How do the physical features of the surroundings affect organisms?
Biomes are main ecological regions in which the land surfaces can be devided.
These are the major types of ecosystems(those that occupy broad geographic regions).
- coniferous forests
- deserts
- temperate grassland
Each of these places has its own type of abiotic environment(eg. the nature of the soil) which determines the type of plants found in that particular habitat. Since animals rely directly or indirectly on plants for food, the animals living in a region is determined by the plants growing there. So, living organisms have to adapt to the abiotic environment of the region in order not to be affected by the surroundings.
What are the physical factors?
Abiotic emvironments consists of non-living factors such as climate and physical features that influencace ecological systems.
These physical factors include:
- temperature
- light intensity
- amount of water available
- oxygen content
- salinity(salt concentration) of soil/water
- pH of soil/water
How organisms adapt to these physical factors
1) Temperature
- affects the rate of biological processes(reactions of enzymes, which control metabolic activities of plants and animals);
- and the inability of most organisms to regulate body temperature.
Most organisms cannot tolerate extremes of temperature; temperature that are too low or high would kill an organism.
eg. - a cell may rupture if the water is below 0°C or above 45 °C, most protein will denature rendering the organisms ability to function;
- desert plants :
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~have small/spiny leaves limit the surface area exposed to the drying heat ~glossy leaves reflect the sun's rays, reducing leaf temperatures and evaporation rates
~waxy leaves prevent moisture from escaping
~some plants only open their leaf pores at night when it is cool and water loss from leaves is low
- desert animals :
~staying in the shade of plants or rocks or by burrowing underground in the heat of the day
~they stay inactive in shelter during the day and hunt at night when it is cool[nocturnal]
2) Light Intensity
- the sun provides energy that drives almost all ecosystems on Earth
- light intensity allows photosynthesis to take place which affect the plants growth, which in turn affect the animals growth too ;D
- and the distribution of aquatic life
eg. - in a forest, the canopy layer tend to be denser as it recieves most of the sunlight, while the undergrowth layer(growing plant) at the bottom is less dense as it recieves little or no light at all
- undergrowth layers :
have large, broad leaves packed with extra chlorophyll to capture and absorb what little light is available.
- low light intensity :
~the anglerfish has a long protrusion on its head which is used lik a fishing rod to 'fish' for smaller fishes instead of relying on its poor eyesight to locate prey
3) Amount of water available
- affect the number and location of plants and animals in a region
- depend on the amount of rain
NO ORGANISMS CAN LIVE LONG WITHOUT WATER!
eg. - desert animals :
~can go 5-7 days with little or no food and water
~fat inside the hump is used to keep the animal going when there is no food or water
- desert plants
~plants have developed very long roots that go deep into the ground to reach underground water
~others have developed spreading root systems lying just below the surface and stretching widely
~this gives the plant many tiny roots that capture water when it rains.
4) Oxygen content
- most organisms require oxygen for aerobic respiration
- thus, they cannot survive in environments of low oxygen content
eg. in low oxygen content :
- mangrove plants
~these air roots, called pneumatophores, extend upward from the underground roots above the soil surface
~during low tides, oxygen is taken up through open passages in the pneumatophores and transported to living root tissues.
- koi
~living in water of low oxygen content
~come to the surface of the water to gulp oxygen
5a) Salinity of water
- in aquatic habitats, the organisms are surrounded by water but there can still be problems due to osmosis
eg. - marine fish :
~in salt-water environments animals can lose water by osmosis as seawater has a higher salt concentration than the fish`s cells and must constantly replace it by taking in the water to replace water loss
- freshwater organisms
~in fresh-water, osmosis causes water to flow into the organism’s body as the freshwater has a higher water potential than the organism`s cells and water must be constantly "pumped out"
5b) Salinity of soil
- mangrove plants
as mangrove grew near the sea area, therefore the soil has a higher salt content
~secreting salts from their leaves, the salt can often be seen sitting on the surface
~excluding salt; prevent larger salt molecules from entering but allow smaller water molecules to pass through
~salt storage; salt is stored in leaves which then fall off the plant taking the salt with them
6a) pH of soil
- soil pH is a measure of soil acidity
- as soils become more acid/alkaline, this has a negative effect on the growth of plants
- when soil become too alkaline, leafs would produce insufficient amounts of chlorophyll
6b) pH of water
- seawater has a pH of 8
- aquatic organisms may die when there is a sudden change in pH as they are sensitive to the pH of water
- hydrogencarbonates determine the pH of water
eg. - in daylight, photosynthesis in aquatic plants use up the carbon dioxide in the water, making the water more alkaline
- during the night, photosynthesis stops and the carbon dioxide produced in respiration makes the water more acidic
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