KINGDOM ANIMALIA
FILL IN THE BLANKS
Q.01: Fill in the blanks:
(i) Protozoans have been placed in a separate kingdom known as ________. (Protoctista)
(ii) The sponges do not have any symmetry and are therefore called ________. (asymmetrical)
(iii) Between ectoderm and endoderm, the coelenterate has a non-cellular ________. (mesoglea)
(iv) Taenia solium has ________ and ________ for attachment to the intestine of host. (suckers & hooks)
(v) In annelids, the body segmentation of the type known as _________. (metamerically)
(vi) In insects, there are ________ pairs of legs present in the ________ region of the body. (three, thorax)
(vii) The organ of locomotion in molluscs is the ________. (muscular foot)
(viii) In animals where there are definite left & right sides the symmetry is ________. (bilateral)
(ix) The system in which water moves inside the body of an echinoderm is called ________. (water vascular system)
(x) Coelom is the body cavity formed from the ________ layer. (mesoderm)
MULTIPLE CHOICE QUESTIONS
Q.01: Each question has five options. Encircle the correct option.
(i) In animals, the bodies of which can be divided in two equal halves only in one plane are:
(a) Asymmetrical
(b) Bilaterally symmetrical
(c) Radially symmetrical
ANSWER: (b) Bilaterally symmetrical
EXPLANATION: In an animal where the right side is approximately the same as the left side and where there is a distinct anterior end is said to have bilateral symmetry. The animal can be divided into two equal parts by an imaginary line only in one plane.
(ii) Animals that have their body cavity filled with parenchyma are:
(a) Acoelomates
(b) Coelomates
(c) Pseudocoelomates
ANSWER: (a) Acoelomates
EXPLANATION: In phylum Platyhelminthes, there is no body cavity or coelom, and the mesoderm forms a loose, cellular tissue called mesenchyma or parenchyma which fills the space between the ectoderm and endoderm. It forms a packing around the internal organs of the animals to support and protect them. Such animals are called acoelomates
(iii) The vertebrates in which placenta is formed during the development of fetus are:
(a) Pisces
(b) Aves
(c) Mammals
ANSWER: (c) Mammals
EXPLANATION: In Eutherian Mammals, during development a structure known as placenta is formed through which the fetus is nourished. Also, the placenta has endocrine function i.e., it produces certain hormones. For this reason, these mammals are also called placental mammals.
(iv) In amphibians, the necessary requirements to spend their life history are:
(a) Land
(b) Water
(c) Both ‘a’ & ‘b’
ANSWER: (c) Both ‘a’ & ‘b’
EXPLANATION: Amphibians typically require both land and water throughout their life history. They lay eggs in water, where larvae hatch and undergo aquatic development. As they mature, they transition to a terrestrial environment, requiring both habitats for different life stages. This dual dependence on land and water is a defining characteristic of amphibian life cycles.
(v) Trypanosome causes the diseases:
(a) Malaria
(b) Sleeping sickness
ANSWER: (b) Sleeping sickness
EXPLANATION: Trypanosomes, transmitted by tsetse flies, cause African Trypanosomiasis, commonly known as sleeping sickness. This parasitic infection affects the central nervous system, leading to neurological symptoms and disruptions in sleep patterns.
(vi) In annelids, the organs for excretion are:
(a) Flame – cells
(b) Nephridia
(c) Kidneys
ANSWER: (b) Nephridia
EXPLANATION: Excretion in Annelids takes place by specialized structures called nephridia. These are ciliated organs present in each segment in the body cavity.
(vii) In Arthropoda, the body cavity is:
(a) Pseudocoelom
(b) Enterocoel
(c) Haemocoel
ANSWER: (c) Haemocoel
EXPLANATION: In Arthropods, coelom is not present as the main body cavity. Instead, a haemocoel has developed. It is reduced coelom and communicates with blood vascular system.
(viii) In Mollusca, the foot is used for:
(a) Capturing prey
(b) Locomotion
(c) Both ‘a’ & ‘b’
ANSWER: (b) Locomotion
EXPLANATION: Mollusks typically use a muscular foot for locomotion. The foot is a large, muscular organ that aids in crawling, burrowing, or gliding, depending on the specific type of mollusk. Some mollusks, like snails, use a crawling motion with their foot, while others, like clams, use it for digging into the substrate.
(ix) Vertebrates that develop embryonic membranes around their embryo are called:
(a) Amniotes
(b) Anamniotes
ANSWER: (a) Amniotes
EXPLANATION: Vertebrates that develop embryonic membranes around their embryos are called amniotes. Amniotes are a group of vertebrates characterized by the presence of specialized embryonic membranes, including the amnion, chorion, yolk sac, and allantois. These membranes collectively form the amniotic egg, which allows amniotes to reproduce on land without the need for an aquatic environment for their eggs to develop. Birds, reptiles (including dinosaurs), and mammals are examples of amniotes.
Q.03: Extensive Questions
(i) What are Cnidaria? Explain the diploblastic origin, alternation of generations in cnidaria.
ANSWER:
Cnidaria: The name Cnidaria has been given to the members of phylum Coelenterata due to the presence of special cells called cnidocytes. These cells give rise to nematocysts-the stinging cells, characteristic of this group.
Diploblastic Organization: Cnidarians have double layer organization and are therefore diploblastic, having tissue grade organization and have organs. During the development, two germinal layers are formed, the outer ectoderm and inner endoderm from which their bodies are constructed. The ectoderm forms outer covering and some cells of this layer in most animals give rise to nematocysts while the endoderm cells become specialized for digestion of food. Between the two layers is a jelly-like mesoglea.
Alternation of Generations: The life cycle of coelenterates is characterized by the presence of alternation of generations. There are two generations, one reproduces by sexual means and the other by asexual means. Both generations are diploid. Often the two generations consist of one free-living and one attached stage. Therefore, asexual generation and sexual generation alternate with one another. This is known as alternation of generations e.g., Obelia.
(ii) Describe the parasitic adaptations in phylum Platyhelminthes. How does tape worms affect a person.
ANSWER:
Parasitic Adaptations in Platyhelminthes: The parasitic Platyhelminthes have completely adapted themselves to parasitic mode of life by the development of the following characteristics:
1. The epidermis is absent and there is the formation of resistant cuticle for protection.
2. They have developed adhesive organs, such as suckers and hooks, for attachment to the host.
3. There is degeneration of muscular system and nervous system.
4. The digestive system has become simplified due to increased dependence on host.
5. The reproductive systems are complicated and the ova are produced in huge numbers to ensure continuity of the species.
6. The complexity of life cycle and presence of more than one host during the life cycle is also an important parasitic adaptation.
Tape Worm—Infestation: In Taenia (tape worm), the development of the zygote begins while it is still inside the uterus of female. The last segments or proglottids and their uteri contain completely developed embryo. The fully mature proglottids break of from the body and pass out of the body of man along with faeces (undigested waste). The embryo inside the egg is round in shape and has six chitinous hooks. It shows limited movement of contraction. In order to develop further it must reach a second host which may be a cow. The parasite remains embedded in the voluntary muscles of cow. If an improperly cooked beef is eaten by a person, the parasite which has not been killed begins to develop further in the intestine of man.
(iii) Give the symptoms of the disease caused by certain nematodes.
ANSWER:
Enterobius vermicularis, commonly known as pin worm, is cosmopolitan but more common in Europe and America. Pinworms are parasites in the human caecum, colon and appendix. Their movement causes intense itching of anus, inflammation of mucous membrane of colon and appendix resulting in insomnia and loss of appetite.
Ancylostoma duodenale is commonly known as hook worm. It is a parasite of human small intestine in Asia, North Africa and Europe. It is very dangerous because it holds the villi of intestine and sucks blood and body fluid. During feeding they produce an anticoagulant to prevent clotting of blood and after feeding leave the wound bleeding. In children, it can cause severe anemia and retard physical and mental growth.
(iv) Give an account of the major groups of Arthropods. What is the economic importance of insects?
ANSWER:
Consult textbook at page 183 — 187.
(v) Give the two major classes of the Pisces and explain the adaptations of aquatic mode of life in fishes.
ANSWER:
Consult textbook at page 194 — 196.
(vi) Give the adaptations for aerial mode of life in birds. What is their origin?
ANSWER:
Consult textbook at page 200 — 201.
(vii) What are the general characteristics of mammals? How do the three subclasses protheria, metatheria and eutheria differ from one another.
ANSWER:
Consult textbook at page 201 — 203.
(viii) Distinguish between the following by giving examples:
(a) Radial and Bilateral Symmetry.
(b) Diploblastic and triploblastic animals.
(c) Anamniotes and amniotes.
ANSWER:
(a)
Radial Symmetry:
1) “In radial symmetry, the animal can be divided into two equal halves by an imaginary line in more than one planes.”
2) Their body parts are arranged around a central axis in such a way that any plane passing through the central axis divides the animal in halves that are almost mirror image of each other.
3) This type of symmetry is only shown by diploblastic organisms.
4) Examples: Coelenterates or Cnidarians.
Bilateral Symmetry:
1) “In bilateral symmetry, the animal can be divided into two equal parts by an imaginary line only in one plane.”
2) The bilaterally symmetrical animals have almost same right and left sides of their body. They have distinct anterior end, with clearly defined dorsal and ventral surfaces.
3) This type of symmetry is shown by triploblastic organisms.
4) Examples: All other phyla from Platyhelminthes to Chordata.
(b)
Diploblastic Animals:
1) Diploblastic animals have body consisting of two layers of cells_ ectoderm & endoderm. Often, a non-cellular jelly-like mesoglea is present between these layers.
2) They show lesser degree of specialization. They do not form specialized organs, lack special transport system & central nervous system, have sac-type digestive system, and are radially symmetrical.
3) Examples: Members of phylum Cnidaria (coelenterate)
Triploblastic Animals:
1) Triploblastic animals have body consisting of three layers of cells_ ectoderm, mesoderm & endoderm.
2) They show greater degree of specialization. They have specialized organs & organ systems, special transport systems, tube-type digestive system, and are bilaterally symmetrical.
3) Examples: Members of Platyhelminthes, Nematoda, Annelida upto Chordata.
(c)
Anamniotes:
1) Anamniotes are the vertebrates without foetal membranes.
2) Examples: Cyclostomata, Chondrichthyes, Osteichthyes & Amphibia.
Amniotes:
1) Amniotes are the vertebrates with foetal membranes like amnion, chorion, allantois etc.
2) Examples: Reptilia, Aves & Mammals.