The blog presents the short Questions and Answers of the Chapter 6, Animal Classification, from Science Part II of Class 10 from Maharashtra State Board. These can be very useful for students preparing for SSC Board exams as well as competitive exams, as it includes the objective type basic concepts & fundamentals.
Q19. What is Asymmetrical Body ?
Ans. In asymmetrical body, there is no any such imaginary axis of the body through which we can get two equal halves.
Example : Amoeba, Paramecium, some sponges.
Q20. What is Radial symmetry ?
Ans. In radial symmetry type of body, if imaginary cut passes through central axis but any plane of body, it gives two equal halves. Example : Star fish.
Q21. What is Bilateral symmetry, give examples ?
Ans. In bilateral symmetry type of body, there is only one such imaginary axis of body through which we can get two equal halves.
Examples : Insects, fishes, frog, birds, human.
Q22. What is the significance of germ layers in multicelular organisms ?
Ans. In case of multicellular animals, germ layers are formed during initial period of their embryonic development and from those germ layers only, different tissues are formed in the body.
Q23. What are Diploblastic germ layers ?
Ans. In case of some animals, only two germ layers [Endoderm ectoderm] are formed germ layers are formed during initial period of their embryonic development, they are called as diploblastic germ layers. Example : All
Q24. What are Triploblastic germ layers ?
Ans. In some animals, three germ layers are formed germ layers are formed during initial period of their embryonic development i.e. mesoderm, endoderm and ectoderm.
Examples : Organisms except Cnidarians.
Q25. What is a Body cavity or Coelom ?
Ans. The cavity between the body and internal organs is called as body cavity/ coelom.
q26. What are eucoelomate animals ?
Ans. In case of multicellular animals, during initial period of their embryonic development, body cavity is formed from either mesoderm or gut. Such type of body cavity is present in animals of phylum Annelida and all phyla coming after Annelida. Such animals are called as eucoelomate (animals with true body cavity).
Q27. What are acoelomate animals ?
Ans. In case of animals from phyla Porifera, Cnidaria and Platyhelminthes the body cavity is absent and such animals are called as acoelomate.
Q28. What are pseudocoelomates animals, give examples ?
Ans. The pseudocoelomates are organisms with a body cavity that is not derived from the mesoderm, as in a true coelom, or body cavity.
Examples : Animals from phylum Aschelminthes.
Q29. What is a segmented body ?
Ans. If the body of animals is divided into small, similar units, then such body is called as segmented body and each small unit is called as segment.
Examples : Animals like earthworm from phylum Annelida.
Q30. Write a short note on Phylum – Porifera.
Ans. The Phylum- Porifera has following features :
(a) These animals are with simplest body plan and are called as ‘Sponges’.
They bear numerous pores on their body. Those pores are called as ‘Ostia’ and ‘Oscula’.
(b) These are aquatic animals. Most of them are marine and few are fresh water dwellers.
(c) Most of the animals have asymmetrical body.
(d) These animals have special types of cells- collar cells.
(e) These animals are always attached to substratum, hence do not show locomotion. Hence, they are referred as sedentary animals.
(f) Their spongy body is supported by spicules or spongin fibres. Spicules are made up of calcium carbonate or silica.
(g) These animals feed upon small organisms taken in their body along with water. Water is taken in through ostia and given out through oscula.
(h) These animals reproduce by budding, an asexual method and / or by sexual method. Besides, they have good ability of regeneration.
(i) Examples: Sycon, Euspongia (Bath sponge), Hyalonema, Euplectella, etc.
Q31. Write a short note on Phylum – Coelenterata/Cnidaria.
Ans. The Phylum – Coelenterata/Cnidaria has following features :
(a) Body of these animals is cylindrical or umbrella-like. If it is cylindrical, it is called as ‘Polyp’ and if it is umbrella like, it called as ‘Medusa’.
(b) Most of these animals are marine. Only few are fresh-water dwellers.
(c) Body of these animals is radially symmetrical diploblastic.
(d) Cnidoblast bearing tentacles are present around the mouth. Tentacles are useful for capturing the prey whereas cnidoblasts inject the toxin in the body of prey. Those are useful for protection too.
(e) Examples: Hydra, Adamsia (Sea anemone), Physalia (Portuguese- man-of war), Aurelia (Jelly fish), Corals, etc.
Q32. Write a short note on Phylum – Platyhelminthes.
Ans. The Phylum – Platyhelminthes has following features :
(a) Body of these animals is slender flat like a leaf or strip. Hence, they are called as ‘flatworms’.
(b) Most of these animals are endoparasites. Few are free-living aquatic.
(c) Body is acoelomate bilaterally symmetrical.
(d) These are triploblastic i.e. their body is made up of three germ layers-endoderm, ectoderm mesoderm.
(e) These animals are hermaphrodite i.e. male and female reproductive systems are present in the same animal body.
(f) Examples: Planaria, Liver fluke,Tape worm, etc.
Q33. Write a short note on Phylum – Aschelminthes
Ans. The Phylum- Aschelminthes has following features :
(a) Body of these animals is long thread-like or cylindrical. Hence, they are called as round worms.
(b) These animals are either free living or endoparasites. Free living animals are either aquatic or terrestrial.
(c) Body of these animals is triploblastic and pseudocoelomate.
(d) Body of these animals is non-segmented and covered with tough cuticle.
(e) These animals are unisexual.
(f) Examples: Ascaris (Intestinal worm), Filarial worm, Loa loa (Eye worm), etc.
Q34. Write a short note on Phylum – Annelida
Ans. The Phylum – Annelida has following features :
(a) Body of these animals is long, cylindrical metamerically segmented.
(b) Most of the animals are free-living, but few are ectoparasites. Free-living animals may be marine or fresh water dwellers or terrestrial.
(c) These animals are triploblastic, bilaterally symmetrical and eucoelomate.
(d) They have setae or parapodia or suckers for locomotion.
(e) Their body is covered with special cuticle.
(f) These animals are either hermaphrodite or unisexual.
(g) Examples: Earthworm, Leech, Nereis, etc.
Q35. Write a short note on Phylum – Arthropoda.
Ans. The Phylum – Arthropoda has following features :
(a) These animals have jointed appendages. Hence they are called as arthropods.
(b) Planet Earth has highest number of animals from this phylum. Hence, this is largest phylum with highly successful animals in animal kingdom.
(c) These animals are found in all types of habitats ranging from deepest oceans to highest mountains.
(d) Body of these animals is triploblastic, eucoelomate, bilaterally symmetrical and segmented.
(e) Chitinous exoskeleton is present around their body.
(f) These animals are unisexual.
(g) Examples: Crab, spider, scorpion, millipede, centipede, cockroach, butterfly, honey bee, etc.
Q36. Write a short note on Phylum – Mollusca.
Ans. The Phylum – Mollusca has following features :
(a) Body of these animals is soft and slimy. Hence they are referred as mollusc.
(b) This is second largest phylum in animal kingdom.
(c) These animals are aquatic or terrestrial. Most Tentacle of the aquatic molluscs are marine, but few are fresh water dwellers too.
(d) Body of these animals is triploblastic, eucoelomate, non-segmented and soft. Except animals like snail, their body shows bilateral symmetry.
Their body is divided into three divisions like head, foot and visceral mass.
(e) Visceral mass is covered with mantle. This mantle secretes a hard, calcareous shell. This shell may be external or internal or even absent in some cases.
(f) These animals are unisexual.
(g) Examples: Bivalve, Snail, Octopus, etc.
Q37. Write a short note on Phylum – Echinodermata.
Ans. The Phylum – Echinodermata has following features :
(a) Calcareous spines are present on the body of these animals; hence they are called as echinoderms.
(b) These animals are found only in ocean.
(c) Their body is triploblastic, eucoelomate. And it is radially symmetrical in adult stage. However, they show bilateral symmetry in larval stage.
(d) They perform locomotion with the help of tube-feet. Tube feet are also useful for capturing the prey. Some animals are sedentary.
(e) They have skeleton made up of calcareous spines and / or ossicles (plates).
(f) These animals have good ability of regeneration.
(g) These animals are mostly unisexual.
(h) Examples: Star fish, sea-urchin, brittle star, sea-cucumber, etc.
Q38. Write a short note on Phylum – Hemichordata.
Ans. The Phylum – Hemichordata has following features :
(a) Body of these animals is divided into three parts as proboscis, collar, trunk.
(b) Notochord is present in proboscis region only. Hence, they are called as hemichordates.
(c) These animals are also called as ‘acorn worms’.
(d) These are marine animals, live in burrows in sand.
(e) They have one to many pharyngeal gill slits. are unisexual or some may be hermaphrodite.
(f) Example : Balanoglossus, Saccoglossus.