This is a really great question I hadn't considered before.  After doing a bit of research on the matter, and asking around with colleagues (both biologists and physisists), it seems that among the physics community there is some debate as to whether String theory is a theory or not.

Some argue it is a mathamatical theory, rather than a scientific theory; which means it is based on first principles, and makes predictions, but cannot [currently] be tested.

Unfortunately, to really get into this and give you a satisfying answer, I think you'll need a physisist, as most biologists (myself included) probably don't know enough about string theory to comment on whether the word is apt or not.

The Theropods are a large group, and contain many different species with a wide range of diets. There are some herbivorous theropods, such as Ornithomimosaurs, or Therizinosaurs.

But by no means were all theropods herbivorous, many were in fact carnivores.

It doesn't seem that there's a preset day terrestrial predator that even comes close to the bite force of T. rex.

Lion bite force is about 4000N.

You can read more in this scientific paper (that has recently been made open access):
http://rsbl.royalsocietypublishing.org/ … 4/660.full

This is to do with the descent of the larynx (http://en.wikipedia.org/wiki/Larynx#Descended_larynx)

I don't think there's full consensus on why this evolved, but it may have to do with allowing us more range in vocalisation by freeing the toungue and mouth to make more shapes.

My initial thought is that these are iron nodules, or mudstone inclusions, rather than fossils.  However, if anyone here thinks differently I'm open to suggestions.

(posted in Evolution)

I think you're misunderstanding where the variation comes from.  The change in colour, or the increase in size does not come from activities, but from natural variation of what is already there.  The fish does not have an activity that tells it to be out of water.  A population of fish are each able to take a different amount of oxygen from the air by gulping.  If the pond or lake they are in becomes de-oxygenated, the fish that can best gulp air will survive, and pass on their genes.  Over many generations, the ability to breath air might evolve.

In essence, you are quite correct that simple rules ultimately govern larger systems, but these rules are acting on random variation. To use your computer anaology, consider that your program would have a random number generator in it.

In this way, colour absolutely can be selected for by evolution.  In the case of the lion, different individuals will all be different shades, and those with a colour closest to the environment will catch more prey, and have more young, passing on their genes for that colour.  But the young will still have some variation, and so selection will act on that, and again for each generation.

(posted in Evolution)

It is worth mentioning that Abiogenesis is not a problem within evolution.  As you need life for evolution to act on, Abiogenesis falls outside the remit of evolution.

Nope.  Tyrannosaurus was almost certainly not an amphibian.  The notochord is a pre-cursor to the backbone in vertebrates, and becomes the backbone as the animal develops.

(posted in Birds)

I'm afraid I've no personal experience of these birds, but Wikipedia has a good lot of detail on them, which will tell you their size (35 cm wingspan):

http://en.wikipedia.org/wiki/Eastern_Kingbird


And you can see one in defensive posture against a much larger crow here:

http://www.youtube.com/watch?v=zYA2Q0-YYQM

I'm afraid from the single photo, I'd be inclined to agree with the pebble identification.  The texture on the inclusion is very grainy, and a tooth would [most likely] be a lot smoother.

Hi Tim, after asking some experts that are fish specialists, it seems the best guess is a ventral armour plate from a catfish.  However, from the one photo it is very difficult to tell.

Hi Karsten, I'm not sure what documentary this was, but I guess based on their website it was Walking with Monsters (the sequel to walking with dinosaurs).  I wouldn't put too much stock in what you see there, we have little to no evidence of Dimetrodon parental behaviour.  I don't even think there's evidence Dimetrodon lived in areas where the climate could get that cold over winter, though other experts here may correct me on that.

It's difficult to tell from the photo, but the different colouration on the inside would suggest this may just be infilled.

(posted in General Biology)

Yes, it absoutely would.  In fact, even when all is constant, depending on whether you measure at the front or the back of the jaw you will get varying results.

This makes it very difficult to compare bite forces, so studies try to keep as much constant as possible between animals, or look at the forces the muscles can produce, rather than the forces exerted by the teeth.

Brown crickets vs black crickets springs to mind.  Brown crickets are smaller and faster, so number of successful strikes vs black crickets could work.

(posted in Birds)

The two-progned head on the left of the image make me think it's a rib.

The wikipedia page for Allosaurus is pretty good in this regard, it might make a good starting point.

http://en.wikipedia.org/wiki/Allosaurus#Paleoecology

You can almost certainly specialise in which animals you study professionally, though it would be advisable to check with relevant organisers before choosing courses to take in order to study animal behaviour.

Wikipedia highlights differences in the use of the word 'Darwinism' in different places:

"The meaning of "Darwinism" has changed over time, and varies depending on context. In the United States, the term "Darwinism" is often used by creationists as a perjorative term in reference to beliefs such as atheistic naturalism, but in the United Kingdom the term has no negative connotations, being freely used as a shorthand for the body of theory dealing with evolution, and in particular, evolution by natural selection."

Link: http://en.wikipedia.org/wiki/Darwinism



I have to say, I have always seen it as synonymous with evolutionary theory, and have never assumed Darwinism implies ignoring genetics or other modern adaptations to the theory of evolution by natural selection.


[edit] Though that article goes on to highlight the views of Alistair and David:

"While the term has remained in use amongst scientific authors when referring to modern evolutionary theory, it has increasingly been argued that it is an inappropriate term for modern evolutionary theory."

(posted in Evolution)

A quick counter to the original point: Sexual selection and associated evolution would not necessarily require a change in environment.

i.e. The peacock didn't get it's tail [in it's current form] as a result of environmental change.

Just to clarify, Big Al and Big Al 2 are very complete specimens of Allosaurus, and their specimen numbers are MOR 693 and SMA 0005 respectively.

More here: http://en.wikipedia.org/wiki/Allosaurus … _Al_Two.22

As you point out, there are differences in skull shape, and some of the variation will come from there.

The other thing to remember is that Rayfield et al's study was looking at what stresses the skull could take, where as Bates and Falkingham were looking at the maximum force produced if all muscles were simultaneously activated.

The real life bite force was probably lower than our maximum - it's extremely unlikely the muscles would have activated in the way we made them, but I'd also wager it was probably higher than at least the lower end of the Rayfield et al values.  The Rayfield et al paper is a major, significant, and pioneering paper, but it is twelve years old and the FEA techniques for skulls have come a long way since then.

It really depends how deterministic you want to get. 

Being a pretty solid determinist myself, I would argue that the originating neuron in your example was stimulated into firing by other neurons which ultimately are stimulated by external factors such as what the senses record.  And all the while the brain is 'ticking over' taking input from what the senses observed some time ago.

However, I don't think (though other AABers please correct me if I'm wrong) that our understanding of the brain has really got that far yet.

(posted in Mammals)

It would almost certainly have died even if you had taken it in.

An interesting philosophical question that sadly can't be (yet) tested.  Probably though, given the personality is the summation of memories and other connections in the brain, the 'person' will travel with the brain rather than the body.

(posted in General Biology)

Unfortunately we cannot help with homework/exams. 

All I will say is this: Instead of looking for relationships between drugs and ATP production, look for the relationship of the inner membrane to ATP production.

Well there are lots of mechanical reasons - gas exchange is one - Maintaining open spaces (the alveoli) in the lungs would be very difficult. 

A circulatory system would also fail, as capiliary forces in such tiny blood vessels would totally change the way the sytem works.

Your point about the brain is probably correct too.

You seem to have a good idea of your options, but unfortunately that makes it difficult for us to help to any greater extent.  There are two sides to specialising early, on the one hand, it can lock you into something that prevents you getting a wider education that would in turn open up the job market, and it may turn out that it's not as exciting as you thought.  On the other hand, if you are certain of wanting to do palaeoanthropology, and you excel at it, then it may be a more direct route to what you want to do.

If you are worried about how specialising early may affect future career options, try to find out what past students who have taken the course you are interested in have gone on to do.

Living dinosaurs - birds- have been known to have symbiotic relationships; Plovers and Crocodiles for instance.

Whether extinct, non-avian dinosaurs had symbiotic relationships I think is unknown.

Well Tyler, on the one hand Palaeo is extremely competitive for positions (i.e. there aren't many!).  However, in line with what David says, you don't need to worry about that too much yet - undertake a more general biology (or geology) course, and that will put you in good stead for both palaeo and a wider range of jobs.

In this regard, the US degree system will be very beneficial, as you'll be able to take majors and minors according to your interests and strengths.  If you were in the UK, you might be choosing a purely palaeo course at this stage, and that can lock you in to a career path a little early.

(posted in Fossils)

Thanks Paolo!

(posted in Fossils)

I had this emailed to me for identification, but felt I may get a more informed answer posting here...

Found in a coal mine, no other locality info yet.

[EDIT - 9/10/12]

Additional info:

Found in coal mine, webster county, western Kentucky. A possible age of 300Ma

Carboniferous limestone in the Peak district, I'd say it's far more likely to be a coral.

Or a sponge.

Mostly, we don't.  We can make educated guesses based on what animals look like today.

However, there are examples where  we can get information about colour, often from feathers.  Have a search on the site, as it has been discussed previously.  You could start here:

http://www.askabiologist.org.uk/answers … hp?id=8474

(posted in General Biology)

The full stop got incorporated into Brent's hyperlink, breaking it.

http://en.wikipedia.org/wiki/Kilocalorie

This is actually Hoyles Fallacy, and there's a pretty detailed Wikipedia page on it:

http://en.wikipedia.org/wiki/Hoyle%27s_fallacy

There is actually a wikipedia article on this, but states itself that current research is not referred to:

http://en.wikipedia.org/wiki/Facial_symmetry


What is of interest there is that it lists a number of health issues related to facial asymmetry.


However, it's not surprising that symmetry should be seen as attractive, or at the very least, not abnormal, given that we are bilatterally symmetrical animals.

Which kind of counter's David's point that we should be seeing symmetrical animals: generally we are.  That's maybe a bit flippant, and obviously not addressing the point that animals should become more symmetrical through time, but then how much more symmetrical can a population become?

Corwin, if you can find a refference that slightly asummetrical faces are more attractive I'd love to see it - I'd find it quite surprising.

Note that 'Britain's most beautiful face' (http://www.whatsontianjin.com/news_imag … gate_1.jpg) is pretty darn symmetrical.

(posted in Research and Careers)

Sometimes it comes from reading, as you say. 

Other times it comes from conversations (usually in the pub rather than the lab) where two or more scientists begin discussing something then realise no-one knows the answer to the question, or that a previous work can be improved upon.

Sometimes it comes from an observation, either in nature or in the lab, that makes a scientist say "Oh!  That's cool, I wonder why/how/what..."

The latter two paths are then followed up by copious amounts of reading to see if the answer is already out there.  If not, it's experimental design time!

Corwin is of course right...  Apologies for the error in my post...  generalising a bit much!

Hi David,

See here, where this question has been discussed before:

http://www.askabiologist.org.uk/answers … hp?id=7056


Basically, we do refer to mammals as reptiles in a strict, phylogenetic sense.  But in common language it seems rather silly to do so. 


So birds are dinosaurs, but the term 'bird' is used in common tounge for a distint subset.

We use the term non-avian dinosaur to distinguish between those dinosaurs that are very close (or belong to) birds,  and those which followed a different evolutionary branch.

Contrary to the image the media portrays of palaeontologists, most of our time is spent at a computer in the office, either writing or processing data, with this norm being broken up for a few weeks or couple of months a year with field work.

A recent article at Palaeontology[Online] about becoming a palaeontologist may be of interest to you, particularly the section "What do Palaeontologist's do":

http://www.palaeontologyonline.com/arti … e-fossils/

1. From fossil teeth and vertebrae, and comparing the size of these to modern sharks.

2. It was larger!  Why it was larger is difficult to ascertain.

3. Real.

Hi Vedant,  this question has been asked before, and you can find an answer there:

http://www.askabiologist.org.uk/answers … hp?id=1091

You should also check out the "how to become a biologist" page on our "From the lab" section: http://www.askabiologist.org.uk/from_th … -biologist

Finally, a recent article on Palaeontology[Online] might be interesting for you to read:

http://www.palaeontologyonline.com/arti … e-fossils/



Essentially, they all boil down to working hard at school and getting good grades, then going to university to study either biology or geology (or both!), or another related subject.

Peter, you may find this article form New Scientist a couple of months back to be of interest:

http://www.newscientist.com/article/mg2 … -them.html

Until recently, the answer would have been that they didn't.  However, recent studies have shed at least some light on this:

Check out these reports of scientific studies:

http://www.calacademy.org/sciencetoday/ … -in-color/

http://news.nationalgeographic.com/news … science/o/

That depends on what 'genetic quality' means. Reproductive potential? No, probably not.

But it may be an indicator of health, i.e. symmetry, complexion etc.

Looks like a Hornet to me, see also:

http://www.askabiologist.org.uk/answers … hp?id=7175

(posted in Mammals)

This paper reports just under 500N at the tip of the canine in a Grey Wolf:

http://www.esajournals.org/doi/full/10. … 2.0.CO%3B2

It's difficult to convert this to PSI, which is a pressure, as the PSI will vary depending on how much tooth is in contact with the object being bitten.

I don't think anyone really considers any part of the human body to have evolved for defence/offence.  It's far more likely that the techniques for using those parts of the body arose much later because they were already there. 

It requires training before a person knows to fight with fists, let alone elbows/knees etc.

If your biology based degree meets the minimum requirements of the Forensic science Masters you wish to undertake, and if you're willing to put the work in, it shouldn't be a problem.