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Oct 21, 2024 · biology, study of living things and their vital processes.The field deals with all the physicochemical aspects of life.The modern tendency toward cross-disciplinary research and the unification of scientific knowledge and investigation from different fields has resulted in significant overlap of the field of biology with other scientific disciplines.
- The Theory of Evolution
Biology - Evolution, Natural Selection, Adaptation: As...
- Biology
Biology - Evolution, Genetics, Classification: There are...
- Kids
Biology is the study of living things. A biologist is a...
- The Discovery of Cells
Biology - Cell Discovery, Microscopy, Histology: Of the five...
- Aristotelian Concepts
Biology - Aristotle, Organisms, Cells: Around the middle of...
- Advances to The 20th Century
Biology - Evolution, Genetics, Microbiology:...
- The Theory of Evolution
Oct 31, 2023 · Biology is a natural science concerned with the study of life and living organisms. Modern biology is a vast and eclectic field composed of many specialized disciplines that study the structure, function, growth, distribution, evolution, or other features of living organisms. However, despite the broad scope of biology, there are certain ...
- Overview
- Definitions of life
- Metabolic
- Physiological
- Biochemical
life, living matter and, as such, matter that shows certain attributes that include responsiveness, growth, metabolism, energy transformation, and reproduction. Although a noun, as with other defined entities, the word life might be better cast as a verb to reflect its essential status as a process. Life comprises individuals, living beings, assignable to groups (taxa). Each individual is composed of one or more minimal living units, called cells, and is capable of transformation of carbon-based and other compounds (metabolism), growth, and participation in reproductive acts. Life-forms present on Earth today have evolved from ancient common ancestors through the generation of hereditary variation and natural selection. Although some studies state that life may have begun as early as 4.1 billion years ago, it can be traced to fossils dated to 3.5–3.7 billion years ago, which is still only slightly younger than Earth, which gravitationally accreted into a planet about 4.5 billion years ago. But this is life as a whole. More than 99.9 percent of species that have ever lived are extinct. The several branches of science that reveal the common historical, functional, and chemical basis of the evolution of all life include electron microscopy, genetics, paleobiology (including paleontology), and molecular biology.
The phenomenon of life can be approached in several ways: life as it is known and studied on planet Earth; life imaginable in principle; and life, by hypothesis, that might exist elsewhere in the universe (see extraterrestrial life). As far as is known, life exists only on Earth. Most life-forms reside in a thin sphere that extends about 23 km (14 miles) from 3 km (2 miles) beneath the bottom of the ocean to the top of the troposphere (lower atmosphere); the relative thickness is comparable to a coat of paint on a rubber ball. An estimated 10–30 million distinguishable species currently inhabit this sphere of life, or biosphere.
Much is known about life from points of view reflected in the various biological, or “life,” sciences. These include anatomy (the study of form at the visible level), ultrastructure (the study of form at the microscopic level), physiology (the study of function), molecular biology and biochemistry (the study of form and function at chemical levels)...
Metabolic definitions are popular with biochemists and some biologists. Living systems are objects with definite boundaries, continually exchanging some materials with their surroundings but without altering their general properties, at least over some period of time. However, there are exceptions. There are frozen seeds and spores that remain, so far as is known, perfectly dormant. At low temperatures they lack metabolic activity for hundreds, perhaps thousands, of years but revive perfectly well upon being subjected to more clement conditions. A candle flame has a well-defined shape with a fixed boundary and is maintained by “metabolizing” its organic waxes and the surrounding molecular oxygen to produce carbon dioxide and water. Similar reactions, incidentally, occur in animals and plants. Flames also have a well-known capacity for growth. These facts underscore the inadequacy of this metabolic definition, even as they suggest the indispensable role of energy transformation to living systems. (See metabolism.)
Britannica Quiz
Physiological definitions of life are popular. Life is defined as any system capable of performing functions such as eating, metabolizing, excreting, breathing, moving, growing, reproducing, and responding to external stimuli. But many such properties are either present in machines that nobody is willing to call alive or absent from organisms, such...
A biochemical or molecular biological definition sees living organisms as systems that contain reproducible hereditary information coded in nucleic acid molecules and that metabolize by controlling the rate of chemical reactions using the proteinaceous catalysts known as enzymes. In many respects, this is more satisfying than the physiological or metabolic definitions of life. However, even here there are counterexamples. Viruslike agents called prions lack nucleic acids, although the nucleic acids of the animal cells in which they reside may be involved in their reproduction. Ribonucleic acid (RNA) molecules may replicate, mutate, and then replicate their mutations in test tubes, although by themselves they are not alive. Furthermore, a definition strictly in chemical terms seems peculiarly vulnerable. It implies that, were a person able to construct a system that had all the functional properties of life, it would still not be alive if it lacked the molecules that earthly biologists are fond of—and made of. (See biochemistry.)
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May 26, 2022 · Biology is the branch of science that primarily deals with the structure, function, growth, evolution, and distribution of organisms. As a science, it is a methodological study of life and living things. It determines verifiable facts or formulates theories based on experimental findings on living things by applying the scientific method.
Human biology. Human biology is an interdisciplinary area of academic study that examines humans through the influences and interplay of many diverse fields such as genetics, evolution, physiology, anatomy, epidemiology, anthropology, ecology, nutrition, population genetics, and sociocultural influences. [1][2] It is closely related to the ...
1.2.4 The Diversity of Life. The fact that biology has such a broad scope has to do with the tremendous diversity of life on Earth. The source of this diversity is evolution. Evolutionary biologists study the evolution of living things in everything from the microscopic world to ecosystems.
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Boundless. Biology is the study of life and living things through rigorously-tested and peer-reviewed scientific research methods. Science is knowledge obtained from logical inferences and deductive experimentation that attempts to comprehend nature. The scientific method is a process by which observations are questioned; hypotheses are created ...
