Class Agnatha

Question 1

Consists of both present (….) e.g ….., …., etc and …. ( …. & ….) species

Answer 1

Consists of both present (cyclostomes) e.g Hamprey, Hagfishes, etc and extinct ( conodonts & ostracoderm) species

Question 2

Characteristics Of Agnatha

In terms of vertebrate
In terms of skeleton
In terms of notochord
In terms of nostril

Answer 2

They are jawless vertebrates
They possess an internal cartilaginous skeleton
Notochord persists throughout life
They possess single median nostril

Question 3

Characteristics Of Agnatha

In terms of mouth
In terms of appendages
In terms of heart
In terms of gaseous exchange
In terms of habitat (2 points)

Answer 3

They have circular mouth or slit-like openings that lack jaws
They lack paired appendages i.e they lack paired fins
Their heart has 2 chambers: One ventricle & One Auricle
Their gills serve as a major site of gas exchange
They are usually found in marine habitat
They are bottom dwellers that wiggled around stream beds or the sea floor but there are also some active, mid water forms with paired fins