Red blood cells(erythrocytes) are biconcave discs. They have no nucleus. Their diameter is about 7 micrometers.Their main function is gas transport mainly oxygen. They also carry some carbon dioxide. The biconcavity increases their surface area for gas exchange. The thin central portion allows fast entry and exit of gases.The cells are flexible so they can squeeze through narrow capillaries. They contain no intracellular organelles thereby giving more room for haemoglobin (the large pigmented protein responsible for gas transport).
Showing posts with label Biology. Show all posts
Showing posts with label Biology. Show all posts
Wednesday, December 2, 2015
Tuesday, June 23, 2015
Amphibia-Arboreal Forms
Previous: Burrowing Form
A number of animals are adapted to Arborial habitats and are called tree frog eg. some species of Rana,Rhacophorus,Hyla etc.They belong to different families. They have certain modifications for clinging on trees and climbing purpose.
1)They have adhesive or sucking disc at end of digits.
2)They develop opposable toes.
3)Their eggs develop mostly inside large eggs.
THE END.
A number of animals are adapted to Arborial habitats and are called tree frog eg. some species of Rana,Rhacophorus,Hyla etc.They belong to different families. They have certain modifications for clinging on trees and climbing purpose.
1)They have adhesive or sucking disc at end of digits.
2)They develop opposable toes.
3)Their eggs develop mostly inside large eggs.
THE END.
Friday, June 5, 2015
Habitat and Adaptation in Amphibia cont'd- Burrowing Forms
Burrowing Forms:
They are found mostly in order Apoda and some other amphibians (Anurans).Apodans are highly specialized for burrowing habit and have following features:
1)Vermiform bodies.
2)Compact bony roofed skull.
3)Absence of limbs.
4)Presence of reduced eyes usually hidden in skin.
5)Presence of some special structure to dig burrow.
6)Dull colored skin.
Next:Arboreal Forms
They are found mostly in order Apoda and some other amphibians (Anurans).Apodans are highly specialized for burrowing habit and have following features:
1)Vermiform bodies.
2)Compact bony roofed skull.
3)Absence of limbs.
4)Presence of reduced eyes usually hidden in skin.
5)Presence of some special structure to dig burrow.
6)Dull colored skin.
Next:Arboreal Forms
Thursday, May 28, 2015
Habitat and adaptation in Amphibia Page 6- Aquatic Forms
They are found to inhabit water bodies and adopt swimming mode of locomotion.They have certain modifications for swimming purpose as well as aquatic habitat.
1)Eel type body construction.
2)Presence of gills for respiration.
3)Development of fins.
4)Presence of weak limbs.
5)Lidless eyes.
Eg.Salamander,Proteus etc
Continued on Page 7 - Amphibious Forms
1)Eel type body construction.
2)Presence of gills for respiration.
3)Development of fins.
4)Presence of weak limbs.
5)Lidless eyes.
Eg.Salamander,Proteus etc
Continued on Page 7 - Amphibious Forms
Wednesday, May 27, 2015
Habitat and Adaptation in Amphibia continued Page 5-Terrestrial Forms
Terrestrial forms
They are toads and frogs. They are less dependent on water for their survival. They require water only during breeding season. For locomotion they have jumping habit and in order to avoid enemies they have small and stout body.For locomotion they have certain modifications as-
1)Elongation of hindlimb and loss of tail.
2)Development of powerful muscles.
3)Shortening of vertebral column with very little mobility to avoid jerk during jumping.
4)Attachment of pelvic girdle to vertebral column is shifted quite forward.
Eg. Rana,Bufo etc.
Continued on Page 6
They are toads and frogs. They are less dependent on water for their survival. They require water only during breeding season. For locomotion they have jumping habit and in order to avoid enemies they have small and stout body.For locomotion they have certain modifications as-
1)Elongation of hindlimb and loss of tail.
2)Development of powerful muscles.
3)Shortening of vertebral column with very little mobility to avoid jerk during jumping.
4)Attachment of pelvic girdle to vertebral column is shifted quite forward.
Eg. Rana,Bufo etc.
Continued on Page 6
Tuesday, May 26, 2015
Habitat and Adaptations in Amphibia continued Page 4
They have not been to leave water completely. Modern amphibian forms are reported to inhabit many possible habitat as aquatic, burrowing, arborial and other possible habitats. In these forms modification or adaptation take place according to habitat. These habitats are listed below along with modification found in these amphibians:
Terrestrial forms
Aquatic firms
Amphibious forms
Burrowing forms
Arborial forms
Continued on Page 5
Terrestrial forms
Aquatic firms
Amphibious forms
Burrowing forms
Arborial forms
Continued on Page 5
Sunday, May 24, 2015
Adaptation and Habits of Amphibia (Page 3)
Page 3
Amphibians are mainly aquatic but they live on land and fresh water also.They are usually confined to neighborhood of slowly moving fresh water or stagnant water.This is particularly true for great majority of species where eggs are laid in water.But there are numerous exceptions in which either the development of young ones take without water or parents carry eggs on their bodies during development. Such forms are confined to land only and called terrestrial forms.Apart from this habit,breeding habit ,protective habit which are peculiar in these amphibians.
Continued on Page 4
Amphibians are mainly aquatic but they live on land and fresh water also.They are usually confined to neighborhood of slowly moving fresh water or stagnant water.This is particularly true for great majority of species where eggs are laid in water.But there are numerous exceptions in which either the development of young ones take without water or parents carry eggs on their bodies during development. Such forms are confined to land only and called terrestrial forms.Apart from this habit,breeding habit ,protective habit which are peculiar in these amphibians.
Continued on Page 4
Tuesday, May 19, 2015
Page 2-Biology,Amphibians cont'nd
Page2 (amphibians cont'nd)
Limbless Amphibians
Limbless amphibians are included in order Apoda and sometimes called as blind worms also(eyes poorly or less developed)
They mostly inhabit tropical and subtropical regions of Americas,Africa and Asia excluding Medagasca.They do not have fossil forms.
Habitat-
1)They are burrowing forms except few strictly aquatic forms.They burrow in moist ground with their strong heads.
2)They are long body worm like burrowing animals and resemble large earthworms.
3)Limbs and girdles abscent.
4)In many genera in grooves a series of small calcified scales are found unlike other amphibians. Due to linear arrangement of these scales in transverse grooves false segmentation appears in their body.
5)Eyes small functionless and covered by skin.
6)Mouth terminal.
7)They are carnivorous in food habit feeding upon small animals which are found on ground.
8)Tail either absent or very small just like Anurans.
9)Anus or Vent present at posterior end of body at ventral surface.
10)There is a characteristic sensory protrusable tentacle present on side of face between nostril and eyes in all species. It arises from a special groove in maxilla and called as facial tentacle. It compensates for sensory organ. It is protruded by being descended with blood like eractile organ and retracted by strong muscles.
11)Tympanic cavity and tympanic membrane absent. Columella also absent.
12)Kidney extends whole length of coelom.
13)Liver posteriorly constricted into many numbers of lobes.
14)Laryngotracheal chamber is prolonged into distinct trachae supported by cartilage.
Tracheal lungs are found in these animals just like snails.Left lung is rudimentary (because body is not narrow, therefore cannot accommodate)
15)Comus arteriosus is without spiral valve.There are only 2 pairs of aortic arches i.e. systemic arch and pulmonary arch.
16)Unlike 4 branchial clefts in embryonic life of Apoda.
17)Fertilization is internal with the help of enlarged,eversible cloacal valve which serves as copulatory organ.It is armed with hooks.
18)Skull differs considerably from modern amphibians and reveals resemblances with extinct labrynthodontia i.e. limbless amphibians are primitive and retain some primitive characters mentioned below:
1.Skull solid,compact on dorsal side and have large number of bones than modern amphibian skull.
2.Cranium covered by dermal bones.
3.A pair of post orbital and post frontal bones are present.
4.Frontal and parietal are not fused and separate unlike modern amphibians.
5.Orbit is small and surrounded by bones.
6.Hyoid apparatus and dentary primitive.
7.Vertebral column also differs in many respect from modern amphibians such as
1.Number of vertebrae numerous i.e. 200 to 300 and centrum is me amphicoelus.
2.Notochord persists.
3.First vertebra devoid of odontoid process.
4.Ribs bifurcated.
20.These are either oviparous, ovoviviparous and sometimes viviparous.In oviparous forms female guards eggs in burrows after egg laying until larvae hatch out.
Continued on Page 3
Limbless Amphibians
Limbless amphibians are included in order Apoda and sometimes called as blind worms also(eyes poorly or less developed)
They mostly inhabit tropical and subtropical regions of Americas,Africa and Asia excluding Medagasca.They do not have fossil forms.
Habitat-
1)They are burrowing forms except few strictly aquatic forms.They burrow in moist ground with their strong heads.
2)They are long body worm like burrowing animals and resemble large earthworms.
3)Limbs and girdles abscent.
4)In many genera in grooves a series of small calcified scales are found unlike other amphibians. Due to linear arrangement of these scales in transverse grooves false segmentation appears in their body.
5)Eyes small functionless and covered by skin.
6)Mouth terminal.
7)They are carnivorous in food habit feeding upon small animals which are found on ground.
8)Tail either absent or very small just like Anurans.
9)Anus or Vent present at posterior end of body at ventral surface.
10)There is a characteristic sensory protrusable tentacle present on side of face between nostril and eyes in all species. It arises from a special groove in maxilla and called as facial tentacle. It compensates for sensory organ. It is protruded by being descended with blood like eractile organ and retracted by strong muscles.
11)Tympanic cavity and tympanic membrane absent. Columella also absent.
12)Kidney extends whole length of coelom.
13)Liver posteriorly constricted into many numbers of lobes.
14)Laryngotracheal chamber is prolonged into distinct trachae supported by cartilage.
Tracheal lungs are found in these animals just like snails.Left lung is rudimentary (because body is not narrow, therefore cannot accommodate)
15)Comus arteriosus is without spiral valve.There are only 2 pairs of aortic arches i.e. systemic arch and pulmonary arch.
16)Unlike 4 branchial clefts in embryonic life of Apoda.
17)Fertilization is internal with the help of enlarged,eversible cloacal valve which serves as copulatory organ.It is armed with hooks.
Copulatory organ
18)Skull differs considerably from modern amphibians and reveals resemblances with extinct labrynthodontia i.e. limbless amphibians are primitive and retain some primitive characters mentioned below:
1.Skull solid,compact on dorsal side and have large number of bones than modern amphibian skull.
2.Cranium covered by dermal bones.
3.A pair of post orbital and post frontal bones are present.
4.Frontal and parietal are not fused and separate unlike modern amphibians.
5.Orbit is small and surrounded by bones.
6.Hyoid apparatus and dentary primitive.
7.Vertebral column also differs in many respect from modern amphibians such as
1.Number of vertebrae numerous i.e. 200 to 300 and centrum is me amphicoelus.
2.Notochord persists.
3.First vertebra devoid of odontoid process.
4.Ribs bifurcated.
20.These are either oviparous, ovoviviparous and sometimes viviparous.In oviparous forms female guards eggs in burrows after egg laying until larvae hatch out.
Continued on Page 3
Camel Milk cures many diseases
Camel milk is well known for its traditional cures and has good nutritive value.
Research on Camel milk suggests it is lower in cholesterol, protein and sugar and so it can be easily tolerated by lactose intolerant people. It is higher in minerals (sodium,potassium, zinc,magnesium, iron and copper),vitamins and insulin which adds to its beneficial properties.
It also has high concentration of volatile fatty acids as linoleic acid and polyunsaturated fatty acids which are beneficial in human nutrition.
Camel milk is antimicrobial, antidiarrheal, antioxudative,antithromboric,antihypertensive and has immune modulatory effects.It is antiulcerogenic as it is effective against gastric ulcers induced by ethanol. It has positive role in treating jaundice, splenic problems, asthma, anemia, piles and diabetes.
Raw camel milk has a role in achieving glycemic control in Type 1 diabetes patients.Camel milk contains approximately 52 units of insulin/litre.
The drawback with oral insulin is coagulum formation and denaturation in acidic pH of stomach. But camel milk does not form coagulum in stomach keeping insulin protein intact.This intact protein is absorbed from intestine and maintains normal glycemic level in Type1 diabetes patients.
Research on Camel milk suggests it is lower in cholesterol, protein and sugar and so it can be easily tolerated by lactose intolerant people. It is higher in minerals (sodium,potassium, zinc,magnesium, iron and copper),vitamins and insulin which adds to its beneficial properties.
It also has high concentration of volatile fatty acids as linoleic acid and polyunsaturated fatty acids which are beneficial in human nutrition.
Camel milk is antimicrobial, antidiarrheal, antioxudative,antithromboric,antihypertensive and has immune modulatory effects.It is antiulcerogenic as it is effective against gastric ulcers induced by ethanol. It has positive role in treating jaundice, splenic problems, asthma, anemia, piles and diabetes.
Raw camel milk has a role in achieving glycemic control in Type 1 diabetes patients.Camel milk contains approximately 52 units of insulin/litre.
The drawback with oral insulin is coagulum formation and denaturation in acidic pH of stomach. But camel milk does not form coagulum in stomach keeping insulin protein intact.This intact protein is absorbed from intestine and maintains normal glycemic level in Type1 diabetes patients.
Monday, May 18, 2015
Plants do Maths to get through the Night
Research shows that plants do accurate maths to prevent starvation at night.By doing so,they use up their starch reserves at a constant rate so that they run out of food almost precisely at dawn.
During day they use sun's energy to make food.By energy from sun they convert carbon dioxide into sugars and starch.Onc the sun sets,they must depend on a store of starch to prevent starvation.
Scientists at John Innes Centre have shown that plants make precise adjustments to their rate of starch consumption. These ensure that the starch lasts until dawn even if night comes early unexpectedly or size of starch store varies.And to adjust starch consumption so precisely they must be performing arithmetic division.
During night,mechanisms inside leaf measure the size of starch store and estimate length of time until dawn. Information about time comes from an internal clock,similar to our own body clock.The size of starch store is then divided by length of time until dawn to set correct rate of starch consumption,so that by dawn around 95% of starch is used up.If it is used up too fast plants will starve during night and stop growing,and if it is too slow,it may be wasted.
Scientists at John Innes Centre have shown that plants make precise adjustments to their rate of starch consumption. These ensure that the starch lasts until dawn even if night comes early unexpectedly or size of starch store varies.And to adjust starch consumption so precisely they must be performing arithmetic division.
During night,mechanisms inside leaf measure the size of starch store and estimate length of time until dawn. Information about time comes from an internal clock,similar to our own body clock.The size of starch store is then divided by length of time until dawn to set correct rate of starch consumption,so that by dawn around 95% of starch is used up.If it is used up too fast plants will starve during night and stop growing,and if it is too slow,it may be wasted.
Saturday, April 25, 2015
Our Frog family Amphibia
Poikelotherms- cold blooded
Home other swarm blooded.
It may be defined as a class of those animals which are cold blooded vertebrates amphibious in habit having tetrapodous limbs or pentadactyle pattern and require presence of water for breathing purpose.Amphibia have got an intermediate position between fishes and reptiles. They resemble in general pattern of their body with fishes and to some extent in anatomical pattern of body they are more reptilian. In development they are fish like and exhibit many important fish characters in larval forms.They possess some important characters which are mentioned below-
1)In animal kingdom amphibians are placed between fish and reptiles. They include frogs,toads,salamanders, Gymnophions(Apoda-order limbless amphibians or Ceacelians).They are amphibious in habit i. e. they may live on land as well as in water.They have 2 pairs of pentadactyle limbs.
2)They are cold blooded animals. Their skin is smooth or rough,moist, glandular and naked without any scales except in Gymnophiona.
3)Eyes with movable eyelids.
4)Nostrils paired and connected to mouth cavity.
5)Skull with occipital condyles to articulate with atlas.
6)Teeth present.
7)Heart 3 chambered,RBCs nucleated and oval.
8)Respiration by gills,lungs,skin and by buccal cavity.
9)Aotic arches symmetrical.
10)Kidney mesonephric provided with permanent nephrostoma.
11)Cloaca present which receives duct from reproductive system, excretory system and opening of digestive system.
12)Brain with 10 pairs of cranial nerves.
13)Eggs with gelatinous covering usually laid in water.
14)Larva pass through aquatic stage before metamorphosis.
15)They reveal some parental care.
Continued on Page 2
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