ADDITIONAL QUESTIONS AND ANSWERS :
1. What is tube within a tube plan ?
Ans: When an animal has an complete gut and has mouth for intaking the food and anus for expelling of faeces is called tube within a tube plan .
2. Write one specific feature of thallophyta plant .
Ans: The body of thallophyta plant is not differentiated into stem , root and leaves .
3. What are cyclostomata ?
Ans: Cyclostomata are group of jawless fishes which have round mouth but lacks jaws . They belong to phylum chordate and sub-phylum agnatha .
4. In what way , are amphibians advanced than the fishes ?
Ans: Amphibians have three chambered heart and lungs for respiration , while fishes have two chambered heart and gills for respiration .
5. How are oviparous and viviparous animals different from each other ?
Ans: Oviparous animals lay eggs , e.g. birds , while viviparous animals give birth to young ones,
e.g. most of the mammals .
6. Explain the meaning of the terms and give an example in each of the following :
a) Symbiotic relationship b) Cotyledons c) Prokaryotic .
Ans:
a) Symbiotic relationship :
It is the relationship where two organisms work together by helping one another with the intent of getting help in return . Example : Egrets and cattle : while the egrets get their food when they eat the insects from the skin of the cattle , the cattles get the benefit of a clean skin .
b) Cotyledons :
Cotyledons is a part of the embryo within the seed of a plant . When the seed germinates , the cotyledons become the first leaves of the seedling . Example : when gram seed germinates , the seed breaks into two parts which look like two leaves . These leaf like structures are called cotyledons .
c) Prokaryotic :
Prokaryotic cells are those that do not have a membrane bound nucleus . Example : bacteria .
7. Write four important features that all chordates possess (vertebrates)
Ans: The four important features that all chordates possess are as follows :
i) They have a notochord and a dorsal nerve cord .
ii) They are triploblastic .
iii) They have paired gill pouches .
iv) They are coelomate .
8. List some adaptations of reptiles towards terrestrial mode of life .
Ans: The adaptations of reptiles towards terrestrial mode of life are :
i) Skin is thick , dry and non glandular to check the loss of water .
ii) Body is covered by an exoskeleton of epidermal scales which forms a water proof coat .
iii) Excretion is uricotelic which requires minimum water loss .
iv) Main mode of respiration is pulmonary respiration .
9. List two differences between lizards and snakes .
Ans: Lizards have limbs and eardrum while snakes do not have limbs and eardrum .
10. Why are amphibians are always present close to the water bodies ?
Ans: Most amphibians lay their eggs in water or in moist location on land so they are always present close to the water bodies.
11. Give one term for the following:
a. An organism having three layers of cells.
Ans: Triploblastic.
b. Organisms able to prepare their own food.
Ans: Autotrophic.
c. Organisms which cannot make their own food.
Ans: Heterotrophic.
d. The plants whose seeds have two cotyledons.
Ans: Dicots.
e. Diversity of life forms.
Ans: Biodiversity.
f. Organisms using decaying organic matter as food.
Ans: Saprophytes.
g. Body cavity in which true organs can be packaged.
Ans: Coelom
12. State the specific function of each of the following:
a. Canal system in Porifera.
Ans: To bring in food and Oxygen
b. The tube system in echinodermata.
Ans: For movement
c. Cilia or flagella in protista.
Ans: For movement.
d. The foot in Mollusca.
Ans: For movement.
13. The features of Monera.
Ans: Prokaryotic i.e. no defined nucleus or organelles.No multicellular body design.
May or may not have a cell wall.
May be autotrophic or heterotrophic
14. Main features of Protista.
Ans:Unicellular eukaryotic organisms. May be autotrophic or heterotrophic.
Move with the help of hair-like cilia or whip-like flagella
15. The characteristics of Fungi.
Ans:
(i) They are heterotrophic
(ii) They are eukaryotic organisms.
(iii) They have a cell wall made of a tough complex sugar called chitin.
16. Any two similarities between Aves and Mammals
Ans: Both aves and mammals are warm-blooded. Both have a four chambered heart.
Respiratory organs in both are the lungs.
17. The characteristics on the basis of which the classified into five divisions.
Ans: Presence of tissues for transporting water and other substances. Presence of well differentiated, distinct components.The plants bear seeds and whether they are naked or enclosed within the fruits.
18. The importance of skeleton in Vertebrates.
Ans: It gives shape to the body. It provides several points for muscle attachment which enables easy movement among animals.
19. Main characteristics of Plantae.
Ans:They are multicellular eukaryotes. They have a cell wall. They have chlorophyll to carry on photosynthesis. They are autotrophs.
20. What is evolution as proposed by Charles Darwin.
Ans: The idea of evolution put forth by Darwin is that most of the life that exist today have arisen by accumulation of a series of changes body design that allow an organism possessing such changes to survive better.
21. Why are older organisms simpler than those which evolved late.
Ans: As the evolutionary time passed more and more changes in the design of an organism were added. Thus the complexity increased with the passage of evolutionary period. Therefore older organisms are simpler than those which evolved later.
22. Whittaker classified the living organisms into five kingdoms.
What was the basis of his classification.
Ans: Whittaker classified living organisms into five kingdoms on the basis of cell structure, mode and source of nutrition and body organization.
23. What are Saprophytes.
Ans: Saprophytes are the organisms which use decaying organic matter as their food.
24. What are Phanerogams.
Ans: Phanerogams are seed bearing plants.
25. What is a Notochord.
Ans: Notochord is a primitive type of endo skeleton. It is a long rod-shaped support structure that runs along the back of the animal. It separates nervous tissue from the gut. It provides a place for attachment of the muscles due to which easy movement is possible.
26. What is symbiosis. Give an example.
Ans: Symbiosis is the co-existence of two organisms for mutual benefit.
Examples are lichens and mosses
27. What are lichens.
Ans: Lichens are the slow-growing coloured patches found on rocks, barks of trees, and so on. They are symbiotic life-forms living in a permanent mutually dependent relationship with blue green algae or cyanobacteria.
28. What is the role of fungi and cyanobacteria in lichens.
Ans: In lichens some varieties of fungi and blue-green algae or cyanobacteria live in symbiosis i.e. they co-exist for mutual benefit. The fungus absorbs water and minerals and supplies it to the algae; while the algae, in turn, prepares food and supplies it to fungus.
29. What is meant by ‘characteristics’ of an organism.
Ans: Characteristics are the similarities between the organisms on the basis of which they can be brought together.
30. Amule, which is produced by interbreeding a horse and an ass, is sterile i.e. cannot reproduce. Why.
Ans: The individuals of a particular species can breed among themselves and produce fertile offspring of their own kind. The horse and as belong to different species and therefore their offspring produced by interbreeding i.e. the mule is sterile.
31. Amphibians lay eggs in water but reptiles do not lay eggs in water. Why.
Ans: The eggs laid by reptiles have a hard covering. Therefore they do not lay eggs in water like amphibians.
32. There is an open circulatory system in Arthropoda. Give a reason.
Ans: There is an open circulatory system in Arthropoda because there is no well-defined.circulatory system in these animals. Blood vessels are absent.
33. Why are cotyledons called seed leaves.
Ans: Cotyledons are called seed leaves because in many cases they become green when the seed germinates in the seed.
34. The cotyledons represent a bit of pre-designed plant in the seed. Justify.
Ans: Cotyledons represent a bit of pre-designed plant they become green leaf-like structures when the seed germinates.
35. Bryophytes and Pteridophytesare called cryptogamae. Why.
Ans: Cryptogamae means those with hidden reproductive organs. In Thallophytes, bryophytes and pteridophytes the reproductive or are inconspicuous, i.e. not well differentiated. Therefore they are called cryptogamae.
36. What is the use of mammary glands in the mammals.
Ans: Mammary glands in the mammals produce milk which they require to feed their young ones.
37. Give two points to distinguish between
(a) Bryophytes and Pteridophytes with reference to
(i) vascular tissues (ii) Body differentiation.
|
Bryophytes
|
Pteridophytes
|
|
They do not contain vascular tissues meant for transportation of water and other substances. |
They contain vascular tissues meant for transportation of water and other substances |
|
Plant body not differen- tiated into roots, stem and leaves. |
Plant body differentiated into roots, stem and leaves. |
(b) Cryptogams and phanerogams
|
Cryptogams
|
Phanerogams
|
|
Plants have very inconspicuous reproductive organs. |
Plants have well differentiated reproductive organs. |
| They do not bear seeds | They bear seeds |
(c) Angiosperms and gymnosperms
| Angiosperms | Gymnosperms |
|
These are flowering plants and fruits. |
These plants do not produce fruits. |
|
The seeds are enclosed inside the fruit. |
The seeds are naked as they do not bear fruits. |
(d) Aves and mammals.
|
Aves
|
Mammals
|
|
The skin is covered with feathers |
The skin is hairy. |
| No glands present in the skin |
Sweat and oil glands present in the skin. |
| Reproduction by egg laying | Give birth to young ones |
|
Mammary glands are present.
|
Mammary glands are absent
|
(e) Pisces and Amphibians.
|
Pisces
|
Amphibians
|
|
The animals live exclusively in water. |
The amphibians live on landas well as in water |
|
The body is covered with scales/plates. |
Scales are absent. Instead there are glands which keep the skin moist. |
|
Their heart is two chambered. |
The heart has three chambers |
(f) Plants and animals:
| Plants | Animals |
|
Plant cells have a cell wall. |
Animal cells have no cell wall. |
| Plants cannot movefrom one place to another | Animals can move from one place |
| Plants are autotrophic |
Animals are heterotrophic. to another. |
(g) Aves and reptiles.
| Aves | Reptiles |
| Aves are warm blooded | Reptiles are cold blooded |
|
Their body is covered with feathers. |
Their body is covered with scales. |
|
They have a four chambered heart except for crocodile whose heart is three chambered. |
They have a three chamberedheart. |
38. Why are trees like pine and deodar called gymnosperms.
Ans: They are called gymnosperms because the seeds they bear are naked.
39. State the advantages of scientific naming of an organism.
Ans: The advantages of scientific naming are: The names indicate evolutionary relationship.They avoid multiple naming,they help in the classification of animals.Scientific names are the same all over the world.
40. State the main features of chordates.
Ans:
(i) They have a notochord,
(ii) They have a dorsal nerve cord
(iii) They are triploblastic
(iv) They have paired gill pouches.
(v) They are coelomate.
41. What are angiosperms.Give an example.
Ans: Angiosperms are the plants whose seeds are enclosed in a fruits. Eg.mango.
42. Why is there a need for scientific naming of organisms .
Ans: A plant or an animal is known by different names in different languages and also in different regions. Therefore there is a need for a unique name i.e scientific name by which it will be known all over the world.
43. What is the convention followed in scientific naming.Give an example.
Ans: The convention that is followed: To write names of genus followed by species in Latin. Name of genus to begin with a capital letter and that of species with a small letter.
Scientific name to be printed in italics and when handwritten genus and species to be underlined separately.
Eg: Scientific name of ‘frog’ is Rana tigrina since its genus is rana and species is ‘tigrina’.
Scientific name of ‘man‘ is Homo sapiens whose genus is homo and species is ‘sapiens
44. Some flowers were kept in a plastic tray. They remained unnoticed for a few days. After a few days it was found that they were covered with a mould. What organisms are present in the mould.
Ans: Fungi
45. Why did they form on the flowers after some days.
Ans: After some days the flowers started decaying and fungi feed themselves on decaying matter.
46. What are such organisms called.
Ans: Saprophytes.
47. State the characteristics used for hierarchical classification of livingorganisms.
Ans: The characteristics used for classification are:The mode of obtaining nutrition. The level of organization of the body in case of autotrophic. The cell structure complexity of the body of the organisms.How the animal body has developed and organised into different parts and the presence of special organs for different functions.