Write an essay on temperature as an ecological factor.

Temperature is a measure of the intensity of heat. Temperature decreases from equator to poles and lower altitude to higher altitude.
 

• Thermal Stratification:
  Water shows maximum density at 4°C. Due to the effect of temperature the water with different density forms the layers in lake.

i) Summer stratification: During summer in temperate lakes 3 layers are formed.

1. Epiliminion: 21°C to 25°C
2. Thermocline: Temperature decreases at the rate of 1°C per meter in depth.
3. Hypolimnion: Water is cool with low O₂ content.

Summer is followed by autumn (fall) overturn.

ii) Winter Stratification: Fall is followed by winter. Upper water freezes at 0°C. Below this layer, the cool water is at 4°C.
Winter is followed by spring overturn.

• Biological Effects of Temperature:

1. Eurythermal – Can tolerate wide range of temperatures. Example: Homeotherms
2. Stenothermal – Can tolerate temperature at a narrow range. Example: Fishes and coral animals

• Temperature And metabolism:

Optimum temperature – Metabolic activities occur at the climax level.
Vant’s Hoff’s Rule: With the increase of every 10°c, the rate of metabolic activities doubles.
Q₁₀ = the rate of reaction at x°c: rate of reaction at x-10°c.
 

Cyclomorphosis: 

1. Head of Daphnia round in winter.
2. Helmet on head develops in spring.
3. Helmet attains maximum size in summer.
    

• Temperature adaptations:

i. Behavioral adaptations: Basking of lizards and some species go into burrows.
ii. Morphological adaptations: Blubber is seen in aquatic mammals. Bergmann’s rule explains surface area to body volume ratio.
iii. Physiological adaptations:
a. Regulate: Some organisms maintain homeostasis by physiological means.

b. Conform: Majority of animals cannot maintain a constant internal environment.

c. Partially regulate: camels act as conformers initially up to certain temperature later as regulators.

d. Migrate: Some organism escape stressful habitat to more hospitable area.

e. Suspend life activities: Bacteria, fungi, and lower plants form thick walls.

f. Hibernation is escape in time.

g. Diapause – Some organisms show delay in development during unfavourable conditions.