why do primitive organism have lesser number cells as compared to more advance form?
Primitive organisms have a lesser number of cells compared to more advanced organisms due to their simpler body structures and functions. The number of cells in an organism is generally determined by the complexity of its body plan and the level of specialization required to carry out various functions.
The process of evolution has led to the development of more complex and specialized organisms over time. As organisms became more advanced, they evolved new structures, organs, and systems to perform specific functions efficiently. This required a greater number of specialized cells working together.
Primitive organisms, such as bacteria or single-celled organisms, have much simpler body plans and can carry out a limited range of functions. They can survive and reproduce with a smaller number of cells because they do not have the need for complex organs or systems like advanced organisms do.
For example, bacteria, which are unicellular organisms, can perform all necessary functions for survival within a single cell. They can obtain and break down nutrients, reproduce, and carry out basic metabolic processes within that single cell. In contrast, more advanced multicellular organisms, like humans, have trillions of cells specialized for various functions to carry out complex processes such as digestion, respiration, circulation, and reproduction.
In summary, the difference in the number of cells between primitive and advanced organisms can be attributed to the increased complexity and specialization of advanced organisms, which require a larger number of cells to perform specialized functions.