الاصطفاء الانتخاب الانتقاء الطبيعي التطور عند الحيوانات بالانجليزي

معلومات قصير موضوع انجليزي بحث تقرير بالانجليزي باللغة الانجليزية انشاء

موضوع عن الحيوانات الاليفة  وانواعها  اين تعيش ماذا ياكل مدة حياتها اسماء صغارها

تعبير عن الجمل بالانجليزي تعبير كتابي عن وصف حيوان اليف عبارات قصيره للاطفال

information about    paragraph معنى برزنتيشن  معلومات بسيطه  اسم  نطق كلمة معنى كلمة برجراف حيوان مفترس لاحم عاشب اليف متوحش وحيش الغابة موسوعة عالم الحيوانات برمائي كل شيئ عن تزاوج انواع الانجليزي  الشائعة معنى كلمة بالانجليزي اختصارات

معلومات عن الحيوانات بالانجليزي موضوع عن الحيوانات الاليفة بالانجليزي دورة حياتها

تغذية الحيوانات والحشرات على ماذا تتغذى كيف تتغذى الموسوعة تتذوق الطعام تصنيف

فوائد الجنس للصف الرابع للصف السابع الاول الثاني الثالث الخامس السادس الثامن التاسع كتابة  ذكر اضرار  معلومات طائر انواع  تربية قصة صفات حديقة الحيوانات

حيوانات المزرعة لرياض الأطفال براعم لائحة اسماء الحيوانات العاشبة اللاحمة حيوانات تاكل النباتات مختلطة التغذية تتغذى 

The evolution of animal species in nature

Evolution is by definition the change that things undergo over time. For the animals that are now found on the globe, they are the survivors of natural evolutions determined by the natural selection that has eliminated the less adapted species.

The evolution of an animal will allow a race to survive or simply disappear. A striking example of evolution is the giraffe, which thanks to its long neck, can eat higher vegetation in the branches, which allowed its species to survive.

Natural selection makes it possible to eliminate weak individuals, but also weak animals that are diminished. However, some mutations will help the individual survive better, and possibly move on to the next generations.

The observation of fossils and the different kinds of animals that form the same family, has allowed to detect certain species that are the product of evolutions of other older animals.

A fairly easy example of the action of evolution, but at a faster rate, is the crossing of purebred dogs. According to the usefulness of the dog, crossbreeds were made which had the characteristics that one wanted to obtain for the animal to produce. So, dogs of small or big size, long-haired or short, aggressive or affectionate ... After several generations of crosses, one ended up obtaining a new breed of dog. It is an evolution forced by the man, by selecting the individuals of the crossing, to obtain a new animal. The same thing is done for cattle, cats ...

The natural evolution of animals is simply dictated by changes in environment, food, temperature, and accidental mutations of the breed. So it's a very slow natural process. The creation of a new animal breed can take thousands of years, but decimating one can be done in a few seasons. Endangered animal breeds are a good example of breeding, even if the cause is man, they simply can not survive their changing environment.

DNA has also helped to better understand the evolution of animal and plant breeds, by making it possible to better identify members of the same genus. It often happened that some specimens were joined to a family, by physical traits, to then see that the DNA pointed to a different race.

Evolution is also observable more rapidly in the case of bacteria and microbes. Seasonal flu is a mutation of the previous one, which is quite different for the immune system to develop a new antibody. In the case of more developed animals, the change is slower and usually occurs from one organ to another.

The use of an organ that is necessary for the survival of a breed determines its persistence, because a mutation that diminishes this function puts the individual at greater risk. If this organ improves, it is possible that it helps this individual to survive, and that his descendants bear this new character. If the improvement is strong enough, the modified organ can save more mutant individuals and eventually become dominant for this breed.

The organ that is no longer truly used can atrophy without risking the life of the animal, and thus become another viable mutation. With time and many generations, it is possible that the organ disappears completely, to give a new breed.

Natural selection will therefore determine the evolution of a race, eliminating weak individuals who lose abilities, and retaining only those individuals who survive or have positive mutations. It is according to this theory that the evolution would have started with the unicellular ones, to then give the microorganisms, the fishes, the amphibians, the reptiles ... until the complex animals of today.

Animal evolution is therefore more likely to improve animal species, since negative mutations are usually less viable in nature. Even if the evolution tends to improve a species, a dominant character that does not help, but does not harm, can take place in the evolution of a species. It is simply a physical trait that does not result in harmful or positive consequences on the evolution and wildlife of the animal.