Saturday, 10 December 2011

Circle Of A Frog

The life cycle of frogs involves at least one major transformation, from tadpole to adult. Many also shed their skins regularly as they grow, and some species eat the shed skin. These spectacular transformations may explain why many cultures see frogs as symbolic of re-creation, or as keepers of the secrets of transformations.

Butterfly Transformation Life Circle

Butterfly Transformation

         It is a popular belief that butterflies have very short life spans. However, butterflies in their adult stage can live from a week to nearly a year depending on the species. Many species have long larval life stages while others can remain dormant in their pupa or egg stages and thereby survive winters.
        Butterflies may have one or more broods per year. The number of generations per year varies from temperate to tropical regions with tropical regions showing a trend towards multivoltinism.
           Butterfly eggs are protected by a hard-ridged outer layer of shell, called the chorion. This is lined with a thin coating of wax which prevents the egg from drying out before the larva has had time to fully develop. 
          Butterfly larvae, or caterpillars, consume plant leaves and spend practically all of their time in search of food. Although most caterpillars are herbivorous, a few species such as Spalgis epius and Liphyra brassolis are entomophagous (insect eating).
          The pupal transformation into a butterfly through metamorphosis has held great appeal to mankind. To transform from the miniature wings visible on the outside of the pupa into large structures usable for flight, the pupal wings undergo rapid mitosis and absorb a great deal of nutrients. If one wing is surgically removed early on, the other three will grow to a larger size. In the pupa, the wing forms a structure that becomes compressed from top to bottom and pleated from proximal to distal ends as it grows, so that it can rapidly be unfolded to its full adult size. Several boundaries seen in the adult color pattern are marked by changes in the expression of particular transcription factors in the early pupa.
         The adult, stage of the insect is known as the imago. As Lepidoptera, butterflies have four wings that are covered with tiny scales. The fore and hindwings are not hooked together, permitting a more graceful flight. An adult butterfly has six legs.

Friday, 9 December 2011



A magnet  is a material or object that produces a magnetic field. This magnetic field is invisible but is responsible for the most notable property of a magnet: a force that pulls on other ferromagnetic materials, such as iron, and attracts or repels other magnets.
A permanent magnet is an object made from a material that is magnetized and creates its own persistent magnetic field. An everyday example is a refrigerator magnet used to hold notes on a refrigerator door. Materials that can be magnetized, which are also the ones that are strongly attracted to a magnet, are called ferromagnetic (or ferrimagnetic). These include iron, nickel, cobalt, some alloys of rare earth metals, and some naturally occurring minerals such as lodestone. Although ferromagnetic (and ferrimagnetic) materials are the only ones attracted to a magnet strongly enough to be commonly considered magnetic, all other substances respond weakly to a magnetic field, by one of several other types of magnetism.

Thursday, 8 December 2011

Carnivore Animals

Carnivores eat meat. A carnivore is a predator because it has to find and catch its prey. Some carnivores, such as wolves, hunt in a group called a pack. They move silently and slowly to form a circle around their prey before they attack.

Omnivore Animals

Omnivores eat both plants and meat. Chickens are omnivores. They eat seeds, but they can also eat worms. human beings are also omnivores, although some people choose not to eat meat. These people are called vegetarians.