What are the basic theories of biology

Wikimedia Commons has media related to Biology theories.

• 
  Biology portal

Not to be confused with Category:Biological theorems.

See also: Category:Biological hypotheses

This category has the following 2 subcategories, out of 2 total.

• Non-Darwinian evolution‎ (8 C, 62 P)

• Obsolete biology theories‎ (6 C, 22 P)

The following 37 pages are in this category, out of 37 total. This list may not reflect recent changes.

• Boveri–Sutton chromosome theory
• Britten–Davidson model

• Cell theory
• Contralateral brain

• Darwinism
• Degeneracy (biology)

• Evolution
• Evolution as fact and theory
• Introduction to evolution
• Evolutionism
• Extended evolutionary synthesis

• Fermentation theory

• Germ theory denialism
• Germ theory of disease

• Holonomic brain theory

• Interpolation theory

• Krogh's principle

• Lamarckism
• Law of specific nerve energies

• Modern synthesis (20th century)
• Multiomics
• Mutationism

• Neomammalian brain
• Nocturnal bottleneck
• Novak–Tyson model

• Ohno's law

• Punctuated equilibrium

• Recapitulation theory

• Saltation (biology)
• Sequence hypothesis

• Triune brain

• Ultrastructural identity

• Venom optimization hypothesis
• Vis medicatrix naturae
• Von Baer's laws (embryology)

• Woese's dogma
• Wonderful life theory

Retrieved from "https://en.wikipedia.org/w/index.php?title=Category:Biology_theories&oldid=809809226"

In order to continue enjoying our site, we ask that you confirm your identity as a human. Thank you very much for your cooperation.

What is biology? Simply put, it is the study of life, in all of its grandeur. Biology concerns all life forms, from the very small algae to the very large elephant. But how do we know if something is living? For example, is a virus alive or dead? To answer these questions, biologists have created a set of criteria called the "characteristics of life." 

Living things include both the visible world of animals, plants, and fungi as well as the invisible world of bacteria and viruses. On a basic level, we can say that life is ordered. Organisms have an enormously complex organization. We're all familiar with the intricate systems of the basic unit of life, the cell.

Life can "work." No, this doesn't mean all animals are qualified for a job. It means that living creatures can take in energy from the environment. This energy, in the form of food, is transformed to maintain metabolic processes and for survival.

Life grows and develops. This means more than just replicating or getting larger in size. Living organisms also have the ability to rebuild and repair themselves when injured.

Life can reproduce. Have you ever seen dirt reproduce? I don't think so. Life can only come from other living creatures.

Life can respond. Think about the last time you accidentally stubbed your toe. Almost instantly, you flinched back in pain. Life is characterized by this response to stimuli.

Finally, life can adapt and respond to the demands placed on it by the environment. There are three basic types of adaptations that can occur in higher organisms.

• Reversible changes occur as a response to changes in the environment. Let's say you live near sea level and you travel to a mountainous area. You may begin to experience difficulty breathing and an increase in heart rate as a result of the change in altitude. These symptoms go away when you go back down to sea level.
• Somatic changes occur as a result of prolonged changes in the environment. Using the previous example, if you were to stay in the mountainous area for a long time, you would notice that your heart rate would begin to slow down and you would begin to breath normally. Somatic changes are also reversible.
• The final type of adaptation is called genotypic (caused by genetic mutation). These changes take place within the genetic makeup of the organism and are not reversible. An example would be the development of resistance to pesticides by insects and spiders.

In summary, life is organized, "works," grows, reproduces, responds to stimuli and adapts. These characteristics form the basis of the study of biology.

The foundation of biology as it exists today is based on five basic principles. They are the cell theory, gene theory, evolution, homeostasis, and laws of thermodynamics.

• Cell Theory: all living organisms are composed of cells. The cell is the basic unit of life.
• Gene Theory: traits are inherited through gene transmission. Genes are located on chromosomes and consist of DNA.
• Evolution: any genetic change in a population that is inherited over several generations. These changes may be small or large, noticeable or not so noticeable.
• Homeostasis: ability to maintain a constant internal environment in response to environmental changes.
• Thermodynamics: energy is constant and energy transformation is not completely efficient.

Subdiciplines of Biology
The field of biology is very broad in scope and can be divided into several disciplines. In the most general sense, these disciplines are categorized based on the type of organism studied. For example, zoology deals with animal studies, botany deals with plant studies, and microbiology is the study of microorganisms. These fields of study can be broken down further into several specialized sub-disciplines. Some of which include anatomy, cell biology, genetics, and physiology.

The word biology is obtained from the Greek words “bios,” which means life, and “logos,” which means study. Aristotle, the father of biology, created the basic theory of biology, which describes five biological processes: metabolism, regulation of temperature, inheritance, processing of information, and embryogenesis.

Biology is a broad scope topic and comprises many disciplines like zoology, botany, anatomy, physiology, cell biology, microbiology, etc. There are five basic principles of biology: cell theory, gene theory, homeostasis, evolutionary theory, and the laws of thermodynamics.

1. Cell theory

Cell theory is one of the basic principles of biology which implies that all living things are composed of cells the basic unit of life. Living organisms are made up of one or more cells, and cells are derived from other pre-existing cells.

Theodore Schwann proposed the cell theory in 1839. It led to the modern cell theory, which has three parts and states that DNA (Deoxyribonucleic acid) is distributed between the cells during cell division. It also says that within a particular species, the organisms possess similar cells both chemically and structurally. And that there is a flow of energy within the cells.

2. Gene theory

Gene theory states that all the characters of living organisms are controlled or directed by genes. Genes are smaller parts of DNA that are passed from parents to the offspring. DNA is a part of chromosomes present in every cell. They possess instructions to encode a protein which in turn directs every action of the cell.

3. Homeostasis

• Homeostasis means maintaining stability within the environment, denoting the principles of biology. It refers to both living and nonliving parts of nature as a whole.
• Living organisms possess the ability to regulate different physiological processes occurring within themselves to survive.
• The chemical and physical conditions within them are maintained at an equilibrium irrespective of the external environment.
• Walter Cannon developed homeostasis in 1926 from the Greek words “Homoios” and “Histemi,” which mean similar and standing still.

4. Evolution theory

Source

• Evolution is the process by which living organisms have matured from ancient single-celled life forms. A change in the characteristics of a living organism over some time is the basic theory of biology.
• This occurs parallel to the theory of natural selection (by Charles Darwin), which states that some living organisms reproduce and generate more offspring than other living organisms and more genes or traits are passed to the next generation than others.
• This process aids adaptation in which the subsequent generations of offspring become better suited to the environment. Adaptation allows a living organism to learn how to survive and reproduce in any environment.

5. Laws of thermodynamics

• Thermodynamics is the science between temperature, work, heat, and energy.

• It explains the energy changes within a particular system and whether it can perform any beneficial work on its surroundings.

• It deals with the transfer of energy from one form to another and from one place to another.

• As the name suggests, thermal means “heat,” a form of energy obtained when a particular amount of mechanical work is performed. Sir Benjamin Thompson put forward this theory in 1798.

• The three basic laws of thermodynamics were initiated by Rudolph Clausius, a mathematician, and physicist.

1. First law of thermodynamics: Energy can neither be created nor destroyed but can only be transferred from one form to another. It is also called the law of conservation of energy.
2. Second law of thermodynamics: Within any particular isolated system, the entropy always increases.
3. Third law of thermodynamics: Entropy of a system tends to move to a constant amount while its internal temperature approaches absolute zero.

Conclusion

• The unifying principle of biological sciences is that living organisms are made up of smaller units called cells; they grow and develop based on the universal genetic code.
• They can adapt and maintain inner stability in any environmental condition through homeostasis, reproduce and evolve over time.
• They can also use a chemical reaction to obtain energy and are interdependent on other living organisms.

FAQs:

1. What are the major principles of biology?

Cell theory, gene theory, evolution, and homeostasis are the four unifying principles of biology.

2. What are the six biological principles?

Six biology principles: Organization and function, adaptation, response to the environment, growth and development, reproduction, and Homeostasis.

3. What are the four principles of biology?

The four principles of biology are cell theory, evolutionary theory, gene theory, and concept of homeostasis.

4. What do principles mean in biology?

Biological principles are based on the fundamental concept that all living organisms are similar in composition, growth, heredity, reproduction, metabolism, and homeostasis.

5. What are the three biological principles?

Variation, selection, and heredity.

6. What are the examples of principles?

Examples of biological sciences are reproduction, homeostasis, evolution, heredity, and metabolism.

*We hope you enjoyed studying this lesson and learned something cool about the Principles of Biology! Join our Discord community to get any questions you may have answered and to engage with other students just like you! Don't forget to download our App to experience our fun VR classrooms - we promise, it makes studying much more fun 😎 *

Sources: