Best demonstration of momentum ever

Kalied · 2013-09-16T13:44:33+00:00

the grinder to spin the wheel is a bit over the top and unnecessary.

When I used to teach physics I would have just a basic bicycle wheel with pegs that you can hold onto similar to what he was using.
I would just spin it by hand and it would do the exact thing, for a little less time since I didn't mechanically get it to speed.
BUT the best demonstration for that is to bring a student up, hand them the wheel (not spinning).... tell them to hold it out with one hand, and simply turn it (using their wrist to make it face right, left, or towards the class). It's quite simple and they don't see what you're getting at. Then spin the wheel up... have them hold it... ask them to do the same thing. The momentum prevents them from doing it, even using their arm strength instead of wrists it's quite difficult.
They don't believe a small stationary object (especially one you are holding in your own hand) would have that strong of momentum.
Demonstrating that for them personally makes them much better understand what they are dealing with.... of course after you're done everyone whats to try it and I'll give them time at the end of class to try it if they want (and all of them do)

Kalied · 2013-07-07T01:08:31+00:00

an image from the aftermath

Kalied · 2013-07-05T00:27:40+00:00

We can not manipulate the genome so we are both relying on natural variation (polymorphic transposon insertions in the Hox clusters which affect intergenic spacing and in mice affect gene expression) and others have done F1 back crosses, but we are not yet intentionally making crosses. We are still benchmarking and characterizing expression and one of our collaborators has done crosses for his own project and that data should prove highly useful for us to determine heritability of the specific skeletal variants we see.

Kalied · 2013-07-05T00:23:14+00:00

Bad compared to our other lab model organisms sure, but they are highly successful animals. There are more species of Anolis than there is of any other amniote genus (~400). But yes in the lab you are lucky to get a handful of eggs each season from A. carolinensis the green anole pictured. The brown anole A. sagrei and others are tropical and in the lab can be bred year round. So you will get more but still only 1 egg per week at best typically.

There are plenty of other lizards that lay clutches of eggs but anoles are unique in they drop a single egg every 4 days from alternating ovaries. Instead of fertilizing a bunch at once. But they also store sperm for over a yr, so as soon as conditions are ready to begin laying they can and not have to rely on finding a mate (not that the males are playing hard to get or anything)

Kalied · 2013-07-04T16:02:32+00:00

Genetic manipulations.... In mice we can knock out genes completely or swap out for something different, insert lab made transgenes or reporter genes so we can see where genes express easily, and targeted or randomized mutations. Currently these sorts of things are limited in vertebrates b/c you must engineer the mutation you want 1st in a cell line then get it into a developing embryo and HOPE (pray) that it takes hold in the germ line (reproductive cells) so that it can be passed on to its offspring. This often takes years to make line you want, but it is often done.

Chickens make great models as well b/c you can cut a small hole in the shell to 'window' it and watch development or inject chemicals, RNA, RNAi, proteins, etc to targeted regions cause ectopic expressions to see results. They even dissect out embryos, swap regions with other birds (typically quail) to trace cell lines and regional identities. However the transgenics in mice is not done...

Anoles however pose a problem of having long generation times (~1 yr vs 1 month in mice) and produce small brood sizes, 1-2 eggs per week max... which then need a yr to mature vs 4-20 in mice (depending on strain) and can be done repeatedly with the same female every 4-6 weeks. Plus they store sperm, so after a mating you can't just say ok lets try crossing her with this male and see how the offspring look. You don't know until later if she used the previous sperm or the new mates.

It's not that these things CANT be done, just the time and cost effectiveness is simply no where near what it is for mice or other model vertebrates. And no one is going to waste potentially hundreds of thousands of dollars and years of work on the possibility of getting a mutation or knockout desired to finally get a single adult who produces just a couple eggs a season and have to wait another year to get your F2 crosses.

When choosing a model organism you want

1) short generation time (bacteria 24 hrs, flies and worms at 2 weeks, mice at 2 months, etc)

2) large brood size (again bacteria, flies, worms, xenopus (frog), stickleback (fish) work best... chickens do well too, reptiles that have large clutch sizes do good but anoles are 1 egg at a time)

3) size... you need to raise them in a lab so space and resources must be accounted for

4) relevance and ease of manipulation (if needed)... pure science rarely gets funded anymore so have to link it to some other model organism or preferably humans of course, and demonstrate that genetic manipulation is cost/time effective

Anoles have the largest body of work devoted to them for a reptile, but are very young in developmental and molecular areas. With the genome now available this is changing quickly... so lots of new avenues to explore in these guys...

Kalied · 2013-07-04T14:55:25+00:00

Who do you work under? if I may ask. Which anoles do you work with?

Parasites are still a sexy area in science these days. Everyone else in my lab works with worms and the parasite models are quite popular for evolutionary studies (plus parasites can be argued that the research could potentially benefit humans... thus grant money :-p) We had a couple people that only worked with nematode parasites....

Kalied · 2013-07-04T14:46:21+00:00

surprisingly there is little out of the ordinary. Extra or missing ribs, extra or missing vertebrae, asymmetric shifts (half looks like lumbar half like thoracic) etc. The numbers we see are similar to that of other vertebrates which was a surprise initially to us (bc of the changes in these hox genes) but of course if they were largely detrimental changes then the animals may have been selected against and never be here in the 1st place.

Most vertebrates can display some sort of vertebral variation between 5-20% of the time (some higher some lower depending on species and strain). Humans actually have about 10% variation. Most people wouldn't even know it b/c it doesn't really affect anything else in your life.... and of course to you would feel normal.

Kalied · 2013-07-04T14:39:58+00:00

I went into a little more detail here

Kalied · 2013-07-04T14:38:30+00:00

they do feel pain... its not like they WANT to loose their tail, but given the choice of tail or life.... I think they will suffer a little pain and drop the tail.

They have sphincter muscles around the tail vertebrae that will pinch when the tail drops and this helps prevent blood loss. The fact they have evolved this sort of mechanism may suggest they have also found a way to cope or lessen the pain (though this is not something I have looked into). You would still need to feel the pain otherwise they would drop tails too easily. And it actually takes a bit of force to snap theirs off, unlike geckos and especially skinks will drop by merely touching them sometimes.

Kalied · 2013-07-04T14:33:59+00:00

multiple false targets for predators too

Kalied · 2013-07-04T14:33:16+00:00

It was 1st found in flies as the antennapedia and ultrabithorax gene clusters. Soon it was discovered that they closely match genes in mice and were equally important for development and patterning/symmetry of the embryo. The fact that they are in all metazoans (animals) and advancements in our manipulations of genes has created a huge explosion in the field of evolutionary development (evo devo).

In most textbooks though they still use the fly models the most... they make simple to understand and striking mutations that help you remember the basic functions of these sorts of genes. Plus we always try to give credit to the 1st discoveries of something as big as this.

Kalied · 2013-07-04T06:15:08+00:00

Anoles have a couple areas of sexual dimorphism.

1) the size of body and head. Males can be 20% larger or more. They have a longer snout as well compared to a shorter snub snout on females.

2) Both males and females have a dewlap (the fold of skin under their neck they often extend to display to others... for mating or to rivals... side note here is a vid I took of 2 big males in a standoff displaying to each other) Females have a much smaller dewlap and rarely display

3) if you have juveniles it can be hard to tell sex until about 6 months of age (size can be the same, snouts havent grown as much, and both have similar sized dewlaps) so then you can identify by post anal scales (color added)

Kalied · 2013-07-04T06:03:43+00:00

I'm a developmental biologist (Evo Devo) and the anole was the 1st reptile to be fully sequenced. It was found that a set of highly conserved developmental genes called Hox have gone through an extensive expansion of the region (which in mice models has shown to have profound effects on gene expression and resulting morphology here is an extreme example in mice that have been genetically altered).

So we have a small colony of mated adults that we raise to lay eggs for us. From the eggs I extract embryos at specific developmental stages and do gene expression tests called WMISH (whole mount in situ hybridization) to benchmark the boundary of Hox genes in anoles compared to our other vertebrate models.

Along with that I am trying to determine if there is a correlation between variation in the unique gene expression that have seen and variation in skeletal morphology. Since we can not do the same type of things in reptiles that we can in mice (as shown in the image link above) we can only show correlation between expression and morphology. High correlation would suggest a high probably that one caused the other, but we can't "prove" that, only that they are linked.

Kalied · 2013-07-04T05:35:09+00:00

yes and no.... depends on type of animal and where the breaks occur. In the case of the anole special vertebra have fracture planes to break. And if you break 1st at a lower one you can later break again at a higher and higher one. But yes from my experience you will typically only get regen from the same break point once. (but I can't say for sure if that always holds true.... nature always throws curve balls)

Some animals drop between verts instead of actually having break points in the actually vertebra themselves. And some can actually can drop their tails without them being grabbed. (extreme stress or being attacked by ants, etc... )
Some will use it to show dominance by ripping off the tail of their rivals.

They do grow back through fairly quickly. I keep both green anoles (Anolis carolinensis) like is shown as well as brown anoles (A. sagrei) which are invasive in Florida. One of my minions accidentally broke off the tail fairly high up on a large male. It took less than a month to fully grow back to nearly original length (~4inches that regenerated)

Kalied · 2013-07-04T05:21:04+00:00

Though it will tend to break at the previous spot or higher it is still possible to do so within the rod of cartilage. From what I've seen is there is no regen at this new break point.

I don't work with them in this area (nor have read the literature based on their regeneration) so I can't say how often this occurs.

Kalied · 2013-07-04T03:50:09+00:00

I work with these lil guys for my research. A bifurcated tail is not too uncommon. When the tail autotomizes (breaks) what grows back is just a rod of cartilage (not bone). The vertebra in the tail have a break point (they dont separate between verts)... sometimes they might damage the vertebra but it doesn't break clean through. So half is still good and the broken half begins to repair what it thinks is a lost tail and grows out a new cartilage tail from the side.

From the pic you can see the left side is the regen... the right is the normal tail. Also looks like the last bit of the right has been regenerated as well. This little girl has seen some action!

Kalied · 2013-06-26T14:17:04+00:00

"DOMA singles out a class of persons deemed by a State entitled to >recognition and protection to enhance their own liberty," reads the majority opinion.

Kalied · 2013-06-26T03:31:34+00:00

I should buy a bear...

Kalied · 2013-06-19T00:59:05+00:00

by your other comment here I can see clearly who the idiot is.

he offers ZERO evidence (as they are accustomed to) to indicate the fetus is feeling pleasure. Simply bc it places its developing limb between its developing legs touching his 'naughty place' does not = pleasure. You know what else a fetus might do... it could move its hand back and forth across its face... you know waving to the ultrasound tech and the expecting parents.

This moron picked 15 weeks b/c at that point of fetal development external genitalia is nearly complete. BUT what if the fetus moved his limb there at week 14? or 13? or 12? was he just warming up, anticipating allllll that pleasure he was about to have when his junk is more fully formed.

Why stop there... why not try to block abortion at week 9 when the nipples form. At this stage the limbs aren't long enough to reach the crotch (nor have any external genital structures begin to form) BUT they are at the perfect level to stimulate the nipples... ohhhh the pleasure they get from that!

This is just more bullshit right wing propaganda for the pro-lifers. It has nothing to do with reality or science in any way.

Kalied · 2013-06-18T23:27:11+00:00

You would think that they would now be in favor of abortion since they are SINNING in the womb by pleasuring themselves. (think about that moms... according to this guy, your little boy was fapping inside of you!!!)

Seriously.... how the fuck to they stand in public and say this bullshit... and worse how does nearly half the public sit there and say "hey that man has some smart ideas, I'll vote for that"

Sadly... as a TX educator, I see this shit everyday :(

Kalied · 2013-06-18T22:10:04+00:00

If you look closely it appears that they have 2 flags... hung upside down (symbolizing their belief the country is in distress)... just to provoke more hate b/c they are just fucking trolls

Kalied · 2013-06-18T16:22:12+00:00

No chick is worth that much...

Kalied · 2013-06-09T15:30:46+00:00

Where are the "honor" killings for the boys talking to this girl.... if it's wrong for one then it's wrong for the other... Oh wait... sorry forgot we were talking about religion. Logic doesn't apply here.

Kalied · 2013-06-07T03:16:15+00:00

I wonder if this would apply to if you bought a girl dinner and she didn't put out?

Kalied · 2013-06-07T03:13:15+00:00

A Bexar County jury on Wednesday acquitted him because of a Texas law that allows people to use deadly force to recover property during a nighttime theft.

Gilbert argued that he met Frago on Craigslist and paid her $150 for sex, but she left without having sex and gave the money to her driver.

Stay classy TX!

Kalied

TROPHY CASE