Biology defination

Biology

Biology defination

Biology is a study of living things like human , aniaml , birds , plants etc . Biology word comes from two words bios and logy bios means life and logy means study.Biology words given by Lamarck of frence and treviranus of germany in 1802.biology is a natural science in which the design , function , growth , origin , distribution and classification of life and living things are studied.

Basics of biology

The Evolution of Life

The Ecuadorian cargo ship Jessica ran aground near some Pacific islands on January 16, 2001, and within a few days diesel and bunker fuel began spilling into the water. Eventually 160,000 gallons of the oily stuff spread throughout the area, threatening to poison huge numbers of animals and perhaps to damage the entire ecosystem. All over the world, environmentalists were horrified by the oil spill and its possibly disastrous results.

, only a few dozen birds and sea lions were poisoned; as often happens with oceanic spills, westward winds and ocean currents carried the spill away within a couple of weeks, lessening its impact on the islands. Ecologists were greatly relieved but still apprehensive about future spills.1 Why were ecologists so upset about this oil spill, when many other spills have caused less outrage? It was because the threatened islands were the Galápagos, the home of blue-footed boobies, unique tortoises, iguanas, and other animals studied by Charles Darwin (1809–1882), the man most people associate with the idea of evolution. The islands were an irreplaceable natural record of Darwin’s evidence.

Darwin’s theory of evolution by natural selection was published—as The Origin of Species by Natural Selection, or the Preservation of Favoured Races in the Struggle for Life—in 1859 and revolutionized the popular idea of evolution. However, the idea of evolution itself had been accepted by many biologists long before Darwin; what was missing was a theory of how organisms changed over time. Darwin provided that theory.

Cells and Genetics

Realizing that natural selection had to act on hereditary differences among individuals ), Charles Darwin studied many kinds of organisms in an effort to learn more about their hereditary variations. Unfortunately, he never learned about the work of an obscure Austrian monk and scientist named Gregor Mendel (1822–1884). In the 1860s, Mendel made the first systematic study of how genes behave and how they are inherited by crossing hundreds of garden peas with assorted traits and keeping track of the results. The gene was still an abstract entity to Mendel (who knew nothing of DNA), however. In fact, it hadn’t yet been named. He called the units of heredity “factors,” and early twentieth-century biologists gave them the name of genes.

Around 1900 several biologists independently rediscovered Mendel’s work, and the era of modern genetics was under way. It progressed rapidly: By 1902 American biologist Walter Sutton (1877– 1916) had proposed that chromosomes— large, dark-staining structures in dividing cell nuclei—were the site of Mendel’s factors. The Hardy-Weinberg principle of equilibrium, showing how genes are maintained in certain proportions in populations, was formulated separately by English mathematician Godfrey H. Hardy (1877–1947) and German physician Wilhelm Weinberg (1862–1937) in 1908. In 1910 Thomas Hunt Morgan (1866–1945), an American geneticist, began his research on the fruit fly, Drosophila melanogaster. Morgan showed not only that genes are on chromosomes but also that if genes are very near each other on the same chromosome, they tend to be inherited together.

Since then, genetics has advanced more swiftly than any other field in biology. During the twentieth century, geneticists found that each chromosome is a long, helical molecule of deoxyribonucleic acid (DNA), and that genes are the segments of chromosomes that carry codes for proteins. They have discovered how genes mutate into new forms and have developed methods for altering the genetic makeup of organisms. Early in 2001, two teams of competing workers published preliminary complete maps of the human genome, an accomplishment of enormous importance for human health and future evolution.

Organs and Systems

All multicellular organisms have specialized structures for functions, such as getting and using food and oxygen, reproducing, ridding themselves of wastes, and so on. Because of the extensiveness of the topic, the focus here is on human anatomy.

Until the sixteenth century, knowledge of human anatomy was based largely on studies of other animals conducted by Galen (129–c. 216). Galen was a Greek physician and teacher whose writings dictated the theory and practice of medicine for about 1,500 years after his death. Born in Greece but doing most of his work in Rome—where the Roman religion prohibited dissecting human corpses—Galen had to base his studies on monkeys, dogs, goats, and other animals. Those observations were fruitful: Galen described seven pairs of cranial nerves, the valves of the heart, and the differences in structure between arteries and veins. In physiology, he was the first to show that the arteries carry blood, not air. Galen’s descriptions of some human organs were erroneous, however; even his description of the human uterus was based on his dissection of a dog. Unlike the human uterus, a dog’s is Y-shaped.

For several hundred years, medical students were taught from Galen’s books, not from the human body. That all changed when young Flemish physician Andreas Vesalius (1514–1564) was appointed a lecturer in surgery at the University of Paris, with the responsibility of giving anatomical demonstrations. Vesalius became suspicious of the textbooks written by Galen and began using his own approach to learning and teaching anatomy—doing dissections himself rather than having his teaching assistants do them, learning body structure from cadavers, and reevaluating ancient teachings. Vesalius wrote his own complete textbook of human anatomy (De humani corporis fabrica libri septem, commonly known as the Fabrica), which was printed in 1543, and went to Venice to supervise the artists who illustrated it. The elaborate drawings were probably made in the studio of the great Renaissance artist Titian.

The classic book is still remarkable today for its detailed illustrations of muscles and other parts of the body, many having background landscapes with details such as the gallows that furnished many of Vesalius’s study cadavers. It was the most accurate and thorough picture of human anatomy that had ever been presented.

having background landscapes with details such as the gallows that furnished many of Vesalius’s study cadavers. It was the most accurate and thorough picture of human anatomy that had ever been presented.

Because of Vesalius, anatomy became a scientific discipline, affecting medicine, physiology, and other fields of biology. Even today, his pragmatic attitude toward studying dead bodies to benefit living patients may help inform our own deliberations about appropriate subjects for medical research and practice.

A Survey of Organisms

Some of the organs and systems in other organisms are remarkably similar to those in humans, and some are completely different. However, the same evolutionary process underlies their characteristics: Each kind of organism has come to be what it is as the result of adapting to changing environments by solving specific problems.

In the long struggle for survival on Earth, living things have continually had to overcome new obstacles to survive or move into new surroundings. Earth itself has warmed and cooled; seas have risen and receded; mountains have been uplifted and eroded. Organisms had to change often enough to adapt to the new physical conditions and the changing organisms around them. Most of them, unable to make the necessary changes in changing environments, became extinct. Others became very different and survived.

Branches of Biology

Anatomy – study of form in animals, plants and other organisms, or specifically in humans. Simply, the study of internal

structure of living organisms.

Comparative anatomy – the study of evolution of species through similarities and differences in their anatomy.

Osteology – study of bones.

Osteomyoarthrology – the study of the movement apparatus, including bones, joints, ligaments and muscles.

Viscerology – the study of organs

Neuroanatomy – the study of the nervous system.

Histology – also known as microscopic anatomy or microanatomy, the branch of biology which studies the microscopic anatomy of biological tissues.

Astrobiology – study of origin, early-evolution, distribution, and future of life in the universe. Also known as exobiology, and bioastronomy.

Bioarchaeology – study of human remains from archaeological sites.

Biochemistry – study of the chemical reactions required for life to exist and function, usually a focus on the cellular level.

Biocultural anthropology – the study of the relations between human biology and culture.

Biogeography – study of the distribution of species spatially and temporally.

Biolinguistics – study of biology and the evolution of language.

Biological economics – an interdisciplinary field in which the interaction of human biology and economics is studied.

Biophysics – study of biological processes through the methods traditionally used in the physical sciences.

Biomechanics – the study of the mechanics of living beings.

Neurophysics – study of the development of the nervous system on a molecular level.

Quantum biology – application of quantum mechanics and theoretical chemistry to biological objects and problems.

Virophysics – study of mechanics and dynamics driving the interactions between virus and cells.

Biotechnology – new and sometimes controversial branch of biology that studies the manipulation of living matter, including genetic modification and synthetic biology.

Bioinformatics – use of information technology for the study, collection, and storage of genomic and other biological data.

Bioengineering – study of biology through the means of engineering with an emphasis on applied knowledge and especially related to biotechnology.

Synthetic biology – research integrating biology and engineering; construction of biological functions not found in nature.

Botany – study of plants.

Photobiology – scientific study of the interactions of light (technically, non-ionizing radiation) and living organisms. The field includes the study of photosynthesis, photomorphogenesis, visual processing, circadian rhythms, bioluminescence, and ultraviolet radiation effects.

Phycology – scientific study of algae.

Plant physiology – subdiscipline of botany concerned with the functioning, or physiology, of plants.[1]

Cell biology – study of the cell as a complete unit, and the molecular and chemical interactions that occur within a living cell.

Histology – study of the anatomy of cells and tissues of plants and animals using microscopy.

Chronobiology – field of biology that examines periodic (cyclic) phenomena in living organisms and their adaptation to solar- and lunar-related rhythms.

Dendrochronology – study of tree rings, using them to date the exact year they were formed in order to analyze atmospheric conditions during different periods in natural history.

Developmental biology – study of the processes through which an organism forms, from zygote to full structure

Embryology – study of the development of embryo (from fecundation to birth).

Gerontology – study of aging processes.

Ecology – study of the interactions of living organisms with one another and with the non-living elements of their environment.

Epidemiology – major component of public health research, studying factors affecting the health of populations.

Evolutionary biology – study of the origin and descent of species over time.

Evolutionary developmental biology – field of biology that compares the developmental processes of different organisms to determine the ancestral relationship between them, and to discover how developmental processes evolved.

Paleobiology – discipline which combines the methods and findings of the life sciences with the methods and findings of the earth science, paleontology.

Paleoanthropology – the study of fossil evidence for human evolution, mainly using remains from extinct hominin and other primate species to determine the morphological and behavioral changes in the human lineage, as well as the environment in which human evolution occurred.

Paleobotany – study of fossil plants.

Paleontology – study of fossils and sometimes geographic evidence of prehistoric life.

Paleopathology – the study of pathogenic conditions observable in bones or mummified soft tissue, and on nutritional disorders, variation in stature or morphology of bones over time, evidence of physical trauma, or evidence of occupationally derived biomechanic stress.

Genetics – study of genes and heredity.

Behavioral genetics – study of genetic and environmental influences on behaviors.

Geobiology – study of the interactions between the physical Earth and the biosphere.

Immunology – study of immune systems in all organisms.

Marine biology – study of ocean ecosystems, plants, animals, and other living beings.

Microbiology – study of microscopic organisms (microorganisms) and their interactions with other living things.

Bacteriology – study of bacteria

Mycology – study of fungi

Parasitology – study of parasites and parasitism.

Virology – study of viruses

Molecular biology – study of biology and biological functions at the molecular level, with some cross over from biochemistry.

Structural biology – a branch of molecular biology, biochemistry, and biophysics concerned with the molecular structure of biological macromolecules.

Neuroscience – study of the nervous system, including anatomy, physiology and emergent proprieties.

Behavioral neuroscience – study of physiological, genetic, and developmental mechanisms of behavior in humans and other animals.

Cellular neuroscience – study of neurons at a cellular level.

Cognitive neuroscience – study of biological substrates underlying cognition, with a focus on the neural substrates of mental processes.

Computational neuroscience – study of the information processing functions of the nervous system, and the use of digital computers to study the nervous system.

Developmental neuroscience – study of the cellular basis of brain development and addresses the underlying mechanisms.

Molecular neuroscience – studies the biology of the nervous system with molecular biology, molecular genetics, protein chemistry and related methodologies.

Neuroanatomy – study of the anatomy of nervous tissue and neural structures of the nervous system.

Neuroendocrinology – studies the interaction between the nervous system and the endocrine system, that is how the brain regulates the hormonal activity in the body.

Neuroethology – study of animal behavior and its underlying mechanistic control by the nervous system.

Neuroimmunology – study of the nervous system, and immunology, the study of the immune system.

Neuropharmacology – study of how drugs affect cellular function in the nervous system.

Neurophysiology – study of the function (as opposed to structure) of the nervous system.

Systems neuroscience – studies the function of neural circuits and systems. It is an umbrella term, encompassing a number of areas of study concerned with how nerve cells behave when connected together to form neural networks.

Physiology – study of the internal workings of organisms.

Endocrinology – study of the endocrine system.

Oncology – study of cancer processes, including virus or mutation, oncogenesis, angiogenesis and tissues remoldings.

Systems biology – computational modeling of biological systems.

Theoretical Biology – the mathematical modeling of biological phenomena.

Zoology – study of animals, including classification, physiology, development, and behavior. Subbranches include:

Arthropodology – biological discipline concerned with the study of arthropods, a phylum of animals that include the insects, arachnids, crustaceans and others that are characterized by the possession of jointed limbs.

Acarology – study of the taxon of arachnids that contains mites and ticks.

Arachnology – scientific study of spiders and related animals such as scorpions, pseudoscorpions, harvestmen, collectively called arachnids.

Entomology – study of insects.

Coleopterology – study of beetles.

Lepidopterology – study of a large order of insects that includes moths and butterflies (called lepidopterans).

Myrmecology – scientific study of ants.

Carcinology – study of crustaceans.

Myriapodology – study of centipedes, millipedes, and other myriapods.

Ethology – scientific study of animal behavior, usually with a focus on behavior under natural conditions.

Helminthology – study of worms, especially parasitic worms.

Herpetology – study of amphibians (including frogs, toads, salamanders, newts, and gymnophiona) and reptiles (including snakes, lizards, amphisbaenids, turtles, terrapins, tortoises, crocodilians, and the tuataras).

Batrachology – subdiscipline of herpetology concerned with the study of amphibians alone.

Ichthyology – study of fishes. This includes bony fishes (Osteichthyes), cartilaginous fishes (Chondrichthyes), and jawless fishes (Agnatha).

Malacology – branch of invertebrate zoology which deals with the study of the Mollusca (mollusks or molluscs), the second-largest phylum of animals in terms of described species after the arthropods.

Teuthology – branch of Malacology which deals with the study of cephalopods.

Mammalogy – study of mammals, a class of vertebrates with characteristics such as homeothermic metabolism, fur, four-chambered hearts, and complex nervous systems. Mammalogy has also been known as "mastology," "theriology," and "therology." There are about 4,200 different species of animals which are considered mammals.

Cetology – branch of marine mammal science that studies the approximately eighty species of whales, dolphins, and porpoise in the scientific order Cetacea.

Primatology – scientific study of primates

Human biology – interdisciplinary field studying the range of humans and human populations via biology/life sciences, anthropology/social sciences, applied/medical sciences

Biological anthropology – subfield of anthropology that studies the physical morphology, genetics and behavior of the human genus, other hominins and hominids across their evolutionary development

Evolutionary psychology – the study of psychological structures from a modern evolutionary perspective. It seeks to identify which human psychological traits are evolved adaptations – that is, the functional products of natural selection or sexual selection in human evolution.

Human behavioral ecology – the study of behavioral adaptations (foraging, reproduction, ontogeny) from the evolutionary and ecologic perspectives (see behavioral ecology). It focuses on human adaptive responses (physiological, developmental, genetic) to environmental stresses.

Nematology – scientific discipline concerned with the study of nematodes, or roundworms.

Ornithology – scientific study of birds.