How many types of animals are there in the sea?

An unimaginable number of creatures live in the sea! There are about 10 animal groups with thousands of species falling under each group. To get a rough idea, look at the table below:

Animal Groups and number of species in each group are listed:

Insects: 10, 00,000

Plants: 3, 75,000

Arachnids: 1, 10,000

Roundworms: 1, 00,000

Mollusks: 50, 000

Fish: 27, 000

Crustaceans: 26, 000

Birds: 9, 000

Reptiles: 6, 500

Mammals: 4, 500

What                    Why                    When                    Where                   Which                   Who

How                    Does                    Do                    Is                   Can