Difference between Multicellular and Unicellular Organisms
Living organisms can be classified as either unicellular or multicellular, depending on the structures and number of cells they possess. The main difference between these two groups is their cellular organization, which affects their mode of existence, reproduction, and overall complexity.
Unicellular Organisms
Unicellular organisms are made up of a single cell that performs all the functions of life, such as growth, metabolism, and reproduction. These organisms are found in almost all habitats, including soil, water, air, and even within other organisms as parasites. Examples of unicellular organisms are bacteria, protozoa, and yeast.
Since unicellular organisms are only made up of one cell, they can carry out all their essential functions independently. Additionally, they reproduce through simple cell division, which is characterized by the replication and separation of their genetic material into two daughter cells.
Multicellular Organisms
On the other hand, multicellular organisms are composed of many cells, which are specialized to perform different functions. These organisms are found in various forms such as plants, animals, fungi, and some algae. They have various organs and tissues that are responsible for different physiological processes such as respiration, digestion, and locomotion.
Multicellular organisms reproduce sexually, and this process involves the fusion of gametes (sperm and egg cells) to form a zygote. The resultant zygote will then divide and develop into an embryo, which eventually forms a mature organism.
Differences in Complexity
Multicellular organisms are more complex compared to unicellular organisms. The presence of various organs and tissues that carry out diverse functions results in an intricate and coordinated network of activities that ensure the proper functioning of the organism. Unicellular organisms, on the other hand, are less complex due to their reliance on a single cell for various physiological activities.
Differences in Size
Multicellular organisms tend to be larger in size compared to unicellular organisms. The presence of numerous cells means that they can form larger structures and can also perform more complex activities. Unicellular organisms, on the other hand, are limited in size due to their reliance on a single cell.
In conclusion, the differences between multicellular and unicellular organisms are significant and affect various aspects of their existence. While unicellular organisms are simpler and tend to be smaller, multicellular organisms are complex and can form larger bodies with specialized functions.
Table difference between multicellular and unicellular
| Multicellular | Unicellular | |
|---|---|---|
| Definition | Organisms made up of many cells | Organisms made up of only one cell |
| Size | Relatively larger in size | Relatively smaller in size |
| Specialization | Cells are specialized for specific functions | Cells do not have any specialization |
| Reproduction | Sexual or asexual reproduction | Reproduction is usually asexual |
| Complexity | More complex organization | Less complex organization |
| Survival | Dependent on other members of the same species for survival | Independent for survival as they are self-sufficient |