Biology/Citable Version: Difference between revisions
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===The Eighteenth and Nineteenth Centuries xxxx=== | ===The Eighteenth and Nineteenth Centuries xxxx=== | ||
As detailed examination of plant and animal species became common, and the knowledge derived from it was shared among geographically distant contemporaries through the print media, similar patterns of structures were | As detailed examination of plant and animal species became common, and the knowledge derived from it was shared among geographically distant contemporaries through the print media, similar patterns of structures were recognized in many different sorts of species. In the Eighteenth Century, the Swedish naturalist [[Carolus Linnaeus]] proposed a way of systematically classifying all living things. His method gives a unique name to each kind of plant and animal, and organizes all of them into a classification scheme that stresses similarities of physical features - based on their [[comparative anatomy]]. This naming system is still used today, and each known species has one unique scientific name that biologists all over the world recognize. The name has two parts: ''[[genus]]'' and ''[[species]]'', the two most refined categories in the classification scheme. The language of these names is Latin, which was the common written language of scholars in Europe in Linnaeus' time. | ||
Although this systematic classification of all living things became widely accepted, at first it did not include the idea that all living things were somehow related. For more than a hundred years afterward, even highly educated thinkers assumed that even complicated life forms (such as mice) could spring to life from a setting of inaminate objects (such as old rags and bread crumbs left in a dark corner). In the Nineteenth Century, experiments of [[Louis Pasteur]] of France showed that this commonly held notion, [[spontaneous generation]], was a fallacy. His life's work in [[bacteriology]], along with the later work of the German physician [[Robert Koch]], was important in establishing the [[germ theory of disease]]. | Although this systematic classification of all living things became widely accepted, at first it did not include the idea that all living things were somehow related. For more than a hundred years afterward, even highly educated thinkers assumed that even complicated life forms (such as mice) could spring to life from a setting of inaminate objects (such as old rags and bread crumbs left in a dark corner). In the Nineteenth Century, experiments of [[Louis Pasteur]] of France showed that this commonly held notion, [[spontaneous generation]], was a fallacy. His life's work in [[bacteriology]], along with the later work of the German physician [[Robert Koch]], was important in establishing the [[germ theory of disease]]. | ||
Revision as of 10:38, 26 November 2006
The word "Biology" is formed by combining the Greek βίος (bios), meaning 'life', and λόγος (logos), meaning 'study of'. "Biology" in its modern use was probably introduced independently by both Gottfried Reinhold Treviranus (Biologie oder Philosophie der lebenden Natur, 1802) and by Jean-Baptiste Lamarck (Hydrogéologie, 1802). Although the word "biology" is sometimes said to have been coined in 1800 by Karl Friedrich Burdach, it appears in the title of Volume 3 of Michael Christoph Hanov's Philosophiae naturalis sive physicae dogmaticae: Geologia, biologia, phytologia generalis et dendrologia, published in 1766.
Biology is the science of life. Biologists study all aspects of living things, including each of the many life forms on earth and the dynamic processes that enable life. Those vital processes include the harnessing of energy, the synthesis of the materials that make up the body, the healing of injuries, and the reproduction of the entire organism, among many other activities.
Living organisms have been of interest to all peoples throughout history, and, accordingly, the roots of biology go back to earliest mankind. Curiosity about the physical beings of people, plants, and animals still runs deep in every human society. How is it that these bodies change; develop, grow, and age? What is it that underlies the divide between inanimate objects and the living entities in the world? Some of those questions stem from our desire to control life processes, and to exploit natural resources. Pursuit of the answers has led to an understanding of organisms that has steadily improved our standard of living through the ages. But questions also come from a desire to understand nature rather than to control it, and the very core of that desire is sparked by a commonly felt need to understand the human condition and the nature of the world. Biology brings its own answers to these questions, and provides a useful way of learning about living things.
Not all natural lore is biology, no matter how accurate or helpful, and no matter that the subject is a plant or animal. Biologists incorporate an understanding of mathematics, physics, chemistry and other sciences, along with the scientific method, to their study of living things. Still, all human interaction with nature eventually adds to our understanding, whether the ideas came from evidence in the laboratory or the studbook of the horseman, from the notebook of the ecologist or the field notes of the hunter.
The Scope of Biology
How did life begin? What features separate something that is alive from something that is not alive?. The biologist uses science to try to answer these fundamental questions, questions that also concern the philosopher, the rabbi, the iman, and the priest - as well as every person who retains a sense of wonder. Whether scientific thinking about these issues is compatable with religious beliefs is itself contentious. Some great thinkers, such as the physicist Albert Einstein, have found no real conflict between the varying teachings of science and religion, but consider Divinity and the Natural Universe to be one and the same (see Albert Einstein for detailed discussion with references). In this view, mathematical equations and the language of prophets are simply two different forms of human expression, each attempting to describe a higher dimension than ordinary human experience. Other notable scientists, such as Francis Crick, have viewed religion much more narrowly, as superstition, and welcomed biology's mechanistic explanations as providing a rational basis for the world.
Although science addresses fundamental issues about life, Biology is also used to answer practical questions, which are posed to advance medical and dental care, agriculture and animal husbandry. It is through applied biology that the health sciences became such effective Healing Arts and that the world's food supply has become both safer and more plentiful.
Many independent scientific fields make up Biology, but all are related. Natural History (the study of individual species like white-tailed deer, sugar maple trees, box jellyfish and timber wolves)
was one of the first areas of biology to develop. In natural history, whole organisms are studied in an attempt to make sense of the order of Nature. When the natural histories of plants and animals are considered in a context of how each affects the other and their environment, then the biologist's focus is on ecology. Some fields of biology focus on the natural history of living organisms and their interactions within a certain realm of the earth, as in marine biology; others focus on particular aspects of the bodies of living organisms, like their structure (Anatomy) or function (Physiology). Studies of animals form the field of Zoology, whereas the study of plants is called Botany. Medicine and the Health Sciences apply biology to understanding disease and to improving health. Many of the academic disciplines that make up biology are listed at the bottom of this article along with a brief description. Further information about each is provided through links to other articles within Citizendium that can be accessed by clicking each discipline's name.
The development of biology
The remainder of this article explores selected themes in biology while providing a very abbreviated overview of the development of the science. Those themes center on concepts about the origin of life (both 'life on earth' and the creation of a human infant) and are followed through the centuries from ancient Greece to contemporary times. It is apparent that a philosophy of critical thinking, investigative methods that rely on empiric evidence, and the availability of technological tools have, in combination, accounted for the maturation of these ideas over that time span. The development of biology certainly has drawn on many more ideas, and a much larger geographical area than referred to here, but the science of biology has had a continuous thread through the centuries that did begin with the Greek philosophers' writings, advanced from those ideas in Europe during the Enlightenment, and matured during the Nineteenth and Twentienth Centuries with widespread investigations performed according to the scientific method. The purpose of the next section is simply to provide a representative sample of that development that illustrates some of the features of its winding course.
For a comprehensive review, please see:
For a more comprehensive introduction to biological science, please see the internal and external links provided at the end of this article.
Roots of Biology in Prehistory and the Ancient World
Whether foragers or farmers, hunters or herders, people have always depended on plants and animals for sustenance, and turned their thoughts to food. Paleolithic cave paintings show that careful observations of prey have been expressed for tens of millennia. Human interest in food is not limited to passive considerations. Rather than take sustenance simply as found, humans generally carry food items from place to place, and process them in various ways. Because of human intelligence, xxxxx this section needs development - explain about start with sugary cob, end up planting seeds. ( Ref -Sweet Beginnings: Stalk Sugar and the Domestication of Maize1/Comments/ReplyJohn Smalley, Michael Blake, Sergio J Chavez, Warren R Deboer, et al. Current Anthropology. Chicago: Dec 2003. Vol. 44, Iss. 5; p. 675). In neolithic times, agriculture became established in many human societies. When intellectual consideration of what plants are was combined with evidence-based experiments used to understand their growth, then botany, the science of plants, joined agriculture as a human endeavor (see Early Biology and the Establishment of the Scientific Method).
The beginnings of Anatomy and Zoology both date back at least as far as the ancient Greek philosopher Aristotle, to the Fourth Century BC. In the first known book on how life in the womb begins, Aristotle suggested that the woman provides the substance needed to build a new baby while the man provides the essence that gives this substance its humanity. On a concrete level, he focused on menstrual blood and semen as the female and male contributions. Aristotle used logic and observation to arrive at his theory, which, in the main, was still accepted 2000 years later. His conclusion that the woman's contribution was the mere soil for the man's seed, and that the man's contribution contained the essential humanity that simply required a nurturing womb to grow in, was likely influenced by the general agreement, in his society, that women were not as highly developed as men. It may also have come from the examination of the seeds of some trees, in which the entire immature plant is contained within the husk, and springs into independant life as a young tree once planted. A popular idea that grew out of Aristotle's musings was that sperm actually contained a perfect miniature version of the new baby - a homunculus.
The writings of the Greek scholars were largely preserved and read by the Romans, who added additional literature on xxxx of the structure and function of animal and human bodies. Galen-dissection and vivisection.
Stasis of Progress in Medieval Europe, Arab World becomes Primary Repository of Western Medicine
With the Fall of Rome in the West, the Greek and Roman works became marginalized. Few texts were preserved, and few people could read them - both the literature and the readers often cloistered together in religious orders.
Early Biology : The European Renaissance and the Establishment of the Scientific Method
When the authority of classic authors (such as Aristotle and Galen) and of religious doctrine (such as the teachings of the Catholic Church) on the nature of living things began to be openly questioned in light of actual observation and experiment, the scientific method became established. By the Sixteenth and Seventeenth Century, the advantages of relying on firm empirical evidence instead of the opinions of authorities were advocated by such influential writers as Francis Bacon in England, and . Rather than memorize the texts of Galen, or perform ritual sorts of dissections as homage to Galen's findings, the anatomy and physiology of animals began to be explored in new directions. Unlike dissections that were carried out in other parts of the world, China for one, the early European biologists followed structures like nerves and veins that travelled between organs and analyzed their findings in an attempt to find general principles of the organization and function of the body. Theories in biology were still in a very preliminary phase in these times, but the publication of evidence for unifying ideas that explained an order to living things revolutionized thinking in biology.
The Englishman William Harvey studied how embryos develop, by observations of hens' eggs and dissection of pregnant deer and other mammals. He speculated that development proceeded from one to another of the fetal forms he found, imagining that each of these forms was a stage in a continuous process. Although other of his experiments famously revealed the circulation of the blood, and identified the workings of the heart as pump, when it came to early development he was stymied. He could not comprehend how discrete organs in the developing fetus might form out of the amorphous materials in the just pregnant womb or newly fertile egg. He chose a spiritual rather than a mechanistic explanation, postulating that the soul or new life was derived from the placement of sperm in the female tract. Still, he modified Aristotle's explanation by insisting that the male and female contributions were equally important. He refuted the notion that the fetus is made up by the specific materials contributed by the male, that grow because of the separate materials contributed by the female. Instead, he argued that "the material out of which the chick is formed in the egg is made at the same time it is formed" and that "out of the same material from which it is made, it is also nourished"[1]
The Eighteenth and Nineteenth Centuries xxxx
As detailed examination of plant and animal species became common, and the knowledge derived from it was shared among geographically distant contemporaries through the print media, similar patterns of structures were recognized in many different sorts of species. In the Eighteenth Century, the Swedish naturalist Carolus Linnaeus proposed a way of systematically classifying all living things. His method gives a unique name to each kind of plant and animal, and organizes all of them into a classification scheme that stresses similarities of physical features - based on their comparative anatomy. This naming system is still used today, and each known species has one unique scientific name that biologists all over the world recognize. The name has two parts: genus and species, the two most refined categories in the classification scheme. The language of these names is Latin, which was the common written language of scholars in Europe in Linnaeus' time.
Although this systematic classification of all living things became widely accepted, at first it did not include the idea that all living things were somehow related. For more than a hundred years afterward, even highly educated thinkers assumed that even complicated life forms (such as mice) could spring to life from a setting of inaminate objects (such as old rags and bread crumbs left in a dark corner). In the Nineteenth Century, experiments of Louis Pasteur of France showed that this commonly held notion, spontaneous generation, was a fallacy. His life's work in bacteriology, along with the later work of the German physician Robert Koch, was important in establishing the germ theory of disease.
Charles Darwin built on the idea of natural selection as a way to explain how different life forms might have common patterns of form. His observations of the variations of animal life on remote islands led him to postulate that individual creatures might thrive, or die, according to how well their characteristics fitted their immediate habitat. In this way, certain inherited features might become more or less pronounced in a species over generations, and entirely new species might eventually arise. His theories became incorporated into the theory of evolution which suggests that all present living things descended from past living things. The existance of common ancestors would account for similar body forms among descendents, and provided a plausible basis for the wide-spread existance of patterns of very similar features among groups of living things: the very patterns that Linnaeus had used to formulate his categories in classification. This idea was not entirely new, but previous proponents were stymied by the question of how such incredibly diverse life forms might come about in the few thousand years that the world was thought to have existed. By Darwin's time, advances in Earth Science had established evidence that the earth was much older than had been previously suspected, on the order of millions of years. Acceptance of this magnitude of time scale among scientists made the notion of incremental change over generations a more reasonable possibilty. Evolutionary change fron ancient life was accepted by biologists as a theory that explained both the diversity of life forms and the existance of patterns of common features.
By the second half of the Nineteenth Century the Austrian monk Gregor Mendel's work on the inheritance of traits had produced a working statistical model that included an equal weight of the contribution of both the male and female parent among its assumptions. This egalatarian view was likely aided by the fact that his primary subjects were garden peas, rather than men and women. Additional Medelian assumptions involved the idea of alleles, forms of traits that were either dominant or recessive.
Technology advances Biology
First Glimpses of the Microscopic World
The features of plants and animals have often been understood on an entirely different levels with technological advances that provided new means for examining them. For example, the microscope, modified by Antoni van Leeuwenhoek in the Seventeenth Century, revealed details of structure in the bodies of organisms that had never before been even suspected. One of the new sights he described were individual ovum and spermatozoa, and being familiar with the theories of Aristotle, he reported that he could actually see homunculi in the heads of the living sperm - an example of even a great scientist sometimes seeing what he expected to see, rather than what was really there. Science is always influenced by past ideas. No scientist can consider any idea, or analyze experiemental results without using his or her mind. That mind is both consciously and unconsciously stamped with the culture that produced it.
File:Drawing of sperm by van Leeuwenhoek showing homunculus.jpg
Not only was the structure of flesh and plants seen at a new level of detail with the microscope, but completely new types of organisms were also revealed: micro-organisms that could not be detected with the naked eye. [2] And so, like all important technological advances in biology, the microsocope led to new ideas about living things. The concept that tissues were composed of cells was initiated, the field of microbiology was born, and the ground was prepared for the germ theory of disease, an idea that helped bring the traditional practice of western medicine (sometimes called allopathy) into the field of health science and modern medicine.
Further developments led to the modern compound microscope by the end of the 19th century, with much higher resolution, and eventually the late 20th century electron microscopes were built using electronic technology. Science differs from religious and political doctrine in at least one major manner – tenants are not to be held sacred but questioned and tested. This has proved damaging for many of them, including the homunculus theory of fetal development. With improved optics and the new imaging techniques of scanning and transmission electron microscopes, that "little man" inside the sperm cell vanished forever.
Ultra-high power magnification imaging creates new knowledge:Cell Biology begins
With ultra-high power examination of cells, another new discipline within biology began to flourish, and the idea that living organisms were all composed of cells clarified. Scientists in the field of cell biology began to unravel the inner architecture of cells, discovering discrete organelles that could only be seen well with tremendous magnification power. Closer visual examination of the structure of the cell was combined with the ability to physically separate out the components of the cells in bulk by weight and chemical properties and analyze each fraction using methods from biochemistry and biophysics. The important techniques that allowed this kind of analysis include ultracentrifugation and gel electrophoresis.
Concepts of Human Reproduction and Evolutionary Change are modified with molecular biology
Understanding the ultrastructure of cells along with correlated chemical and physical properties of the organelles brought more new ideas to biology. An example of both a new organelle and, new idea -mitochondria. Cell biologists applied their findings to the systematic classification of plants and animals, and relationships were further refined.
Molecular Biology.
Double Helix
RNA
With DNA chemistry, biologists took off their parkas and came out of the refrigerated cold rooms that were the only workplaces in which RNA remained stable long enough to perform experiments with it that had elucidated the general functions of the endoplasmic reticulum and xxxx. The technique of PCR allowed automated experiments on tiny samples of DNA in a standard laboratory setting, and progress in molecular biology accelerated tremendously.
Using molecular biology techniques to study the organelles discovered through electron microscopy did not just add more details but led to startling new concepts. The mitochondria seen in active human cells were not human at all, at least not in origin. These organelles had been assimilated into eukaryotic cells and divided along with them, but according to their own genetic code, a circular strand of DNA that resembles the genome of bacteria. These energy producing organelles of animal cells were not the only organelles found that derived from a different life form. The chloroplast of plant cells are another.
The age-old discussion of just how a new baby came to be born of man and woman took unexpected turns as well. Apparently, the single cell that every human begins with does not receive identical types of genetic contributions from mother and father, at all. One of the biggest differences between what each parent gives their baby has to do with what’s in the egg, but not in the sperm, and that would be cell organelles, specifically these mitochondria. Each individual human being is made up of cells with mother's mitochondria only, including the mitochondrial DNA.
Imprinting of genes by parental origin another inequality in genetics that had been unsuspected. Back to corn,
Main topics and discoveries
Major discoveries in biology include:
Disciplines within biology
- Anatomy: The study of structure
- Behavior: Study of the actions and reactions of an organism
- Biochemistry: The chemistry of living things is a field of both biology and chemistry
- Biodiversity: The study of the diversity of life
- Biogeography: The study of patterns of species distribution and the processes that result in such patterns
- Botany: The study of plants
- Cell Biology: The study of the components of cells
- Developmental biology: The study of the lifecycles of organisms
- Ecology: The study of the distribution and abundance of organisms and how they are affected by the environment
- Ethology: The scientific study of animal behavior
- Evolutionary biology: Study of the origin and descent of species, as well as their change, multiplication, and diversity over time
- Genetics: The study of the inheritance of characteristics, genes and DNA
- Marine Biology: The study of life in the seas and oceans
- Molecular biology: The study of the interactions between the various systems of a cell
- Physiology: The study of the mechanical, physical, and biochemical functions of living organisms
- Systematics: The study of the diversity of organism characteristics, and how they relate via evolution
- Taxonomy: The principles underlying classification, often in a heirarchy
- Zoology: The study of animals
References
- Citations
- ↑ (Van Speybroeck L, De Waele D, Van de Vijver G (2002) Theories in early embryology: close connections between epigenesis, preformationism, and self-organization. Annals of the New York Academy of Sciences 981:7-49 UI 12547672).
- ↑ Anton van Leeuwenhoek. Encyclopedia of World Biography, 2nd ed. 17 Vols. Gale Research, 1998. Reproduced in Biography Resource Center. Farmington Hills, Mich.: Thomson Gale. 2006
- Further reading
The Evolution of Darwinism: Selection, Adaptation and Progress in Evolutionary Biology. Timothy Shanahan. Cambridge University Press, New York, 2004. 342 pp. (ISBN 0521834139 cloth)
Selected external links
The following links have been reviewed and are recommended because, at the time of their inclusion, they provided accurate information and portals to additional excellent web resources. Many other excellent links have been omitted through no fault of their own.
Plain and technical language
- The American Institute of Biological Sciences (ABIBS) Virtual Library is free to all visitors
- The Bio-Web reviews and gives access to information in Cell and Molecular Biology, includes "news" in plain language
- Cell and Molecular Biology Online is a resource for professionals that includes links and some information for all
- Kimball's Biology Pages are a online elementary college biology textbook, based on the author's 1996 printed edition.