Biology is fundamentally about the study of all living creatures or organisms, which are classified into taxonomies and systematics. The difference between living organisms and nonliving material is identifiable by their structure and whether they have the necessary structures to carry out certain processes. One main characteristic of living organizations is that they are composed of cells - these cells are usually highly organized and have the ability to utilize energy through a complex series of chemical reactions.


Biology is fundementally about the study of all living organisims Image source 

There are seven characteristics that are common to all living organisms:

Coordination and Regulation

All living organisms have the ability to move in some way or another in order to maintain  an internally stable environment. This can be defined as a ‘response’ to stimuli. For example, plants retain chemicals such as auxins and gibberellins that allow plants to elongate their stems or cause the plant to lean to one side as a response to the movement of the sun. Similar responses can be seen in animals, such as mammals, that perspire in response to elevated heat and shivering in the absence of heat. Any material that lacks such complex capabilities, such as rocks, do not fall under the realm of biology.


Living organisms are able to react to changes in their environment. The manner in which organisms react to such changes can vary greatly. Bears hibernate in winter, buffalo immigrate hundreds of kilometers to greener and warmer pastures, bison grow thicker fur hair, plants lose their leaves to conserve energy, Arctic foxes change color from brown to white to become less visible to predators, while humans dress warmer clothes. It is the very ability to adapt to those changes that is unique to living organisms, which is critically important as these adaptations increase the chance of their species’ survival.


Every living organism requires a constant supply of energy, which occurs through a chemical reaction, allowing respiration to take place. When humans consume energy-rich food, such as glucose, it is broken down by complex cell reactions that produces energy to be utilized by the body. These reactions produce the ability for respiration in order to maintain life processes. 


All living organisms produce various waste products through metabolism. These waste products, which can greatly vary in composition, need to be removed or excreted to ensure the continued functionality of the organism. Plants excrete oxygen through photosynthesis, while organisms such as birds excrete uric acid that are developed by the breakdown of proteins. 

Growth and Reproduction

It is necessary for all living organisms to grow in size. This growth can greatly differ between different organisms. For instance, humans grow the entire length of their bodies, while other organisms such as plants grow only at the tips of their bodies and leaves. Furthermore, some organisms’ growth is indefinite while others only grow to a certain size before stopping completely. Some organisms, such as certain types of lizards and earthworms, can continue to grow new limbs or parts of their body that are damaged or lost. 


While reproduction is not necessary for each individual organism, it is critical for the survival and existence of a species. Reproduction can occur in one of two ways: asexual and sexual. In asexual reproduction, only one parent is involved in the reproduction process, which pass on identical genetic material to the offspring. For example, dandelions due their roots for asexual reproduction, where the offspring become original clones of the parent plant.

Sexual reproduction involves two parents and normally results in offspring that is not genetically identical to either parent. While sexual reproduction can take place inisde the body, such as in the case of humans and apes, it can also take place externally, such as the case with frogs and other amphibians. Sexual reproduction can occur between two parents of separate but related species, such as horses and donkeys, and lions and tigers. In these cases, the offspring is normally sterile and unable to produce.

Producing or Obtaining Food

All living organisms need food in order to produce the necessary energy to sustain themselves. Organisms such as plants and algae, are considered autotrophs, as they produce their own food through a complex series of reactions to the presence of sunlight. These chemical reactions typically take place within cells, converting water, carbon dioxide, and light into sugar and oxygen. This is the basic foundation of photosynthesis.

Organisms that need to obtain their food, do so from their environment, and are referred to as heterotrophs. Many heterotrophs feed on autotrophs, such as gazelle and cows eating grass. Other heterotrophs feed on on other heterotrophs, such as lions feeding on deer or buffalo.

Scientists and biologists consider autotrophs as the basis of life on earth, as almost all other organisms depend either directly or indirectly on autotrophs for their own food.


Viruses in biology are unique. While viruses are able to metabolize and reproduce, they are not considered living organisms by biologists. The reason for this is that in order to for them to accomplish reproduction, they can only do this within living cells. Hence, they are actually considered parasites and cause various diseases and alignments. __________________________________________________________________________________________

Biology is a vast topic, and includes a vast array of other disciplines and eclectic fields, such as botany (the study of plants), zoology (the study of animals), taxonomy (organisms classification), and ethology (study of animal behavior), among many others.


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