What are the difficulties that you would face in classification of animals, if common fundamental features are not taken into account?
How useful is the study of the nature of body cavity and coelom in the classification of animals?
What are the reasons that you can think of for the arthropods to constitute the largest group of the animal kingdom?
The phylum, Arthropoda, consists of more than two-thirds of the animal species on earth. The reasons for the success of arthropods are as follows.
(i) Jointed legs that allow more mobility on land.
(ii) Hard exoskeleton made of chitin that protects the body from the harsh conditions.
(iii) The hard exoskeleton also reduces water loss from the body making them more adapted to terrestrial conditions.
(iv) The fertilisation is internal which provides protection to the progeny from the external harsh conditions.
Water vascular system is the characteristic of which group of the following:
Porifera
Ctenophora
Echinodermata
Chordata
“All vertebrates are chordates but all chordates are not vertebrates”. Justify the statement.