Class 9 Diversity in living organisms Sample Paper Question Answers

 Class 9 Diversity in living organisms Sample Paper Question Answers


1.(i) State reasons why Echidna and platypus lay eggs but are considered as mammals.

Ans.They have mammary glands for the production of milk to nourish their young ones.

(ii) Forelimbs of birds are modified

Ans.To reduce body weight for flight.


2.Give difference between vertebrates and invertebrates.

Ans.

3.(a) Write any four features that all chordates possess.

Ans.(a) The four main characteristics of chordates are as follows:
(i) Presence of notochord at any stage of life.
(ii) Presence of dorsal hollow nerve cord.
(iii) Presence of gill slits at any stage of life.
(iv) Presence of tail behind the anal opening


(b) Explain the three basic features for grouping a ll organisms into five major kingdoms.

Ans.The groups are formed on the basis of their cel l structure, mode and source of nutrition and body organization.
Whittaker based his scheme of classification on the following three levels of organization:
(i) Prokaryotic versus Eukaryotic cell structure.
(ii) Three different modes of nutrition- Photosynth esis (plants), Absorption from the environment (fungi) and Ingestion (animals).
(iii) Unicellular versus Multicellular organization .

4.How would you choose between two characteristics to be used for developing a hierarchy in classification?

Ans.We should choose the characteristic which is depend ent on the previous one and would decide the variety in the next level for developing a hier archy in classification.

5.What are the major divisions of the kingdom plantae ? What is the basis of these divisions?

Ans.Major division of kingdom plantae - thallophya, bry ophyta, pteridophyta, gymnosperms and angiosperms. This kingdom includes Basis for classi fication:
(a) All organisms which are multicellular, eukaryot ic and green autotrophs.
(b) Green plants are further classified on the basi s of differentiation of the plant body.
(c) Second level of classification plant body has v ascular tissue or not. Further classification is based on
(i) Whether seeds are present or not
(ii) Whether seeds are enclosed within fruit or not .

6.Describe the three main characteristics that are us ed for a hierarchical classification.

Ans.The three main characteristics used for a hierarchi cal classification are:
(i) Complexity of cell structure, i.e., type of cel l – prokaryotic or eukaryotic. As a eukaryotic cell has membrane-bound organelles including a nucleus, the cellular processes can be carried out efficiently in isolation from cells. On the oth er hand, the organisms without a clearly demarcated nucleus and other organelles need to hav e very different biochemical pathways. This would naturally have a great effect on every a spect of cell design. Moreover, the nucleated cells would have the capacity to particip ate in making a multicellular organism as they are capable of taking up specialised functions .

(ii) Body organisation, i.e, whether the organism i s unicellular or multicellular. In a eukaryotic multicellular organism, cells that group together t o form a single organism use the principle of division of labour. In this type of body design, all cells would not be identical. Rather, groups of cells will carry out specialised function s. Thus, this makes a very basic distinction in the bodydesigns of organisms. As a result, an am oeba will be very different in its bo design from a fish.

(iii) Mode of nutrition: autotrophic or
heterotrophic. Plants make their own food while animals depend on plants or other animals for their food. F or they will definitely have different body design.


7.In the hierarchy of classification, which grouping will have the smallest number of organisms with a maximum of characteristics in common and whi ch will have the largest number of organisms?

Ans.Smallest number of organisms with a maximum of char acteristics in common will be Species while grouping with largest number of organisms wit h common characteristics will be the Kingdom.

8.What is classification? What is the need of classification? What is the basis of classification?

Ans.Classification - The process of grouping similar th ings into groups or categories on the basis of similarities and differences is called classificati on.
Need of classification - It is very difficult to st udy large number of organisms individually. So organism having similar characters grouped together and the studied easily.
Classification - Cell structure, mode &source for t he nutrition and body organization.

9.Thallophyta, Bryophyta and Pteridophyta are called as ‘Cryptogams’. Gymnosperms and Angiosperms are called as ‘Phanerogams’. Discuss wh y. Draw one example of a gymnosperm.

Ans.The thallophyta, bryophyta and pteridophyta ar e called as ‘cryptogams’ because the reproductive organs of these groups are inconspicuo us or hidden. Seeds are absent. On the other hand ‘Phanerogams’ include gymnosperms and an giosperms which have well differentiated reproductive tissue and the embryo w i th stored food. Their embryo develops into a seed

10.Will advanced organisms be the same as complex organisms? Why?

Ans.Yes we can say that the advanced organisms are the same as complex organisms because advancement has occurred due to the process of evol ution where a group of simple organisms have changed themselves into the complex forms of life for better survival.

11.Write characteristics of angiosperms

Ans.Characteristics of angiosperms:
(a) The angiosperms are the dominant group of land plants. These are the most common flowering plants.
(b) The angiosperms are seed bearing plants and th e seeds are enclosed inside the fruit formed from ovary.
(c) Carpel is like of megasporophyll as gymnosperms, but it is differentiated ovary, st yle and stigma.
(d) The pollen grain is received by the stigma cau sing pollination.
(e) Ovary develops into fruit and ovules into seed s after the act of fertilization.

12.

Ans.(a) A, B, D
(b) A – Amoeba, B – Starfish (asterias) D – Hydra.
(c) (i)Amoeba-
1. It is uninucleate
2. locomotion is by finger like pseudopodia
(ii) Asterias (starfish)-
1. Body is radially symmetrical
2. Body cavity is modified into a water – vascular system with elastic tube – like outword extension for locomotion called tube – feet or podi a.
(iii) Hydra-
1. Mouth is surrounded by tentacles which helps in feeding
2. Respiratory, circulatory and excretory organs ar e absent.

13.Give four main features of phylum coelenterate.

Ans.Four main feature of phylum coelenterate are:
(a) These animals live in water.
(b) The body has a sac like body cavity with a single o pening to the outside for ingestion and egestion.
(c) These are the first multicellular animals which pos sess tissue level organization with distinct division of labour.
(d) The body is made of two layers of cells – one makes up cells on the outside of the body and the other makes up inner lining of body.

14.Give three examples of range of variations that you see in life-forms around you.

Ans.The range of variations that we see in life-forms a round us are:
(a) Size: There is a lot of variation in the size of o rganism that we see. The size of microscopic bacteria is few micrometers while the size of blue whale is about 30 meters and height of red wood tree s of California is about 100 meters.
(b) Life Span: There is lot of variation in the life sp an of organisms. The life span of insects like mosquito is only a few days whereas, the life span of a pine tree is thousand of years.
(c) Colour: There is a lot of variations seen in colour . Worms are colorless or transparent whereas flowers and birds are brightly coloured.

15.Define pseudocoel.

Ans.A false body cavity between body wall and gut, e.g. in roundworms.

16.Write the difference between male and female cone o f Pinus?

Ans.Female cones are: Large and woody Male cones are: Smaller and tender

17.Give two peculiar characteristics of sponges.

Ans.(a) Presence of pores like ostia and osculum. (b) Presence of Canal system.

18.How do poriferan animals differ from coelenterate a nimals?

Ans.PoriferanAnimals :
a. They posses cellular level organization.
b. The body has several pores, ostia and osculum.
c. The body design of these animals involves mini mal differentiation.
d. Appendages are absent.
e. Digestion is intracellular.
f. Muscles and nerve cells are absent. Coelenterate animals:
a. They posses tissue level organization.
b. The body has a single opening.
c. The body design of these animals shows more di fferentiation.
d. Appendages occur in the form of tentacles.
e. Digestion is both intracellular and intercellu lar.
f. Muscles and nerve cells appear for the first t ime in coelenterates.

19.What is haemocoel? Which group of animals have haemocoel?

Ans.Haemocoel is a psedocoel with blood. It is found in arthropods and mulluscs.

20.Which organisms are called primitive and how are th ey different from the so-called advanced organisms?

Ans.The group of organisms which have ancient body desi gns and have not changed much are called “Primitive” organisms. They are different from the advanced organisms as advanced organisms are group of organisms which have acquired their pa rticular body designs recently.

21.Describe the characteristics of the division Thallophyta

Ans.The characteristics features of Thallophytaare : a. The plant body consists of individual thallus. b. The sex organs are single celled. c. After fertilization, no embryo is formed.

22.Name the stages in life cycle of mosquito.

Ans.The stages during the life cycle of mosquito is : (a) eggs (b) Larva (c ) Pupa (d) adult

23.Differentiate between taxonomy and systematics.

Ans.Taxonomy is the process of identification, nomencla ture and classification of organisms, whereas systematic is the practice of identificatio n, nomenclature, classification and study of evolutionary relationship among organisms.

24.Give two characteristics of pisces

Ans.1. They have stream lined body which helps in swimm img.
2. Respiration occurs with the help of gills.

25.State the phylum to which centipede and prawn belong.

Ans.Phylum arthropoda

26.What are gymnosperms? Give two characteristics.

Ans.Gymnosperms are naked seeded plants. Two characteri stics of gymnosperms are
1. The plants are usually perennial, evergreen and woo dy.
2. The flowers are represented by unisexual cones, bot h being present on same plants

27State the appropriate terms for the following:
a. Plants which bear seeds with two cotyledons.
b. Animals which do not have coelom.
c. Edible fungi


Ans.a. Plants which bear seeds with two cotyledons are called dicotyledons.
b. Platyhelminthes do not have coelom.
c. Edible fungi is mushroom.

28.Why is there need for systematic naming of living organisms? Write four conversations that are followed while writing scientific names of the species.

Ans.There is a need for systematic naming of living org anisms because of the following reasons: In a community local name serves the purpose of rec ognizing an organism but people in different region call the same organism with differ ent name. For eg. A dog is called Kutta in Hindi, Kukur in Ba ngla, naai in tamil and Kutra in Marathi, and it is difficult to know different language hence, s ystem of scientific naming was introduced by Carolus Linnaeus called as the Binomial system of n omenaclature. The four conventions that are followed while writin g scientific name of the species are as follows:-
(a) The name of genus begins with a Capital Letter.
(b) The name of species begins with small letter.
(c) When printed, the scientific name is given in itali cs.
(d) When written in hand, the genus name and the specie s name have to be underlined separately.

29.Differentiate between a plant and an animal.

Ans.

30.a. Write any four features that all chordates possess.

Ans.a. The four main characteristics of chordates are a s follows:
i) Presence of notochord at any stage of life.
ii) Presence of dorsal hollow nerve cord.
iii) Presence of gill slits at any stage of life.
iv) Presence of tail behind the anal opening.

b. Explain the three basic features for grouping a ll organisms into five major kingdoms.

Ans.The groups are formed on the basis of their cell structure, mode and source of nutrition and body organization.
Whittaker based his scheme of classification on the following three levels of organization:
i) Prokaryotic versus Eukaryotic cell structure.
ii) Three different modes of nutrition- Photosynthesis (plants), Absorption from the enviro nment (fungi) and Ingestion (animals).
iii) Unicellular versus Multicellular organization.
31.Why are local names not sufficient to recognize the organisms? What are the advantages of keeping names?

Ans.Names are essential to distinguish one organism fro m the other. The local names serve their purpose in a community of a particular region. The names used in a region may not be understood in other regions and therefore, cause co nfusion. So, the local names are not sufficient to recognize the organism. On the other hand, Scientific names are followed an understood all over the world. Each scientific name is specific and therefore, there is no chance of any confusion. Moreover, scientific name immediately provide information about the generic origin of the species.