Understanding Biology

What characteristics make a life? How can we distinguish between what is living and what is not? The majority of individuals intuitively know what it means for something to be alive and know your purpose. It’s very hard to define life precisely, though. Because of this, many definitions of life are only operational—they let us distinguish between living and nonliving entities but don’t truly define what life is. We need to create a list of traits that, taken as a whole, are specifically distinctive of living things in order to draw this distinction.

Biologists have found a number of characteristics that all known living things share. Although some of these distinguishing characteristics may be displayed by nonliving entities, only living creatures exhibit them completely.


Living creatures have well-coordinated, specialized pieces, making them highly organized. Cells, which are regarded as the basic building blocks of life, make up every living thing.

2. Metabolism 

An large number of interconnected chemical processes are essential to life. These processes let organisms to develop, reproduce, and maintain the structure of their bodies as well as perform tasks like moving or catching prey. To carry out the chemical processes required for life, living creatures must expend energy and absorb nutrients.

3. Homeostasis

Living things experience controlled development. The size of individual cells increases, and multicellular organisms amass a vast number of cells through cell division. You began as a single cell and today your body has tens of trillions of cells 1 1 start superscript, 1 end superscript! Anabolic processes, which produce huge, complex molecules like proteins and DNA, the genetic material, are essential for growth.

4. Self-reproduction

Living things may reproduce to make new creatures. Asexual reproduction, involving a single parent organism, is possible, as is sexual reproduction, needing two parents. Single-celled creatures, like the bacteria that is dividing in the left panel of the image on the right, may simply split in two to reproduce!

5. Response

Living things have “irritability,” which is the ability to react angrily to environmental cues or alterations. People, for instance, swiftly remove their hand from a flame.