This document discusses characteristics of the animal kingdom phylum Vertebrata and class Pisces. It describes how vertebrates possess a notochord that is replaced by bone or cartilage, and have features like a heart, kidneys and paired appendages. It outlines characteristics of jawless fish class Cyclostomata and cartilaginous fish class Chondrichthyes. Finally, it provides details about bony fish class Osteichthyes, including examples of marine and freshwater fish.
5. Vertebrata
These are true chordates
The members of subphylum vertebrata possess
notochord during the embryonic period
The notochord is replaced by a cartilaginous or bony
vertebral column in the Adult.
All vertebrates are chordates but all chordates are
not vertebrates.
Vertebrates have a ventral muscular heart with two,
three or four chambers, kidneys for excretion and
osmoregulation and paired appendages which may
be fins or limbs.
6.
7. Class Cyclostomata
They are not true fish
Jaw-less fish
They are ectoparasite on some fishes
They get stuck on fish and suck nutrition
They have an elongated body bearing 6-15
pairs of gill slits for respiration.
Cyclostomes have a sucking and circular
mouth without jaws
8. Their body is devoid of scales and paired
fins.
Cranium and vertebral column are
cartilaginous.
Circulation is of closed type.
Cyclostomes are marine but migrate for
spawning to fresh water. This type of
migration is called Anadromous migration
After spawning, within a few days, they
die. Their larvae, after metamorphosis,
return to the ocean.
Examples: Petromyzon (Lamprey) and Myxine
(Hagfish).
Source NCERT
10. Characteristic features of Fish
Body-Streamlined body
Fins-helps them in movement
The various fins are:
Caudal fin(1)
Pectoral fin(2)
Dorsal fin(1)
Pelvic fin(2)
Anal fin(1)
12. Class Condrichthyes
They are marine animals with streamlined body and
have cartilaginous endoskeleton .
Mouth is located ventrally.
Notochord is persistent throughout life.
Gill slits are separate and without operculum (gill
cover).
The skin is tough, containing minute placoid scales.
Teeth are modified placoid scales which are
backwardly directed.
13. Their jaws are very powerful. These animals are
predaceous.
Due to the absence of air bladder, they have to swim
constantly to avoid sinking.
Heart is two-chambered (one auricle and one
ventricle).
Some of them have electric organs (e.g., Torpedo)
and some possess poison sting (e.g., Trygon).
They are cold-blooded (poikilothermous) animals,
i.e., they lack the capacity to regulate their body
temperature.
Source NCERT
14. Reproduction
Sexes are separate.
In males pelvic fins bear claspers.
Fertilization- internal fertilisation and many
of them are viviparous.
Examples: Scoliodon (Dog fish), Pristis (Saw
fish), Carcharodon (Great white shark),
Trygon (Sting ray).
15.
16. Class Osteichythes
It includes both marine and fresh water fishes bony
endoskeleton.
Their body is streamlined.
Mouth is mostly terminal .
They have 4 pairs of gills which are covered by an
operculum on each side.
Skin is covered with cycloid/ctenoid scales.
Air bladder is present which regulates buoyancy.
(Angel fish)
17. Heart is two chambered (one auricle and one
ventricle).
They are cold-blooded animals.
Sexes are separate.
Fertilization is usually external.
They are mostly oviparous and development is
direct.
Examples: Marine – Exocoetus (Flying fish),
Hippocampus (Sea horse); Freshwater – Labeo
(Rohu), Catla (Katla), Clarias (Magur); Aquarium –
Betta (Fighting fish), Pterophyllum
Source NCERT
18.
19. MCQ
Q1.Osteichthyes belongs to
(a) class amphibia
(b) super class pisces
(c) super class tetrapoda
(d) division agnatha
Ans:(b) super class pisces
20. Q2.Water-Vascular system is found in
(a) Sea-anemone
(b) Sea-pen
(c) Sea-cucumber
(d) Sea-horse
Ans:(c) Sea-cucumber
21. Q3.Sharks, skates, and rays are also called ______fishes.
(a) Jawless
(b) Bony
(c) Cartilaginous
(d) Freshwater
Ans:(c) Cartilaginous
22. Q4.Which one of the following is NOT a characteristic of phylum
Annelida?
(a) Ventral nerve cord
(b) Closed circulatory system
(c) Segmentation
(d) Pseudocoelom
Ans:(d) Pseudocoelom
23. Q5.Excretion in flatworms occurs by
(a)Nephridia
(b)Flame cells
(c)Malpighian tubules
(d)Green glands
Ans: (b) Flame cells