CBSE class 11 Biology Solutions

NCERT Exemplar Solutions for Class 11 Biology Chapter 4 Animal Kingdom

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NCERT Exemplar Solutions for Class 11 Biology Chapter 4 Animal Kingdom

These Solutions are part of NCERT Exemplar Solutions for Class 11 Biology. Here we have given NCERT Exemplar Solutions for Class 11 Biology Chapter 4 Animal Kingdom.

VERY SHORT ANSWER QUESTIONS

Question 1.
What is the importance of pneumatic bones and air sacs in Aves?
Solution:
Birds possess light wfi’ght bones that contain internal spaces filled with air, which are pneumatic bones. They are an adaptation for flight as they help in, reducing the body weight. Aerodynamic lungs with specialized air sacs are an additional feature that aids birds in flying (e.g., bald eagle, pigeon).

Question 2.
What is metagenesis? Mention an example which exhibits this phenomenon.
Solution:
The phenomenon in which one generation of certain plants and animals reproduce asexually, followed by the sexually reproducing generation is metagenesis. Both the forms in metagenesis are diploid hence, it is known as the false alternation of generation. Coelenterates exhibit metagenesis (e.g., Obelia) where in its life cycle polyp form alternates with medusa.

Question 3.
What is the role of feathers?
Solution:
Feathers are the epidermal out growths that form distinctive outer covering or plumage in birds.
A variety of role are played by feathers which includes:
(i) They provide life and help in flight, by creating airfoil shape for wings.
(ii) They help in maintaining body temperature.
(iii) Feathers play a vital role in mating by providing secondary sexual that characters in both the sexes the colour and markings determine the alteractiveness of mate.

Question 4.
Which group of chordates posses sucking and circular mouth without jaws?
Solution:
Class-Cyclostomata is comprised of living jawless fishes. They have a circular mouth and lack jaws, hence they are also called agnathans. The mouth works like a sucker and is surrounded by tentacles (e.g., lampreys and haglish). These also prosses rectroctable teeth that are homy.

Question 5.
Mention two modifications in reptiles required for terrestrial mode of life.
Solution:
Certain characters acquired by reptiles for the terrestrial adaptations include.
(i) Body is covered with dry and comified skin and epidermal scales or scutes.
(ii) Internal fertilisation.

Question 6.
What is the role of radula in molluscs?
Solution:
The radula is a special rasping structure present many molluscs. It is used to scrape and scratch the food and to create depressions in rocks used as habitat.
It bears many rows of tiny teeth that are replaced
as they wear down e.g., Limplet is a marine invertebrate that uses its radula for creating home by boring a shallow hole in the rock.

Question 7.
Name the animal, which exhibits the
phenomenon of bioluminescence. Mention the
phylum to which it belongs.
Solution:
Bioluminescence is the phenomenon of production and emission of light by an organism as a result of chemical reaction during which chemical energy is converted to light energy. The phenomenon of bioluminescence is exhibited by Ctenoplana from phylum- Ctenophora.

Question 8.
Write one example for each of the following in the space providing.
(a) Cold blooded animal
(b) Warm blooded animal
(c) Animal possessing dry and comified skin
(d) Dioecious animal
Solution:
(a) A cold blooded animal is Crocodilus (crocodile)
(b) Elephas maximus (elephant), (mammal) is a warm blooded animal.
(c) Testudo (tortoise) bears dry and comified skin.
(d) Ascaris (roundworm) is a dioecious animal.

Question 9.
Differentiate between a diplobastic and triploblastic animal.
Solution:
Diploblastic animals are animals in which the cells are arranged in two embryonic layers, an external ectoderm and an internal endoderm (e.g., coelentrates). Animals in which the developing embryo has a third germinal layer, i. e., mesoderm lying between the ectoderm and endoderm are calledtriploblastic animals, (e.g., chordates).

Question 10.
Give an example of the following
(a) Roundworm
(b) Fish possessing poison sting
(c) A limbless reptile/amphibian
(d) An oviparous mammal
Solution:
(a) Roundworm – A scans
(b) Fish possessing poison sting – Trygon
(c) A limbless reptile/amphibian – Ichthyophis
(d) An oviparous mammal – Duck billed platypus.

Question 11.
Provide appropriate technical term in the space provided.
(a) Blood-filled cavity in arthropods
(b) Free-floating form of cnidaria
(c) Stinging organ of jelly fishes
(d) Lateral appendages in aquatic annelids
Solution:
(a) The blood-filled cavity in arthropods containing haemolymph is haemocoel.
(b) A form in cnidarians in which the body is shaped like an umbrella which can float freely in sed water is medusa.
(c) Capsules of specialised cells in cnidarians which act as a paraylysing sting are nematocytes.
(d) The paired unjointed lateral outgrowth in annelids bearing chaetae are parapodia.

Question 12.
Match the following.
NCERT Exemplar Solutions for Class 11 Biology Chapter 4 Animal Kingdom 1.1
Solution:
A. —> (iii)
B. —> (i)
C. —> (iv)
D. —> (ii)
(a) Octopus The appendages in invertebrates that are used for grasping food and for locomotion are tentacles.
(b) Crocodile for locomotion, and swimming limbs are used.
(c) Catta Fins are means of locomotion and are used to generation optimum thrust thus controlling the subsequent motion.
(d) Ctenoplana Locomotory organs formed by strong cilia with fused bases are comb plates.

SHORT ANSWER QUESTIONS

Question 1.
Differentiate between
(a) Open circulatory system and closed circulatory system.
(b) Oviparous and viviparous characteristic.
(c) Direct development and indirect development.
Solution:
Differentiation between these are as below
NCERT Exemplar Solutions for Class 11 Biology Chapter 4 Animal Kingdom 1.2

Question 2.
There has been an increase in the number of chambers in heart during evolution of vertebrates. Give the names of the class of vertebrates having two, three or four chambered heart.
Solution:
(a) In organisms like fishes two chambered heart is present. Mixing of oxygenated and deoxygenated blood blood occurs as only one atria and one ventricle is present which are not separated.
(b) After division of auricle into right and left halves three chambered heart develops and in amphibian. In ventiricles mixing of oxygenated and deoxygenated blood occurs.
(c) In reptilies an intermidiary heart is present in which ventricles get partially divided through a septum which is incomplete thus having a false four-chambered heart e.g., Crocodiles.
(d) Both the auricle and ventricle are divided into two halves in four chambered heart and so no mixing of oxygenated and deoxygenated blood occurs, e.g., birds and mammals.

Question 3.
Fill up the blank spaces appropriately
NCERT Exemplar Solutions for Class 11 Biology Chapter 4 Animal Kingdom 1.3
Solution:
Excretion involves the elimination of metabolic waste products from the animal body. In the process of excretion in different animals different organs are involved.
(a) In arthropods excretory products from haemolymph are removed by the malpighian tubules.
(b) The excretory organ occurs as segmentally arranged coiled tubules called nephridia in annelids.
(c) Excretion occurs by paired structures called organ of Bojanus in molluscs also called metanephridia.
(d) Mesonephric kidneys are associated with excretion in amphibians.
The circulation of blood and lymph along with oxygen carbondioxide, hormones, blood cells, etc, within the body system for the nourishment of cells, fighting diseases, and for stabilising body temperature and pH is involved blood circulation.
NCERT Exemplar Solutions for Class 11 Biology Chapter 4 Animal Kingdom 1.4

Respiratory organs are involved in the
exchange of gases from the atmosphere.
Different respiratory organs in various animals.
(a) Lungs and skin in amphibians.
(b) Lung/gills/tracheal system in arthropoda and molluscs.
(c) Skin in annelids.

Question 4.
Match the following
NCERT Exemplar Solutions for Class 11 Biology Chapter 4 Animal Kingdom 1.5

Solution:
A. —> (v)
B. —> (iii)
C. —> (ii)
D.—> (i)
E. —> (vi)
F. —> (iv)
A. Amphibians are found in both aquatic and terrestrial habitat. Their large is completely aquatic while adult lives in terrestrial as well as in aquatic habitat.
B. Mammals produce milk in the mammary glands and feed their young one. The mammary glands are enlarged exocrine modified sweat glands functional in female mammals.
C. Chondrichthyes have (notochord) in the young stage which is gradually replaced by cartilage.
D. Osteichthyes possess air bladder which is a vesicle or sac containing air.
E. Cyclostomes have sucking and circular mouth without jaws which is surrounded by tentacles and the tongue bears teeth, e.g., lamprey and hagfish.
F. Aves comprise of light weighted bones with internal spaces field with air called pneumatic bones and aerodynamic lungs with specialised air sacs. These are the adaptations which enable birds to fly.

Question 5.
Endoparasites are found inside the host body. Mention the special structure, possessed by these and which enables them to survive in those conditions.
Solution:
Endoparasites such as Taenia solium and Fasciola hepatica (liver fluke), etc., are found inside body the host and survive due to the presence of certain characters.
Endoparasites special characters which include:
(i) The is respiration is anaerobic and the gaseous exchange in via general body surface.
(ii) They bear additional organs for the attachment to the host. Taenia solium posses hooks and suckers for the attachment with the host. Fasciola hepatica possesses acetabulum or posterior sucker for the attachment.
(iii) they have well developed reproductive organs. They are generally, harmaphrodite and self fertilisation occurs commonly.
(iv) They have a thick tegument (body covering) which is resistant to the host’s digestive enzymes and antioxins.
(v) Locomotary organs are absent.
(vi) They lack digestive organs because digested and semi digested food of the host is directly absorbed through their body surface.

Question 6.
Mention two similarities between
(a) Aves and mammals
(b) A frog and crocodile
(c) A turtle and Pila
Solution:
(a) Following are the similarities between aves and mammals
(i) Presence of four chambered heart.
(ii) The members of both the groups are homeotherms, i.e., warm blooded. They are able to maintain constant body temperature.
(b) Similarities between frog and crocodile include:
(i) They are cold blooded animals. The members of both the groups are poikilotherms, i.e., they lack the capacity to regulate their body temperature.
(ii) Frogs and crocodiles are oviparous animals.
(c) Similarities between turtle and Pila include
(i) Body is covered with dry and comified skin in both animals. In turtle, the epidermal covering is known as scales whereas in case of Pila, it is known as calcareous shell.
(ii) Both animals are oviparous.

Question 7.
Name
(a) A limbless animal
(b) A cold blooded animal
(c) A warm blooded animal
(d) An animal possessing dry and comified skin
(e) An animal having canal system and spicules
(f) An animal with cnidoblasts
Solution:
(a) Ichthyophis does not possess limbs.
(b) A cold blooded animal scoliodon (dog fish).
(c) warm blooded animal is Columba (pigeon).
(d) Naja naja (snake) possesses dry and cornified skin.
(e) Sycon (sponge) possesses canal system and bear spicules.
(f) Obelia bears cnidoblast.

Question 8.
Excretory organs of different animals are given below. Choose correctly and write in the space provided.
NCERT Exemplar Solutions for Class 11 Biology Chapter 4 Animal Kingdom 1.6

Solution:
Metabolism in body leads to the formation of waste that can affect body’s vital organs so it has to be removed from body. Different classes of organisms possess different types of excretory organs to eliminate the byproduct of metabolism.
A. —> (vi)
B. —> (ii)
C. —> (v)
D. —> (iii)
E. —> (vi)
F. —> (i)
A. Balanogolossus – Proboscis glands. This gland excretes brown granules and is present in front of central sinus.
B. Nephridia in Leech. It helps in osmoregulation and excretion.
C. Malpighian tubules in Locust open into gut and help in excretion.
D. The Flame cells of liver fluke are specialised cells in Platyhelminthes which helps in osmoregulation and excretion. These are also called protonephridia.
E. Sea urchin-absent Specialised excretory organs are absent in sea urchin.
F. It TV/a-Metanephridia is a type of excretory gland or nephridium found in many types of invertebrates such as annelids, arthropods, and molluscs (in molluscus nephridia is also known as Bojanus organ).

LONG ANSWER QUESTIONS

Question 1.
What is the relationship between germinal layers and the formation of body cavity in case of coelomate, acoelomates andpseudocoelomates?
Solution:
Multicellular organisms typically possess a concentric arrangement of tissues in the body. These tissues are derived from the three embrycnio cell, layers called germinal layers.
(i) The outer layer is the ectoderm, the middle layer is the mesoderm and the innermost layer is the endoderm.
(ii) Ectoderm is associated with the formation of CNS, eye lens, ganglia, nerves and glands.
(iii) Mesoderm forms the that in structural components of the body like the skeletal muscles the skeleton, the dermis of the
skin connective tissue, etc.
(iv) Endoderm layer is associated with the formation of the stomach, colon, liver, pancreas urinary bladder and other vital organs is an organism.
(v) Coelom is the body cavity that is lined by mesoderm and the animals possessing coelom are called as ceolomates. e.g., phylum-Annelida, Mollusca, Arthropoda, Echnidermata, Hermichordata and Chordata.
(vi) In some organisms, body cavity is not lined by mesoderm, instead mesoderm is present in the form of scattered pouches in between ectoderm and endoderm, Such body cavity is called pseudocoelom and animals possessing there stusturs are refered to as pseudocoelomates e.g., As car is.
(vii) The animals in which there is complete absence of body cavity are called acoelomates. e.g., Platyhelminthes.
NCERT Exemplar Solutions for Class 11 Biology Chapter 4 Animal Kingdom 1.7

Question 2.
Comment upon the habitats and external features of animals belonging to class- Amphibia and Reptilia.
Solution:
Amphibians
(i) They can dwell in aquatic as well as terrestrial habitats. They are ectothermic or (cold blooded).
(ii) They are tetrapods having (4 limbs) which facilitate movement on land.
(iii) Their limbs have evolved from the pectoral and pelvic fins.
(iv) Skin is thin, covered by mucus and remains mostly moist. It also serves as an accessory source of oxygen.
(v) They breathe through gills and lung gills usually appear in the larval stage, replaced by lungs in the adults stage.
(vi) Their heart is three chambered with two atria and one ventricle.
(vii) Females are oviparous and fertilisation is mostly external.
(viii) Larva is a tadpole, which metamorphose into adult e.g., Rariu frog, Nectureus (mud puppy), Salamandera (salamander).
NCERT Exemplar Solutions for Class 11 Biology Chapter 4 Animal Kingdom 1.8
Reptiles
(i) They are mostly terrestrial animals and their body is covered by dry, and comified skin, epidermal scales or scutes.
(ii) In reptiles the mode of locomotion is creeping and crawling.
(iii) Lungs are well developed and present in all stages of life.
(iv) Claws are present in toes.
(v) s Appendages are well adapted for land movement.
(vi) Heart possesses a partially divided ventricle and 2 atria.
(vii) They lay amniotic eggs which are inclubated on land.
(viii) They are poikilothermic or cold blooded animals. Temperature is regulated mechanically and not metabolically by moving in and out; source of heat is usually the sun.
(ix) Fertilisation is internal. They are oviparous and development of young ones is direct e.g., Chelone (turtle), Naja (cobra), Crocodicus (crocodile).
NCERT Exemplar Solutions for Class 11 Biology Chapter 4 Animal Kingdom 1.9

We hope the NCERT Exemplar Solutions for Class 11 Biology at Work Chapter 4 Animal Kingdom, help you. If you have any query regarding NCERT Exemplar Solutions for Class 11 Biology at Work Chapter 4 Animal Kingdom, drop a comment below and we will get back to you at the earliest.

NCERT Exemplar Solutions for Class 11 Biology Chapter 3 Plant Kingdom

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NCERT Exemplar Solutions for Class 11 Biology Chapter 3 Plant Kingdom

These Solutions are part of NCERT Exemplar Solutions for Class 11 Biology. Here we have given NCERT Exemplar Solutions for Class 11 Biology Chapter 3 Plant Kingdom.

VERY SHORT ANSWER QUESTIONS

Question 1.
Food is stored as floridean starch in Rhodophyceae. Mannitol is the reserve food material of which group of algae?
Solution:
Mannitol is a reserve food material of the members of Phaeophyceae (brown algae).

Question 2.
The plant body in higher plants is well differentiated and well developed. Roots are the organs used for the purpose of absorption. What is the equivalent of roots in the less developed lower plants?
Solution:
Root like structure called rhizoids are present instead of roots in less developed lower plants (bryophytes and pteridophytes). The plant tissue system in these is not differentiated into true leaf, stem and roots as it is found in higher plants (gymnosperm and angiosperm).

Question 3.
Most algal genera show haplontic life style. Name an alga which is
(a) Haplo diplontic
(b) Diplontic
Solution:
Haplo diplontic type of life cycle is exhibited by Ectocarpus, Polysiphonia and Kelps. The main plant body is saprophytic in Fucus and it shows diplontic type of life cycle.

Question 4.
In bryophytes male and female sex organs are called …………….. and …………..
Solution:
In bryophytes the male sex organ in antheridium and female sex organ is archegonium.
Antheridium produces flagellate antherozoids which are male gametes.
Archegonia is the female part which bears a single egg cell.

SHORT ANSWER QUESTIONS

Question 1.
Why are bryophytes called the amphibians of the plant kingdom? Amphibians can their in water as well as on terrestrial habitat.
Solution:
Bryophytes are a group of primitive plants having a dominant gametophytic plant body. These plants can live in soil but depend on water for movement of male gametes called antherozoids to reach the archegonium (female organ bearing egg cell) so that fertilisation can occur, so bryophytes are called the amphibians of the plant kingdom.

Question 2.
Heterospory, i.e., formation of two types of spores— microspores and megaspores is a characteristic feature in the life cycle of a few members of pteridophytes and all spermatophytes. Do you think heterospory has some evolutionary significance in plant kingdom?
Solution:

  1. The production of spores of two different sizes and sexes by the sporophytes of land plants is heterospory. Two types ofspores are produced by heterosporic plants.
  2. Small spores are microspores which germinate into the male gametophyte and large spores are macrospores which develop into the female gametophyte.
  3. Pteridophytes are intermediate between bryophytes and gymnosperms in the evolution of plants.
  4. All bryophytes are homosporous and all gymnosperms are heterosporous. This condition is advanced as sexual dimorphism results in cross fertilisation.
  5. Primitive or earlier pteridophytes are homosporous while later pteriodophytes are heterosporous e.g., Dryopteris, Pteris homosporous Selaginella, Sn/vrao-heterosporous.

Question 3.
Each plant group of plants has some phylogenetic significance in relation to evolution Cycas, one of the few living members of gymnosperms is called as the ‘relic of past’. Can you establish a phylogenetic relationship of Cycas with any other group of plants that justifies the above statement?
Solution:
Cycas is an evergreen plant which resembles palm. It has an unbranched stem and large compound leaves. It exhibits phylogenetic relationship with pteridophyte. Its evolutionary characters include thefollowing:
(i) Growth is redundant.
(ii) Shedding of seed while the embryo is still immature.
(iii) Minimal secondary growth and manoxylic wood.
(iv) Megasporophylls are leaf like.
(v) Sperms are flagellate even when pollen tube is present.
(vi) Leaf bases are persistent.
(vii) Ptysix is circinate.
(viii) Arrangement of microsporangia in well defined archegonia.

Question 4.
Comment on the life cycle and nature of fem prothallus.
Solution:
The life cycle of ferm (Dryopteris) clearly depicts the alternation of generation. The gametophytic stage (n) alternates with the sporophytic stage (2n) in the life cycle as shown in the figure.
NCERT Exemplar Solutions for Class 11 Biology Chapter 3 Plant Kingdom 1.1
The prothallus of the fem is a multicellular, free living, thalloid, haploid and autotrophic structure. It develops from the spores produced by sporophyte after reduction division.
These spore germinate within a germtube with an apical cell and forms a filament of 3-6 cells and one or two rhizoids at the base which later develops into gametophytic plant.
NCERT Exemplar Solutions for Class 11 Biology Chapter 3 Plant Kingdom 1.2

Question 5.
How are the male and female gametophytes of pteridophytes and gymnosperms different from each other?
Solution:
The male and female gametophytes of pteridophytes and gymnosperms different from each other as:
NCERT Exemplar Solutions for Class 11 Biology Chapter 3 Plant Kingdom 1.3

Question 6.
How are the male and female gametophytes of pteridophytes and gymnosperms different from each other?
Solution:

  1. Symbiosis is a type of interaction of two living organisms where both the associated partners derive some benefit from each other both co¬exist and flourish well.
  2. Mycorrhiza is a symbiotic association between fungus and the roots of vascular plants. The fungus colonizes the roots of the host either intra or inter cellularly. It helps in the nutrient absorption from soil for the plant.
  3. Mycorrhizal associations are present in conifers, i.e.,Pinus, Cedrus, Abies and Picea.
  4. Coralloid roots develop in Cycas. It is produced in clusters at the base of the stem and protrudes out on the ground.
  5. It is dichotomously branched and greenish in colour. It contains algal zone in cortex.
  6. This algal zone contains blue green algae like Anabaena and Nostoc which grow in symbiotic association with coralloid roots.

LONG ANSWER QUESTIONS

Question 1.
Explain why sexual reproduction in angiosperms is said to take place through double fertilisation and triple fusion. Also draw a labelled diagram of embryo sac to explain the phenomena.
Solution:

  • An angiospermic plants reproduces sexually by the formation of male and female gametes.
  • The male gamete is a pollen which contains two male nuclei and the female gamete is an egg cell produced in ovule (female gametophyte).
  • The pollen grains germinate on the stigma of a flower and the results in growth of pollen through the tissues of stigma and style and reach the egg apparatus.
  • The two male gametes are discharged within the embryo sac. One of the male gamete fuses with the egg cell to form a diploid zygote.
    This’fusion is known as fertilisation or syngamy. The second male gamete fuses with the diploid secondary nucleus and forms the triploid Primary Endosperm Nucleus (PEN). This fusion is known as triple fusion.
  • Because of the involvement of two fusion, this event in angiosperms is termed as double fertilisation. The zygote then develops into embryo and PEN develops into endosperm which provides nourishment to the developing embryo.
    NCERT Exemplar Solutions for Class 11 Biology Chapter 3 Plant Kingdom 1.4

Question 2.
Draw labelled diagrams of
(a) Female and male thallus of a liverwort.
(b) Gametophyte and sporophyte of Funaria.
(c) Alternation of generation in angiosperm.
Solution:
NCERT Exemplar Solutions for Class 11 Biology Chapter 3 Plant Kingdom 1.5
(a) Liverworts
(i) Male thallus of Marchantia polymorpha
(ii) Female thallus of Marchantia polymorpha
(b) Funaria
(gametophyte and sporophyte)
NCERT Exemplar Solutions for Class 11 Biology Chapter 3 Plant Kingdom 1.6

We hope the NCERT Exemplar Solutions for Class 11 Biology at Work Chapter 3 Plant Kingdom, help you. If you have any query regarding NCERT Exemplar Solutions for Class 11 Biology at Work Chapter 3 Plant Kingdom, drop a comment below and we will get back to you at the earliest.

NCERT Exemplar Solutions for Class 11 Biology Chapter 2 Biological Classification

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NCERT Exemplar Solutions for Class 11 Biology Chapter 2 Biological Classification

These Solutions are part of NCERT Exemplar Solutions for Class 11 Biology. Here we have given NCERT Exemplar Solutions for Class 11 Biology Chapter 2 Biological Classification.

VERY SHORT ANSWER QUESTIONS

Question 1.
What is the principle underlying the use of cyanobacteria in agricultural fields for crop improvement?
Solution:
Cyanobacteria are abfs to fix atmospheric nitrogen and make it available to the plants and thus are used in agricultural crop improvement.
This improves crop yield and also reduces the cost of application of nitrogen fertilisers, e.g., Anabena and Nostoc.

Question 2.
How is the five kingdom classification advantageous over the two kingdom classification?
Solution:
The five kingdom classification, proposed by RH whittaker is based upon cell structure, body structure (unicellular, multicellular), nutrition (autotrophic, heterotrophic) reproduction and habitat either aquatic, terrestrial, or aerial and phylogenetic relationship.
It is thus more useful as compared to two kingdom system of classification which does not distinguish between prokaryotes and eukaryotes and no other kingdom except plant and animal are identified.
Polluted water bodies have high growth of algae due to the presence of nutrient. These nutrients increase the rapid growth of water plants, i.e.,

Question 3.
Polluted water bodies have usually very high abundance of plants like Nostoc and Oscillitoria. Give reasons.
Solution:
algae especially Nostoc and Oscillitoria, etc., and result in colonies. These colonies are generally surrounded by a gelatinous sheath and leads to the formation of blooms in water bodies.

Question 4.
Are chemosynthetic bacteria autotrophic or heteroterophic?
Solution:
Chemosynthetic bacteria are capable of oxidising various inorganic substances such as nitrates, nitrites and ammonia and use the released energy for production of ATP and thus they are autotrophs and not heterotrophs.

Question 5.
The common name of a pea is simpler than its botanical (scientific) name Pisum sativum why then is the simpler common name not used instead of the complex scientific/botanical name in biology?
Solution:
The common or vernacular names cause confusion regarding the identification of specific specimen as they change with the change in place whereas the scientific names are in latin and universally accepted and understood. Scientific names are thus preferred over the common vernacular names.

SHORT ANSWER QUESTIONS

Question 1.
Diatoms are also called as ‘pearls of ocean’, why? What is diatomaceous earth?
Solution:

  1. Diatoms and desmids are included under chrysophytes, kingdom-Protista.
  2. These are the main producers in the ocean. They prepare food for themselves and for the other life forms in the ocean as were a siliceous shell known as frustule cores the body of diatoms, this is the reason they are also called as ‘pearls of ocean. ‘
  3. Diatomaceous earth’ is the accumulation of large deposits of diatoms that forms a siliceous covering extending for several 100 metres formed in billions of years.
  4. The material obtained from these deposits is used in polishing and filtration of oils and syrups.

Question 2.
There is a myth that immediately after heavy rains in forest, mushrooms appear in large number and make a very large ring or circle, which may be several metres in diameter. These are called as ‘fairy rings’. Can you explain this myth of fairy rings in biological terms?
Discuss the mycilial structure in Agaricus and its soil borne nature.
Solution:
The fruiting bodies in Agaricus are known as basidiocarps. They form a concentric ring like structure from the mycelium present in the soil. These basidiocarps resemble button in shape and develop to form a ring like structure.
NCERT Exemplar Solutions for Class 11 Biology Chapter 2 Biological Classification 1.1
This fairy ring structure in Agaricus stimulate productivity in plants. This rings are the fruiting bodies of this fungus and the diameter of this fairy ring increases every year due to the spread of mycelium.

Question 3.
Neurospora an ascomycetes fungus has been •arsed as a biological tool to understand the mechanism of plant genetics much in the same way as Drosophila has been used to study animal genetics. What makes Neurospora so important as a genetic tool?
Solution:
Neurospora fungus can be grown easily under laboratory conditions by providing ‘minimal medium’ like inorganic salts, carbohydrates source and vitamin (biotin) and thus was selected to be a very good tool in genetics. The mutations can be also easily introduced in the fungal cells and meiotic division can be easily seen under X-ray treatment.

Question 4.
At a stage of their cycle, ascomycetes fungi produce the fruiting bodies like apothecium, perithecium or cleistothecium. How are these three types of fruiting bodies different from each other?
Discuss the type of fruiting bodies formed by ascomycetes fungus and differentiate accordingly on the basic of there structures.
Solution:
Ascomycetes consist of sporangial sac called ascus. Asci (singular-ascus) may occur freely or in aggregated form with dikaryotic mycelium to form the fruitification bodies called ascocarps.
The fruitification formed by asci include the following :
(i) Apothecium is cup like structure, e.g., Peziza.
NCERT Exemplar Solutions for Class 11 Biology Chapter 2 Biological Classification 1.2
(ii) Perithecium is flask shaped, e.g., Neurospora
NCERT Exemplar Solutions for Class 11 Biology Chapter 2 Biological Classification 1.3
(iii) Cleistothecium is closed with a slit, e.g., Penicilium
NCERT Exemplar Solutions for Class 11 Biology Chapter 2 Biological Classification 1.4

Question 5.
What obsrevable features in Trypanosoma would make you classify it under kingdom- Protista?
Discuss cell structure of Trypanosoma also discuss its different strain brief.
Solution:
Trypanosoma is included under flagellated protozoans on the basis of locomotary organ. It resembles Protisia in the following characters.
NCERT Exemplar Solutions for Class 11 Biology Chapter 2 Biological Classification 1.5
(i) It is unicellular.
(ii) It reproduces asexually i.e., by binary fission.
(iii) Possess centrally located nucieus and also contain an prominent nucleus endosome.
(iv) Reserve food material is in the form of granules.

LONG ANSWER QUESTIONS

Question 1.
Algae are known to reproduce asexually by variety of spores under different environmental conditions. Name these spores and the conditions under which they are produced.
Solution:
Asexual reproduction in algae is very common mean of reproduction. Algae and their spores exhibit significant diversity and vary greatly in their level of specialisation. Asexual reproduction by spores and their types include:
(i) Zoospores are mobile flagellated spores. In this protoplasm of each vegetative cell undergoes repeated longitudinal division either into 2 or 4, rarely 8 or 16 daughter protoplasts. Before the onset of division the parent cell loses its flagella.

  • Each daughter protoplast after the last series of division secretes a cell wall and a neuromotor apparatus that develops two flagella, eyespots and contractile vacuoles.
  • Each of the daughter cell thus formed resembles the parent cell in all aspects except the small size.
  • Under favourable conditions formation of zoospores is very common.
    NCERT Exemplar Solutions for Class 11 Biology Chapter 2 Biological Classification 1.6

(ii) Aplanospores are the non-motile spores. They are formed asexually within a cell, in which protoplast withdraws itself from the parent wall, rounds up and develops into aplanospores which germinate either directly or may divide to produce zoospores.
NCERT Exemplar Solutions for Class 11 Biology Chapter 2 Biological Classification 1.7

(iii) Hypnospores- In this, the protoplasm withdraws from the cell wall, rounds up and develops a thick wall under unfavourable conditions. These resting spores are called as hypnospores. Due to presence of haematochroma they are red in colour e.g., Vancheria, Ulothrix.
(iv) Akinetes are special vegetative thick walled cells present in the filaments which remain under dormant state and resume germination under favourable conditions. They can also withstand unfavourable condition as Spirogyra.
(v) Statospores are thick walled spores ‘ produced in diatoms.
(vi) Neutral spores are the protoplast, of vegetative cells directly functioning as spores (e.g., Ectocarpus).

Question 2.
Apart from chlorophyll, algae have several other pigments in their chloroptast. What pigments are found in blue, green, red and brown algae, that are responsible for their characteristic colours?
Solution:

  • All photosynthetic organisms comprise of one or more organic pigments that are capable of absorbing visible, radiations, which will initiate the photochemical reaction of photosynthesis.
  • The three major classes of pigments found in plants and algae are the chlorophylls, the carotenoids and the phycobilins.
  • Carotenoid and phycobilins are called accessory pigments since, the quanta absorbed by theese pigments can be transferred to chlorophyll.
  • The diversity of light harvesting pigments in alga implies that the common ancestor was primitive and that no close affinity exist between blue, green, red, brown, golden brown and green algae.
    NCERT Exemplar Solutions for Class 11 Biology Chapter 2 Biological Classification 1.8

 

Question 3.
Make a list of algae and fungi that have commercial value as source of food, chemicals, medicines and fodder.
Solution:
Algae
Around 70 species of marine ailgae are used for food, chemical and medicinal purpose.
NCERT Exemplar Solutions for Class 11 Biology Chapter 2 Biological Classification 1.9
Fungi
The role of fungi was established in early history. Since, the beginning of cultivation yeast have been used in making of bread and alcohol. The discovery of penicillin that marked the beginning of a new approach to microbial dis eases in human health.
Products of fungi in medicine, chemical and food include.
Around 70 species of marine aigae are used for food, chemical and medicinal purpose.
NCERT Exemplar Solutions for Class 11 Biology Chapter 2 Biological Classification 1.10

We hope the NCERT Exemplar Solutions for Class 11 Biology at Work Chapter 2 Biological Classification, help you. If you have any query regarding NCERT Exemplar Solutions for Class 11 Biology at Work Chapter 2 Biological Classification, drop a comment below and we will get back to you at the earliest.

NCERT Exemplar Solutions for Class 11 Biology Chapter 1 The Living World

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NCERT Exemplar Solutions for Class 11 Biology Chapter 1 The Living World

These Solutions are part of NCERT Exemplar Solutions for Class 11 Biology. Here we have given NCERT Exemplar Solutions for Class 11 Biology Chapter 1 The Living World.

VERY SHORT ANSWER QUESTIONS

Question 1.
Couplet in taxonomic key means……. .
Solution:
Couplet in taxonomic key is a pair of a contrasting characters used as tool foi” identification to aid in identification of a newly discovered organism.

Question 2.
What is a monograph?
Solution:
Monograph is a specialised work of documenting information on a particular taxon, /. e., family or genus or on aspect of subject, usually by a single author.
The main purpose of monograph is to present primary research and original work.

Question 3.
Amoeba multiplies by mitotic cell division. Is this phenomena growth or reproduction? Explain.
Solution:
Amoeba multiplies by simple mitotic cell divisions giving rise to two daughter Amoebae. Growth here is synchronous with reproduction, i.e., increases in number.

Question 4.
Define metabolism.
Solution:
Metabolism is the sum total of all biological reactions occurring in any living cell, which are controlled absolutely by enzymes. These reactions are of two types breaking down reactions (catabolism, e.g., cell ‘ respiration) and synthesing reactions (anabolism,
e.g., photosynthesis).

Question 5.
Which is the largest botanical garden in world? Name a few well known botanical gardens in India.
Solution:
A botanical garden is dedicated to collection, cultivation and display of wide range of plants labelled with their botanical names.
The largest botanical garden in the world is Royal Botanical Garden (in Kew, London). In India the famous well known botanical gardens are
(i) National Botanical Garden (NBG) Lucknow, UP.
(ii) Botanical Garden of FRI, Dehradun (UK).
(iii) Lloyd Botanical Garden, Daijeeling.
(iv) Indian Botanical Garden, Sibpur, Kolkata.

SHORT ANSWER 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 living organisms? Why?
Solution:

  1. Living organisms, grow, have metabolism and respond to external stimuli and reproduce as well. These characteristics are not shown by non-living objects.
  2. In biological terms growth is characteristic feature of all living organisms. It relates to increase in size by accumulation of protoplasm in the cell thus resulting in increase in the size of the cell.
  3. Increase in number of cell by cell division on other hand results in the size of individual organism.
  4. Snow is an inanimate (non-living) object, while rolling over, it gathers more snow on its surface thus, it increases in size by physical phenomenon but not by biological phenomenon.
  5. This growth cannot be thus compared to that seen in living organisms.

Question 2.
In a given habitat we have 20 plant species and 20 animal species. Should we call this as ‘diversity or biodiversity’? Justify your answer.
Solution:
There are existing 20 plant species and 20 animal species in the given habitat. They will exhibit the biodiversity in that given habitat because diversity refers to variation in a broad term and can be applied to any area whereas biodiversity is a degree of variation of life forms within a specified area.

Question 3.
International Code of Botanical Nomenclature (ICBN) has provided a code for classification of plants. Give hierarchy of units of classification, botanists follow while classifying plants and mention different ‘suffixes’ used for the units.
Solution:
ICBN has specified certain rules and principles in order to facilitate the study of plants by botanists. It helps in correct positioning of any organism newly discovered through the pressure of proper identification and nomenclature.
The taxonomic hierarchy, which is used while
classifying any plant given below
Kingdom-Plan tae
Division-phyta
Class-ae
Order-ales
Family-eae/ceae
Genus-First name of organism usually Latin word and written in italics.
Species-Second word of scientific name, also written in italics.

Question 4.
What are hormone receptors? What are the modes of their action ?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?
Solution:
These morphological variants are called bio types. It includes group of genetically similar plants showing similarity when grown in same environmental and geographical regions. The same environment provides them the similar abiotic factors like soil, pH, temperature, etc.
When growth in two different geographical regions, they are exposed to different abiotic characters which affects their growth, and development bringing changes in their external morphological features but, their genetic constitution remain same.

Question 5.
What is the difference between flora, fauna and vegetation? Eichhornia crassipes is called as an exotic species, while Rauwoljia serpentina is an endemic species in India. What do these terms exotic and endemic refer to?
Solution:
Following are the difference between flora, fauna and vegetation
NCERT Exemplar Solutions for Class 11 Biology Chapter 1 The Living World 1.1

Question 6.
Brinjal and potato belong to the same genus Solamim, but to two different species. What defines them as seperate species?
Solution:
Genus is a taxonomic rank used in bionorr.’al nomenclature comprising of a group of related species sharing few common characters.
Solanum is the largest genus of flowering plants which includes few economically important plants, e.g., potato, tomato, tobacco and brinjal. All these plants show some common morphological structures related to vegetative and reproductive similarities. So, they are are included in the same common genus Solanum.

Question 7.
The number and kinds of organism is not constant. How do you explain this statement? Change is law of nature.
Solution:
The number and kind of organisms is not constant, because of the following reasons new organism are added due to mechanisms of.
(i) sexual reproduction
(ii) mutation
(iii) evolution
The number of organisms get reduced due to
(i) environmental threats
(ii) loss of habitat
(iii) anthropogenic activities

LONG ANSWER QUESTIONS

Question 1.
Brassica campestris Linn
(a) Give the common name of the plant.
(b) What do the first two parts of the name denote?
(c) Why are they written in italics?
(d) What is the meaning of Linn written at the end of the name?
Solution:
Brassica campestris Linn
(a) The common name of Brassica compestris Linn is mustard.
(b) The first part of the name denotes the genetic name and the second part is the species name of the plant.
(c) According to ICBN, all scientific names are comprised of one genetic name followed by a species name, which require to be always written in italics. It is a rule of bionomial nomenclature.
(d) Linn means Linnaeus. He was the first to discover the plant. He identified, named and classified the plant, so the plant is named after him by adding suffix ‘Linn’, after the scientific name B. campestris.

Question 2.
What are taxonomical aids? Give the importance of herbaria and museums. How are Botanical gardens and Zoological parks useful in conserving biodiversity?
Solution:
The aids which help in identification, classification and naming of a newly discovered organisms (plant or animal) the taxonomic aids.
It could be in the form of a preserved document like herbaria or specimen kept at museums or scientific institutions. Other aids include written document like monography, taxonomic keys, couplets, etc.
A new organism found can be studied while comparing it with living plants and animals living in protected areas like Botanical gardens, Zoological parks, etc. Botanical gardens helps in conservation of plants by
(i) Plant species growing important local and keeping record of them.
(ii) Growing and maintaining species that rare are and endangered.
(iii) Supplying seeds for different aspects of botanical research.
Zoological parks contribute in conserving biodiversity by
(i) Providing natural environment and open space to animals.
(ii) Providing home to different native and exotic wild animals.
(iii) Rescue of endangered species.
(iv) Facilitating breeding animal and releasing them free. Thus, both botanical gardens and zoological parks play an important role in conservation of biodiversity.

We hope the NCERT Exemplar Solutions for Class 11 Biology at Work Chapter 1 The Living World, help you. If you have any query regarding NCERT Exemplar Solutions for Class 11 Biology at Work Chapter 1 The Living World, drop a comment below and we will get back to you at the earliest.