Homeostasis Biology Notes Class 10 Chapter No 11
Q 1: What is Homeostasis? Define the aspects of homeostasis?
Ans:Homeostasis:
Meaning
Homo — same, stasis — condition
Definition:
“The the ability to live organisms to maintain internal body condition constant is called homeostasis.”
The condition and components of the external environment keep on changing continuously but the organisms resist and try to overcome the effect of these changes by making an adjustment in their internal environment.
Type of environment:
There are two types of environments.
i.Internal environment:
The environment inside the body of a living organism is called the internal environment.
ii. External environment:
The surrounding of an organism is called external environment.
Aspects of Homeostasis:
a). Osmoregulation:
The ability of an organism to maintain the normal concentration of water and salts inside the body is called osmoregulation.
b). Excretion:
The removal of metabolic wastes and toxic materials from the body of an organism are called excretion
c) Thermoregulation:
The ability of an organism to regulate internal temperature at a normal level is called thermoregulation.
Q 2:Explain Osmoregulation in the plant?
Ans: Osmoregulation in the plant:
The ability of an organism to maintain a normal concentration of water and salts inside the body is called osmoregulation.
For plants, in all the environmental factors water, is considered to be the most important one. Therefore osmoregulation has enabled the plants to be distributed in a wide range of habitat.
On the basis of availability of water plants is classified into four main categories.
- Mesophytes
- Hydrophytes
- Xerophytes
- Halophytes
- Mesophytes:
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These have moderate water availability.
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In a limited supply of water, they close the stomata to prevent loss of water.
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In a rich supply of water, they keep the stomata open to transpire water quickly.
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Hydrophytes absorb more water than their actual requirement.
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The leaves of hydrophytes have a large surface area to transpire water excessively.
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Large numbers of stomata are present on leaves to promote loss of water.
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These plants have deep roots to absorb water from almost dry soil.
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Some xerophytes have water storage tissue in stem and roots
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Such stem is soft and juicy and is called succulent organs.
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They have small leaves.
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Their leaves are modified into thorn to reduce the evaporation of water.
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Their leaves are covered by a thick cuticle.
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