Question

Distinguish between the following:
(i) Vertebrates and Invertebrates
(ii) Marsupials and Egg-laying mammals
(iii) Marsupials and Placental mammals.

Answer 1

Marsupials	Placental mammals
They do not have internal placenta	They have a well-developed internal placenta
They give birth to an undeveloped young one that develops in the pouch of mother	They give birth a well-developed young ones
Their gestation period is short	Their gestation period is longer
Examples include kangaroos, koala etc,	Examples include humans, whales etc.

Marsupials	Egg-laying mammals
They give birth to under-developed young ones that develop in the pouch of the mother	They lay large yolky eggs. These are also called monotremes.
They have a simple placenta	They do not have placenta
They have mammary glands	They do not have mammary glands
Kangaroos, koala are examples.	Echidna, platypus are examples.

Vertebrates	Invertebrates
They do not possess a backbone.	They possess a backbone and internal skeleton.
They have an open circulatory system	They have a closed circulatory system
They have a simple and unorganised nervous system.	They have a complex nervous system with specified sense organs.
They do not show the presence of notochord.	They show the presence of the notochord at least at some stage of their life cycle.
Insects, earthworms, flatworms are some examples.	Birds, reptiles, mammals are some examples.