Vertebrata, Biology

VERTEBRATA

It is divided into two parts -        1. Agnetha                    2. Gnetha

S.No.

Character

Agnetha

Gnetha

 

1

 

True Jaws

 

Absent

 

Present

2

Paired apendages

Absent

Present

3

Semi circular canal in internal ear

2

3

4

Nostril

1

2

 

1.

AGNETHA

 

Agnetha is divided into two parts -

1. Ostracodermi

2. Cyclostomata

(I)      OSTRACODERMI

  • First vertebrate. Greatly armoured. All fossils.

EXAMPLES -   Cephalospis

(II)     CYCLOSTOMATA

Body eel like. Mouth sucker type.  Ectoparasite.

Gills 5-16 pairs. Pineal eye present.

Unicellular shin glands present.

Scales absent. Sanguivorous.

On tongue horny teeth present.

EXAMPLES -

1.       Petromyzon                                - lamprey, lampredin present, 7 pairs gills, larva is ammocoet for seven years, living fossil

2.       Myxine                                        - Hag fish, lips as of old lady, bisexual, development direct

 

Note :- Before pisces & after cyclostomata placodermi is a group of extinct fishes (jawed).

These are most primitive fishes. Example- climatius

2.      GNETHA

Gnetha is divided into 5 classes -

1. Pisces

2. Amphibia

3. Reptilia

4. Aves

5. Mammalia

Posted Date: 10/1/2012 1:46:08 AM | Location : United States







Related Discussions:- Vertebrata, Assignment Help, Ask Question on Vertebrata, Get Answer, Expert's Help, Vertebrata Discussions

Write discussion on Vertebrata
Your posts are moderated
Related Questions
Amount of intracellular chloride ions in neuron A Neuron A is a healthy neuron with all the usual ion channels.  When at rest with a membrane voltage of R millivolts, neuron A

Explain Regulation of Water Balance for Cells in the kidneys? Cells in the kidneys respond to low blood pressure by releasing an enzyme called renin, which in turn causes the k

Temperature Stress We know that temperature alongwith water is an important influence on the geographical distribution and range of organisms. Every organism is restricted to a

living organisms and their excretory products

Of which type of tissue is the heart made? How is this tissue oxygenated and nutrified? The heart is made of striated cardiac muscle tissue. The heart muscle is known as the my

Question 1 Write briefly about the Bacterial growth curve Question 2 Define Virus. List out the general properties and classification of virus Question 3 What is Immunog

What are venous vessels, veins and venules? Venous vessels are each blood vessel that carries blood from the tissues to the heart. Veins and venules are venous vessels. Venules

Typhoid  Typhoid vaccine is recommended for travellers to developing countries in Central and South America, Africa and Asia, especially if they plan a long stay or may be livi

Difference between Artificial selection and natural selection - S.No Artificial selection Natural selection 1. It

Which of the following is true for the sodium-glucose co-transporter? A. The net flux of sodium ions is from a region of high sodium ion concentration to a region of low sodium