This document discusses homeostasis and various mechanisms organisms use to regulate their internal environments. It defines homeostasis as the protection of the internal environment from fluctuations in the external environment. It discusses osmoregulation as the regulation of solute and water balance between an organism and its environment. Thermoregulation is defined as maintaining internal temperature within a tolerable range. Excretion is the removal of nitrogenous wastes from the body. The document goes on to describe different types of plants and their adaptations for water regulation and osmoregulation in both plants and animals.

1. Chapter 15 (2nd year)
HOMEOSTASIS

2. Environment
It can be defined as “the
surroundings or conditions in
which a person, animal, or plant
lives or operates.
Environment may be
1: external environment
2: internal environment

3. Homeostasis
It can be defined as” the protection of internal
environment from the harms of fluctuations in
external environment is called as homeostasis”

4. Osmoregulation
It can be defined as” the
mechanism of regulation ,
generally between organism
and its environment , of
solute and the gain and loss
of water is osmoregulation

5. Thermoregulation
It can be defined as”
maintenance of internal
temperature within a
tolerable range is
designated as
thermoregulation.

6. Excretion
It can be defined as “ the process in
which nitrogenous wastes are
removed from the body is called as
excretion”

7. Control system

8. Water relations of cell

10. Osmoregulation in
plants
Click to play the
video

11. Distribution of plants according to
different habitats
Hydrophytes
Extensive stomata are present.
They have very large leaves to
transpire water excessively.
Example: Water lily
Mesophytes
They have moderate water availability
Stomata are kept open to promote
transpiration while in restricted
supply of water, stomata are closed.
Example. Brassica . Mango etc.
xerophytes
They have thick small leaves to
reduce water loss
Thick waxy cuticle is present
Stomata are on the lower surface of
leaves, present in depressions.
They have thick stem to store water,
during rainy season.
Some plants shed their leaves to
restrict transpiration , completely.
Example Cactus

12. Hydrophyte
Waterlily

13. Mesophytes
Rose Plant

14. Xerophytes
Cactus

15. Osmoregulation in animals
OSMORECONFORMERS
OSMOREGULATORS

16. Osmoconformers
Their internal and outer
water solute balance is
isotonic
So they do not need to
regulate it actively.
Examples: invertebrates,
including starfish and
jelly fish
Among the vertebrates
the osmoconformers are,
hagfish , sharks, skates

17. Paramecium
Contractile vacuole for
osmoregulation

18. Terrestrial
environment.
Kangroo rat

19. Excretion
 In plants
 In animals

20. Excretion in plants
By:
Leaves
Trunk
Roots
Bulb
By crystal formation
Ebony formation

21. Bulb of Blue bell flower

22. conifers
Release waste compounds in
soil.

23. Rasins , latex, in
trees

24. Excretophore
Excretory leaf and chlorosis in
Leaves are different.

25. Nature of excretory
products in animals

26. Urea cycle.
2 ammonia and 1 Carbon
dioxide combine to form 1
urea molecule,

28. Excretion in
planaria
• Flame cells.
• * protonephridium

29. Excretion in
earthworm
Metanephridium

30. Excretion in
cockroach

31. Liver
Synthesis
Storage
Detoxification
Conversion
recycling

33. Skin as
osmoregulatory
organ
Sebaceous glands
Sweat glands