دانلود کتاب اصول زیست شناسی

No matter if you are referring to a cell or a large herd of elephants, life is a symphony of natural phenome that connects all living things. In order for something to be considered living, it must possess all of the essential characteristics of life. These characteristics include being composed of cells, being able to obtain and utilize energy, growth and development, reproduction, homeostasis, evolution, and all living organisms must possess genetic material in the form of deoxyribose nucleic acid (DNA). Life gives us a reason to learn about other fields of study such as mathematics, physics and chemistry, but without physic and chemistry life would not possible. “Principals of Biology” includes multiple articles which bring to light the interdisciplinary nature of multiple scientific fields which allows life to not only be possible but more importantly understood. Aspects of life on Earth are connected in many ways. One of the most important connections is through the carbon cycle. Without the element carbon, life on Earth would not be chemically possible. The term “organic” refers to compounds being composed of carbon bonded to additional elements such as hydrogen and oxygen. Because of the carbon cycle, photosynthesis and cellular respiration are able to occur and provide the necessary oxygen for almost all forms of life and carbon dioxide needed by plants and other organism which rely on the sun as an energy source. The understanding of physics allows scientists to provide explanations of the mechanics of organ systems within the human body. Biology is the study of all forms of life. This study is not limited to organisms individually but also extends to the habitats in which those organisms live. To understand the many fields of biology, scientists obverse multiple aspects of living organisms. A goal of natural biologists is to be able to provide explanations of an organism’s structure, function, growth, origin, and evolution. These explanations help provide a clear picture of the organization of the natural word. The biological natural world is classified into taxonomic groups which help us understand the differences and similarities between species of plant, animal, fungi, bacteria and protist. The majority of this book focuses on the principals of biology as they relate to the classification of Homo sapiens, humans. By studying human fossil, cultural, and genetic evidence, researchers continue to trace development of humans. It is believed by many that the earliest form of human life appeared almost 350,000 years ago and that the modern humans appeared somewhat before 100,000 years ago, with major diversification of the human species continuing thereafter. From the basics of physiology to modern advances in medicine, Principals of Biology provides relevant articles which will help the reader understand the multiple aspects of biology.