Table of Contents
Living Things Definition
Biology refers to the scientific study of living things. These biological entities interact with each other and with the environment they live in. There are considerable differences in these living organisms in terms of size and shape.
Human beings have a different shape than other organisms like a tiger or elephant. Some organisms cannot be seen by naked eyes like microbes that are only visible under a microscope. While others are big enough to be seen without the aid of a microscope.
Even though living things have so many variations, they also have certain basic similarities. Plants are also considered living organisms because they grow and can respond to stimuli.
Characteristics of Living Things
(1) Movement: Living things do move from one place to another for different purposes like in search of food, mate, or other resources. When organisms change their position or place, this is termed movement. Organisms also alter their body movements. Plants show different types of movements as a result of tropism and stimuli. For instance, they grow towards the direction of light.
(2) Respiration: The living organisms prepare or acquire their food that is broken down into simpler forms by a series of chemical reactions that results in ATP synthesis. This reaction known as respiration is common for all living organisms since they all require energy for different metabolic processes.
(3) Sensitivity: Living organisms monitor changes in their environment as they are sensitive to these variations and are able to respond to them. These factors that bring out the responses are termed stimulus. They can detect and signal environmental signals. These responses can be observed as adaptations.
(4) Growth: It refers to the increase in size and number of cells. This is a permanent change seen in all living organisms that increase dry mass. Growth can be observed in the life cycle of various organisms. For instance, in the case of humans, the child shows an increase in height as they grow.
(5) Reproduction: It is the process through which organisms produce more of their kind. It is a vital process for the continuation of the species due to which extinction is impeded.
(6) Excretion: As a result of metabolism waste materials are generated that need to be excreted from the living organisms. The process of this removal is termed excretion. It can be harmful if these waste products are not removed.
(7) Nutrition: Nutrition is required for growth and renewal. There are different modes of nutrition in organisms. Some are autotrophic, heterotrophic, and while others are saprophytic. The food is catabolized to release energy via respiration.
These 7 properties or characteristics are shown by all living organisms and can be considered fundamental.