Variation in temperature:
Ecologically temperature is very important factor which effect different physiological functions of plants and animals. Sun is the temperature main source. So on the Land temperature varies from one region to other i,e.
Altitude, air humidity, changing season, day and night, distance from sea and ocean.
According to temperature variations plants are classified into four groups:
1)Megatherms:
Such plants which require high temperature for growth throughout the year. Such plants mostly in tropical areas.
2) Mesotherms:
Such plants require low temperature in winter season and high in summer for growth.
3) Microtherms:
Such plants require low temperature for growth. Such plants mostly in alpine areas.
4) Hekistotherms:
Such plants can grow very well in very cold winter season.
