World of Change: Global Temperatures
Mean temperatures are rising – these may result in physiological and ecological effects on living organisms. Describe and explain these effects.
Rising global temperatures, due to an increased concentration of greenhouse gasses in the atmosphere, are likely to have enormous consequences on many, if not all, species. Although the effects may not be direct potential outcomes include: loss of habitat, reduced species diversity, disturbed food chains and weather cycles, denaturation of enzymes.
One of the biggest potential issues of global warming is causing a rise to sea levels. Low-land countries and cities (e.g: Venice) are likely to become frequently flooded. This means the habitat changes and organisms whose niche is not specific to the new conditions are likely to either move away from these environments or die – this is most likely to happen to terrestrial animals. This is likely to have a massive consequence on both the ecology and the economy in that location.
The loss of species could have wide-spread effects on food chains. Reduced food for some organisms means those lower on the trophic level will die out (the effects of rising sea water will affect smaller organisms the most!). Therefore, the numbers of top predators will also fall. In terms of the economy, many countries are famous for specific dishes or nature reserves. If the beauty of these nature reserves, or the availability of the animals for the specific dishes is affected this could significantly reduce the number of tourists to that country.
Rising temperatures could have a more permanent effect on food webs world-wide. Most organisms are adapted to a specific niche and will be unable to adapt to changing environments. Organisms living in extreme environments will be affected most. The loss of their habitat could lead to species extinction.
It is a known that if air currents above the sea are above 25oC (or thereabouts) then hurricanes and tornadoes are more likely to occur. These hurricanes and tornadoes could have devastating effects on the economy of many countries. Increasing global temperatures, however, can also affect the ability to grow crops in certain areas. Plants that require cold conditions could die out completely and plants requiring warm (but not hot) conditions will be able to be grown in countries not thought possible!
Pathogens such as bacteria and viruses thrive at higher temperatures (they reproduce fastest at high temperatures). As global temperatures rise, the spread of disease is likely to increase. If the disease spreads to crops this is likely to adversely affect yield.
Despite all this bad news, photosynthesis and respiratory rates are likely to increase due to increased activity of enzymes. This could result in an increased yield of crop which is a great bonus. These increased rates will be matched by faster diffusion and active transport rates. Thus plants will be able to take up the required nutrients and minerals more quickly, again increasing the yield!
A major physiological effect will be on proteins. All proteins have an optimum temperature. As temperatures rise, ectothermic organism who are unable to control their core temperature, are the most likely to be affected first. Rising temperatures could cause Hydrogen bonds to break thus the tertiary structure of these proteins will change. These changes could render the proteins useless as they are no longer specific to their original needs. Thus organisms could have difficult in digestion (enzymes denatured), cell division (controlled by proteins) and hormonal control (hormones are proteins).
