Introduction:
Approx 75-80% of all known animals are arthropods; they comprise largest phylum in animal kingdom. Arthropods are found at all depths in brackish, marine, and fresh waters. They are common in temporary ponds, hot springs, saline lakes, and underground rivers. On dry land they are located in deserts, forests, grasslands and tundra. Their success as terrestrial animals possibly owes lot to their water-conserving excretory system, gaseous exchange organs and desiccation-resistant impermeable cuticle. Arthropods have segmented bodies having two or more distinct regions known as tagma. Body is enclosed by the tough, at times flexible, chitinous exoskeleton which serves for both protection and attachment of muscles and other soft tissues. This covering is simple device which may describe part of amazing success of group. Discarded casts were frequently preserved as fossils.
The Exoskeleton of arthropods:
The main distinguishing feature of arthropods, immediately visible to the casual observer, is a tough, semi-rigid cuticular exoskeleton secreted by the epidermis and consisting basically of chitin, a polysaccharide, enmeshed with the protein arthropodin. The cuticle is a layered structure, with a thin, non-wettable outer surface. Although the cuticle is always built on a foundation of chitin, this may be invaded or overlaid by different materials in the various arthropod groups, as we mentioned in the 'Introduction'. In insects, the cuticle is rather thin and light but is impregnated with tanned proteins that give it strength and made waterproof by an outer layer of wax. In forms like crabs the cuticle is thick and hard due to the deposition of calcium salts in the endocuticle; a degree of water-proofing is provided by lipids in the outer epicuticle, and the whole structure is protected by an outer layer of cement.
Categorization and features of Arthropoda:
Features of Phylum Arthropoda are given below:
Subphylum Trilobitomorpha primitive arthropods), Trlobites:
The extinct group of arthropods signified by fossils in which body was molded longitudinally in three lobes, therefore the name Trilobitomorpha. They had pair of antennae and all appendages on post-antennal somites were of common type. They were marine arthropods and were extremely abundant in Cambrian and Silurian but became extinct by secondary period. E.g. Olenus etc.
Subphylum Chelicerata (Greek: chele, talon; cerata, horns)
There are approx 63,000 described species of Chelicerata. Subphylum represents one of the major arthropod evolutionary lines and it comprises well-known spiders, scorpions and ticks. Chelicerates do not have antennae and first pair of appendages (chelicerae), are utilized in feeding; name of subphylum is derived from chelicerae. Body is separated in two main regions, prosoma, composed of head and thorax, and opisthosoma, which is abdomen.
Features of Chelicerata are given below:
Tutorsglobe: A way to secure high grade in your curriculum (Online Tutoring)
Expand your confidence, grow study skills and improve your grades.
Since 2009, Tutorsglobe has proactively helped millions of students to get better grades in school, college or university and score well in competitive tests with live, one-on-one online tutoring.
Using an advanced developed tutoring system providing little or no wait time, the students are connected on-demand with a tutor at www.tutorsglobe.com. Students work one-on-one, in real-time with a tutor, communicating and studying using a virtual whiteboard technology. Scientific and mathematical notation, symbols, geometric figures, graphing and freehand drawing can be rendered quickly and easily in the advanced whiteboard.
Free to know our price and packages for online biology tutoring. Chat with us or submit request at [email protected]
automatic frequency control stage automatically controls the variations in horizontal frequency. therefore it is known as automatic frequency control.
entropy and second law of thermodynamics tutorial all along with the key concepts of change in entropy, change in entropy during adiabatic and isothermal processes, efficiency of carnot engine
Theory and lecture notes of Tracking the Macroeconomy all along with the key concepts of Tracking the macroeconomy, Economic Statistics, Economic Activity and Six Key Indicators. Tutorsglobe offers homework help, assignment help and tutor’s assistance on Tracking the Macroeconomy.
tutorsglobe.com unit cell assignment help-homework help by online solid state chemistry tutors
tutorsglobe.com normal flora of the body assignment help-homework help by online medical bacteriology tutors
Theory and lecture notes of Market Structure and Game Theory all along with the key concepts of market structure, Game Theory, Foundations and Principles of game theory, Static Games of Complete Information. Tutorsglobe offers homework help, assignment help and tutor’s assistance on Market Structure.
tutorsglobe.com proteins assignment help-homework help by online cell membrane tutors
tutorsglobe.com ig g assignment help-homework help by online properties and functions of immunoglobulins tutors
buoyancy-archimedes principle tutorial all along with the key concepts of concepts of buoyancy, archimedes' principle, relative density, application of archimedes' principle, law of floatation
Circuit Analysis tutorial all along with the key concepts of Passive Components, Ohm's law, Kirchhoff's law, Node and Mesh analysis, Equivalent circuit, Thevenin's and Norton equivalents, DC and AC equivalent circuits
tutorsglobe.com monera assignment help-homework help by online five kingdom system of classification tutors
tutorsglobe.com invasive soft tissue infection assignment help-homework help by online streptococcal diseases tutors
tutorsglobe.com sequential process of replication assignment help-homework help by online biosynthesis of dna tutors
Storage Water Heaters (Geysers) heat and store water in a tank that is why hot water available to the service point (for example home) at any time.
Theory and lecture notes of Complex Numbers all along with the key concepts of complex numbers, Imaginary number, Equality of Complex Numbers, Complex Conjugates and Graphing Complex Numbers. Tutorsglobe offers homework help, assignment help and tutor’s assistance on Complex Numbers.
1933997
Questions Asked
3689
Tutors
1442966
Questions Answered
Start Excelling in your courses, Ask an Expert and get answers for your homework and assignments!!