Punjab State Board PSEB 11th Class Biology Important Questions Chapter 1 The Living World Important Questions and Answers.
PSEB 11th Class Biology Important Questions Chapter 1 The Living World
Very short answer type questions
Define living things.
The organisms exhibiting growth, development, metabolism, response to stimuli, reproduction and other characteristics such as movement, etc., are called living things.
In which organisms reproduction is synonymous with growth?
In unicellular organisms like Amoeba, bacteria and unicellular algae, reproduction is synonymous with growth, i. e., increase in number of cells.
Amoeba multiplies by mitotic cell division. Is this phenomenon growth or reproduction? Explain. [NCERT Exemplar]
The phenomenon is reproduction in which unicellular organisms like Amoeba, cell division is a means of multiplication, while in multicellular organisms, it is a means of growth.
Can we relate metabolism with growth of the body?
Metabolism occurs due to two phenomena, i.e., anabolism and catabolism. While growth of living things occur when quantity of anabolic reactions exceeds quantity of catabolic reactions.
Linnaeus is considered as father of taxonomy. Name two other botanists known for their contribution to the field of taxonomy. [NCERT Exemplar]
John Ray and Bentham and Hooker.
What does ICZN stand for? [NCERT Exemplar]
ICZN: International Code of Zoological Nomenclature
How is diversity in living world related to taxonomy?
The spectrum of diversity in the living world can be known only through the study of taxonomy.
Which is the largest botanical garden in the world? Name a few well known botanical gardens in India. [NCERT Exemplar]
Largest botanical garden in the world is Royal Botanical Garden, Kew
(London). Some well known botanical gardens in India are as follows:
- National Botanical Garden, Lucknow
- Lloyed Botanical Garden, Darjeeling
- Indian Botanical Garden Sibpur, Kolkata
The concept of new systematics was developed by which scientist?
Julian Huxley (1940)
How correlated characters help in defining genus?
Correlated characters are those common features, which are used in delimitation of a taxon above the rank of species.
Short answer type questions
What do you know about herbarium?
Herbarium is a store house of collected plant specimens that are dried, pressed and preserved on sheets. Further, these sheets are arranged according to k universally accepted system of classification. These specimens, along with their descriptions on herbarium sheets, become a store house or repository for future use. The herbarium sheets also carry a label providing information about date and place of collection, English, local and botanical names, family, collector’s name, etc. Herbaria also serve as quick referral systems in taxonomical studies.
How is botanical garden useful for scientists?
In a botanical garden various plant species are reared. Special artificial climate is created for a plant’s specific needs. The purpose of botanical garden is to maintain a rich flora of diverse species. Since, they are live specimens so they help scientists in studying physiology and anatomy over a long duration. Imagine if Mendel were given a botanical garden full of variety of species. He could have done experiment on so many plants and may have come with more insights.
Write a short note on museum.
Museums are those places which have collections of preserved animals and plants for taxonomic studies. The organisms are exhibited in the following manners:
- The plant and animal specimens are kept in chemical solutions and are preserved for longer duration.
- Plant and animal specimens may also be preserved as dry specimens.
- Insects are preserved in insect boxes; the collected insects are dried and pinned in these boxes.
- Larger animals like birds and mammals are usually preserved as stuffed specimens.
- Skeletons of animals are also collected in the museums.
How is a zoological park helpful to scientists?
It is difficult and dangerous to study ferocious animals in their natural habitats. Further, it is cruel to study them in captivity. So zoological park is a better option. Scientists can study different behavioural patterns, like feeding habits, mating rituals. This can help in a better understanding about them.
Long answer type questions
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? [NCERT Exemplar]
The key for identification of plants is a taxonomic key. It is a important taxonomic aid. Key can be defined as a set of alternate characters arranged in such a manner that by selection and elimination one can quickly find out the name of an organism. Depending upon the category, a key may be class key, order key, family key, genus key and species key.
Taxonomic keys can be of following two types:
(i) Indented or Yolked key
(ii) Bracketed key
Indented key, provides a sequence of two or more alternate characters from which selection and elimination are carried out. In bracketed key, the alternate characters are given numbers in brackets. For example, take four genera of family – Ranunculaceae to explain this,
(i) Ranunculus: Leaves alternate or radical, flowers not subtended by involucre, carpels ovuled, fruit achenes.
(ii) Clematis: Leaves opposite, compound petals absent, sepals 4, carpels uniovulated and fruit achenes.
(iii) Nigella: Flowers regular, carpels united at base, many ovulated, fruit follicles.
(iv) Anemone: Leaves alternate or radical, flowers subtended by involucre, carpels 1-ovulated, fruit achenes.
Some of the properties of tissues are not the properties of constituents of its cells. Give three examples to support the statement. [NCERT Exemplar]
A living thing has multiple level of organisation. Each level of organisaton i has its own properties, which are not found in its constituents.
Examples of three tissues supporting the statements are
(i) Cardiac muscle tissue: It is a contractile tissue present only in heart. Cell junctions fuse the plasma membrane of cardiac muscle cells and make them stick together. When one cell receives a signal to contract, its neighbours also starts to contract. It means a single cell cannot contract, while there are some fusion points, which allow the cells to contract as a unit.
(ii) Blood: It is a fluid connective tissue. The individual components of blood, i.e., RBCs, WBCs and platelets have different properties but as a unit they make the blood, a tissue serving many functions.
(iii) Bone: It is a hard connective tissue that forms the framework of the body. The individual cells inside the bone do not have this property.