Animal Products and What You Should Know About Them
Animals are multicellular, living organisms in the Kingdom Animalia. They are the descendants of single-celled algae which were the first animals on earth. Like plants, animals use the sunlight to create energy and nourish their tissues; they do so in a process called Photosynthesis. Other animals, such as insects, also use light to produce food and other energy useful to their lives. In most animals, external means of nutrition are used to feed the animals.
Animals can move because of the muscular action of their legs, but most animals have slow, lumbering movements. Limbic muscles give rise to the trunk and tail, while muscular pouches are found around the organs that are not muscular. The muscular cords, arteries, veins, blood vessels, and digestive system connect the muscle tissue to other parts of the body. The heart pumps blood through the body, drawing nourishment from the various parts. All animals need certain proteins to survive, and some are manufactured by the body itself; i.e., eggshells, hair, horns, bones, teeth, and other elements that animals are composed of.
Animals also consume food to sustain them. It depends on what the animals eat, for example, plant or animal matter, carbohydrates or proteins. Animals live off their foods, but they may eat other things, too. Insects are an important part of an animal’s diet, as is leaf litter and insects’ waste. The remainder of the food is made up of various types of fats and oils that supply dietary nourishment. A small percentage of an animal’s meat is also considered its own food; this is known as feeds.
A number of animals are herbivores and some are vegetarians, meaning they eat only vegetation, although milk is still produced by some bovine species. Some animals are omnivores and prey on other animals as their main source of food. Fish and birds, for example, eat fish and other aquatic animals while herbivores such as cattle, sheep and goats eat mainly plants. Birds and insects are sources of protein.
Food habits of different animals vary, depending on their environment and the needs of their species. Humans have been feeding animals since before recorded history. Their diets depend on their location and availability of food. In the wild, animals eat a variety of plant materials including leaf litter, twigs, seeds, insects, fruits and others. In domestic settings, people eat cattle, pigs, poultry, snakes and various farm animals. In some regions, people feed deer, elk, moose, bears, sheep, poultry, buffaloes and a few birds, as well as small numbers of ungulates.
Domestic animals were probably first domesticated in China over ten thousand years ago. Since then, people have been using animals for transportation, hunting and other purposes. People caught animals and brought them into civilized society. Livestock was used for milk, meat and fur. Today, people still use animals for food.