Animals with backbones and without backbones

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  • Publicado : 12 de octubre de 2010
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INTRODUCTION

The following report talk about vertebrates and invertebrates animals, their characteristics and their life forms.
This report shows some pictures of different kinds of animals that are classified in those groups.
Next a little introduction about the information contained in these report:
Animals with an internal skeleton made of bone are called vertebrates. Vertebratesinclude fish, amphibians, reptiles, birds, mammals, primates, rodents and marsupials.
Although vertebrates represent only a very small percentage of all animals, their size and mobility often allow them to dominate their environment.
Of the million or more animal species in the world, more than 98% are invertebrates. Invertebrates don't have an internal skeleton made of bone. Many invertebrateshave a fluid-filled, hydrostatic skeleton, like the jelly fish or worm. Others have a hard outer shell, like insects and crustaceans. There are many types of invertebrates. The most common invertebrates include the protozoa, annelids, echinoderms, mollusks and arthropods. Arthropods include insects, crustaceans and arachnids.

ANIMALS WITH BACKBONES
Fishes are vertebrates that have a skeletonmade of either bone or cartilage. About 95% of fishes have skeletons made of bone. These bony fishes have a swim bladder, a gas-filled sac, that they can inflate or deflate allowing them to float in the water even when not swimming. Fishes with a cartilage skeleton tend to be heavier than water and sink. They must swim to keep afloat. Cartilaginous (cartilage) fish include the ray and the shark. |Most fish swim using a tail fin. Muscles in the tail fin move it from side to side, forcing water backward, and propeling the fish forward. Other fins help the fish change direction and stop. Pectoral fins on their side help them swim up and down. Dorsal and anal fins on the top and bottom keep the fish upright. Pelvic fins on the underside help steer left and right.Many fish eat plants, whileothers such as the shark, eat other fish. |
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Marsupials are members of the mammal family. However, they are different from other mammals because they have an abdominal pouch to carry their young. The marsupial female gives birth very early and the baby animal climbs from the mother's birth canal to her pouch. Here the baby marsupial continues to develop for weeks, or even months, dependingon the species. |
At birth, marsupial babies are not fully developed. The baby's hind legs are just nubs. The baby lives and continues to develop in the mother's pouch. The pouch, or marsupium, also has the mother's mammary glands for feeding the baby. A baby kangaroo may live in its mother's pouch for 6 months. |
Koalas and wombats are a little different from Kangaroos. The kangaroo'spouch is on the front, while the koala and wombat pouches are on the back. |
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Primates. Humans are part of the primate family. Other common primates include the monkey, baboon, orangutan, chimpanzee and gorilla. While humans inhabit much of the world, most other primates live in tropical or subtropical regions of the Americas, Africa and Asia.Primates have several distinctive features thatseparate them from other mammals. Primates have well developed hands and feet, with fingers and toes. Their opposable thumb makes it easy for them to grab things. Primates also have large, highly developed brains. Their intelligence allows them to control and manipulate their environment.The highly developed visual center of the brain helps primates distinguish colors. Their large brain also allowsthem to develop complex language and communication skills.Monkeys and apes walk on all four limbs, but they may run upright using only their hind legs. |
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Although primates are born fully formed, they tend to have a long gestation period in their mother's womb. Parents also care for and educate their young much longer than other animals. This results in a strong bond between a baby and the...
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