constant because evolution is a never-ending process, and the variations in the species keep happening. The species that are able to adapt to the changing conditions survive, else the species become extinct.

Long Answer Type Question:

Question:1

What is meant by living? Give any four defining features of life forms.

Answer:

An organism is considered to be living if it is capable of evolving, self-replicating, responding to external stimuli, etc. Nutrition, response to stimuli, reproduction, growth are several aspects of living beings, but they are not the defining features of life forms. Growth is often mistaken to be a defining feature of life forms, but it is not the case as a few non-living things like snowball, cloud, etc. can also gain mass, volume, and space. So, growth is not a defining feature for living beings.

The four defining features of life forms are: -

• Metabolism: The collection of carrying out several biological reactions in the living being comprises of the metabolism. Metabolism includes the breakdown and the formation of various molecules to carry out the biological reactions in living organisms. Since metabolism requires a system comprised of cells to be carried out, it is quite evident that this cannot be done in non-living things. Though a few in-vitro reactions have been tried in the laboratories to imitate metabolism, that is not real metabolism. Thus, metabolism is one of the defining features of life.
• Reproduction: Reproductions is carried out by the living organisms to produce off-springs like them. The reproduction could be either sexual reproduction or asexual reproduction, but the act of producing off-springs of your own kind is a feature of the living organisms alone. Though there are a few living organisms like the worker bee, that does not reproduce, that does not take reproduction down as a defining feature of the life forms because reproduction cannot be carried out in the non-living things. Thus, reproduction is a defining feature of life forms.
• Response to stimuli: The stimuli can be felt by the organisms wither externally in the form of temperature, touch, light, etc. or internally via the hormones like dopamine, estrogen, etc. The response to the stimuli is a defining feature for the living beings because they are able to sense a change in their environment whether externally or internally and respond to it in the most suitable way according to their own convenience. This sense of consciousness is absent in the non-living beings, and thus, it is a defining feature of the living forms.

This arrangement from the cellular level up to the organs level is an extremely advanced and complicated manner of structural organization which cannot be made in the non-living beings. The arrangement of each cell organelle matter as the different arrangements form different cells; each cell arrangement further makes different tissues, and each arrangement of tissues makes different organs. This level of the hierarchy is not possible in the non-lining things, and thus the structural organization is a defining feature of the living beings.

Question:2

A scientist has come across a plant which he feels is a new species. How will he go about its identification, classification, and nomenclature?

Answer:

The scientist should first start by examining the morphological features of the plant like the type of roots or the venation. If the plant has fibrous roots, then it should belong to the monocotyledons, and if it has a tap root, then it should belong to the dicotyledons. This can also be checked by examining the venation of the plant, whether it is parallel or reticulate. Another way is to count the number of cotyledons present in the seeds of the plant.

After that the scientist could go ahead with finding out the inflorescence, phyllotaxy, etc. that will help the scientist to find out about the order and the family that the plant belongs to. If the sample plant is a flowering plant, then the scrutinization of the floral parts could give the details about the order and the family of the plant. The arrangement of the seed in the fruits can also tell about the type of placentation in the plant sample.

After that, the arrangement of the antheridium and gynoecium should be examined to see it the plant sample belongs to a new species of a plant. This research work done by the scientist needs to be verified on the basis of these features so that the new species of the plant can be verified. Also, when it comes to naming a new species of plant, the scientist needs to rule out the similarity of it with any other existing plant species so that a unique name could be kept for the discovered plant species.

Question:3
Brassica Campestris linn

1. Give the common name of the plant
2. What do the first two parts of the name denote?
3. Why are they written in italics?
4. What is the meaning of linn written at the end of the name?

Answer:

a) Mustard is the common name for Brassica Campestris linn.

b) The first term of the name denotes the genus that the plant belongs to and the second part denotes the family of the plant.

c) The scientific names are written in italics because it is a rule to write the scientific names in italics; and also, in this case, it could also be to represent that they have a Latin origin.

d) The linn written at the end of the name shows that this name was discovered and studied by Linnaeus.

Question:4

What are taxonomical aids? Give the importance of herbaria and museums. How are botanical gardens and zoological parks useful in conserving biodiversity?

Answer:

The tools that are used by scientists to learn about plants and animal species are known as taxonomical tools. The plants and animals species are often preserved by scientists for research purposes. The plant species are stored and preserved in a herbarium, and the animal species are preserved in the museums.

The herbarium is used to preserve and store the plant specimen with their details about classification for future reference. The herbarium is useful and can be used to refer to when people are studying the specimens belonging to the various species of the plants. Apart from being a referral system, it is also convenient to maintain a herbarium, and it could also be transported that makes it easier and more convenient.

The museums, on the other hand, have a huge collection of various plant and animal species, but mostly animal species. The skeletons of various species of animals that have gone extinct could be found in the museums for research and other purposes. The museums are often maintained by the educational institutions as they are important for the students to refer to and learn about their science lessons in real life. They get to experience it all in the museum that helps them learn better.

The role of botanical gardens and zoological parks in conserving biodiversity is immense as these places were actually created to work towards conserving the degrading biodiversity. The botanical gardens and the zoological parks are the places that provide the most comfortable and safe place to live for the plants and the animals without having to give up on the feeling of living in their natural habitat. The personnel that are appointed to take care of the plants and the animals also carry out selective breeding amongst them to ensure the continuity of various species. The personnel are always there to take care of the plants and the animals and to provide proper treatment and care if they fall sick. This helps in the conservation and betterment of biodiversity. Thus, botanical gardens and zoological parks are important for the conservation of biodiversity.

Question:5

Define a taxon. What is meant by taxonomic hierarchy? Give a flow diagram from the lowest to the highest category for a plant and an animal. What happens to the number of individuals and the number of shared characters as we go up the taxonomical hierarchy?

Answer:

A taxon is used to refer to a level of the biological classification such as order, phylum family, etc.

In the taxonomy, the different taxa are assigned their levels, and they follow a certain order that cannot be changed. For example, a species always follows up after a genus, and this order cannot be reversed.

Flow diagram from the lowest category to the highest category for plants and animals are given below:

Plant: Kingdom Division Class Order Family Genus Species

Animal: Kingdom Phylum Class Order Family Genus Species

As we go up the taxonomical hierarchy, the number of shared characters reduces as the level of classification decreases. For example, the number of shared characters of a species will be more than the number of shared characters for a family.

As we go up the taxonomical hierarchy, the classification decreases and thus, the number of individuals increases.

Question:6

A student of taxonomy was puzzled when told by his professor to look for a key to identify a plant. He went to his friend to clarify what 'key' the professor was referring to? What would the friend explain to him?

Answer:

Question:7

Metabolism is a defining feature of all the living organisms without exception. Isolated metabolic reactions in vitro are not living things but surely living reactions. Comment.

Answer:

The collection of the biological reactions that occur in living beings is referred to as metabolism. The metabolism requires the presence of the cells to be carried out successfully and cannot be carried out in the non-living things that are not composed of cells. Though the scientist is capable of carrying out in-vitro reactions which are similar to the metabolic reactions, in the laboratory, that does not count for real metabolism. They are called living reactions because they are carried outside of the living bodies of the animals, but they are not living beings. Thus, metabolism is considered to be a defining feature of life.

Question:8

Do you consider a person in coma - living or dead?

Answer:

Question:9

What is the similarity and dissimilarity between 'whole moong dal' and 'broken moong dal' in terms of respiration and growth? Based on these parameters, classify them into living or non-living.

Answer:

Question:10

Some of the properties of tissues are not the constituents of its cells. Give three examples to support your answer.

Answer:

It is true that not all the properties of the tissues are the constituents of the cells that they are made up of. The following statements show why this is true:

• The muscle tissue can contract and relax, but the cells that it is made up of, might not be capable of carrying out such actions.
• The bones and the cartilage together form the skeletal system. The bone is hard, and the cartilage is soft. The bone is also lightweight, but the skeletal system has different properties as compared to its constituents.
• The WBCs that are one of the constituents of blood does not have the capability of carrying oxygen, whereas the blood carries the oxygen.