HEAT
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HEAT & LIVING-BEINGS
How changes in temperature affect different living-beings. How life on dry land adapted itself to vastly-different habitats on our planet.
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INTRODUCTION
- The planet Earth is at just the right distance from the Sun for the development of life.
- It is the only known world that has oceans of liquid water, an essential element for the development of life.
- Temperature influences the geographical distribution of living-beings.
- Links between the animals’ sizes and the climate they inhabit.
TEMPERATURE AND LIFE
- Living-beings need to live within a fairly narrow margin of temperature in order to survive.
- Generally speaking the temperatures are between 0º and 50ºC.
- Even microscopic beings, such as bacteria or viruses, are sensitive to temperature.
- Plants are very sensitive to environmental conditions since their internal temperature is usually more-or-less that of their surroundings.
- We find most variety and richness of plants in tropical forests.
- The size and diversity of plants is affected by altitude.
- Plants have adapted themselves to increase their chances of survival.
ECTOTHERMIC ANIMALS
- Insects, reptiles and fish: their internal temperature.
- On dry land, animals have developed mechanisms in order to cope with environmental conditions.
- Mechanisms to regulate the temperature of insects, anfibians and reptiles.
ENDOTHERMIC ANIMALS
- Birds and mammals maintain their internal temperature constant.
- Advantages of these mechanisms: they reduce the depence upon their surroundings. This enables them to colonise areas which would otherwise be considered as being unfavourable by other animals. Besides, they can remain active at night and during the winter months.
- 80% of a mammal’s diet is employed in maintaining its temperature.
- How animals avoid losing heat.
- Why mammals and birds have maternal instincts.
- Hypothalamus: an internal thermostat.
- Mechanisms used by different species to regulate their temperature.
SUMMARY |
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