Q  
1. List three distinguishing features between gymnosperms and angiosperms in tabular form.

Solution

Gymnosperms Angiosperms

(i)Plants bear naked seeds.  

(ii)Endosperm cells are haploid.  

(iii)Sporophylls are aggregated to form cones.

(i)Plants bear seeds which develop inside the fruit. (ii)Endosperm cells are triploid.

(iii)Sporophylls are aggregated to form flowers.

Q  2. Which organism is known as devil fish?

Solution

Octopus is also known as devil fish due to appearance of eight muscular arms or tentacles.

Q  3. What is mesoglea?

Solution

Mesoglea is a non-cellular jelly-like layer present in between endoderm and ectoderm in diploblastic animals.

Q  4. Write a short note on Methanogens.

Solution

A microorganism that produces methane as a byproduct of its metabolism are called methanogens. They belong to subdivision Archaebacteria. Methanogens cannot survive in the presence of oxygen. They are found in swamps and marshy areas.

Q  5. Give one example of each:

i. Reptile with four-chambered heart

ii. Flightless bird

iii. Cartilaginous fish

iv. Egg-laying mammal

Solution

i. Crocodile ii. Ostrich iii. Dogfish iv. Duck-billed platypus

Q  6. Differentiate between Thallophyta, Bryophyta and Pteridophyta.

Solution

Differences between thallophyta, bryophyta and pteridophyta are: Characters Thallophyta Bryophyta Pteridophyta Habitat Mostly aQ  uatic (fresh and marine- both forms exist). Terrestrial, present in damp places. Terrestrial, present in damp and shady places. Body Structure Body is undivided in the form of thallus. Body is flat, green thallus (liverworts) or leafy and erect (mosses) Plant body is erect and rigid. True roots, stems and leaves Absent Absent Present Vascular system Absent Absent Present Sex organs Single-celled Multicellular Multicellular and jacketed in sterile cells.

Q  7. What are the salient features of Phylum Mollusca?

Solution

Salient features of Phylum Mollusca: i. Members of Phylum Mollusca are bilaterally symmetrical and soft-bodied. ii. Their body is divided into an anterior head, ventral muscular foot and dorsal visceral mass. iii. Visceral mass is covered by a specialized tissue called mantle, formed from the folds of the dorsal body wall. iv. Members of Phylum Mollusca respire through ctenidia, mantle or lungs.

Q  8. Name the two groups of animals which have been classified on the basis of origin of mouth.

Solution

On the basis of origin of mouth, animals are categorized into two groups; Protostomia and Deuterostomia.

Q  9. On the basis of symmetry, how is Sea Urchin different from Earthworm?

Solution

Sea urchin is radially symmetrical whereas earthworm ins bilaterally symmetrical.

Q  10. What are nematocysts? What are their functions?

Solution

Nematocysts are organelles that have stinging cells. They are present in Cnidarians. Nematocyst paralyses the preys by injecting poison and helps Cnidarians to catch their prey.

Q  11. What are the five kingdoms that R. H. Whittaker proposed? Also, define the term species.

Solution

R. H. Whittaker categorized organisms in the following five kingdoms:

1.Kingdom Monera

2.Kingdom Protista

3.Kingdom Fungi (Mycota)

4.Kingdom Plantae

5.Kingdom Animalia. Species is a basic category of taxonomic classification, ranking below a genus or subgenus and having related organisms capable of interbreeding.

Q  12. Which division among plants has simplest organisms?

Solution

Thallophyta has simplest organisms as they do not have a specific body design.

Q  13. Name the phylum to which Hydra and Tapeworm belong?

Solution

Hydra belongs to Phylum Coelenterata whereas Tapeworm belong to Phylum Platyhelminthes

Q  14. How does the writing of scientific names in binomial nomenclature differ in print and when written by hand?

Solution

When printed, the scientific name is given in italics. But when written by hand, the genus name and the species name have to be underlined separately.

Q  15. Pick up the odd one out and justify your choice by giving reasons. Crocodile, salamander, sparrow, bat

Solution

Salamanders, as they have three chambered heart. All other organisms have four chambered heart.

Q  16. You are given Leech, Neries, Prawn and Scorpion; and all have segmented body organizations. Will you classify them in one group? If not, give the important characters based on which you will separate these organisms into different groups.

Solution

All the organisms given here do not belong to the same group. Leech and Nereis belongs to phylum Annelida. They have segmented body and closed circulatory system. Prawn and scorpion belongs to Arthropoda. They have jointed legs and open circulatory system.

Q  17. List any two differences between pteridophytes and phanerogams

Solution

Pteridophytes  Phanerogams 

  • Do not produce seeds.
  • They have hidden reproductive organs.

(iii) Primitive Vascular tissues are present.

  • Produce seeds.
  • They have well differentiated reproductive organs.

(iii) Advance vascular tissues are present.

Q  18. Define

  • triploblastic 

(ii) bilateral symmetry.

Solution

(i)The animals in which three germ layers are present are called triploblastic animals.

(ii)The body symmetry in which the two sides of the body are mirror images of one another is called bilateral symmetry.

Q  19. State the role of canal system in Poriferans.

Solution

The canal system is a filter-feeding system of sponges. It helps in circulating water throughout the body to bring food, oxygen and water.

Q  20. What are cotyledons?

Solution

Cotyledons are the structures in plant embryos that may give rise to leaf on germination.

Q  21. What is the need for classification?

Solution

It is necessary to classify organisms because: Classification allows us to understand diversity better. It helps in the identification of living organisms as well as in understanding the diversity of living organisms. Classification helps us to learn about different kinds of plants and animals, their features, similarities and differences. It enables us to understand how complex organisms evolve from simpler organisms. To understand and study the features, similarities and differences between different living organisms, they are grouped under different categories. Classification is a tool which helps us to deal with a great diversity of living forms. It is essential to understand the inter-relationships among the different groups of organisms. Classification forms a base for the development of other biological sciences. 

Q  22. (a)Why do we classify organisms? (b)State the basis of classifying plants and animals into different categories. (c)Which organisms are called primitive and how are they different from the advanced organisms?

Solution

(a)We have bewildering variety of life and a very large number of organisms, so we cannot look at them one by one. So we have to make groups on the basis of similarities and dissimilarities. It will help us to study them easily and systematically.

(b)

(i)Presence or absence of cell wall.

(ii) Mode of nutrition – autotrophic (presence of chloroplast) or heterotrophic.

(c)Primitive organisms are those which have ancient body design but they have not changed very much with the passage of time. Advanced organisms are those which have acquired their particular body designs relatively recently.

Q  23. Why do we keep both snake and turtle in the same class?

Solution

Because snake and turtle:

  • are cold blooded
  • have scales
  • breathe through lungs

(iv) have three chambered heart.

Q  24. Differentiate between protostomia and deuterostomia.

Solution

Difference between protostomia and deuterostomia are following:                Protostomia                   Deuterostomia 1.A group of animals in which mouth arises from or near the blastopore of gastrula.

2.Coelomic activities are variable in number

3.Example- Annelida, Arthropoda

1.A group of animals in which mouth arises anteriorly at some distance from the blastopore.

2.Coelomic activities are in three pairs

3.Example- Echinodermata, Hemichordata

Q  25. Write the common name for Ascaris, Wuchereria

Solution

Ascaris – Roundworm Wuchereria – Filarial worm

Q  26. Peculiar water vascular system is a characteristic feature of which phylum?

Solution

Peculiar water vascular system is a characteristic feature of Phylum Echinodermata.The water vascular system helps in locomotion, food capturing, and respiration.

Q  27. Write short note on Phylum Arthropoda.

Solution

Phylum Arthropoda:

  1. Their body is divided into head, thorax and abdomen.
  2. Appendages are jointed.
  3. They are triploblastic, bilaterally symmetrical organisms having a reduced body cavity.

iv. Members of Phylum Arthropoda have a complete digestive system and an open circulatory system.

  1. In Arthropods, respiration takes place via the body surface, gills, trachea or book lungs.

vi. They have paired excretory glands and some have excretory organs called malpighian tubules.

Q  28. Why Linnaeus has been considered as the “father of taxonomy”?

Solution

Linnaeus has been considered as the “father of taxonomy” since he developed the binomial system of nomenclature  and system of classification.

Q  29. What is the common feature between bryophytes and frogs?

Solution

Both are amphibians.

Q  30. What is classification?

Solution

Classification is the method of arranging organisms into groups on the basis of similarities and dissimilarities.