Features of Organisms

Characteristics of Living Organisms

All living organisms share a set of fundamental characteristics, these traits help differentiate between living and non-living things.
Movement: All living organisms exhibit movement in some way. This ranges from the obvious movements of animals to the growth and cell division of plants.
Respiration: All living organisms perform respiration, a process where energy is produced from food. This energy is necessary for growth, repair, movement, and reproduction.
Sensitivity: Organisms are sensitive to and can respond to stimuli in their environment. For example, plants grow towards light and animals react to changes in temperature.
Growth: All living organisms grow and develop. In animals, there is a clear growth cycle from childhood to adulthood, whereas in many plant species, growth continues throughout the organism’s life.
Reproduction: Living organisms have the ability to reproduce and generate offspring. This can be through either sexual reproduction, involving two parents, or asexual reproduction, involving a single parent.
Excretion: The life processes result in the production of waste products which must be removed. This process of removal of waste products from the body of an organism is known as excretion.
Nutrition: Organisms require nutrients for energy, growth, and repair. Plants make their own food through photosynthesis, whereas animals must consume other organisms to obtain nutrients.

Classification of Organisms

All living organisms can be grouped into five kingdoms based on their structure and characteristics: Monera (bacteria), Protista (single-celled organisms), Fungi, Plantae (plants), and Animalia (animals).
Monera are unicellular organisms with a simple cell structure that lacks a nucleus.
The Protista kingdom is a diverse group of organisms that are mostly unicellular but have a more complex cell structure than monera as they contain a nucleus.
Fungi are a group of organisms, which include yeast, moulds and mushrooms, that obtain nutrients by decomposing organic material or parasitising other organisms.
Plantae include all green plants. They are autotrophic, meaning they produce their own food through photosynthesis.
Organisms in the Animalia kingdom are multicellular and heterotrophic, meaning they obtain their nutrients by consuming other organisms. This group is very diverse and includes everything from sponges to humans.

Taxonomy

The classification of organisms into hierarchical categories, based on shared characteristics, is called taxonomy.
The major taxonomic ranks in order from most inclusive to least inclusive are: Kingdom, Phylum, Class, Order, Family, Genus, and Species.
Each species is given a unique two-part name, or binomial nomenclature, which is used universally by biologists. The first part of the name identifies the genus to which the species belongs; the second part identifies the species within the genus.
For example, the house cat is known as Felis catus. Felis is the genus name, and catus is the species name. This system of naming organisms was developed by Carolus Linnaeus in the 18th century.
These names are in Latin and provide a uniform way to name species, irrespective of language or geographical location, preventing any confusion that can arise from common names.