Biology is the scientific study of life. It is a natural science with a wide scope, but it has many integrated disciplines that combine it as a single, coherent field. For example, all organisms are made up of cells that process hereditary information encoded in genes, which can be passed on to future generations. Another major theme is evolution, which explains the unity and diversity of life. Finally, all organisms are capable of regulating their internal environment.
Biologists are able to study life at many levels of organization, from the molecular biology of a cell to the anatomy and physiology of plants and animals and the evolution of populations. Therefore, there are many sub-disciplines within biology, each defined by the nature of their research questions and the tools they use. Like other scientists, biologists use the scientific method to observe, ask questions, generate hypotheses, conduct experiments, and draw conclusions about the world around them.
Life on Earth, which emerged 3.7 billion years ago, is extremely diverse. Biologists have sought to study and classify various forms of life, from prokaryotic organisms such as archaea and bacteria to eukaryotic organisms such as protists, fungi, plants and animals. These different organisms contribute to the biodiversity of an ecosystem, where they play a special role in the cycling of nutrients and energy through their biophysical environment.
Biology is derived from the Ancient Greek words βίος romanized bios meaning ‘life’ and -λογία; romanized -logía meaning ‘branch of study’ or ‘speaking’. Together they form the Greek word βιολογία romanized biología meaning ‘biology’. Despite this, the word βιολογία did not exist in Ancient Greek as a whole. Historically another word for biology in English was lifelong; It is rarely used today.
The Latin language form of the word first appeared in 1736 when Swedish scientist Carl Linnaeus (Karl von Linne) used the term biology in his Bibliotheca Botanica. It was used again in 1766 by Michael Christoph Hanov, a disciple of Christian Wolff, in a work entitled Philosophia Naturalis sive Physica: Tomas III, Continence Geologian, Biologion, Phytology Generalis. The first German experiment, Biology, was in a 1771 translation of Linnaeus’s work. In 1797, Theodor Georg August Roose used the term in the preface to a book, Grundzuge der Lehre van der Lebenscraft. Karl Friedrich Burdach used the term in 1800 in the more restricted sense of the study of man from a morphological, physiological and psychological perspective.
The subject of our research will be the various forms and manifestations of life, the conditions and rules under which these events occur, and the causes by which they have been affected. The science that deals with these objects, we shall indicate by the name biology [biology] or the theory of life [Lebenslehr].
Many other words used in biology to describe plants, animals, diseases, and medicines are derived from Greek and Latin due to the historical contributions of ancient Greek and Roman civilizations, as well as the continued use of these two languages in European universities. went. In the Middle Ages and the beginning of the Renaissance.
The oldest roots of science, including medicine, can be traced back to ancient Egypt and Mesopotamia, around 3000 to 1200 BCE. His contributions later entered and shaped the Greek natural philosophy of classical antiquity. Ancient Greek philosophers such as Aristotle (384–322 BCE) contributed extensively to the development of biological knowledge.
His works such as The History of Animals were particularly important because they revealed their naturalist leanings, and later more empirical works that focused on biological causes and the diversity of life. Aristotle’s successor at the Lyceum, Theophrastus, wrote a series of books on botany which, even into the Middle Ages, survived as the most important contributions of antiquity to plant science.
Medieval Islamic scholars who wrote on biology include al-Jahiz (781–869), al-Dinawari (828–896), who wrote on botany, and Razzz (865–925) who wrote on anatomy and physiology. wrote. Medicine was particularly well studied by Islamic scholars working in the Greek philosophical traditions, while natural history focused on Aristotelian ideas, especially on maintaining a definite hierarchy of life.
The rapid growth and development of biology began with the dramatic improvement of Anton van Leeuwenhoek’s microscope. Jan Swammerdam’s investigations sparked new interest in entomology and helped develop the basic techniques of microscopic dissection and staining.
Advances in Microscopy A Biological thinking also had a profound effect. In the early nineteenth century, many biologists pointed to the central importance of the cell. Then, in 1838, Schleiden and Schwann began promoting the now universal idea that (1) the basic unit of organisms is the cell and (2) that individual cells have all the characteristics of life, though they opposed the idea that ( 3) All cells come from the division of other cells. However, Robert Remak and Rudolf Virchow were able to reformulate the third theory, and by the 1860s most biologists accepted all three theories that were consolidated into cell theory.
Atoms and molecules
All living beings are made of matter and all matter is made of elements. Oxygen, carbon, hydrogen and nitrogen are the four elements that make up 96% of all living organisms, with calcium, phosphorus, sulfur, sodium, chlorine and magnesium constituting the remaining 3.7%. Life on Earth began with water and remained there for about three billion years before migrating to land. Matter can exist in different states as solid, liquid or gas.
The smallest unit of an element is an atom, which is composed of an atomic nucleus and one or more electrons revolving around the nucleus, as described by the Bohr model. The nucleus is made up of one or more protons and many neutrons. Protons have a positive electric charge, neutrons are electrically neutral, and electrons have a negative electric charge. Atoms with the same number of protons and electrons are electrically neutral.
The atom of each specific element has a unique number of protons, known as its atomic number, and the sum of its protons and neutrons is the mass number of an atom. The masses of individual protons, neutrons and electrons can be measured in grams or daltons (Da), with the mass of each proton or neutron rounded off to 1 Da.
Although all atoms of a specific element have the same number of protons, they can differ in the number of neutrons, thus existing as isotopes. For example, carbon may exist as a stable isotope (carbon-12 or carbon-13) or as a radioactive isotope (carbon-14), which is used in radiometric dating (especially radiocarbon dating) to determine age. dating) can be done. of organic materials.
Life arose from Earth’s first ocean, which formed about 3.8 billion years ago. Since then, water has remained the most abundant molecule in every organism. Water is important to life because it is an effective solvent, capable of dissolving solutes such as sodium and chloride ions or other small molecules to form an aqueous solution. Once dissolved in water, these solutes are more likely to come into contact with each other and therefore participate in the chemical reactions that sustain life.
In terms of its molecular structure, water is a small polar molecule, formed by the polar covalent bonds of two hydrogen (H) atoms to one oxygen (O) atom (H2O). Since the O–H bonds are polar, the oxygen atom has a slight negative charge and the two hydrogen atoms a slight positive charge.
This polar property of water allows it to attract other water molecules through hydrogen bonds, causing the water to clump together. Surface tension arises from the adhesive force caused by the attraction between molecules on the surface of the liquid. Water is also adhesive because it is able to adhere to the surface of any polar or charged non-water molecules.
Water is denser as a liquid than as a solid (or ice). This unique property of water allows ice to float over liquid water such as ponds, lakes and oceans, insulating the liquid below from the cold air above. The low density of ice compared to liquid water is due to the small number of water molecules that make up the crystal lattice structure of ice, which leaves a large amount of space between the water molecules. In contrast, liquid water has no crystal lattice structure, which allows more water molecules to be captured in the same volume.