It describes temperature-Abiotic factor and its effects

1. Topic:
temperature – Abiotic factor
Presented By: ALI HAIDER
ROLL number : 0003.BS.ZOO.2019
semester: 3rd
Group No. 4
department : Zoology

2. Table of content:
Introduction of Temperature
Temperature as an Ecological factor
Effects of temperature on Plants and Animals
Classification of plants on basis of temperature conditions
Classification of Animals on basis of temperature conditions
Adaptations in response to temperature

3. Introduction
 Temperature is defined as:
“The degree or intensity of heat or coldness present
in a substance, object or an organism.”
 Temperature is a measurement of the average kinetic energy of the particles
in an object.
 It can be measured using a thermometer on a Fahrenheit, Celsius and
Kelvin scales.
 Temperature is one of the essential and obvious changeable environmental
factors. It varies not only between climatic regions, but also in the temporal
changes of all habitats. It is one of the most extensively studied
environmental factors.

4. Temperature AS an ecological factor
 Temperature is one of the most important ecological factors.
 It regulates many physiological processes of the plant.
 The metabolic processes are low at a certain minimum temperature. It
increases at particular temperature called optimum temperature. The plant
grows best at optimum temperature.
 Metabolism again decreases at maximum temperature.The plants cannot
survive above this temperature.
 Both extremely low and high temperatures have adverse effect on plant
growth.

5. Effects of temperature on Plants and
animals
 Effect on metabolism
 Effect on reproduction
 Effect on fecundity
 Effect on Growth and Development
 Effect on crossing over
 Effect on sex-ratio
 Effect on colouration
 Effect on morphology

6. 1. Effect on Metabolism
All metabolic processes are influenced by temperature
and regulates the activity of enzymes.
Chemical reactions in the body of organism are
controlled by the temperature.
It affects the rate of photosynthesis, transpiration,
respiration rate and metabolic rate and in both plants
and animals.
Increase in temperature results in increase of kinetic
energy of molecule, as a result the subtract molecule
collides with enzyme at faster rate, thus,increasing the
rate of reaction.

7. 2. Effect on reproduction
 Flowering of the plants is affected by temperature through the
Thermoperiodsm (the response of plant to rhythmic diurnal fluctuation
in temperature). It also plays an important role in Phenology of plants
(study of periodical phenomena of plants with relation to climate).
 In animals maturation of gonads or sex cells are affected by the
temperature. For example: In blow fly the number of eggs laid per
female, increases with the increase in temperature up to 32ºC.

8. 3. Effect on fecundity
Fecundity is the reproductive capacity of the animal which is
affected by the temperature.
For example:
Grasshoppers produce 20-30 times more eggs at 32ºC than
those at 22ºC.

9. 4. Effect on growth anddevelopment
 Both extremely low and high temperature have adverse effect on
growth of plants as low temperature brings about such cold injuries like
desiccation, chilling injury and freezing injury.
 Extremely high temperature causes stunned growth of the plant due to
adverse effect on processes like respiration, transpiration rate, and protein
metabolism.
 In animals temperature affects the growth and development. For
example: In oysters the length of the body increases from 1.5mm to
10.3mm with increase in temperature from 10ºC to 20ºC.

10. 5. Effect on crossing over
 In animals like fruit fly Drosophila sp.
temperature is shown to affect the crossing
over and somatic expression of gene
characters.
 For example: In larval or pupae stage
wings tend to be longer at high temperature
and shorter at low temperature.

11. 6. Effect on sex-ratio:
 In animals like rotifers and daphnids, sex
ratio is affected by temperature.
 For example:Under normal conditions
daphnids give parthenogenetic eggs that
develop into females, whereas with
increase in temperature they give sexual
eggs which after fertilization develops into
either male or female.

12. 7. Effect on colouration
 Some insects, birds, and mammals in warm humid climates
bear darker pigment than the races of same species present in
cool and dry climate.This phenomena is know as Gloger rule.
 Reason: This colouration is because of the melamine pigment
present in the skin, as the temperature increases the melamine
pigment also increases, thus, the organisms on the tropical and
temperate regions appear dark in colour as compared to
organisms present at poles.

13. Exception:
In the frog Hyla and the horned toad,low temperature
induced darkening.

14. 8. Effect on morphology
 Temperature affects the absolute size of the
animal and relative proportions of various body
parts –Bargman’s rule. For example: birds and
mammals attain greater body size in cold regions
than in warm areas.
 Poikilotherms are smaller in colder areas.There
snout, tail, ear and legs are comparatively shorter
in colder parts than in the warmer areas – Allen’s
rule. For example: ear size in artic fox and desert
fox.

15.  Birds having relatively narrow and acuminate
wings tend to occur in colder regions, while in
warmer areas tend to be broader – Rensch’s
rule.
 Temperature also affects the morphology of
fishes and is found to have some relatioships
with the number of vertebrate – Jordon’s rule.

16. Distribution of vegetation
 Temperature and moisture determine the general
distribution of vegetation. Different belts of vegetation occur
between the equator and the poles.
 Vegetation is primarily determined by heat. Thus plants which
grow in a hot climate cannot grow in a cold climate and vice
versa.
 Therefore, same crop are not cultivated in all regions of the
world. Different crops are cultivated in different region of the
world

17. classification of plants
The plants are classified into the
following categories on the basis of temperature requirements;

18. 1. Megatherm:
The plants live in high temperature throughout the
year are called megatherms.These plants are found in equatorial
and tropical rain forests.
2. Mesotherm:
The plants living at high temperature of summer,
alternating with low temperature of winter are called
mesotherms.They are found in deciduous forest of tropical and
subtropical regions.

19. 3. Microtherm:
The plants which live in extremely low
temperature are called microtherms.
 It includes plants of temperate and high altitudes (upto 12000
feet of tropical and subtropical region).
For example: Coniferous forest.
4. Hekiskotherm:
It includes plants of Arctic and Alpine regions
(above 16000 feat in tropics and 12000 feet in temperate) with very
low temperature.
 Alpine vegetation prevails in such locality.

20. classification of animals
Animals on the other
hand, are grouped into two categories on the basis of effect
of temperature.

21. 1. Hoemothermic:
These animals are able to maintain their
body temperature at a constant level irrespective of the
environmental temperature.
These animals can regulate there body temperature thus they
are also called as warm blooded animals.
The warm blooded animals are generally active throughout all
seasons.
Examples:
Birds and mammals

22. 2. Poikilothermic:
These are animals like in which the body
temperature fluctuates with changes in environmental temperature.
These animals cannot regulate there body temperature thus
they are also called as cold-blooded animals.
These cold blooded animals become inactive below 80 C and
above 400 C. Most of the cold blooded animals become
dormant during extreme cold, called hibernation or during
extreme hot condition called aestivation.
Examples:
Reptiles, fishes, Amphibians

23. Adaptations in response to temperature
.
During the course of evolution plants and
animals have adopted a number of morphological and physiological
characters to survive in extreme high and low temperature.
 Production of spores, cysts, eggs, pupa, seeds: To resist
extreme temperature plants and animals produce thick-walled
structures like cysts, spores, pupa, eggs, seed etc. E.g Amoeba
in encysted state may tolerate a temperature of 0ºC.
 Increase in the osmotic concentration: Increase in the osmotic
concentration prevents freezing. Increase in the osmotic values
enhance the amount of bound water in colloidal form. E.g In
winters rye at 0ºC, leaves and stem are flexible, but not brittle.

24.  Removal of water molecule:- Dried seed, cyst, and spores avoid
freezing because no liquid is present in them to freeze. E.g. Dry
seeds are able to germinate even after their exposure to -190ºC
for a period of 3 weeks.
 Dormancy:- This includes both hibernation and aestivation.

25.  Homoiothermy:- Birds and mammals are able to maintain a
constant body temperature irrespective of the external
environmental temperature by evaporation of water in summers
and through insulating actions like fur, fats in winters.
 Migration:- The journey taken by the animals that enable them to
escape from extremely hot or cold situations are referred to as
migration. It majorly occurs in fishes, mammals, birds and desert
amphibians.
 Phenotypic changes:- Temperature affects the phenotype of the
animals such as in Drosophilla melanogaster temperature affects
the development of eyes and number of legs.