levels of biological organization
Organization of Life
You have read that cell is the basic unit of structure and function of living organisms. These organisms may be unicellular or multicellular. A unicellular (single-celled) organism like a multicellular organism is capable of performing all the functions of life. Multicellular organisms are made up of many cells. These cells are different from one another in the structure, from a function. All the cells having similar size and structure perform similar functions.
Cells Form Tissues
Similar type of cells arranges themselves in the form of groups or layers. Such a group of cells is called a tissue. All cells of a tissue perform similar function.
Tissues Form Organs
Different tissues organize to form an organ. An organ performs one or more functions in the body. Examples of different organs in the animals are heart, lungs, stomach, kidneys etc. similarly root, and stem, leaves and flowers are different organs of a plant.
Organs Form Systems
As cell forms tissues and tissues form organs, likewise organs form systems. Different systems perform one or more than one special functions.
Plants have two main systems
- Root system
- Shoot system
Human body has many systems
System for digestion of food.
System for breathing.
System for removal of waste materials.
System to conduct the messages.
System for transport of blood in the body.
Systems Form an Organism
All organisms, animals or plants are formed of different systems, which work together in coordination. For example all human systems which have been discussed above together form a human body_ an organism. Similarly a plant that is an organism is made up of root system and shoots system.