Class Polychaete

Question 1

Characteristics Of Polychaeta

In terms of species
In terms of abundance
In terms of segmentation arrangement
In terms of parapodia
In terms of suckers

Answer 1

Has about 10,000 species
Abundant in marine habitats
Body bears segmentally arranged chaetae; usually numerous & arising from ectodermal outs
They have paired, fleshy paddle-like lateral projections called Parapodia, on most of their segments
They have no suckers

Question 2

Use of Parapodia

Major role of Parapodia

Examples Of Polychaeta

Answer 2

Parapodia are used in swimming, burrowing or crawling and bear bristle-like chaetae

They also play a major role in gas exchange because they greatly increase the surface area of the body

E.g: Ragworm; Nereis, Aphrodite, Glycera, etc
Lungworm; Arenicola, Sabella, Terebella

Question 3

Characteristics Of Polychaeta

In terms of segments
In terms of gonads
In terms of sexes, type and occurrence of fertilization
In terms of gametes production
In terms of clitellum

Answer 3

The segments are usually numerous and variable in numbers
They lack permanent gonads
The sexes are separate, fertilization is external and occurs in water
They produce their gametes directly from germ cells in the lining of the coelom or in their septa
There is no clitellum