Weekly Update #3: High levels of organochlorides may affect hatching sex ratio in glaucous gulls

I talked about this study some during my presentation today but I thought I would give you all the information on this study because I though it was really cool. In my paper I talk about how poor maternal condition can lead to largely skewed sex ratios. When a mother is in good condition, she is generally able to produce the sexes equally. However, when the mother is in poor condition she produces more of the sex that is least taxing on her body, is better able to sustain itself in harsh environments, or reaches sexual maturity soonest. 

I found a study on the condition of the female glaucous gull and how its condition affects its offspring. First, because of changing ocean currents a large amount of organochlorides have been introduced into the food-webs of the glaucous gull. The organochlorides are harmful and therefore result in an overall decrease in the health of the mother. Mothers with low levels of organochlorides in their body are able to produce equal amounts of male and female offspring. However, mothers with high levels of organochlorides in their body produce many more female offspring than male offspring. This makes sense because glaucous gulls are size dimorphic, so the males are much larger than the females and therefore more taxing on the female body to produce. Therefore, when her health is compromised it would make more sense for her to produce viable females than to produce males that she cannot adequately give the resources to, resulting in low fitness males. 

This goes along with one of my other something interesting blogs about how more female offspring are produced in high stress, unhealthy conditions in the human species as well. I think its so interesting that females in both species produce more females than males when their bodies are in poor condition.

To read the whole article here is the citation:

Erikstad, K., Moum, T., Bustnes, J. O., Reiertsen, T. K. 2011. High levels of organochlorines may affect hatching sex ratio and hatchling body mass in arctic glaucous gulls. Functional Ecology, 25(1), 289-296. 


Weekly Update 11/25-12/1

Hope everyone had a wonderful Thanksgiving break! I must say, for most of this week I took full advantage of the break and ate way too much food and took way too many naps! But I did do some senior sem because my presentation is tomorrow! I can’t believe it’s already here! I’m really excited to get to share with the class all the research I’ve found on the topic because I’ve really enjoyed hearing about all the hard work everyone has put into their chapters! This week I’ll be putting the finishing touches on my paper and trying to make it perfect for the book! Can’t believe this semester is coming to a close! 

Weekly Update 11/18-11/24

Sorry this is a day late… Physics test (you guys know how that goes)! Anyways, this week I got feedback on my first draft so I’ve been working on fixing format problems, grammar issues, and adding in things where my paper is weak. I am adding in a paragraph about the Trivers-Willard hypothesis that I am super excited about and I think it is going to make my argument a lot stronger. Basically, I am introducing the hypothesis sooner and giving a lot more information on it because it is really important to my argument and I think will make the direction of argument more clear. I am also working on a new conclusion, and in the conclusion am going to talk about how humans fit into the Trivers- Willard hypothesis and follow animal species when it comes to sex ratios. I’m hoping these changes really pay off and make my argument stronger.

Can’t believe we only have one week left! Happy Thanksgiving to everyone! 

Weekly Update 11/11-11/17

This week I realized that I had completely forgotten about the something interesting blogs. So, I’ve been working on getting up to date on those. I’ve posted two so far that I think are pretty cool if you all want to check them out:)

I’ve also been working on putting together my power point for my presentation. I’ve been trying to figure out what info to include and what info I can take out and choosing is actually a lot more difficult than I expected. I just want to include it all haha! I do have a couple of question about images on the slides though:

Does anyone know how to get the figures from the PDF’s onto powerpoint? and if we have random pictures from google do we have to cite those too? ANY help or tips on this would be awesome! 

Hope everyone’s papers and presentations are coming along great! 

Something Interesting: Skewed sex ratios result from maternal condition in humans

In many animal species it has been found that poor maternal condition can lead to skews in the sex ratio. A study by Navara in 2010 about abnormal sex ratios in humans found that significantly fewer males are produced after severe environmental stress. The study found that nine months after the Kobe earthquake hit Japan in 1995, there was a decline in the number of male babies born in Japan. Although, the total number of babies decreased, the ratio of females to males was greater. Similarly, 11 months after an earthquake hit Iran, there was a decrease in the number of males born. Significant natural disasters, such as these earthquakes, are linked to increased cortisol levels as well as changes in food consumption. Also, during times of economic depression there are skewed sex ratios towards females. For example, in Germany after World War II where there was extreme economic depression, there were many more females than males born. Again, because of stress and lack of resources the females were in very poor health. So, periods of extreme stress severely compromised the health of the mothers and led to significantly more males that females.

I think this is so interesting and crazy that stress can cause changes in the sexes of even human offspring. We can easily see how stress and malnutrition affect our own bodies but we don’t think about how they can affect our offspring. If there was some kind global disaster, the effects on the next generation could be outrageous. Just thought this was something really weird and cool to think about!

 If want to read the full article just put this into google scholar:

Navara, K. J. 2010. Programming of offspring sex ratios by maternal stress in humans:
              assessment of physiological mechanisms using a comparative approach. Journal of
             Comparative Physiology B, 180(6), 785-796.


Something Interesting: Male Billionaires on the Forbe’s Billionaire List Skew Sex Ratios Towards Male Offspring

First off, I can’t take full credit for this really cool source because Dr. Bray actually sent me this but it’s too cool not to share!

There is a well known hypothesis called the Trivers-Willard hypothesis which states that natural selection should favor parents who selectively bias the sex of their offspring to improve their own fitness. A study looking at this hypothesis in humans used a very interesting group of people as their subject, billionaires from the Forbe’s wealthiest people. The study found that male billionaires have 60% sons versus the 51% sons that the rest of the populations has. The study also showed that the billionaires had more grandchildren from their sons than from their daughters. So, skewing the offspring sex ratio in favor of sons is a huge reproductive advantage. Also, if billionaires had both male and female children they put more of their resources into their male children because males rank higher on the list of wealth than females. What really makes this article interesting is that female billionaires do not skew the offspring ratio towards males but have about an equal number of sons and daughters. So, the advantage of having male children for female billionaires must not be as great and in fact women often have more control over the success of their daughters than they do of their sons. 

Just though this article was awesome because the same thing that tiny bugs, birds, furry animals, and  really every species on the planet is doing to enhance their fitness is exactly what the richest people on the planet are doing! 


Here’s the citation for the full article ( if you put this in google scholar it will come up):

Cameron, E.Z., Dalerum, F. 2009. A Trivers- Willard effect in contemporary humans: A male biased sex ratio among billionaires. PLoS One, 4, 1-4. 


Weekly Update: 11/4-11/10

I turned in my first draft on Friday, wohoooo!!! I must say I am so so so excited to be one step closer to finishing the paper. Having finished the first draft, I am really excited about how the final paper is going to turn out. I added in information where my argument was weak and really tried to add my perspective into the paper and make a strong argument. I know that there is always room for improvement though so I’m looking forward to getting my feedback so that I can improve it even more. I am hoping that the conclusion works and that the paper is clear! 

This week I am going to work on putting together my presentation and then once I get my corrections back am going to work on putting together my final draft. 

Hope everyone’s is coming along great! 

Weekly Update 10/28-11/3

I cannot believe that my first draft is due this week! It seriously feels like just yesterday I was panicking because I couldn’t decide what I wanted to write about. Now, there has been so much time, effort, and research that have gone into my topic and I am really excited about watching it all come together! This week I have worked on strengthening the weak parts of my annotated outline. I’ve been filling in the little holes in my research and now am working on putting it all together in the first draft. I have written my introduction and now am working on my body paragraphs and creating the connections between my research and my thesis. I am just a little worried about what to do with my conclusion. So I’m hoping that this coming week while I’m working on my paper I have a revelation and think of what to do with the conclusion. Here’s hoping! 

Weekly Update October 21 – October 27

This past Monday I turned in my annotated outline. After receiving my feedback from Dr. Bray I have been working on touching up the weak parts in my outline. I have been adding more examples to the section on human skewed sex ratios to further develop my argument that when there are skewed sex ratios, whether they are caused by environmental stress or selection, the consequences on human and animal populations are the same. I am also working on finding more sources that support my argument that skewed sex ratios cause populations to be less efficient in utilizing resources. Once I am done touching up the weak parts of annotated outline, I will start writing my first draft. I am hoping to get a really good start on my first draft this week!

If you are reading this and are in my group for tomorrow: Will you take a look at the section on consequences for animal populations with skewed sex ratios and human skewed sex ratios; Do these sections mirror each other? Are there parts that are stronger in the section on animals vs. the section on humans?

Also, will you look at the conclusion section: what do you think about discussing the global consequences here? Does it fit or should I focus on something else?

I’m really excited to get group feedback tomorrow and apply the feedback I get to writing my first draft this week!

Weekly Update 10/14-10/20

This has probably been my most productive week by far! I met with Dr. Bray and worked a lot on coming up with a structure for the last two paragraphs that made it easy to see the similarities between skewed sex ratios in animals and humans. By setting it up this way it also helps me make some strong predictions and base those predictions for the human population off of the research on animals. I’ve also worked on taking a stronger stance in my thesis. THis has really helped me to set up my paper with a logical flow and a goal for what I want the reader to get out of the paper. My outline is due today so I am putting the final touches on it and then am ready to get working on my first draft this coming week!