When were the first land animals?

Land animals - first appeared on earth about 430 million years ago, but did not begin to resemble the ones we known today until 360 million years later. Sharks, however, were already abundant about 340 million years ago. It seems that the first land animals were insects such as scorpions and millipedes. But they were greatly different from today's insects. Next to develop were reptiles, the ancestors of lizards and crocodiles. About 180 million years ago the first mammals began to develop on land along with primitive birds. During this period the forerunners of apes began to appear. The earliest species lived both on the land and in the water. It took about 20 million  years for animals to develop the art of breathing air and so to live on land.

When was rubber discovered?

Rubber - although the remarkable properties of the rubber tree were known to the Aztecs and other South American Indians, for perhaps a thousand years rubber was unknown in Europe until the discovery of the New World. Pietro Martyre d'Anghiera, chaplain to the court of Ferdinand of Aragon, Castileand leon, gave the first written account of the elastic gum in his book De Orbo Novo. In it he described a game played by Aztec children using rubber balls. He was particularly amazed by the ball's ability to bounce back into the air after being thrown to the ground. In 1615, about 100 years later, another Spaniard, Juan de Torquemada, described how the Indians made incisions into rubber trees and collected the milk or sap which oozed out. When dried, this rubber milk was used for making bottles and soles for footwear.

When does a drone die?

Drone - the male bee, or drone, dies when there is no more nectar available from the fields. The reason for this is that, when the worker bees can no longer collect nectar for the hive, the production of honey stops. Deprived of their food the drones rapidly grow weak and are carried from the hive by the workers to die. The drone takes 24 days to develop from the egg to a fully grown male and may live as an adult for several months. It's only function in the bee's community is as a potential mate for the queen. Drones are male honey bees. They develop from eggs that have not been fertilized, and they cannot sting, since the worker bee's stinger is a modified ovipositor (an egg laying organ). 

When does a lizard shed its tail?

Lizard's tail - is capable of shedding its tail at any time. If a lizard is attacked it may sacrifice its tail in an attempt to surprise and confuse the enemy. When a lizard's tail is caught by an assailant or a trap, it will simply snap off and enable the reptile to escape. Although some lizard's tail can be four times as long as the rest of their bodies, the loss is only temporary. A new tail can be grown quickly from the old stump.  

Why can owls see well at night?

Owls - the night vision of owls is 100 times as keen as that of human beings, because their eyes are especially adapted for seeing in the dark. But most are almost colour blind and the pictures they receive are slightly blurred. This is because their eyes contain more rod shaped receptor cells than cone shaped ones. Operating in bright light, cone cells sharpen details and react to colour. Rod cells gather light and owls have 10 times as many of these as do human beings. Each cell contains "visual purple", a substance capable of transforming the slightest glimmer of light into a sight impression.

Owls have exceptionally large eyes and can control the amount of light entering by expanding or contracting the pupil. Each pupil can act independently of the other so that owls can see objects in the shadows and in bright light at the same time. Owls eyes are so large that they are supported by thin, bony, tubular structures called sclerotic rings. Because of this the eyes are almost immovable and nature has compensated for this by giving owls extremely flexible necks, which enable them to turn their heads through an arc of 270 degrees. These birds have excellent binocular vision as their eyes are in the front of their heads. This gives them a tremendous advantage in swooping on small lively prey, because distance judgment depends on binocular vision. To add to their advantages at night, the owls have outstanding hearing, keener than that of any other carnivorous bird. But owls can also see well in the daytime. Although most species hunt by night, others are active at dusk or in full daylight.    

Why does wood have a grain?

Wood grain - in a piece of wood is the pattern produced by the annual bands or rings which grow in the trunk of the tree during its lifetime. The tree's rate of growth varies with the seasons. In the spring soft porous wood is needed to carry sap. In the summer, stronger cells of hard wood develop to support the growing weight of new leaves and branches. The number of these alternate bands of soft and hard wood gives the age of the tree. In close-grained wood, which has grown slowly, the annual rings are narrow and packed closely together. If the coarse grained wood has grown more quickly, the rings are broader and spaced more widely apart. Sometimes the rings are irregular, and the grain may be straight, spiral, interlocked or wavy. Skilful sawing is necessary to make the most of the grain and enhance the beauty of furniture made from the wood.

What is a Manx cat?

Manx cat - is a tail less cat found principally upon the Isle of Man a lozenge shaped island about 30 miles long and 20 miles wide, which is situated in the Irish Sea, at roughly the same distance from England, Ireland, Scotland and Wales. The Manx cat is a common household pet on the Isle of Man and is easily recognized by its lack of tail, the pronounced hollow at the end of its backbone, and its very thick, or double, coat. Its back legs are longer than those in front and it therefore runs with a peculiar and very characteristic hopping motion. The Manx cat may be of any colour and its fur is short. It has the reputation of being an excellent mouser. The only other tailless breed is found in Japan. The Manx (Kayt Manninagh or Stubbin) is a breed of cat with a naturally occurring mutation of the spine. This mutation shortens the tail, resulting in a range of tail lengths from normal to tail-less. Many Manx have a small "stub" of a tail, but Manx cat are best known as being entirely tail less this is the distinguishing characteristic of the breed and a cat body type genetic mutation. The Manx are said to be skilled hunters, known to take down larger prey even when they are young. They are often sought by farmers with rodent problems. Manx cat generally prefer warmer climates without snow.

What are termites?

Termites - are soft bodied insects belonging to the family Isoptera. They are sometimes called "white ants" but they are like ants only in that both species live in social colonies. They live in the tropics and temperate countries and make various kinds of nests. Some make galleries in decaying tree trunks, some make nests below the ground, but the most spectacular are large structures built above ground called "termitaria". They are built from earth excavated below ground and cemented together by saliva. Some of these nests are 20 feet high and almost two hard to break open even with a pickaxe. The termite community is divided into four groups, but only two can breed. Each colony is founded by by a "royal pair" and the queen's life is devoted to laying eggs.

What is a praying mantis?

Praying mantis - is an insect belonging to the family Mantoidea. The name "mantis" means "a diviner" and the insect has always been surrounded by superstition and legend because of its habit of remaining motionless or swaying gently backwards and forwards with its head raised and front legs outstretched as if in prayer. In fact it is a ferocious killer and could more aptly be described as a "preying mantis". Most mantids are camouflaged and look very like the vegetation amongst which they live. The front legs are shaped like clasp knives to grasp the mantis's victim in an inexorable grip while it is torn apart by its captor's mandibles. The mantis even devours poisonous insects as well as its own kind. A male mantis may often be eaten by the female after mating. Most species of mantids are tropical or sub-tropical, but about 20 species occur in Europe. Mantodea or mantises is an order of insects that contains approximately 2,200 species in 15 families worldwide in temperate and tropical habitats. Most of the species are in the family Mantidae. Historically, the term "mantid" was used to refer to any member of the order because for most of the past century, only one family was recognized within the order; technically, however, the term only refers to this one family, meaning the species in the other 14 recently established families are not mantids, by definition they are empusids, or hymenopodids, etc.), and the term "mantises" should be used when referring to the entire order.

What is photosynthesis?

Photosynthesis - is a process by which green plants make food for themselves-and, indirectly, for all animals, including human beings. Without it life as we known it on this earth would be impossible. In photosynthesis plants combine water and salts in the soil and carbon dioxide, in the air to build up organic compounds, such as sugar starch and proteins. To do this they use the energy of sunlight, which is absorbed with the help of the green dye in their leaves called Chlorophyll. This process of manufacturing food from what they absorb through their roots and leaves makes green plants the primary food producers in the world. All animals draw their nourishment from them, either by feeding on the plants themselves or by eating others animals that do so. During photosynthesis, which takes place only in daylight, excess in oxygen is produced and released into the atmosphere for animals to breathe. After the Second World War the American scientist Melvin Calvin wrote a book about how plants capture the carbon dioxide in the atmosphere. At 1961 he received the Nobel Prize in chemistry in recognition of his work.

What is a camel's hump for?

Camel's hump - a camel uses its hump as a portable storehouse of fat from which to draw nourishment when food is scarce. A chemical process enables the camel to covert some of this fat into water, an advantage which enables it to survive for up to 17 days in the desert without drinking. The Arabian camel or dromedary, found in Arab countries of the Mediterrian, has only one hump. But the Bactrian camel of western Asia has two, giving it greater powers of endurance. A camel has a especial way of running called "pacing", which looks like an slow run and saves energy. Yet another advantage which enables the camel to survive in regions where food is scarce is its ability to eat twigs and thorny plants which other animals would not touch.As is the case with all animals, including the human beings, the greater part of a camel's body weight consists of water. But, unlike us, this "ship of the desert" can lose up to a quarter of the water through dehydration and live to make another journey. When it does get a chance to replenish supplies, it can put all that weight back in 10 minutes by drinking 25 gallons of water at a time. The Bactrian is slower than the Arabian, but has more stamina.

When does a forest become petrified?

Petrified forest - becomes petrified or turned to stone under certain conditions through the action over the centuries of water containing large quantities of minerals. Tree trunks buried ages ago under mud, sand or volcanic ash have been gradually transformed as water seeped into the empty cells of the decaying wood filling them with mineral matter and preserving every detail of the original structure. Petrified forests have been found in many parts of North or South America dating from different geological periods and containing stone replicas of the tree that grew in those eras. The most famous of these forests is the Petrified Forest National Park in north Arizona, in the United States. There thousands of stone trunks and logs have been exposed to view through the rain washing away the soil in which they were buried. Although now composed of a mineral called Silica, the original details of the trees can be studied through a microscope. Some of the trunks are up to 80 feet long and three to four feet in the diameter. They are the fossils of cone bearing trees belonging to Triassic times, the age of the dinosaurs, and are more than 150 million years old.

When do snakes shed their skins?

Snake skins - shed their skins when they outgrow them. This happens continually because snakes keep growing throughout their lives although more slowly as they get older. The skins are discarded at regular intervals of one to three months, according to the variety of snake. During this process which is known as sloughing, the old skin is turned back on itself beginning at the lips and gradually revealing the new skin underneath. When sloughing has ended, the old skin will have been turned completely inside out and left in one piece.

When do stags fight?

Stags - the red deer of Europe fight in autumn and winter for possession of the females or does. Most stags are polygamous and collect harems. A stag wishing to add to its harem at the expense of another will challenge its rival to a duel. At other times stags are prone to solitary wandering. But when the breeding season arrives their fighting instincts are aroused. Occasionally the stags antlers become so firmly interlocked in combat that they cannot free themselves. In such cases the battle ends with the deaths of both contestants from starvation.

Why do cats purr?

Cats purr - most people think that cats purr to show pleasure or contentment. Purring is a kind of low continous rattling hum but it is nothing to do with a cat's real voice for the vibration frequency is far lower than that of the vocal chords. In fact a mother cat uses purring to call her kittens to feed. At birth kittens cannot see hear or smell but they can feel the purring of their mother as a vibratory movement and so come towards it to nurse. Once the kittens are feeding, the mother stops purring. So it would seem that purring began as a kind of homing device and your cat may simply be reminding you that he is there so that you will continue to stroke him. On the other hand he is quite likely to give a sudden playful bite even when he is purring.

Why do some animals hibernate?

Hibernate - some animals in cold climates escape the severest weather by hibernating. That is they spend the winter months in a very long deep sleep. The word "hibernate" comes from the Latin hibernare, which means "to winter". Many animals find sheltered places underground or at the base of trees and hedges in which to hibernate. Hibernating animal include frogs, newts, toads, lizards, dormice, bats, snails, tortoises, hedgehogs and squirrels. During hibernation the animal appears to be lifeless. Breathing almost stops and the heartbeat is slow. The feet tails and snouts of warm blooded animals are much colder than usual although the blood in their hearts remains at a high temperature. The animals are nourished by sugars stored in the liver and by fat that has been built up during the summer. Mild winters are bad for hibernating animals because they wake up during warm spells and use energy in moving about. But they do not feed normally and, by the end of the winter, are very thin. Creatures which cannot burrow find cracks and holes in which to shelter. Some have been known to return to the same place year after year. Just as animals in cold climates escape winter by hibernating so some in the tropics avoid hot dry spells by sleeping underground. This is known as a estivation from the Latin word meaning heat.

Why are frogs, toads, and newts called Amphibia?

Amphibia - the word amphibia comes from two Greek words: amphi meaning "of both kinds" and bios meaning "life". Amphibia are a class of vertebrate (back boned) animals that can live both in water and on land. They are descended from fishes that lived more than 300 million years ago. The first amphibia to crawl out of the water were heavily built and slow and clumsy on land but more active in water. They had long bodies and tails and some developed into the highly efficient class of reptiles. About 160 million years ago many amphibia became extinct. But a few survived to develop into the present-day frogs, toads, newts, salamanders and the worm like caecilians. Modern amphibia usually have moist, tough skins. They breathe partly through their skins, although they also have lungs. They usually lay their eggs in water. Here the young live, breathing chiefly through gills, until they change into their adult forms. They eat insects, snails, worms and similar food, and are eaten by fish, snakes and birds. They are usually small. But the Giant Salamander of the Far East is 5 1/2 feet long and the Giant Frog of west Africa grows to a mature length of almost one foot.