1. What effect does sunlight have on temperature, humidity, and available water
ID: 132432 • Letter: 1
Question
1. What effect does sunlight have on temperature, humidity, and available water and how are these factors related to sunlight and to one another?
2. Structurally, how do plants respond to high temperature, low humidity, or limited water in an effort to conserve water?
3. How does this structural resopnse explain low photosynthetic performances seen under less tah opitmal conditions?
4. In what parts of the world are conditions ideal (optimal) for photosynthesis during most of the year? What type of forests develop here? Why are these forests so important?
5. How does burning of rainforests contribute to global warming?
6. How can conservation of rainforests or replanting of deforested areas help to counteract global warming?
Explanation / Answer
1] Sunlight has a direct effect on the temperature of the earth. The solar energy does not heat the air through which it passes, rather, it heats the surface on which it falls. When the sunrays fall on land or on the water surface, it heats it and then the air just above these surfaces are heated. Hot air moves up, creating a low pressure as a result of which the surrounding cooler air rushes to take its place. In this way a convection current is set up which results in the breeze or storms, depending upon the intensity of the pressure difference.
When the sunlight is strong, the evaporation of water is faster. This results in an increase in the humidity in the air. As the humidity increases, the evaporation rate might slow down as the air is getting saturated with water droplets. The moisture in the air might move higher in the atmosphere and condense to form clouds at the cooler temperatures. When saturation reaches its maximum limit, the cloud might precipitate and fall down as rain.
The whole process is controlled by the intensity of sunlight or the solar energy available at that place.
2] When the temperature is high, the plants will transpire water from their aerial parts at a faster rate. Transpiration serves two functions in plants-
first, it helps in the conduction of water to all the plant parts by creating a transpirational pull in the xylem
second, it helps to keep the plants cool as the water which evaporates through the stomata reduces the temperature of the plant
Therefore, if the temperature is high and humidity is low, the rate of transpiration will be faster. This means that the guard cells around the stomatal opening will be swollen so that the pore is open.
But if there is a scarcity of water, the plant will close its stomatal opening. The guard cells will shrink, thus closing the stomatal pore to prevent loss of water by transpiration. This is done to conserve the water available for the plant.
3] As the stomata close to stop transpiration and conserve water, the exchange of CO2 and O2 is also slowed. We know that CO2 and water are essential for photosynthesis, so lack of availability of these will automatically slow down the process of photosynthesis.
4] The tropical regions ae ideal for plant growth and maximum rate of photosynthesis throughout the year. In the tropical areas, there is plenty of rainfall and the temperature is warm, ranging from 30 to 45 degree Celsius. This warm and moist climate promotes maximum plant growth and a wide variety of animal life in the region.
The forests of this region are the tropical rain forests. The world's most dense forests grow in this region. Several tiers of vegetation are found here. There is a lush forest cover, called canopy, which is followed by a layer of understorey formed by shorter trees. The forest floor is covered by a thick undergrowth. Animals are found at every layer of the rain forests as there is an abundance of food and places to hide for the animals. The ideal conditions make the rain forests the richest and the most diverse areas in terms of flora and fauna.
The rainforests are important not only because they support and sustain a diverse animal life but also because they act as the 'lungs' of the earth. They help in maintaining the balance of CO2 and O2 in the atmosphere, keeping pollution levels and greenhouse gases in check. Besides this, they also cause rainfall due to the clouds which are formed by the water vapor evaporated by these trees through transpiration. These forests help to increase the groundwater levels too by holding back the rainwater and facilitating their seepage through the soil. In short, rainforests play a major role in water-cycle and in maintaining a balance between CO2 and O2 levels in the atmosphere.
5] If the rainforests burn, the level of CO2 and O2 in the air will be affected adversely. The level of CO2 in air will increase as the process of photosynthesis will be affected due to less number of trees. The level of O2 will fall down as a direct consequence of the slowing down of photosynthesis.
Since it is not wrong to call the rainforests as the 'lungs of the earth', burning down of these trees will raise the level of greenhouse gases in the atmosphere.
6] Besides conserving the rainforests, all the countries falling in the tropical belt need to carry reforestation and afforestation on a huge scale.
While reforestation means replanting trees in those areas which have been deforested, afforestation means bringing new land areas under forest cover.
As the forest cover on the earth will increase, a lot of adverse changes in the climate and the environment will be corrected. More forests will mean less pollution in the air, as the trees will absorb the CO2 and replace it with O2 by the process of photosynthesis.
CO2 traps the heat radiated by the earth, thus increasing the temperature. If CO2 is within limits this problem will not exist and this is only possible if there are enough trees to use the CO2 for photosynthesis.
Thus conservation and protection along with rejuvination of the rainforests is absolutely essential to counteract the dangers of global warming.
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.