advantages and disadvantages of exoskeleton
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Answers:a. Advantages of an exoskeleton 1. protection 2. retardation of water movement 3. protection - physical damage and abrasion 4. barrier 5. concealing colors and shapes b. Disadvantages of an exoskeleton 1. special modification for gaseous exchange and sensory pickup 2. major restriction on growth http://entomology.unl.edu/tmh/ent115/lectures/arthropods.htm
Answers:One advantage is armour... a disadvantage is it needs to be shed in order for the organism to grow.
Answers:As above In exoskeletons it is more difficult to regulate body temperature and they limit the size of the organism (No post-nuclear 20 foot tall ants, sorry). Exoskeletons also cause differences in support muscle/organ development. For example, and endoskeleton is a frame and other organs are attached to it. The outer skin is the only tissue requiring support from inside the body. In an exoskeleton, the outer shell requires much more support to resist implosion (crushing the internal organs). Some exoskeletons avoid this by being self supporting (rounded or spherical shaped for instance), but this leads to another problem. Exoskeletons are heavier than endoskeletons. Bone is the densest of all tissues. Thus a human-sized exoskeleton organism (assuming it could exist) would weigh far more than and endoskeleton of the same size. While it may have stronger muscles, these muscles would have to contend with keeping the exoskeleton supported. Once breached, and the internal organisms of an exoskeleton are very vulnerable as there are no bones to absorb the damage. Exoskeletons would also be very difficult to mend, requiring bone grafts to replace damaged sections. Bones also tend to shatter. The mythical 20 ft ant would be very strong, barley able to move, and easy to kill with most rifles and shotguns, or any crushing force. This is because any shock to the shell would cause fragments, or shrapnel, to peel off the inner shell and go flying through the creature due to the force of the shock, even if the shell was not penetrated. In the Army, we call this effect "spall". It would also be very difficult to repair the carapace after any fight. You would have to break the shell in order to operate, thus causing much more damage. Exoskeletons are not all bad (or else they would not exist). Exoskeletons are very resistant to most "natural", or non-firearm, damage. The organs, while easily damaged once the shell is broken, are usually well protected from normal wear and tear. Vital organs are safe from most predators and competitors. Endoskeleton creatures protect vital organs with the ribcage, but this is rarely enough to withstand the damage inflicted in a fight to the death with a similar sized creature (i.e. a mating fight). Endoskeletons offer greater size for the creature, greater mobility, easier "damage control", and a regenerative and breathable outer skin. The cross-overs, like turtles or some dinosaurs with both endo and exoskeletons show the best, and worst, of both worlds. A turtle's shell is self supporting, but limits mobility. Damaging it also tends to kill the turtle. It also limits the turtle's defenses as it can only attack (if it is a snapper) with its mouth. Some dinosaurs (stegosaurus, ankylosaurus, and others) had this arrangement but were better defended and had longer legs, or a weaponized tail. That's my first SWAG. If I find more I will edit this.
Answers:It provides excellent protection against many predators and accidental injury. However, it limits the size of a species, because fairly quickly the volume of muscle needed to lift the skeleton exceeds the internal volume of the skeleton.