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Acrocanthosaurus was a dinosaur of the Cretaceous period, remains of which were first discovered in 1950 in Oklahoma, USA, Acrocanthosaurus was a carnivore, about 12 metres long, believed to walk semi-upright on two hind legs and had 30 cm long spines on its backbone which may have supported a ridge or sail along its back.
 Research Acrocanthosaurus
Fish (Pisces) are an aquatic class of vertebrates, the lowest class of vertebrates. Fish may be briefly described as vertebrate animals living in water and respiring the air therein contained by means of gills or branchiae, having cold red blood, and a heart consisting of one auricle and one ventricle; and having those organs which take the form of limbs in the higher vertebrata represented by fins.
There are more kinds of fish than all other kinds of aquatic and terrestrial vertebrates put together. The smallest fish is the Trimmaton nanus, a goby of the Indian Ocean, which grows to about one centimetre long. The largest fish is the whale shark, which may grow more than 12 metres long and weigh over 14 metric tons. It feeds on plankton and is completely harmless to most other fish and to human beings. The most dangerous fish weigh only a few kilograms. They include the deadly stonefish, whose poisonous spines can kill a human being in minutes.
Fish live almost anywhere there is water. They are found in the near- freezing waters of the Arctic and in the steaming waters of tropical jungles. They live in roaring mountain streams and in quiet underground rivers. Some fish make long journeys across the ocean. Others spend most of their life buried in sand on the bottom of the ocean. Most fish never leave water. Yet some fish are able to survive for months in dried-up riverbeds.
Fish have enormous importance to human beings. They provide food for millions of people. Fishing enthusiasts catch them for sport, and people keep them as pets. In addition, fish are important in the balance of nature. They eat plants and animals and, in turn, become food for plants and animals.
Fish thus help keep in balance the total number of plants and animals on the earth. All fish have two main features in common. (1) They have a backbone, and so they are vertebrates. (2) They breathe mainly by means of gills. Nearly all fish are also cold-blooded animals - that is, they cannot regulate their body temperature, which changes with the temperature of their surroundings. In addition, almost all fish have fins, which they use for swimming. All other water animals differ from fish in at least one of these ways. Dolphins, porpoises, and whales look like fish and have a backbone and fins, but they are mammals. Mammals breathe with lungs rather than gills. They are also warm-blooded - their body temperature remains about the same when the air or water temperature changes. Some water animals are called fish, but they do not have a backbone and so are not fish. These animals include jellyfish and starfish. Clams, crabs, lobsters, oysters, scallops, and shrimps are called shellfish. But they also lack a backbone.
The first fish appeared on the earth about 500 million years ago. They were the first animals to have a backbone. Most scientists believe that these early fish became the ancestors of all other vertebrates.
Research Fish
Homocercal is a term applied in the case of fishes which have tails with rays diverging symmetrically from the backbone, as opposed to heterocercal.
Research Homocercal
An invertebrate is an animal without a backbone.
Research Invertebrate
Ouranosaurus was a dinosaur of the Cretaceous period. Ouranosaurus was a medium-sized dinosaur, about seven metres long, that walked on its hind legs and was similar in appearance and related to Iguanodon. However, Ouranosaurus had a 'sail' of skin that ran along the backbone and was supported by spines, one on each vertebra. Remains of Ouranosaurus have been found in North Africa and from sediments found with the remains we know the climate Ouranosaurus lived in was warm and dry.
Research Ouranosaurus
The potto is an arboreal, nocturnal, African prosimian primate Perodicticus
potto belonging to the loris family. It has a thick body, strong limbs, and grasping feet and hands, and grows to 40cm long, with horny spines along its backbone, which it uses in self-defence. It climbs slowly, and eats insects, snails, fruit, and leaves.
Research Potto
In man and the higher vertebrates, the chest is the cavity formed by the breast-bone in front and the ribs and backbone at the sides and behind, shut off from the abdomen below by the diaphragm or midriff. It contains the heart, lungs, etc, and the gullet passes through it.
Research Chest
A laminectomy (or rachiotomy) is a surgical incision into the backbone to gain access to the spinal cord.
Research Laminectomy
In computing terminology, a backbone is a high-speed network that connects several powerful computers. In the USA, the backbone of the Internet is often considered to be the NSFNet, a government funded link between a handful of supercomputer sites across the country.
Backbone Facilities are a transmission facility designed to interconnect tributary facilities from clusters of dispersed users or devices; the viewpoint of what is a 'backbone' can range from a single building's wiring to an intercontinental network.
Research Backbone Facilities
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The Probert Encyclopaedia was designed, edited and programed by
Matt and Leela Probert
©1993 - 2009 The Probert Encyclopaedia
Southampton, United Kingdom
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