Class of subphylum uniramia - insecta, Biology

Class of Subphylum Uniramia - Insecta

Class Insecta consists of nearly a million described species. There are more species of insects as compared to all the other species of animals combined. The most significant characteristic features of insects are the division of body into three tagmata that is, head, thorax and abdomen; presence of three pairs of legs and two pairs of wings on the thoracic region of the body hence some insects may have no wings. Insects have conquered the terrestrial environment so totally that they occupy every possible niche. They have' also invaded the aquatic habitats hence there are only a few marine species. Insects affect the ecology and human life in a number of ways. They have been both friends and foes of man. Evolution of flight, an impermeable cuticle and tracheal respiration are some of the issues which have contributed to their success on land. The head of insects is a composite structure. It bears a pair of antennae and a pair of compound eyes. There are also generally three ocelli. Three pairs of appendages comprise the mouth parts.

They are a pair of mandibles and two pairs of maxillae, of which the second pair of maxillae are fused to make the labium. The mandibles are covered in front by an upper lip or labrum. Into the anterior region of buccal cavity projects a median lobe such as process, the epipharynx. This arises from the base of the labium. The head is followed through a three segmented thorax - prothorax, mesothorax and metathorax. The tergum of the thoracic segments of insects is known as notum. The two pairs of wings articulate with meso and metathorax. While some primitive insects do not have wings (apterygotes), some higher forms have lost their wings secondarily. A pair of legs articulate with each of the three thoracic segments. Each leg is a jointed structure formed by coxa, trochanter, femur, tibia, and tarsus. The legs of different insects are variously modified to suit several functions such as walking, food collecting etc. The abdomen is composed of 9 to 11 segments. Abdomen bears a pair of sensory structures called anal cerci on the 11th segment. An intromittent organ in males for the transfer of spermatozoa and an ovipositor in females for the deposition of eggs are as well present in the genital segments of insects.

Posted Date: 2/4/2013 12:44:03 AM | Location : United States







Related Discussions:- Class of subphylum uniramia - insecta, Assignment Help, Ask Question on Class of subphylum uniramia - insecta, Get Answer, Expert's Help, Class of subphylum uniramia - insecta Discussions

Write discussion on Class of subphylum uniramia - insecta
Your posts are moderated
Related Questions
It is defined as the total amount of heat produced, when unit mass/volume of the fuel has been burnt completely and the products have been cooled to room temperature (~ 15 0 C).

How does the federal government regulate plant-incorporated protectants and ensure their safe use in foods? EPA regulates the manufacture, sale and use of pesticides, containin

Briefly Describe about the Micro Minerals? The last unit focused on the macro minerals. Now in this unit we will study about the micro minerals, namely, iron, zinc, copper, sel

Tapetum - Anther Wall Layers Tapetum is the innermost and most important layer of the anther wall. It is generally composed of a single layer of cells. These cells completely

Adverse Effects of Famciclovir Famciclovir has been generally well tolerated. Headache, nausea and diarrhea have been reported. Like acyclovir, famciclovir has been associated

Starch It is a plant polysaccharide synthesized by  the plant by photosynthesis and stored mainly  in  grains,  legumes,  roots  and  tubers.  Its molecular formula is (C 6 H 1

What is inflammation? Inflammation is the initial response of the unspecific defense system versus aggressions against the body (the aggressions might be caused by infectious p

What is the difference between embryo and endosperm?

Within the cell nucleus the major structures are: the nucleolus, an optically dense region, spherical shaped, where there are concentrated ribosomal RNA (rRNA) associated to protei

what are the functions of cytoplasm ?