HSEB General characteristics of phylum Chordata

The General characteristics of phylum Chordata are as follows :

1. Presence of Notochord : It is stiff, flexible and solid rod like structure which helps in supporting the internal body . It is situated between the alimentary canal and nerve chord. It may be present in the embryonic stage only or throughout the life.  Later on in an adult it is replaced by vertebral column or backbone.

2. Presence of Nerve chord : It is hollow , tubular nerve tissue. It is situated dorsally above the nerve chord. It is later on replaced into brain and spinal chord.

3. Presence of Gill slit : It is paired lateral gill opening situated in both side of pharynx. It is respiratory opening that take part in the exchange of gases.

4. They have closed circulatory system with RBC.

5. Presence of post anal tail.

6. Presence of ventrally situated heart.

7. They are triploblastic, bilaterally symmetrical and coelomate.

HSEB zoology notes | General characteristic of Aves

The general characteristic of Aves are : 

1. The body of aves is covered by feather and they are adapted to for aerial mode of life.

2. Body form : Their body is streamed lined and divided into head, tail ,trunk and neck. Head is small and round , neck is flexible and monocondylic (can rotate 360 degree) and tail is short and stumpy.

3. Locomotion : Locomotion is aves is served by two pair of limbs. fore limbs are modified into wings for flying and hind limb to support  the body, for piercing mechanism , swimming and walking purpose. There are four fingers. 3 fingers are directed forward and one is directed backward called hallux. Thus it shows bipedal.

4. Respiration : They respire through spongy and inelastic lungs. It consists of many air sac.

5. Nervous System : Their consists of 12 pair of cranial nerve.

6. To reduce their body weight their bone is hallow , pneumatic , porous without bone marrow.

7. Skin : Their skin is dry and without gland. However oil gland or peer gland is which is present at the root of tail secrete oil to soften and greasy the feathers.

8. Excretion : They perform excretion by metanephric kidney. Urinary bladder is absent. They are ureotelic(those who excrete uric acid) .

9. Reproduction System : Sexes are separate in them. Sexual dimorphism is usually distinct. Male have paired testes. Female have only one ovary.

10. Fertilization is internal preceded by courtship (attracting female) and copulation and they are oviparous (egg laying) and development is direct.

HSEB zoology notes | General characteristics of Reptile

The general characteristics of reptile are as follows:

     1.       Habitat : They are mostly terrestrial and some are aquatic. They are cold blooded (poikilothermic) animal.

    2.       Body form : Their body is elongated and cylindrical and divided into head ,trunk , neck and tail. Skin is dry , rough and non-glandular. It is covered by scales or bone plates. 

    3.  Locomotion: Locomotion in amphibian is carried out by two pair of pentadactyle limbs. Horny claws are present aquatic form, digits in terrestrial form.

   4.       Respiration : They respire through lungs. In turtle, gaseous exchange take place through cloaca.

   5.       Nervous System : They have 12 pair of carnial nerve arising from brain.

   6.       Reproduction : Sexes are separate and they are oviparous. Eggs are covered by CaCO3.

Eg : Hemidactylus (wall lizard) , turtle etc

HSEB zoology notes | General characteristics of Amphibians

    HSEB notes

    The general characteristics of Amphibian are as follows:

1.  Habitat: They live both in land and water. They are cold blooded (poikilothermic) animal.

     2.       Sleeping period: They undergo hibernation (winter sleep) and aestivation (summer sleep) period during unfavorable condition.

     3.     Body : Their body is cylindrical and divided into head trunk and mobile neck. Their head is triangular and bears pair of eye, external nosestril and tympanum. Eyes are protected by nictitating membrame.

  

    4.     Locomotion: It takes place by pentadactyle fore and hind limbs. Claws are absent. Fore limbs has 4 fingers and hind limb has  5 fingers with webbed and longer toes.

  

    5.     Nervous System: They have 12 pair of carnial nerve arising from brain.

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    6.       Reproduction system :  Sexes are separate in them(diocious) .

    7.    Development is indirect and fertilization is external.

    Eg : Hyla, Rana(frog) , Toad(bufo) etc.

HSEB zoology notes | General characteristic of Pisces

The general characteristics of Pisces are as follows :

1.  Habitat : They are completely aquatic found in marine or freshwater. They are cold blooded (poikilothermic) animals.

2.  Body form : They have streamlined body or boat shaped and laterally compressed. Body is covered by cycloid or placetoid scales.

3.  Locomotion : Locomotion in Pisces is performed by paired fins (pelvic, pectorial fins) and unpaired fins (anal , dorsal , caudal fins).

4. Respiration : They respire through gills. Gills may or may not be covered by operculum.

5. Swim bladder may or may not be present and they two chambered heart.

6. Reproduction system : Sexes are separate in them (diocoius) and some show sexual dimorphism like cartilaginous fish and some don't like bony fish. Those who show sexual dimorphism have clasper for transferring sperm to female genital tract.

7. Development is direct and fertilization in Pisces is both internal and external.

HSEB zoology notes | Difference between cartilaginous fish and bony fish

The difference between Chondrichthyes (cartilaginous fish) and Osteichthyes (bony fish) are as follows: 

Chondrichthyes (cartilaginous fish)	Osteichthyes   (bony fish)
1.       They are marine.	They are both marine and fresh water.
2.       Swim bladder is absent.	Swim bladder is present.
3.     Endoskeletion is cartilaginous.
4.   Endoskeletion is bony.	No operculum. Spiracles are present.
5.  Gills are enclosed by operculum.	Mouth is at the presnt at the ventral region.
6.  Mouth is present at the terminal region of the     body.	Fertilization is internal.
7. Sexual dimorphism is distinct. They have clasper for transferring sperm to female genital tract. eg : Scoliodon , Torpedo (electric fish) etc	Sexual dimorphism is not distinct. Clasper are absent. eg : Labeo (rohu) ,  Exocoetus (flying fish) etc