In this post, I am sharing the Class 12 Biology Chapter 15 Full Chapter Notes PDF for the students of Intermediate Part 2. This chapter’s name is Homeostasis. Students can download the Class 12 Biology Chapter 15 Full Chapter Notes PDF on their laptops or mobile. These Biology Notes are for all the boards working under the Punjab Board like Gujranwala Board, Lahore Board, Faisalabad Board, Multan Board, Rawalpindi Board, Sargodha Board, DG Kahn Board, and Sahiwal Board. Here are the complete FSC 2nd Year Biology Notes PDF chapters.
FSC Part 2 Biology Chapter 15 Full Chapter Notes – Homeostasis
Defination
Protection of internal environment from the harms of fluctuation in external environment.
Importance
(i) Homeostasis is the central requirement in the maintenance of suitable environment for an organization.
(ii) It brings the adaptions in organism due to constant changing environmental conditions and contributes in the evolutionary process.
(iii) Homeostasis keeps the internal fluctuation in a narrow range with various control systems (sweating/shivering etc.) as compared to wider external changes.
Components of Cell and Effect of External Change:
Water solutes and temperature are the components of cell which are affected by changes in external environment of a n organism. These are controlled by following methods:
1. Osmoregulation: The mechanism of regulation of solutes and gain or loss of water is called osmoregulation.
2. Excretion: The mechanism which removes nitrogenous wastes from the body is called exretion.
3. Thermoregulation: The maintenance of internal body temperature whithin a tolerable range is called thermoregulation.
Homeostasis: (At Cellular Level)
Homeostasis does not mean to keep a fixed interval envirnonment at cellular level, as changes within a specific range are necessary for normal body functions. For example water availability may vary tremendously for the organism in the external environment from abundant supply to almost dry conditions. However, the central system of homeostasis process would not let the body flooded with water in abundant supply and also not to dehdrate in dry conditions.
How to Download 2nd year Biology Chapter 15 Full Chapter Notes
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