The Dog Essay

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The Dog

Domestic dog, carnivorous mammal, generally considered the first domesticated animal. The domesticated dog has coexisted with human beings as a working partner and household pet in all eras and cultures since the days of the cave dwellers. It is generally believed that the direct ancestor of the domestic dog is the wolf, originally found throughout Europe, Asia, and North America.
Remains of a dog, estimated to be 10,500 years old, have been found in Idaho.

TAXONOMY Kingdom: Animalia Phylum: Chordata Class: Mammalia Order: Carnivora
Family: Canidae Genus: Canis Species: Canis familiaris

ECOLOGY & HABITAT

Little is known about wild dogs of the past but that they are carnivores: hunters and scavengers. This means that they
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Inside of this group of joints there are various types: the hinge, the ball-and-socket, the pivot, and the gliding joints. The most movable joints are present in the appendages. Joints are held together by a fibrous wrapping, the joint capsule, which reinforced by ligaments. Muscles and tendons also help keeping the bones together.

MUSCLES

There are three types of muscles in a dog: the skeletal muscle, cardiac muscle, and smooth muscle. The skeletal muscle works in pairs, a flexor and an extensor.
It permits the movement of the skeleton and it also moves the skin of the dog
(cutaneal muscle is very developed in dogs). The cardiac muscle is the muscle which is exclusively in the heart. The smooth muscle is the one present in the walls of the digestive organs, arteries, veins, in the diaphragm (which separates the two cavities of the body: the thorax and abdomen), and in some other internal organs.

DIGESTIVE SYSTEM

The digestive system of a dog is very similar to a human one. It ensures the ingestion of food and it’s transformation (by mechanical and chemical acts) to simple substances which the dog’s body can absorb and assimilate. It all starts in the mouth, where food is broken down mechanically and also a little chemically (saliva and teeth). Then they pass through the esophagus to the stomach to the small intestine (only 3 meters long but it has a very strong digestion) and to the large intestine where the feces are made. Then

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