موضوع عن الحشرات بالانجليزي

 معلومات بحث موضوع تعبير فقرة تقرير  برزنتيشن

موضوع عن الحشرات بالانجليزي انواعها اصنافها ايجابيات سلبيات فوائدها اسماء الحشرات  الضارة والنافعة   بالانجليزي والعربي

مترجم نطق كلمة حشرة بالانجليزية معلومات عن  اسماء زواحف بالانجليزي

اسم ام علي بالانجليزي معنى حشره بعوض المضرة مصطلحات انجليزي عربي عن الحشرات

كلمة حشرة  اسماء زواحف  اسم ام علي بالانجليزي معني كلمة ink بعض أنواع الحشرات

Insects make up the fifth class of the arthropod branch, the other classes being Crustaceans, Arachnids, Myriapods, and Onychaphores. The best definition of Insects seems to be that of Claus

, which states it as follows: Arthropods with aerial respiration, divided into head, thorax and abdomen; head carrying a pair of antennae, thorax composed of three rings, carrying three pairs of legs and most often two pairs of wings; abdomen formed of ten rings, often very small. Insects are sometimes called Hexapods, because of the number of their members.

The metamorphosis of insects

The development of Insects can be done without metamorphosis. This is the case of Thysanoures and Collembola coming out of the egg with their final form. But most often, this development presents metamorphoses. They are very incomplete in Orthoptera and Hemiptera. All these groups constitute the Ametabolians. The metamorphoses are much more important in the other groups: Neuroptera, Panorpes, Trichoptera, Lepidoptera, Hymenoptera, Diptera and Coleoptera. In this case we are dealing with what entomologists call Metabolites or Heteromorphs.

Insects may change their skin several times, and many undergo metamorphoses as singular as those of frogs, for example; as they come out of the egg, their shape differs a lot from that of their parents and the one they will affect later. After hatching of the egg laid by the female in the final state, the insect usually passes through the following states:

1st larva, more or less resembling a worm, and having an elongated, soft body, divided into mobile rings, sometimes in the larvae of insects which, in the perfect state, will have a sucker); these larvae are called caterpillars or worms, depending on their size, shape and habitat. Rudimentary wings form under their skin, after they have lived for some time in the water, in the air or underground, and the insect undergoes its new transformation; the larval stage usually lasts for several months, from autumn to the following summer, and sometimes for a much longer period, as is the case with cicadas and cockchafers. Larvae are usually voracious and active;

2nd Pupa or Nymph, state during which the insects remain motionless and do not eat; they then affect a particular form: sometimes, the skin of the larva, hardening, forms a horny or scaly envelope; at other times, it changes into a thin film through which the animal can be distinguished. Before undergoing this change, the larva often prepares shelter, by spinning a cocoon of silk secreted by itself; this chrysalis may be suspended from a small branch by silky filaments, or hidden in some crevice. In the state of chrysalis, the growth of the animal is accomplished rapidly and the shape of the future insect develops gradually. These metamorphoses are easily studied in the common caterpillar, the bee, the mosquito, the fly and the silkworm;

3rd Final State or Imago. The life of the perfect insect is short; it is prolonged at most during the months of summer, until the work of the reproduction is finished; in ephemera, the adult state lasts only a few hours.

Sometimes the transformation is particularly complex and we talk about hyper metamorphosis. In all cases, there are major changes in the organization of tissues, which correspond to histolysis and histogenesis processes

 .

The ecology of insects

The life style of Insects is so varied that a general picture can not be presented. They live in every latitude, land and water; even some hornbeams are swimming on the waves of the high seas and many beetles are completely covered by high tide. Cold or hot countries have their species, like mountains and plains; the sand deserts enclose particular ones, like the lush forests of the tropics.

The distribution of insects on the globe is subject to fairly fixed laws and can be reduced to essential principles quite clear, hence the separation into fauns. The largest species, the most brilliant of colors, live mainly in hot countries; the farther you go to the cold regions, the more the forms become small and obscure. The richest countries in extraordinary forms are the Austro-Malayan region (Australia, Malaysia, Papua) to which must be joined Madagascar, the Brazilian region and the African countries extending from Mozambique to the coast of Seeds and neighboring countries. The poorest fauna are the Patagonian countries and those around Cape Horn, Tierra del Fuego, the southern lands and also the extreme north of Europe. In Europe, wildlife close together, are constructed in such a way that the pollen can never, without extrinsic help, reach the pistil of its own flower or serve to impregnate that of any other. Cross-fertilization is also necessary for flowers of the same species, in order to promote the greatest vigor of the product and to prevent individual peculiarities from perpetuating themselves.

Classification of insects

 Classification

To recognize and study the millions of species of animals and plants that exist on the planet, it is easier when we rank them by order and rank. Scientists are now using a universal classification, based on the work of the Swedish naturalist Linné (1707-1778). This classification is based on units of fixed sets (reign, branch, class, order, family, genus and finally species).

Let's go back to the insects now! They are part of the branch of ARTHROPODES, which is itself divided into classes:

 the Crustacea class (shrimps, crabs ...),

 the class of Arachnids (spiders, scorpions, mites),

 the class of Myriapods (Millipedes),

 and the class INSECTS.

Insects are divided into several orders according to the structure and number of wings, the structure of the head, the body and the antennae, the way of life, etc.

You will notice that at the end of the names of the different orders, we often find the ending -ptera, a Latin word for "wings".

Now we present a summary of the most important orders of insects.

Orders

There are 2 main groups:

 Aptérygotes - originally wingless insects

 Pterygotes - insects normally winged in the adult state. Some may have lost one or two pairs of wings during evolution.

Insects in nature

Despite an often unpleasant image and reputation, insects are useful to the environment. Although they are vectors of certain diseases such as malaria, insects are nevertheless essential for the survival of the animal species. The majority of species play a predominant role. Coprophagous species and insect necrophages contribute to the destruction of excrement, dead bodies and waste. They thus fulfill a primary function in the process of decomposition of animal and plant matter in the natural environment. In addition, some larvae live in the soil and produce humus throughout the year. It is the waste and manure produced by insects that produces countless soil fertilizers. Some species, such as beetles or hymenoptera, are phytophagous. They feed on dead or diseased wood and thus reduce the amount of dead wood by accelerating their decomposition. Insects participate in the survival of the planet. In the environment, insects are also very useful. They are an essential part of the diet of birds and various mammals. They are an integral part of the food chain and the maintenance of the natural balance. The species are complementary and indispensable to each other. As for the main predators of insects, they are insects themselves. By pollinating flowers, recycling plant waste, cleaning the natural environment, fertilizing soils, insects play a predominant role in the ecosystem. Hence the importance of being aware of the disappearance or regression of certain species of insects. It profoundly changes biodiversity. Because of these disappearances, changes in insect habitats. For example, deforestation in some parts of the world has significantly reduced the number of species present in these areas. Climate change also plays an important role in the survival of species that are sensitive to temperature changes. Pollution will probably also be important in the disappearance of some species. Insects are small animals that must leave a large space!