Rabu, 27 Juli 2011

Biology

Ilmuwan yang mempelajari kimia sering disebut kimiawan. Sebagian besar kimiawan melakukan spesialisasi dalam satu atau lebih subdisiplin. Kimia yang diajarkan pada sekolah menengah sering disebut "kimia umum" dan ditujukan sebagai pengantar terhadap banyak konsep-konsep dasar dan untuk memberikan pelajar alat untuk melanjutkan ke subjek lanjutannya. Banyak konsep yang dipresentasikan pada tingkat ini sering dianggap tak lengkap dan tidak akurat secara teknis. Walaupun demikian, hal tersebut merupakan alat yang luar biasa. Kimiawan secara reguler menggunakan alat dan penjelasan yang sederhana dan elegan ini dalam karya mereka, karena terbukti mampu secara akurat membuat model reaktivitas kimia yang sangat bervariasi.

Ilmu kimia secara sejarah merupakan pengembangan baru, tapi ilmu ini berakar pada alkimia yang telah dipraktikkan selama berabad-abad di seluruh dunia.
Meanwhile, taxonomy and classification became a focus in the study of natural history. Carolus Linnaeus published a basic taxonomy for the natural world in 1735 (variations of which have been in use ever since), and in the 1750s introduced scientific names for all his species.[8] Georges-Louis Leclerc, Comte de Buffon, treated species as artificial categories and living forms as malleable—even suggesting the possibility of common descent. Though he was opposed to evolution, Buffon is a key figure in the history of evolutionary thought; his work influenced the evolutionary theories of both Lamarck and Darwin.[9]

Serious evolutionary thinking originated with the works of Jean-Baptiste Lamarck. However, it was the British naturalist Charles Darwin, combining the biogeographical approach of Humboldt, the uniformitarian geology of Lyell, Thomas Malthus's writings on population growth, and his own morphological expertise, that created a more successful evolutionary theory based on natural selection; similar reasoning and evidence led Alfred Russel Wallace to independently reach the same conclusions.[10]

The discovery of the physical representation of heredity came along with evolutionary principles and population genetics. In the 1940s and early 1950s, experiments pointed to DNA as the component of chromosomes that held genes. A focus on new model organisms such as viruses and bacteria, along with the discovery of the double helical structure of DNA in 1953, marked the transition to the era of molecular genetics. From the 1950s to present times, biology has been vastly extended in the molecular domain. The genetic code was cracked by Har Gobind Khorana, Robert W. Holley and Marshall Warren Nirenberg after DNA was understood to contain codons. Finally, the Human Genome Project was launched in 1990 with the goal of mapping the general human genome. This project was essentially completed in 2003,[11] with further analysis still being published. The Human Genome Project was the first step in a globalized effort to incorporate accumulated knowledge of biology into a functional, molecular definition of the human body and the bodies of other organisms.

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