Are there fishes that survive out of water

It is difficult to dissociate fish from water.  They are adapted for an aquatic life.  They breath by means of gills.  This is the main reason why fishes cannot remain on land.  They are incapable of utilising air direct for breathing.

Image Source: www.wikipedia.org
The mudskipper lives on mud flats and mangrove swamps in many parts of West Africa to South east Asia and the South western Pacific.  They spend much of their time out of water.  But they have to return constantly to the pools, left by the tide.  They can breathe air through the membranes lining the back of the mouth and the throat, which are supplied with blood vessels.
In the Malayan mudskipper (Periophthalmus chrysopilos) the pelvic fins have moved anterior to the pectoral fins and joined to form a sucker which enables them to climb vertical trunks of mangroves!  This fish is also called “climbing perch”.
There is one group of fresh water fishes that do beat their fins to achieve true flight through the air.  These are the hatchet fishes of northern South America found from the River Plate to Panama!  The fresh water butterfly fish (Pantodon buchholzi) is capable of leaping out of water for a distance of 6 feet or more.
The freshwater Bichir fish (Polypterus bichir), about two feet long, living in the Upper Nile, is a strange one.  It not only breaths air, but also uses its front fins like legs.  It has gills in addition to the lung like swim bladder.  Yet if denied air for even short time it dies!  To take air it swims slowly to the surface, takes a quick gulp, then rapidly swims down to the bottom!
Any one trabvelling in ship in Bay of Bengal must certainly have seen fishes leaping into the air in groups in al directions.  They are called Parava in Malayalam and are often described as “blue birds of the sea”.  Their wings are pectoral fins, spread while the fish is in the air.  Before take off, the tail is whipped up rapidly to drive the fish out of water.  They does not fly but glides on the fins extended like wings.  This is a method of escaping from enemies.  There are three varieties that are usually gathered by fishermen for use (Cypsilurus coromandelensis, C.spilopterus, C.habiensis).
There are over 43 species of flying fish, world wide.

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The History of Tapioca
What are ice ages
How do seeds germinate?
How did plants originate

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How do we smell

Many animals live in a world dominated by smells. Probably this was the first of the senses to develop.

In the human face, the outside nose is obvious. But there is another nose in the upper nostrils. On its sides, a spot about the size of a nayapaisa, contains special nerve cells. Even though our nose cannot distinguish smells very well, it can detect remarkably minute concentrations of odours. The chemoreceptors lie there. Embedded in this tissue are several million chemoreceptors. They are long, thin cells with hair-like cilia forming a web lying on the surface of the tissue that is bathed in mucus. These receptors are connected to a part of the brain called olfactory bulb. The olfactory bulb of a dog is muchg larger than that of man!

The scent molecules pass from the air travelling up the nose to the mucus, where they stimulate the chemoreceptors. The smell centre in the brain receive the messages and tell us what we are smelling.

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What are ice ages
How do seeds germinate?
How did plants originate

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What is plankton

They are the smallest animals and plants found in the sea.  Yet they have a profound effect upon the balance of carbon dioxide, the major green house gas.  Planktons absorb a vast quantity of carbon dioxide gas and can thus be said to be helping to prevent global warming.

This word itself came into biological use in 1886 to describe these microscopic plants and animals, floating, swimming and drifting in the surface waters of the seas.

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How do seeds germinate?
How did plants originate
How do seeds germinate

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Origins of plant life

Evidence collected from western Argentina samples shows that land plants (Embryophytes), which played a critical role in changing the global climate and in the evolution of multicellular life, had established themselves on the dry parts of the globe about 8-12 million years earlier than previously thought. A paper in the New Phytologist journal (“Early Middle Ordovician evidence for land plants in Argentina, eastern Gondwana” by C.V. Rubinstein et al) reports that spores representing five genera were found in samples recovered from western Argentina. The spores belong to liverworts (cryptospores), the basal group of land plants that still exist and are 473-471 million years old. Similar evidence from 463-461-million-year-old land plants came from liverwort spores recovered from Saudi Arabia and the Czech Republic. The latest evidence from Argentina indicates that terrestrial plants had already diversified as early as 473-471 million years ago. Thus the most remarkable chapter in the earth's history: the invasion of the land by plants had probably taken place during the Cambrian period, millions of years earlier than what the fossil record currently reveals. The study reaffirms the assumption that land plants had evolved in the eastern parts of the supercontinent Gondwana before the continents split millions of years ago and moved to their present positions.

The possibility of plant terrestrialisation at multiple locations at almost the same geological time appears quite unlikely. But the possibility of long-range dispersal of spores from western Argentina to Saudi Arabia and the Czech Republic in a span of 8-12 million years cannot be completely ruled out. In fact, present day western Argentina and Saudi Arabia and the Czech Republic were located in the same latitude (35° S) 470 million years ago. The spores, in turn, were also equipped for long-range dispersal, both in aerial and aquatic environments. After all, the outer cell wall of liverwort spores is covered by sporpollenin, the most resistant polymer known to man. The coating protects the spores from abrasion, ultraviolet light, desiccation and micro-organism attack. That scientists could extract the spores from samples by dissolving the rocks in acid indicates the spores' ability to withstand chemical action. After all, such protection was necessary to survive in the harsh aerial conditions that prevailed at that time. Early land plants lacked lignified tissues that enable plant fossilisation. This makes clear that spores and pollens hold the key to the search for the earliest origins of plant life rather than plant megafossils which are much harder to recover.

Source: www.thehindu.com

Can animals see colour

The ability to discriminate light is found in man and other primates, in certain species of birds, fishes, reptiles and insects.  They have visual receptors that respond differently to various wavelengths of visible light.

Image Source:  www.wikipedia.org

There are several theories of colour vision.  More than a hundred years ago Clerk Maxwell showed that colour vision was trichromatic or based on a three-colour system.

Recent investigations of retina have shown that each cone has one of three pigments absorbing red, green or blue.  The ability to see colours cannot be deduced in animals merely by finding cones in their retinas as some colour blind animals have cones! Most people will now accept that a bull is reacting to the waving of a rag rather than to its red colour.  Pets are able to distinguish colours especially dogs!  Experiments show that golden hamsters are colour blind, dogs and cats have a faint colour sense, giraffes can see some colours but confuse green, orange and red.  Horses, sheep, pigs and squirrels can also see a few colours.  Monkeys and apes have good colour vision as do most birds.  Penguins and gulls prefer red!  Frogs are particularly sensitive to blue light.  Bees are able to distinguish six different colours!  Their colour range has been pushed towards longer wave lengths than that of man! They see ultra violet but not red.  A few insects do see red notably fireflies and day flying butterflies.

The colours of flowers are very closely linked with insect colour vision.  Some flowers do more than attract insects by their bright colours:  they guide the insects to the nectar store by radiating lines contracting with general petal colour!

How did plants originate
How do seeds germinate
What are Viviparous

Where did rice cultivation begin

Rice is the principal grain crop of the tropical countries of Eastern and South Eastern Asia, where it is generally used daily in large quantities as the principal food.

Image Source: www.vikipedia.org
It is not definitely known where man first cultivated it.  But most authorities believe it originated in South India in the remote past.  It has been cultivated all over India for many thousands of years.  Rice spread from there to China, and westward to Persia and Egypt soon afterward.  It was introduced to the Western Hemisphere in the 17th century.
Rice and millet have been staple crops in China since the dawn of history and long distance voyagers in ancient times invariably carried a supply of grain so as to replenish food supplies by pausing to grow crops wherever possible.
Key Words: Rice, Crops

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How do seeds germinate
What are Viviparous
Dolphins

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History of Dogs

All living members of the dog family are descended from a dog – like ancestor Cynodictus and from Tomarctus.  They were wolf like and lived about thirty million years ago.

Image source: www.wikipedia.org

The dog is not a brother of the wolf, but  cousin as he is descended from the same ancient relatives.  Dogs’  scientific name is Canis familiaris and is a species of the family Canidae – meat eating mammals.

The dog first appears as a domesticated friend of ancient Egyptians.  The early paintings of Egypt and some inscriptions show that dogs had some religious significance.  The Egyptian God Anubis is depicted as having the body of a man and head of a dog!  Dogs played a part of the religion of Greeks, usually as guardians of temples or animal sacrifices.  Romans’ used dogs for sacrifices.

Of all animals, the dogs seems to be the most rewarding pet for man.

Key words: Dogs, Canidae, Anubis, Mammals

What are Viviparous
Dolphins
Sea Mammals