FACT
Endothermic (warm
blooded) animals
are able to regulate
their body
temperature so they
are not affected by
extreme
temperatures, and
are able to live in
habitats over a wide
range of
temperature. In cold
regions, animals
have developed a
layer of insulating
fat or hibernate
during the colder
months. In very hot
regions animals
have adapted by
becoming nocturnal
in their habitats.
Cold blooded
animals
(ectotherms) are
unable to regulate
their body
temperature, and
therefore the change
in environmental
temperature will
affect their
distribution and
activities.
FACT
In northern
hemisphere
countries where the
day length is
substantially longer
in the summer the
rate of growth of
plants is very high.
- Allow the water to pass through the water sample.
Results:Write down your resultsObservations:Which sample of water retained the most water?Which sample of water retained the least water?Conclusions:Explain your observations and which soil would you recommend for your pot plants.3.Climatic factors- Sunlight: is essential for the process of photosynthesis. Heterotrophs, such as ani-
mals, use light from the sun indirectly by consuming plants or other heterotrophs. All
organisms receive the energy required for survival through the break down of sugars
and other molecular components that are produced by the autotrophs which are then
broken to release the energy stored in them, by the process of cellular respiration. - Temperature: varies greatly across various parts of earth and throughout the year. Tem-
perature affects the rate of evaporation and transpiration and causes seasonal changes
in weather. Seasonal variation in vegetation also occurs as the germination of seeds
requires warm temperatures. Plants and animals have special adaptations that make
them suited to the temperature of their specific environment. Temperature affects the
rate at which photosynthesis, cellular respiration and decomposition take place. As
you learnt in the earlier section on enzymes, this is linked to the optimal temperature
profile for enzymes. The rate of reaction increases with increasing temperature and
decreases at lower temperatures. - Water: is one of the most important factors in the ecosystem. It is the main component
of living cells and is essential for all living organisms. About 80% of the human body
and 90% of the plant body consists of water. Water is not evenly distributed over the
earth. It is abundant in aquatic ecosystems and least abundant in deserts. Plants are
adapted to the available amount of water in the following ways:- Xerophytesare plants that are able to live in dry habitats, or in regions with
low annual rainfall. These plants are resistant to drought, have to cope with
shortage of water, high temperatures and light intensities and dry warm winds.
We discussed in detail the adaptations developed by xerophytes in order to avoid
water loss in the earlier chapter on plant structure. - Mesophytesare plants that need an average, regular supply of water.
- Hydrophytesare plants that are able to live entirely or partially in submerged
water or in very wet soil. These plants have to cope with a water surplus as found
in wetlands discussed in the earlier section of this chapter, dealing with biomes.
- Xerophytesare plants that are able to live in dry habitats, or in regions with
- Air/gases
- Wind: speeds up evaporation and assists in pollination of plants and the dispersal of
their seeds.
272 9.5. Ecosystems