My blog is lacking pictures of late... Here's one of Annie kissing a Stellar sealion at Hornby Island, BC.
Sunday, February 25, 2007
Annie and a Sealion, Kissing
My blog is lacking pictures of late... Here's one of Annie kissing a Stellar sealion at Hornby Island, BC.
Thursday, February 15, 2007
In Response to Reid
Pour la version française de mon blog, visitez ce lien.
I want to respond to Reid, who posted a very thoughtful response to my last blog. He raises a few very important points, and I thank him for bringing them up. Here is my reply…
Pesticides are Not Evil
First, I realized from reading his comments that I need to qualify my position on DDT, lest it be misunderstood. I hope I was not perceived as “jumping on the bandwagon” and promoting a strictly evil perception of pesticides. I am not advocating a complete ban on pesticides. DDT and other pesticides are needed to control insects, most notably malaria. Furthermore, agriculture simply could not produce as much unspoiled food as it does without the use of pesticides and herbicides. However, the important point is that we must use these chemicals responsibly, because once released into the environment, they do not decay easily and they influence the ecosystems in which they are released. In addition, insects WILL develop a resistance to any pesticide we use, so responsible use is necessary to ensure that pesticides will work when we really need to defend ourselves against a bug invasion.
How Do I Know What I Know?
Ok, onto the question of whether DDT is benign or whether it really causes physiological effects in animals, most notably birds and mammals. First, by pointing out the references that he did, Reid is providing me with an excellent opportunity to talk about the importance of SOURCE of information. You cite a report from the American Council on Science and Health. Is this organization impartial? Who are they? Who sponsors this organization? In fact, I had never heard of them before, so I did a bit of research and discovered that this organization receives a significant portion of its funding from the chemical and pharmaceutical industry. Knowing this, how much credibility do you want to ascribe to their reports? As for the webpage whose link Reid provided, it is a person’s personal webpage, expressing this person's opinion. He is entitled to them, and he makes a case for them, but personally, I prefer to go to government-sponsored sources of information, preferably peer-reviewed, when I seek impartial information. Websites you may want to consider to research health information are the National Institutes of Health (NIH), which is the US’s foremost health research agency, Pubmed which is a database of most of the published, peer-reviewed health research ever produced (it is maintained by the NIH for the scientific community), and the World Health Organization (WHO), which is the United Nation’s agency for health. Researching these sites, I think you will find little doubt that DDT is linked to thinning of eggshells, and that while it has never been conclusively demonstrated that DDT causes cancer in humans, it has been shown to cause it in other mammals (Find the NIH report HERE). From this information, I have decided that we should be careful about using DDT without restrictions.
Climate Change, DDT, Cigarettes, and Other Controversial Issues
On the grandeur question of which information you should be listening to when you are bombarded with often contradictory information, sometimes from several trustworthy sources… well, that is the world we live in, isn’t it! People have been examining the evidence for and against global climate change for at last 40 years and not being able to reach any decisive conclusion… but now, the evidence seems to be finally swaying in one direction. The responsibility of an educated person in the 21st century is to be mindful of the credibility of the sources of information one gets, to weigh the evidence from those sources that are trustworthy, to make your mind based on the evidence presented, and finally, to keep an open mind, if new evidence challenges your previous decision. That sort of flexibility and critical thinking is what’s needed to lead a judicious life in the 21st century.
Reid: A Critical Thinker in the 21st Century
Reid - I hope this answers your questions and concerns. Thank you again for bringing this up. This was an excellent question (triggered by your own critical mind!), and I will be expecting more of these from you and others in the future!!! :)
I want to respond to Reid, who posted a very thoughtful response to my last blog. He raises a few very important points, and I thank him for bringing them up. Here is my reply…
Pesticides are Not Evil
First, I realized from reading his comments that I need to qualify my position on DDT, lest it be misunderstood. I hope I was not perceived as “jumping on the bandwagon” and promoting a strictly evil perception of pesticides. I am not advocating a complete ban on pesticides. DDT and other pesticides are needed to control insects, most notably malaria. Furthermore, agriculture simply could not produce as much unspoiled food as it does without the use of pesticides and herbicides. However, the important point is that we must use these chemicals responsibly, because once released into the environment, they do not decay easily and they influence the ecosystems in which they are released. In addition, insects WILL develop a resistance to any pesticide we use, so responsible use is necessary to ensure that pesticides will work when we really need to defend ourselves against a bug invasion.
How Do I Know What I Know?
Ok, onto the question of whether DDT is benign or whether it really causes physiological effects in animals, most notably birds and mammals. First, by pointing out the references that he did, Reid is providing me with an excellent opportunity to talk about the importance of SOURCE of information. You cite a report from the American Council on Science and Health. Is this organization impartial? Who are they? Who sponsors this organization? In fact, I had never heard of them before, so I did a bit of research and discovered that this organization receives a significant portion of its funding from the chemical and pharmaceutical industry. Knowing this, how much credibility do you want to ascribe to their reports? As for the webpage whose link Reid provided, it is a person’s personal webpage, expressing this person's opinion. He is entitled to them, and he makes a case for them, but personally, I prefer to go to government-sponsored sources of information, preferably peer-reviewed, when I seek impartial information. Websites you may want to consider to research health information are the National Institutes of Health (NIH), which is the US’s foremost health research agency, Pubmed which is a database of most of the published, peer-reviewed health research ever produced (it is maintained by the NIH for the scientific community), and the World Health Organization (WHO), which is the United Nation’s agency for health. Researching these sites, I think you will find little doubt that DDT is linked to thinning of eggshells, and that while it has never been conclusively demonstrated that DDT causes cancer in humans, it has been shown to cause it in other mammals (Find the NIH report HERE). From this information, I have decided that we should be careful about using DDT without restrictions.
Climate Change, DDT, Cigarettes, and Other Controversial Issues
On the grandeur question of which information you should be listening to when you are bombarded with often contradictory information, sometimes from several trustworthy sources… well, that is the world we live in, isn’t it! People have been examining the evidence for and against global climate change for at last 40 years and not being able to reach any decisive conclusion… but now, the evidence seems to be finally swaying in one direction. The responsibility of an educated person in the 21st century is to be mindful of the credibility of the sources of information one gets, to weigh the evidence from those sources that are trustworthy, to make your mind based on the evidence presented, and finally, to keep an open mind, if new evidence challenges your previous decision. That sort of flexibility and critical thinking is what’s needed to lead a judicious life in the 21st century.
Reid: A Critical Thinker in the 21st Century
Reid - I hope this answers your questions and concerns. Thank you again for bringing this up. This was an excellent question (triggered by your own critical mind!), and I will be expecting more of these from you and others in the future!!! :)
Sunday, February 11, 2007
Eagles and Valentine's Day - the DDT Connection
Allow me to attempt a tour de force and link the subject of the last blog entry, bald eagles, with the holiday on everyone’s mind this month (whether you want to admit it or not), Valentine’s Day.
DDT is the Link
The 1950s were blessed with a wonderful new chemical called DDT (Dichloro-Diphenyl-Trichloroethane), which killed every insect known to man, and hence could be used in a myriad of industries from agriculture to head lice treatments. Unfortunately, like everything that seems too good to be true, DDT turns out to be… well, let me put it to you this way: its use is now completely banned in North America. The red flags were first noticed when the number of bald eagles started dwindling in the United States. Pretty soon, the link was explained: DDT causes thinning of eggshells, and hence lost eagle clutches. The eagle population was nearly decimated, but luckily the problem was caught in time, DDT banned, and eagles are now rebounding.
DDT Affects Sexual Behaviour, Too!
But wait – DDT had other interesting effects on animal development and behaviour. It turns out that DDT is mistaken for estrogen (the “female sex hormone”) by the body of many animals. On a strongly DDT-contaminated site in California, male gulls developed oviducts (typically a female reproductive organ). Many males also failed to engage in reproductive behaviour, and the scarcity of reproductively competent males meant females had few males to help them rear their young. As any single-parent will tell you, it is difficult to do it all on your own. To solve this conundrum, some female-female pairs arose to care for the young, the so-called “lesbian gulls”. (Ref.: Fry & Toone, 1981). If you think that’s unexpected, check out this BBC article about a similar environmental pollutant that is transforming polar bears into hermaphroditic mammals (having both male and female sex organs!).
Your Woes?
DDT takes a long time to decay in the environment, and while it has been banned since 1972 in the United States, it can still be detected in most of our bodies (yes, YOUR body too – In fact, 4 prominent Canadian politicians were recently tested for pollutants in their bodies and found to be “contaminated” (link to the CTV report HERE). DDT is thought to affect the reproductive behaviour of many amphibian, reptile, bird, and mammal populations, but the big question on everyone’s mind is: Is it affecting OUR sexual development and behaviour?
Are Men Becoming Extinct?
In the recent movie Children of Men, the human species has become infertile, leading to hopelessness and the collapse of civilization. Is this science-fiction or a preview of things to come (yikes!)? The incidence of cryptorchidism in human males (a condition where the testes fail to drop after birth – a vital development since the testes need to be at a slightly lower temperature than the body to ensure the sperms’ survival) appears to be on the rise, more than doubling since the 1950s (Ref.: Carlsen et al., 1992). Testicular cancer has tripled in the last 50 years (Ref.: Giwercman & Skakkebaek, 1992). Sperm count also appears to be declining across the board in all human populations (Ref.: Carlsen et al., 1992). Whether the environmental estrogen mimics are causing these alarming trends is a matter of some debate, but it is one that needs to be resolved soon!
Of Eagles of Men
DDT almost wiped out eagles from the face of this planet, and it is possible that the same thing is happening to us now. More studies are required, but evidence is accumulating that environmental pollutants affect sexual behaviour in many animal species. Humans are part of this biosphere – we cannot escape it. So this Valentine’s Day, as you celebrate the fact that your sexual behaviours are still intact, take a moment to ponder that every chocolate you eat may contain traces of DDT…and may be altering the behaviour you will display in future Valentine’s Day…
DDT is the Link
The 1950s were blessed with a wonderful new chemical called DDT (Dichloro-Diphenyl-Trichloroethane), which killed every insect known to man, and hence could be used in a myriad of industries from agriculture to head lice treatments. Unfortunately, like everything that seems too good to be true, DDT turns out to be… well, let me put it to you this way: its use is now completely banned in North America. The red flags were first noticed when the number of bald eagles started dwindling in the United States. Pretty soon, the link was explained: DDT causes thinning of eggshells, and hence lost eagle clutches. The eagle population was nearly decimated, but luckily the problem was caught in time, DDT banned, and eagles are now rebounding.
DDT Affects Sexual Behaviour, Too!
But wait – DDT had other interesting effects on animal development and behaviour. It turns out that DDT is mistaken for estrogen (the “female sex hormone”) by the body of many animals. On a strongly DDT-contaminated site in California, male gulls developed oviducts (typically a female reproductive organ). Many males also failed to engage in reproductive behaviour, and the scarcity of reproductively competent males meant females had few males to help them rear their young. As any single-parent will tell you, it is difficult to do it all on your own. To solve this conundrum, some female-female pairs arose to care for the young, the so-called “lesbian gulls”. (Ref.: Fry & Toone, 1981). If you think that’s unexpected, check out this BBC article about a similar environmental pollutant that is transforming polar bears into hermaphroditic mammals (having both male and female sex organs!).
Your Woes?
DDT takes a long time to decay in the environment, and while it has been banned since 1972 in the United States, it can still be detected in most of our bodies (yes, YOUR body too – In fact, 4 prominent Canadian politicians were recently tested for pollutants in their bodies and found to be “contaminated” (link to the CTV report HERE). DDT is thought to affect the reproductive behaviour of many amphibian, reptile, bird, and mammal populations, but the big question on everyone’s mind is: Is it affecting OUR sexual development and behaviour?
Are Men Becoming Extinct?
In the recent movie Children of Men, the human species has become infertile, leading to hopelessness and the collapse of civilization. Is this science-fiction or a preview of things to come (yikes!)? The incidence of cryptorchidism in human males (a condition where the testes fail to drop after birth – a vital development since the testes need to be at a slightly lower temperature than the body to ensure the sperms’ survival) appears to be on the rise, more than doubling since the 1950s (Ref.: Carlsen et al., 1992). Testicular cancer has tripled in the last 50 years (Ref.: Giwercman & Skakkebaek, 1992). Sperm count also appears to be declining across the board in all human populations (Ref.: Carlsen et al., 1992). Whether the environmental estrogen mimics are causing these alarming trends is a matter of some debate, but it is one that needs to be resolved soon!
Of Eagles of Men
DDT almost wiped out eagles from the face of this planet, and it is possible that the same thing is happening to us now. More studies are required, but evidence is accumulating that environmental pollutants affect sexual behaviour in many animal species. Humans are part of this biosphere – we cannot escape it. So this Valentine’s Day, as you celebrate the fact that your sexual behaviours are still intact, take a moment to ponder that every chocolate you eat may contain traces of DDT…and may be altering the behaviour you will display in future Valentine’s Day…
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