Zoo Animals

Well good news is that I picked up some juvenile virgin males at the zoo. Now I am waiting for some juveniles to molt. Basically, I have 8 virgin females and I have 16 males. Soon, I should be able to run one trial run. I will mate two sterile males to one female. Then I will vary the number of intromissions allowed which will be a 1 to 5 first to second male ratio. Then I will do the same two manipulations for the other groups (the 1st sterile, 2nd fertile & 1st fertile, 2nd sterile & 1st fertile, 2nd fertile). Then I should have some data hopefully. The idea is to be able to manipulate number of sperm so that we can control priority pattern. Usually, in this species, the first male has the advantage because he plugs up the female. However, we are not allowing the male to form a plug. Therefore, if there is sperm mixing going on in the female's spermatheca (storage sac), then we should be able to influence the priority pattern. We also sat down and dissected a female the other day and the storage sac is perfectly round, which would seem to facilitate sperm mixing. The other hypothesis is that priority pattern is determined by placement of sperm (location in the spermatheca). I am excited and hope that this first run goes well.

Baby Spiders

Well lost another male to a voracious female the other day!! Oh, well. Anyways, I have finally figured out how to rear my spiderlings successfully! I have isolated them in screw cap vials. I feed them about once a week with a knat-like insect. These babies are about the size of your pencil point and they spin the much larger insect up in their web. It is pretty phenomenal! I should be doing some more collecting at the zoo with Dr. Christenson on Friday. Hopefully, I will be able to ask him some questions about the experimental design. More to come about the project after Mardi Gras...

JV Ch.3 in class

I really liked the way we worked on Chapter 3 in lab yesterday. It was extremely helpful to be able to target one problem and do it well. Then we could even move onto others if we finished. I thought that everyone presenting a problem was very helpful because everyone brought a different way of doing things. I feel like I learned so much more about UsingR in this week's session versus in the past. Keep it up Mike!!

Floating Islands

I am taking a Primate Behavior and Ecology course this semester, which has so far been really interesting. I am learning about the differences between apes and monkeys and all that jazz. New World monkeys or platyrrhines diverged from Old World monkeys about 35 mya, but South America split off of Africa much earlier around 100 mya. The earliest fossils were established 26 mya in the New World probably because fossils do not form as well in wet, tropical climates. The real question is: How did the platyrrhines get to South America? The best supported hypothesis is by rafting across on islands of floating vegetation.

A study by Alaine Houle was conducted to examine the effects of wind velocity and direction as well as current velocity and direction on the number of days that it would take take to cross a water barrier during the Paleogene. Very simple summary statistics were used like in G&E Chapter 3 like mean, variance, and standard deviation. Conclusions were that around 40 mya, it would have taken about 11 days to cross the Atlantic Ocean at a most conservative measurement. The shortest measurement was 7 days. In this light, this theory does not seem all that implausible because the survival limit of monkeys has been estimated to be 11-15 days. Rafting earlier would also have decreased the amount of time. It is likely that monkeys could survive this trip and find enough food on the island to sustain them for two weeks. Now, what sort of population size would be needed, I have no idea. But imagine that Houle did this study with just summary statistics!! By the way, the link is http://www.jstor.org/view/13669516/di005208/00p0189i/0.

Warming

I have been taking this ecosystem ecology class this semester, and we have been talking a lot about global warming. Apparently, the concentration of carbon dioxide in the atmosphere has risen 30% since the Industrial Revolution. It is around 380 ppm. Just for reference, the glacial maximum concentration of carbon dioxide is 180 ppm, while that of an interglacial period is 280 ppm. Scientists have gotten these measurements by directly measuring the carbon dioxide concentration from the Vostok ice core. Then they have manipulated this data to somehow look at the flux of temperature over millions of years ago. How they do this, I am not really sure. It seems like an unbiased statistician would have to take into account the natural cycles instead of just human impact. The temperature rise should not be solely based on the rise in carbon dioxide concentration because in the past great changes in climate have taken place before humans. Anyway, just a thought. I was just trying to think of ways to be less biased about global warming because a lot of people seem to think that ecologists have an agenda.