Class 11 Biology Chapter 4 Animal kingdom Question Answer


Chapter 4

 Animal Kingdom 



Q1. What are the difficulties that you would face in classification of animals, if common fundamental features are not taken into account?
Answer:  If common fundamental characteristics are not taken into account then it would be a tuff job to segregate the species in different groups as in this case each organism would be put in a separate group and the entire classification goal will not be achieved. Classification of animals helps us in distinguish different organisms.



Q2. If you are given a specimen, what are the steps that you would follow to classify it?
Answer: The steps that we would follow to classify a specimen are:
• Observe the presence or absence of vertebral column.
• Identify the level of organisation.
• Identify the body symmetry.
• Observe the presence or absence of body cavity.



Q3. How useful is the study of the nature of body cavity and coelom in the classification of animals?
Answer: The absence or presence of body cavity in the evolutionary ladder provides a hint about the location of a particular species. The lack of coelom means that there is yet to develop a functional division of labour to carry out various activities and the presence of coelom paves the way for evolutionary of a more complex and more efficient organ system for various activities.



Q4. Distinguish between intracellular and extracellular digestion?
Answer: 
In intracellular digestion, the food digestion occurs within the cell. The digestive enzymes are secreted by the cytoplasm into the food vacuole. It occurs in unicellular organisms.
In extracellular digestion, the food digestion occurs in the cavity of alimentary canal. The digestive enzymes are secreted by special cells into the alimentary canal cavity. It occurs in multicellular organisms. 



Q5. What is the difference between direct and indirect development?
Answer:  Direct development: When an adult individual’s life cycle lacks any larval stage in their life cycle, then it is called as direct development. In this case the adults give rise to young ones that develop directly into the adult, example: mammals.
Indirect development:  When an adult individual gives rise to eggs and develop into the adult after several larval stages, example: cockroaches.



Q6. What are the peculiar features that you find in parasitic platyhelminthes?
Answer: The features are:
   • They are free living, parasitic forms.
   • They do not have any special organs for respiration.
   • They have hooks and suckers, for attachment to the host.
   • For excretion they have specialised cells called flame cells.



Q7. What are the reasons that you can think of for the arthropods to constitute the largest group of the animal kingdom?
Answer: Arthropods are the first phylum to have well-developed systems where different activities can be carried out. They have distinct respiratory, reproductive, and locomotion systems. Due to elaborate system their survival ability is great. This help them to survive in diverse conditions. 



Q8. Water vascular system is the characteristic of which group of the following:
      a) Porifera  
      b) Ctenophora   
      c) Echinodermata   
      d)  Chordata

Answer: c) Phylum Echinodermata



Q9. “All vertebrates are chordates but all chordates are not vertebrates”. Justify the statement.
Answer: The phylum Chordata has notochord and paired pharyngeal gill slits. In sub-phylum Vertebrata, the notochord present in embryos is substituted in adults by a cartilaginous or bony vertebral column. Thus, it can be said that all vertebrates are chordates but all chordates are not vertebrates.



Q10. How importance is the presence of air bladder In Pisces?
Answer: The presence of air bladder in Pisces is important because it is like a gas filled sac that helps in maintaining buoyancy. Thus, it helps fishes to descend or ascend and stay in the water current.



Q11. What are the modifications that are observed in birds that help them fly?
Answer:  the modifications that are observed in birds that help them fly are:
   • They have streamlined body for rapid and smooth movement.
   • Their body are covered with feathers and act as insulation.
  • Their forelimbs modified into wings and hind limbs used for walking, swimming, and perching.
  • Due to presence of pneumatic bone their body weight is less.
  • They have additional air sacs to supplement respiration.



Q12. Could the number of eggs or young ones produced by an oviparous and viviparous mother be equal? Why?
Answer: The number of eggs or young ones produced by an oviparous and viviparous mother is not equal. The number of eggs produced by oviparous mother will be more because their eggs are prone to environmental conditions and predators. So, they produced more eggs to overcome their loss because it will help them to survive some eggs even under harsh environmental conditions. On the other hand, in viviparous organisms the development of young ones takes place in the wombs of the mother which is safe inside the body of the mother.



Q13. Segmentation in the body is first observed in which of the following:
a) Platyhelminthes    
b)  Aschelminthes    
c) Annelida     
d) Arthropoda

Answer:  c) Annelida



Q14. Match the following:

a) Operculum              i) Ctenophora
b) Parapodia ii) Mollusca
c) Scales iii) Porifera
d) Comb plates            iv) Reptilia
e) Radula v) Annelida
f) Hairs vi) Cyclostomata and Chondrichthyes
g) Choanocytes vii) Mammalia
h) Gill slits viii) Osteichthyes

Answer: 
a) viii)
b) v)
c) iv)
d) i)
e) ii)
f) vii)
g) iii)
h) vi)



Q15. Prepare a list of some animals that are found parasitic on human beings.
Answer:  
• Wucheraria
• Ascaris
• Taenia
• Acylostoma
• Taenia
• Fasciola



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