Category: Biology Second Paper

1. The body is dry and composed of scales or hard plates arising from the epidermis.
2. Each foot has 5 clawed toes.
3. Their body is divided into three parts. Head, neck and body.
4. The ventricles of their heart are incompletely bifurcated (except in crocodiles).
5. They are ectothermic land animals. That is, their body temperature changes with the rise and fall of the environment temperature.
6. They are cold blooded animals. So it goes into hibernation in winter.
7. They walk on the chest.
8. Their number of carotid nerves is 12 pairs or 24.
9. They lay eggs. ie Oviporous. Eggs are covered with a leathery calcareous shell.
10. The crown of the head is connected to the spinal cord by an occipital condyle.
11. Retractable holes are located transversely.
12. Four extra-embryonic membranes (amnion, chorion, yolk sac, allantois) are formed during the development of the embryo.
13. They are unisexual animals. Fertilization occurs. Muscular male sexual organs exist. Dr. Siddique Publications
14. They have no larval stage.
[key words to remember characteristics: epidermis, hard plate, finger, heart, ectothermic, hibernation, thoracic mass, cranial nerve, ovipore, occipital condyle, excretory pore, copulatory organ, larva]

The class Reptilia is named after the Greek word rep meaning chest walking. Reptilia means reptiles. They walk with their chest full. The Mesozoic era of 16 and a half million years ago is called the Age of Reptiles. Their number of species is 9,831. 3 classes, 25 tribes and 167 species have been identified in Bangladesh.

The class Reptilia is named after the Greek word rep meaning chest walking. Reptilia means reptiles. They walk with their chest full. The Mesozoic era of 16 and a half million years ago is called the Age of Reptiles. Their number of species is 9,831. 3 classes, 25 tribes and 167 species have been identified in Bangladesh.
Features of Reptilia
1. The body is dry and composed of scales or hard plates arising from the epidermis.
2. Each foot has 5 clawed toes.
3. Their body is divided into three parts. Head, neck and body.
4. The ventricles of their heart are incompletely bifurcated (except in crocodiles).
5. They are ectothermic land animals. That is, their body temperature changes with the rise and fall of the environment temperature.
6. They are cold blooded animals. So it goes into hibernation in winter.
7. They walk on the chest.
8. Their number of carotid nerves is 12 pairs or 24.
9. They lay eggs. ie Oviporous. Eggs are covered with a leathery calcareous shell.
10. The crown of the head is connected to the spinal cord by an occipital condyle.
11. Retractable holes are located transversely.
12. Four extra-embryonic membranes (amnion, chorion, yolk sac, allantois) are formed during the development of the embryo.
13. They are unisexual animals. Fertilization occurs. Muscular male sexual organs exist. Dr. Siddique Publications
14. They have no larval stage.
[key words to remember characteristics: epidermis, hard plate, finger, heart, ectothermic, hibernation, thoracic mass, cranial nerve, ovipore, occipital condyle, excretory pore, copulatory organ, larva]

Some animals of the class Reptilia
Lizard- Hemidactylus frenatus
Flying lizard – Chameleon vulgaris
Tortoise – Trionyx gangeticus
Sea turtle – Caretta caretta
Takshak – Gekko gecko
Gharial – Gavialis gangeticus
Gokhra snake – Naja naja
Guisap – Varanus komodoensis
Chameleon – Calotes versicolor
Crocodile – Crocodylus porosus
Fresh water crocodile – Crocodylus palustris

Kuno frog – Duttaphrynus melanostictus
Ghecho frog – Chiromantis simus
Hyla chinensis
Golden frog – Rana tigrina
Flying frog – Rhacophorus reinwardtii
Golden Frog – Phyllobates terribilis
Salamander – Salamandra maculosa
Red salamander – Pseudotriton ruber
Ceylon Sicilian – Ichthyophi sglutinosus
Crested Newt – Triturus cristatus
Siren – Siren lacertina
Necturus – Necturus maculosus
Tuatara – Sphenodon guntheri
Chameleon – Chamaeleo chamaeleon

1. The skin is glabrous, glandular, moist and non-scaly which is conducive to both aquatic and terrestrial environments.
2. Respires by gills and complete lungs in the larval stage. Therefore the first stage of life can easily live in water and the full stage in water.
3. Contains paired carotid nerves that transport impulses.
4. The heart has three chambers, two atria and one ventricle. In the process of evolution, Nilaya bifurcation will be divided into four chambers.
5. The eye has three lobes. It protects the eyes.
6. 4 fingers on the front foot and 5 on the back foot. Movement is easy because of fingers.
7. Cold-blooded or ectothermic animals. When the heart becomes four-chambered, they become hyper-blooded or endothermic animals.
8. The life cycle of the tadpole consists of lava stages. The first stage lives in water and the adult stage lives on land. That is, living a double life.

1. Body skin glabrous, glandular, non-scaly, smooth and moist.
2. Respiration is by gills in the larval stage and by lungs in the adult stage.
3. There are 4 clawless toes on the forefoot and 5 on the hindfoot.
4. They are cold-blooded ectothermic animals. That is, their body temperature changes with the rise and fall of the environment temperature.
5. The first stage of life lives in water and the adult stage lives on land. That is, they live a double life.
6. The heart has three chambers. The heart consists of two atria, one ventricle, one sinus venosus and one conus arteriosus.
7. Renal and hepatic portal systems are advanced.
8. Their body is divided into head, neck and trunk.
9. The crown of the head is connected to the spinal cord by two occipital condyles.
10. The nervous system is divided into three parts. Central, peripheral and automated. There are 10 pairs of carotid nerves.
11. They are unisexual animals. They are excreted.
12. Their life cycle includes the tadpole larval stage.
[key words to remember features: skin, gills, lungs, fingers, ectothermic, bivalve, heart, hepatic portal system, occipital condyle, nervous system, tadpole]

The word Amphibia is formed from the Greek word amphi meaning both and bios meaning life. Animals of this class were the first to conquer land. They are known as amphibians because they live in water and on land. There are currently 7,700 living amphibian species. Among them 715 species of amphibians with tails, 200 species of amphibians without legs and 6,785 species of amphibians with four legs. 2 classes, 4 tribes, 47 frogs and 2 Sicilian amphibians have been identified in Bangladesh.

The word Amphibia is formed from the Greek word amphi meaning both and bios meaning life. Animals of this class were the first to conquer land. They are known as amphibians because they live in water and on land. There are currently 7,700 living amphibian species. Among them 715 species of amphibians with tails, 200 species of amphibians without legs and 6,785 species of amphibians with four legs. 2 classes, 4 tribes, 47 frogs and 2 Sicilian amphibians have been identified in Bangladesh.

Characteristics of amphibians
1. Body skin glabrous, glandular, non-scaly, smooth and moist.
2. Respiration is by gills in the larval stage and by lungs in the adult stage.
3. There are 4 clawless toes on the forefoot and 5 on the hindfoot.
4. They are cold-blooded ectothermic animals. That is, their body temperature changes with the rise and fall of the environment temperature.
5. The first stage of life lives in water and the adult stage lives on land. That is, they live a double life.
6. The heart has three chambers. The heart consists of two atria, one ventricle, one sinus venosus and one conus arteriosus.
7. Renal and hepatic portal systems are advanced.
8. Their body is divided into head, neck and trunk.
9. The crown of the head is connected to the spinal cord by two occipital condyles.
10. The nervous system is divided into three parts. Central, peripheral and automated. There are 10 pairs of carotid nerves.
11. They are unisexual animals. They are excreted.
12. Their life cycle includes the tadpole larval stage.
[key words to remember features: skin, gills, lungs, fingers, ectothermic, bivalve, heart, hepatic portal system, occipital condyle, nervous system, tadpole]

Amphibians bear evidence of evolution
1. The skin is glabrous, glandular, moist and non-scaly which is conducive to both aquatic and terrestrial environments.
2. Respires by gills and complete lungs in the larval stage. Therefore the first stage of life can easily live in water and the full stage in water.
3. Contains paired carotid nerves that transport impulses.
4. The heart has three chambers, two atria and one ventricle. In the process of evolution, Nilaya bifurcation will be divided into four chambers.
5. The eye has three lobes. It protects the eyes.
6. 4 fingers on the front foot and 5 on the back foot. Movement is easy because of fingers.
7. Cold-blooded or ectothermic animals. When the heart becomes four-chambered, they become hyper-blooded or endothermic animals.
8. The life cycle of the tadpole consists of lava stages. The first stage lives in water and the adult stage lives on land. That is, living a double life.

Some animals of class Amphibia
Kuno frog – Duttaphrynus melanostictus
Ghecho frog – Chiromantis simus
Hyla chinensis
Golden frog – Rana tigrina
Flying frog – Rhacophorus reinwardtii
Golden Frog – Phyllobates terribilis
Salamander – Salamandra maculosa
Red salamander – Pseudotriton ruber
Ceylon Sicilian – Ichthyophi sglutinosus
Crested Newt – Triturus cristatus
Siren – Siren lacertina
Necturus – Necturus maculosus
Tuatara – Sphenodon guntheri
Chameleon – Chamaeleo chamaeleon

Cold-blooded aquatic vertebrates that carry out respiration with the help of gills and move with the help of fins are called fish. The classes Myxini, Cephalospidomorpha, Chond

When two segments of the caudal fin of a fish are united to form a uniform and flexible fin, it is called diphyserical. Fishes of the class Sarcopterygiae have diphycercles. Eg – Latimeria chalumnae