SS1 First Term Biology Lesson Note – Phylum Chordata – Vertebrates

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SUB – TOPIC 3: PHYLYM CHORDATA – VERTEBRATES

Vertebrata is a subphylum of the phylum chordate. The chordates have a notochord, a flexible rod of tightly packed cells, a tubular nerve chord (dorsal) and gill slit at some stage in their life history. The back bone or vertebral column replaces the notochord in vertebrates.

GENERAL FEATURES OF VERTEBRATES

Vertebrates are animals with back bone.

1. All vertebrates have the following features
2. A well-developed central nervous system
3. Two pairs of limbs
4. Kidney for eliminating body waste
5. Well-developed sense organs
6. An internal or external skeleton
7. A bilaterally symmetrical body divided into head trunk and tail

CLASS OF VERTEBRATES

There are five classes of vertebrates

1. Pisces
2. Amphibians
3. Reptiles
4. Aves
5. Mammals.

TILAPIA FISH

Fishes of the genus Tilapia are popular as both aquarium and food fishes. Some species of tilapia are mouth brooders, protecting unhatched eggs and newly hatched young by carrying the eggs and young in their mouths. Usually the female carries the offspring, but in a few species the male also participates in mouth brooding.

Frog and Toad

Although both amphibians, frogs and toads have several basic anatomical differences between them. The smooth, moist skin characteristic of frogs covers long legs specialized for jumping and swimming. (It is these musclebound limbs that give the Edible frog, left, its name.) The skin of toads like the Green toad, right, is dry and covered by knobby glandular projections often referred to as “warts.” With relatively short legs, toads lack the jumping ability and range of frogs.

Indian Gavial

The Indian gavial, found only in the Brahmaputra, Ganges, and Mahamadi rivers of India and the Koladon River of southeastern Asia, is differentiated from all other species of crocodilians by its long, narrow snout and weak legs. Growing to a size of 7 m (23 ft), the gavial feeds primarily on fish.

Gouldian Finches

Gouldian finches are one of about 153 species of finches found worldwide. The bills of finches are structurally adapted for shelling seeds, their primary food. A seed wedged in a small groove on the side of the palate is crushed when the lower portion of the bill is raised up against it. The tongue then removes and discards the husk, after which the seed is swallowed.

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