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Diversity In The Living World

Solution for Class 12, Biology, Diversity In The Living World

Question 1

2.3.1 Phycomycetes (Algal (ungi) Members of phycomycetes are found in aquatic habitats and on decaying wood in moist and damp places or as obligate parasites on plants. The mycelium is aseptate and coenocytic. Asexual reproduction takes place by zoospores (motile) or by aplanospores (non-motile). These spores are endogenously produced in sporangium. A zygospore is formed by fusion of two gametes. These gametes are similar in morphology (isogamous) or dissimilar (anisogamous or oogamous) Some common examples are Mucor (Figure

2.5 a

), Rhizopus (the bread mould mentioned earlier) and Albugo (the parasitic fungi on mustard).

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Question 2

Ghoeter

- 4

1. What are the measures one has to take to prevent: from contrac -ting STDS?

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Question 3

The similai characters are less in number as compared to different genera included in a

family
Species
Order
Kingdo

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Question 4

Which is an intermediate stage between protonema and leafy gametophyte :-

Spore
Bud
Prothallus
Thalloid body

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Question 5

Some of the structures are given below which are related to life cycle of gymnosperms. Endosperm, Nucehus, MicrosporopRYyl, Megasporophyll, seed, archegonia, integument. How many of above structure/s is/are haploid?

One
Two
Three
Four

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Question 6

8. Energy Living beings constantly require energy not only to perform various activities of the body but also to overcome entropy or tendency to randomness. The source of energy is food. It is roguired by every cell of the body. DIVERSITY IN THE LIVING WORLD (BIODIVERSITY) Diversity in the living world or biodiversity is the occurrence of variety of life forms differing in

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Question 7

The branch of science that deals with the classification of organisms based on their evolutionary history is

Taxonomy
Phylogeny

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Question 8

Pick the mammal with true placenta (KCET-11)

Kangaroo
Echidna
Platypus
Mongoose

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Question 9

Pick the mammal with true placenta (KCET-11)

Kangaroo
Echidna
Platypus
Mongoose

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Question 10

1.4.5

Key Key is another taxonomical aid used for identification of plants and animals based on the similarities and dissimilarities. The keys are based on the contrasting characters generally in a pair called couplet. It represents the choice made between two opposite options. This results in acceptance of only one and rejection of the other. Each statement in the key is called a lead. Separate taxonomic keys are required for each taxonomic category such as family, genus and species for identification purposes. Keys are generally analytical in nature.

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Question 11

For the synthesis of 8 molecules of ammonia, how many protons and ATPs are required respectively?

16,32
8,16
4,8
32,64

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Question 12

Energy flow and energy transformation in a living system follow

Biogenetic law
Law of thermodynamics
Law of limiting factor
Liebig's law of minimum

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Question 13

2.1 Kingdom Monera Since the dawn of civilisation, there have been many attempts to cuss

2.2

Kingdom Protista living organisms. It was done instinctively not using criteria that wo

2.3 Kingdom Fungi food sher and clothing. Aristotle was the earliest to attempt a mo scientific but borne out of a need to use organisms for our own use-1

2.4

Kingdom Plantae scientific basis for classification. He used simple morphological characta

2.5 Kingdom to classify plants into trees, shrubs and herbs. He also divided animal into two groups. those which had red blood and those that did not.

Animalia In Linnaeus' time a Two Kingdom system of classification wit

2.6

Viruses, Viroids Plantae and Animalia kingdoms was developed that inciuded a) and Lichens plants and animals respectively. This system did not distinguish betwee the eukaryotes and prokaryotes, unicellular and multicellular organism and photosynthetic (green algae) and non-photosynthetic (fung) organisms. Classification of organisms into plants and animals was easit\} done and was easy to understand, but, a large number of organism did not fall into either category. Hence the two kingdom classificatio? used for a long time was found inadequate. Besides. gross morpholog a need was also felt for including other characteristics like cell structure nature of wall, mode of nutrition, habitat, methods of reproduction evolutionary relationships, etc. Classification systems for the living organisms have hence, undergone several changes over the time. Though plant and animal kingdoms have been a constant under all different systems, the understanding of what groups/organisms be included under these kingdoms have been changing; the number and nature of other kingdoms have also been understood differently by different scientists over the time.

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Question 14

Question: The function of contractile vacuole, in protozoa, is

osmoregulation
reproduction
locomotion
digestion of food.

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Question 15

Sexual reproduction was first reported in plants by:

Kolreuter
Camerarius
Van Beneden
Nawaschin

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Question 16

The three-domain system has also been proposed that divides the Kingdom Monera into two domains, leaving the remaining eukaryotic kingdoms in the third domain and thereby a six kingdom classification. You will learn about this system in detail at higher classes. Let us look at this five kingdom classification to understand the issues and considerations that influenced the classification system. Earlier classification systems included bacteria, blue green algae, fungi, mosses, ferns, gymnosperms and the angiosperms under 'Plants'. The character that unified this whole kingdom was that all the organisms included had a cell wall in their cells. This placed together groups which widely differed in other characteristics. It brought together the prokaryotic bacteria and the blue green algae (cyanobacteria) with other groups which were eukaryotic. It also grouped together the unicellular organisms and the multicellular ones, say, for example, Chlamydomonas and Spirogyra were placed together under algae. The classification did not differentiate between the heterotrophic group - fungi, and the autotrophic green plants, though they also showed a characteristic difference in their walls composition - the fungi had chitin

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Question 17

2. 1.2 are thousands of different eubacteria or truel There are' They are characterised by the presence of

a^{capswe}

cyanopacteria (alsorefere d

have chlorophyll a similar to green plants and are freshwater/marine or terrestrial algae. The colonies aregenerally surrounded by gelatinous sheath. They often form blooms in polluted water bodies. Some of these organisms can fix atmospheric nitrogen in specialised cells called heterocysts, e.g., Nostoc and Anabaena. Chemosynthetic autotrophic bacteria oxidise various inorganic substances such as nitrates, nitrites and ammonia and use the released energy for their ATP production. They play a great role in recycling nutrients like nitrogen, phosphorous, iron and sulphur. Heterotrophic bacteria are most abundant in nature. The majority are important decomposers. Many of them have a significant impact on human affairs. They are helpful in making curd from milk, production of antibiotics, fixing nitrogen in legume

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Question 18

2.2.3

Buglenoids

\to

connectixy link biw plank Majority of them are fresh water organisms found in stagnant water. Instead of a cell wall, they have a protein rich layer called pellicle which makes their body flexible. They have two flagella, a short and a long one. Though they are photosynthetic in the presence of sunlight, when deprived of sunlight they behave like heterotrophs by predating on other smaller organisms. Interestingly, the pigments of euglenoids are identical to those present in higher plants. Example: Euglena (Figure 2.4a).

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Question 19

'The Evil Quartet' causing loss of biodiversity are (i) habitat loss (ii) overexploitation (iii) alien invasion and (iv)

endangered
critically endangered
nearly threatened
co-extinctions

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Question 20

URIOSITY 1. Why red algae reach the maximum depth in sea where no other

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Solution for Class 12, Biology, Diversity In The Living World

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