June 27, Fossil records tell us that the first macroscopic animals appeared on Earth about million years ago. New depth limit for deep-sea marine burrows January 10, Scientists have found fossil evidence of deep-sea marine life burrowing up to eight metres below the seabed—four times the previously observed depth for modern deep-sea life. Recommended for you Emissions from most diesel cars in Europe greatly exceed laboratory testing levels September 21, In Septemberthe German automaker Volkswagen was found to have illegally cheated federal emissions tests in the United States, by intentionally programming emissions control devices to turn on only during laboratory
General considerations Historical background Historical evidence, like that from currently developing nations, indicates that veterinary medicine originally developed in response to the needs of pastoral and agricultural man along with human medicine. It seems likely that a veterinary profession existed throughout a large area of Africa and Asia from at least bce.
Ancient Egyptian literature includes monographs on both animal and human diseases. Evidence of the parallel development of human and veterinary medicine is found in the writings of Hippocrates on medicine and of Aristotlewho described the symptomatology and therapy of the diseases of animals, including man.
Early Greek scholars, noting the similarities of medical problems among the many animal species, taught both human and veterinary medicine. In the late 4th century bce, Alexander the Great designed programs involving the study of animals, and medical writings of the Romans show that some of the most important early observations on the natural history of disease were made by men who wrote chiefly about agriculture, particularly the aspect involving domesticated animals.
Most of the earliest suggestions of relationships between human health and animal diseases were part of folklore, magic, or religious practice. From the pre-Christian Era to aboutthe distinctions between the practices of human and veterinary medicine were not clear-cut; this was especially true in the fields of obstetrics and orthopedics, in which animal doctors in rural areas often delivered babies and set human-bone fractures.
It was realized, however, that training in one field was inadequate for practicing in the other, and the two fields were separated.
Rinderpest cattle plague was the most important livestock disease from the 5th century until control methods were developed. Many aspects of animal diseases are best understood in terms of population or herd phenomena; for example, herds of livestock, rather than individual animals, are vaccinated against specific diseases, and housing, nutrition, and breeding practices are related to the likelihood of illness in the herd.
The work of Pasteur was of fundamental significance to general medicine and to agriculture. Veterinarians became concerned with foods of animal origin after the discovery of microorganisms and their identification with diseases in man and other animals. Efforts were directed toward protecting humans from diseases of animal origin, primarily those transmitted through meat or dairy products.
Modern principles of food hygiene, first established for the dairy and meat-packing industries in the 19th and early 20th centuries, have been generally applied to other food-related industries. The veterinary profession, especially in Europe, assumed a major role in early food-hygiene programs.
Inadequate diet claims many thousands of lives each day.
When the lack of adequate food to meet present needs for an estimated world population of more than 4,, in the s is coupled with the prediction that the population may increase to 7,, by the yearit becomes obvious that animal-food supplies must be increased. One way in which this might be accomplished is by learning to control the diseases that afflict animals throughout the world, especially in the developing nations of Asia and Africa, where the population is expanding most rapidly.
Most of the information concerning animal diseases, however, applies to domesticated animals such as pigs, cattle, and sheep, which are relatively unimportant as food sources in these nations.
|Lack of oxygen led to first mass extinction | ScienceNordic||Certified Educator Old Major eloquently depicts the lot of animals.|
|To advance scientific understanding||The effect that climate has on extinction is very big.|
|What are the different causes of the animals' rebellion in Animal Farm by George Orwell? | eNotes||External mold of the extinct Lepidodendron from the Upper Carboniferous of Ohio  A species is extinct when the last existing member dies.|
|World's first animals caused global warming||He states that animals live short, miserable lives filled with drudgery. They are given just enough food to survive and are forced to work to their last days.|
|Extinction - Causes||Print Why Animals are Used Animals are used in research when there is a need to find out what happens in the whole, living body, which is far more complex than the sum of its parts. It is difficult, and in most cases simply not yet possible, to replace the use of living animals in research with alternative methods.|
Remarkably little is known of the diseases of the goatthe water buffalothe camelthe elephantthe yakthe llamaor the alpaca ; all are domesticated animals upon which the economies of many developing countries depend. It is in these countries that increased animal production resulting from the development of methods for the control and eradication of diseases affecting these animals is most urgently needed.
Despite the development of various effective methods of disease control, substantial quantities of meat and milk are lost each year throughout the world. In countries in which animal-disease control is not yet adequately developed, the loss of animal protein from disease is about 30 to 40 percent of the quantity available in certain underdeveloped areas.
In addition, such countries also suffer losses resulting from poor husbandry practices. Role in human disease Animals have long been recognized as agents of human disease.
Man has probably been bitten, stung, kicked, and gored by animals for as long as he has been on earth; in addition, early man sometimes became ill or died after eating the flesh of dead animals. In more recent times, man has discovered that many invertebrate animals are capable of transmitting causative agents of disease from man to man or from other vertebrates to man.
Such animals, which act as hosts, agents, and carriers of disease, are important in causing and perpetuating human illness. Because about three-fourths of the important known zoonoses are associated with domesticated animals, including pets, the term zoonosis was originally defined as a group of diseases that man is able to acquire from domesticated animals.
But this definition has been modified to include all human diseases whether or not they manifest themselves in all hosts as apparent diseases that are acquired from or transmitted to any other vertebrate animal.
Thus, zoonoses are naturally occurring infections and infestations shared by man and other vertebrates. Although the role of domesticated animals in many zoonoses is understood, the role of the numerous species of wild animals with which man is less intimately associated is not well understood.Rabies is caused by lyssaviruses, including the rabies virus and Australian bat lyssavirus.
It is spread when an infected animal scratches or bites another animal or human. Saliva from an infected animal can also transmit rabies if the saliva comes into contact with the eyes, mouth, or nose.
The first mass extinction of animal life on Earth was previously blamed on a rise in the oxygen concentration in the oceans as a result of a cooler climate.
But a new study shows the catastrophe was really caused by a massive decrease in oxygen. Rabies — the word probably brings to mind an enraged animal frothing at the mouth.
An encounter with an infected animal can result in a painful, life-threatening condition. •In the Americas—80% of large animals became extinct around the same time as first human presence there Based on these, and other studies done by The international Union for Conservation of Nature and Natural Resources (IUCN), human induced extinctions are not necessarily a new phenomena.
Problem: Extinction of Plant and Animal Species Massive extinctions have occurred five times during the earth's history, the last one was the extinction of the dinosaurs, 65 million years ago. Scientists are calling what is occurring now, the sixth mass extinction.
the men whipped the animal sand so the animals rode hem off animal farm what did the animals do after they overtook the farm. what did they do first made sure no other humans were on the farm, they destroyed the items in the harnest room.