On pages 38-39, Carroll says “Living for the moment has the dangerous disadvantage that if circumstances change more rapidly than adaptations can arise, faster than the fittest can be made, populations and species are at risk.” Is it possible with this greenhouse effect that is going on in today’s society that carbon dioxide gas will kill off humans before they adapt to have a greater affinity for oxygen? How long could such an adaptation take place? On this note, do people living in higher altitudes that are used to breathing in thinner air already have a an adaptation in their genes for a greater affinity for oxygen gas than people on sea-level ground, or are they simply used to it.
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Humans, like all other organisms, are still susceptible to quick changes in the environment. Carroll states, “as circumstances have changed, globally or locally, many eras’ fittest have been replaced” (39). He uses the example of icefish that have adapted to extremely cold water conditions They have lost capabilities in the process of abandoning a warmer lifestyle and these cannot be gained back. Biologists have found that air temperature in the Antarctic Peninsula has risen by 4 to 5 degree F in the last fifty years and both air and water temperatures are expected to rise dramatically. When this occurs, many cold adapted species like the icefish will not be able to adapt fast enough to to drastic climate changes. While evolution has allowed for many advantageous traits in organisms, the rate of evolution doesn’t compare to the rate that conditions are changing on our planet.
ReplyDeleteCO2 production from increased industrial activity and other human activities such as cement production and tropical deforestation has increased the concentrations in the atmosphere. Measurements of CO2 from the Mauna Loa observatory show that concentrations have increased from about 313 ppm in 1960 to about 375 ppm in 2005. While green technology and reducing carbon emissions has been promoted in recent years, our society is still heavily dependent on the burning of fossil fuels and other environmentally destructive actions in order to function. Without drastic change in our industries and daily lives, CO2 increases and the subsequent temperature increases will affect every living organism. At first, climate changes will affect certain populations more drastically than others (ex: cold adapted species) but then later, changes in these populations will drastically alter food chains and predator/prey interactions.
People living on higher altitudes do not necessarily have a selective advantage in their genome as compared to people living in lower elevations because oxygen affinity can be increased without relying on evolution. For example, climbers preparing for a long journey up a mountain often prepare by altitude acclimatization; this process takes them up the mountain days before their real hike in order to gradually adjust their lungs to decreases in oxygen. Oxygen affinity doesn’t solely rely on ones genetic traits. However, it would take hundreds of years for humans to develop a trait for increased oxygen affinity because as Carroll states, changes to the genome are not rapid by any means; evolutionary time is much longer than the scale of time than humans are used to thinking about.
http://books.google.com/books?id=jDkfPYF-gNYC&printsec=frontcover#PPA99,M1
http://en.wikipedia.org/wiki/Greenhouse_effect
http://74.125.95.132/search?q=cache:PVeaQ_Q-hlAJ:www.aiaccproject.org/meetings/Dakar_04/STAKEHOLDER%2520PAPERS/Lesolle.doc+global+warming+human+adaptation&cd=3&hl=en&ct=clnk&gl=us
ReplyDeleteAdaptation is something all organisms must go through to survive different challenges and, a lot of times if they face the same stress for long periods of time it will lead to evolution and complete change into a new organism. This means that as different ages in the world come and go, it creates new levels of the fittest that replace the old and they then find their niche in the environment. With the increase of CO2 levels in the environment, it means the concentration of O2 in the air decreases. However, in the long term the total amount of O2 actually increases. This happens because as more CO2 comes along, it allowed for more photosynthesis to be happening. One large byproduct of photosynthesis is O2 which will help try to keep the levels and concentration at the same level, and the majority of the organisms on earth go through with photosynthesis. The increased CO2 production has come about from the industrialization of the world, and the burning of fossil fuels to help in the process of doing this. The byproduct of many fossil fuels is CO2 being released. The first noticed spike was in the 1850’s-1900. It then leveled off and not being thought of as much until the car became affordable. Then as so called inferior countries are catching up to the world, they also demand the use of many of the fossil fuels and it will then increase further CO2 levels. To further compound the amount CO2 in the atmosphere, humans are going through a so called genocide by deforestation of many large tropical forests. This reckless care leads to less CO2 consumption; less O2 produced meaning less affinity for oxygen. Compared to prehistoric times, the level of oxygen in the earth's atmosphere has fallen by over a third and in polluted cities the decline could be more than 50 percent. Meaning that humans are losing their source of oxygen at a drastic rate. The oceans and especially the phytoplankton, which are the worlds largest producers of O2 and consumers of CO2 has declined. The concentrations of phytoplankton dropped 30% since the 1980’s, and nobody knows how much loss was before and since the start of the industrial revolution. Now beside the fact that we have lower concentrations of oxygen this increased industrialization has led to the degrading of the ozone layer, and has happened because of Chlorofluorocarbons (CFC). They are the main component that leads to it increasing ozone degregation. Then with the increase of CO2, which is a green house gas, it will trap the heat of UV rays and increase global temperatures. This then will lead to polar icecaps melting to increase water levels, air temperature will increase, and water temperature will increase. The icefish and its closest relatives will not be able to survive because the increase in the water temperature. They have completely adapted to life in coldwater, because as water is colder the oxygen molecules come together and are more closely compacted together. Due to this fact they lost their heme gene which is very important in oxygen affinity and collecting oxygen. If temperatures increase to where they won’t be able to survive because oxygen has become more scattered, this means that they won’t be able to make a change back to a warmer environment because they completely lost their gene.
ReplyDeleteLike the icefish, humans can also be facing a problem in the environment unless drastic changes are made in our energy demands and how we will be able to meet them. For the past millions of years the level of O2 has been decreasing, but at a constant rate those humans and many organisms were able to adapt. This is not the case with the last two centuries, where the level O2 has decreased more drastically then has ever been known. I think that with many green and helping the environment cases going around, levels will never get bad enough to kill of humans. I also feel that if cases did start to become that bad, humans would find an answer through some invention that will help create more oxygen. Humans are innovative people and the fact that we have many of these tools and abilities to adapt to almost any situation; it will not lead to the demise of humans. If nothing was made, however, I think people living in higher altitude areas will be affected just as much, because bodies are made to consume certain amounts of oxygen. I think the people living higher altitudes are just adapted to that level of affinity and will have a better chance to live, but in the end there bodies will need certain amounts of oxygen. For humans to evolve will need to take long amounts of times, and their process must become more efficient, or the energy demands of a human must be reduced drastically. For this to happen it will need to take hundreds if not thousands of years, for a process that is able to live to be efficient and able to provide life for humans. I also believe for this to happen, there need to have the chance or real natural selection which means humans inventions and things that help humans out to be stopped because it limits natural selection.
http://www.chinadaily.com.cn/world/2008-08/15/content_6937226.htm
http://www.c-f-c.com/supportdocs/cfcs.htm
Humans just like the other species have to adapt to the environmental changes that are being brought on by primarily our mistakes. The essence of global warming is scary to think about as our land masses have been shrinking due to the increase of temperature, which is melting the polar caps that are on our north and south poles. The fact that there is a significant increase in the amount of carbon dioxide in the air is threatening to our way of life. In order for us to adapt to these changes, it would take a hundreds of years. The process of natural selection is very is very slow.
ReplyDeleteAs for the people living at high altitudes, they do not have a mutation in their gene which allows for this. It is their adaptation to the climate. Oxygen affinity is not related at all to where a person lives. It is based on where they live. It is due to the increase in hemoglobin. Hemoglobin is a protein that is in the blood that transports oxygen to the body cells and organs, while also transporting the waste carbon dioxide to the lungs where it can be released. For hemoglobin to function properly, the oxygen needs to bind to the oxygen in an oxygen rich environment such as the lungs. It needs to release the oxygen in areas where oxygen is low. This is because of partial pressure. When the carbon dioxide exits the hemoglobin in the lungs, the partial pressure of oxygen is greater on the outside of the hemoglobin. Since pressure goes from hi to low the oxygen rushes into the hemoglobin, binding to the iron, which is in the hemoglobin. When the hemoglobin is being transported to areas where there is less oxygen. The partial pressure of the oxygen is higher in the hemoglobin, and since pressure goes from hi to low, the oxygen rushes out of the molecule and into the oxygen deprived area. Since people that are living in high altitudes have less oxygen in the air, the amount of hemoglobin needs to be increased to carry more oxygen. So, their body creates new hemoglobin molecules, so they can carry more oxygen. This process is called erythropoiesis. Without such an adaptation, maintenance of the arterial oxygen delivery to the tissues would require an increased cardiac output, an energy-intensive response. So, no this would not a mutation in their genes, but an adjustment by the body to assimilate with the thin oxygen. Mutations take time and it goes with natural selection.
Carbon dioxide in the air is really a big issue because of our continued dependence on fossil fuel, and deforestation. The co2 issue needs to be fixed. In the last 40 years our depende on fossil fuel and continued deforestation has increased from 315 ppmv to 385 ppmv. That is almost an 18 percent increase. We need to stress on our dependence on fossil fuel and the amount of co2 emitted.
http://en.wikipedia.org/wiki/Carbon_dioxide
http://en.wikipedia.org/wiki/Hemoglobin
http://www.bio.davidson.edu/Courses/Molbio/MolStudents/spring2005/Heiner/hemoglobin.html