1) Living organisms cope with changing abiotic factors in four main ways: regulate, conform, migrate, and suspend. 2) Regulation allows some species like mammals and birds to maintain homeostasis by keeping their internal body temperature and osmotic concentration constant through physiological means. 3) Most species conform to changes in external conditions and cannot regulate their internal environment. Their body temperature and osmotic levels fluctuate with the environment. 4) Migration allows some organisms to temporarily move to more hospitable areas during periods of environmental stress and return later. 5) Suspending activity through dormancy, hibernation, or aestivation allows other organisms to avoid stressful conditions through reduced metabolism or by escaping

1. RESPONSES TO
ABIOTIC FACTORS
BY - ADWAITH S

2. The abiotic conditions of many habitats may vary drastically
in time.
One would expect that during the course of millions of years of
their existence, many species would have evolved a relatively
constant internal (within the body) environment that permits all
biochemical reactions and physiological
functions to proceed with maximal efficiency and thus, enhance
the overall ‘fitness’ of the species.
This constancy, for example, could be in terms of optimal
temperature and osmotic concentration of body fluids. Ideally
then, the organism should try to maintain the constancy of its
internal environment.

3. Homeostasis- An ability of an organism to
maintain a constant internal environment

5. FIG:DIAGRAMATIC REPRESENTATION OF
ORGANISMIC RESPONSE

6. ANS) HERE ARE THE DIIFERRENT WAYS BY
WHICH THEY OVERCOME THE CHANGE IN
ABIOTIC FACTORS:
Q.HOW DO THE LIVING ORGANISMS
COPE UP WITH THE CHANGING
ABIOTIC FACTORS?
1.REGULATE
2.CONFORM
3.MIGRATE
4.SUSPEND

7. 1) REGULATE
Some organisms are able to maintain homeostasis by
physiological (sometimes behavioural also) means which
ensures constant body temperature, constant osmotic
concentration, etc.
All birds and mammals, and a very few lower vertebrate and
invertebrate species are indeed capable of such regulation
(thermoregulation and osmoregulation).
Evolutionary biologists believe that the ‘success’ of mammals
is largely due to their ability to maintain a constant body
temperature and thrive whether they live in Antarctica or in the
Sahara desert

8. . FOR EXAMPLE:
The mechanisms used by most mammals to regulate their body
temperature are similar to the ones that we humans use. We
maintain a constant body temperature of 370C.
In summer, when outside temperature is more than our body
temperature, we sweat profusely. The resulting evaporative
cooling, similar to what happens with a desert cooler in
operation, brings down the body temperature. In winter when
the temperature is much lower than 370C, we start to shiver, a
kind of exercise which produces heat and raises the body
temperature.
Plants, on the other hand, do not have such mechanisms to
maintain internal temperatures

9. IMPORTANT TERMS
THERMOREGULATION- It is a mechanism by which
mammals maintain body temperature with tightly
controlled self-regulation independent of external
temperatures.
Osmoregulation- This process of passive
regulation of osmotic pressure is known as
osmoregulation

10. 2)CONFORM
An overwhelming majority (99 per cent) of animals and nearly
all plants cannot maintain a constant internal environment.
Their body temperature changes with the ambient
temperature. In aquatic animals, the osmotic concentration
of the body fluids change with that of the ambient air, water
osmotic concentration. These animals and plants are simply
conformers.
During the course of evolution, the costs and benefits of
maintaining a constant internal environment are taken into
consideration. Some species have evolved the ability to
regulate, but only over a limited range of environmental
conditions, beyond which they simply conform.
If the stressful external conditions are localised or remain
only for a short duration, the organism has two other
alternatives for survival

11. 3)MIGRATE
The organism can move away temporarily from the stressful
habitat to a more hospitable area and return when stressful
period is over.
In human analogy, this strategy is like a person moving from
Delhi to Shimla for the duration of summer. Many animals,
particularly birds, during winter undertake long-distance
migrations to more hospitable areas.

13. 4)SUSPEND
Suspend: In bacteria, fungi and lower plants,
various kinds of thick-walled spores are formed
which help them to survive unfavourable
conditions – these germinate on availability of
suitable environment.
In higher plants, seeds and some other vegetative
reproductive structures serve as means to tide
over periods of stress besides helping in dispersal
– they germinate to form new plants under
favourable moisture and temperature conditions.
They do so by reducing their metabolic activity and
going into a state of ‘dormancy’.

14. In animals, the organism, if unable to migrate, might
avoid the stress by escaping in time. The familiar
case of bears going into hibernation during winter is
an example of escape in time.
Some snails and fish go into aestivation to avoid
summer–related problems-heat and dessication.
Under unfavourable conditions many zooplankton
species in lakes and ponds are known to enter
diapause, a stage of suspended development.

15. IMPORTANT TERMS
Dormancy- the state of being temporarily inactive or
inoperative.
Hibernation- an extended period of remaining inactive
or indoors
Aestivation- prolonged torpor or dormancy of an
insect, fish, or amphibian during a hot or dry period.
Dessication- the state of extreme dryness, or the
process of extreme drying.
Diapause- a period of suspended development in an
insect, other invertebrate, or mammal embryo,
especially during unfavourable environmental
conditions

16. QUESTIONS?
1)SNAILS ESCAPE FROM STRESSFUL TIME IN SUMMER BY
a)Hibernation
b)Aestivation
c)Diapause
d)Homeostasis
2)WHICH OF THE FOLLING ORAGANISMS ENTER INTO
DIAPAUSE?
a)Snails
b)Bear
c)Zooplankton

17. .
3)MENTION HOW DO BEARS ESCAPE FROM STRESSFULL
TIME IN WINTER ?
4)__________ IS THE REGULATION OF CONSTANT
INTERNAL ENVIRONMENT IN CHANGING ENVIRONMENTAL
CONDITIONS.
5)WHICH AMONG THESE IS NOT AN EXAMPLE OF
RESPONSES TO ABIOTIC FACTORS?
a)Regulate
b)Suspend
c)Dormancy
d)Migrate

18. ANSWERS!
1)b)Aestivation
2)c)Zooplankton
3)Hibernation
4)Homeostasis
5)c)Dormancy

19. THANK
YOU!