Division of Subphylum

Vertebrata is the largest subphylum of chordata which is characterized by the formation of cranium and vertebral column instead of notochord and brain, spinal cord instead of dorsal nerve cord. It is also called craniata due to presence of cranium and euchordata as most of the characters of chordata are expressed in vertebrata.

Characteristics features of vertebrata are:

1. Dorsal nerve cord get differentiated into brain and spinal cord.

2. Notochord is replaced by vertebral column around the spinal cord and cranium around the brain.

3. Exoskeleton and endoskeleton is differentiable.

4. Gill slits occur at least in embryo stage.

5. Heart is ventral.

6. Blood contains haemoglobin in red blood cells.

7. Paired lateral appendages ,tail, endocrine glands, autonomous nervous system and portal system ( hepatic, renal, hypophyseal) are the other traits present in subphylum Vertebrata.


Division of Vertebrata -  the subphylum Vertebrata can be divided into two groups . They are – 

1. Agnatha – It is a group of poikilothermic animals.  Vertebrates of this group donot  contains paired appendages, girdles and jaws . Mouth is sectorial. External naris is single whereas internal naris is absent. It can be divided into two – Ostracodermi (a group of fossil Agnatha, osteostracs and heterostraciare included in this category. Another group is cyclostomata. Lamprey, Hagfish are example of cyclostomata.Agnathaconsist of class cyclostomata. Characteristics of cyclostomata are –

Mouth is circular, jawless, suctorial, horny teeth, skin is smooth , without scales and has mucous glands. Notochord and imperfect vertebrae occur. Gills are without sacrificing like pouches (marsipobronchi). Heart is two chambered,RBC s are irregular, digestive system is without stomach. External naris, olfactorysac,gonad, find are unpaired. Kidneys are mesonephros,gonoduct is absent.External fertilization is occurred larval stage (ammocoete) occurs. Example- lamprey, hagfish etc.


2. Gnathostomata – The animals of this group possesses jaws ,paired appendages, pared nares and an exoskeleton. It contains different classes. They are –

Fish/Pisces: Exclusively aquatic, appendages are fins for swimming, respiration through gills, body covered by dermal scales, cold blooded gnathostomata, heart two chambered. It is of two types – Chondrichthyes (skeleton made up of cartilage), ostecthys (bony fish). Example of pisces are Catla, rohu, hilsa etc). Example of condrichthyes are shark etc.

Rohu Fish


Amphibians: Their phases of life cycle are dependent on both land and water. They are three chambered heart, cold blooded animals. Limbs are first observedin amphibian (two pairs). Thus they are first tetrapods. Example of amphibians are frog, toad etc.

Frog


Reptiles: They are tetrapodswhich have incomplete four chamber heart. Bodies are covered by dry scale, maximum of them are terrestrial.

Example of reptiles are snake, lizard , crocodile etc.

Snake


Aves: They are the first warm blooded (their body temperature remain unchanged with the change of their temperature of surrounding)animals that appeared on the earth. They have four chambered heart where the fore limbs are converted into wings. Whole body is covered by feather.

Mammals: Mammals are the most advanced and intelligent animals on the earth.They are having, mammary gland, give direct birth to the baby.







From Division of Subphylum to HOME PAGE

New! Comments

Have your say about what you just read! Leave me a comment in the box below.


Recent Articles

  1. Respiratory Balance Sheet | TCA Cycle | ATP Consumption Process

    Feb 18, 24 01:56 PM

    ATP Synthase in Mitochondria
    The major component that produced during the photosynthesis is Glucose which is further metabolised by the different metabolic pathways like glycolysis, Krebs cycle, TCA cycle and produces energy whic…

    Read More

  2. Electron Transport System and Oxidative Phosphorylation | ETC |Diagram

    Feb 04, 24 01:57 PM

    Electron Transport Chains
    It is also called ETC. Electron transfer means the process where one electron relocates from one atom to the other atom. Definition of electron transport chain - The biological process where a chains…

    Read More

  3. Tricarboxylic Acid Cycle | Krebs Cycle | Steps | End Products |Diagram

    Jan 28, 24 12:39 PM

    Aerobic Respiration
    This is a type of process which execute in a cyclical form and final common pathway for oxidation of Carbohydrates fat protein through which acetyl coenzyme a or acetyl CoA is completely oxidised to c…

    Read More

  4. Aerobic Respiration | Definition of Aerobic Respiration | Glycolysis

    Dec 15, 23 08:42 AM

    Aerobic Respiration
    This is a type of respiration where molecular free oxygen is used as the final acceptor and it is observed in cell. Site of Aerobic Respiration - Aerobic respiration is observed in most of the eukaryo…

    Read More

  5. Fermentation | Definition | Types of Fermentation | Application

    Nov 29, 23 10:27 PM

    Fermentation
    Definition of fermentation- It is a process that is energy yielding process of anaerobic oxidation of organic compounds which are carried out by the enzyme action of micro organisms where neither gase…

    Read More