(posted in Birds)

Sorry no one seems to know the answer to your question.

it will depend entirely on the age and fitness of the individual, the rate of blood loss and how quickly the blood loss is stopped and then replaced with a transfusion. For example a fit soldier in a battle field situation could definitely survive a 2 litre loss if then treated quickly.

sorry no-one seems to know the answer to your question.

correct.

Penile size in an individual and when it stops growing will be determined by many genetic (including various transcription factors) and sex hormonal determinants. the specifics of both are still largely unknown and are surprisingly poorly studied.

your question is unclear. If you mean the area of the cortex that represents sensory and motor functions then they are well defined in a number of species. That said, the genes that code for that are still poorly undersatood and therfore so is its evolution

(posted in Plants & Fungi)

Sorry no one seems to know the answer to your.

(posted in General Biology)

I can see no reason why a dream couldn't include anything (real or imaginary). Any ideas that certain things like reading are not possible is wrong.

Sorry no one seems to know the answer to your question.

(posted in Birds)

Sorry no one seems to know the answer to your question.

(posted in Genes, Genetics and DNA)

agreed thought to be semantic a mutation causes a functional change. single nucleotide changes that cause no known functional change (and  to note may be subtle and thus missed) are called polymorphisms.

leaving aside nerve transplants are still in their infancy and little of what you describe is technically possible at present, the answer depends on which bit of the nerve you move where.

Remember peripheral nerves send information to the spinal cord and thus to the brain. if you somehow moved the nerve input from a foot nerve and grafted it onto the inputs from the arm into the spinal cord then the expectation would be that stimulating the foot would be perceived as signal from the arm/hand.

also take at look at the link below which in part addresses the ideas you have suggested
https://en.wikipedia.org/wiki/Preferent … nnervation

see
https://en.wikipedia.org/wiki/Wound_healing

you will see that the damaged and dead cells in the dermis and epidermis are cleared and then new cells replace them. That takes days to weeks depending on the amount of damage that has occurred. Regeneration occurs day and night though many other factors will affect the rate of healing some of which may have diurnal rhythm to them.

you have answered your own question! you are absolutely correct when you say:
I hypothesise that the difference lies in the simplicity of the simulations compared with the extraordinary complexity of life as we know it (e.g the simulated environment is too homogeneous, small and static while the genes and anatomy are too "rigid").

I an not an expert in AI simulators but I would expect they would have to be improved by many orders of magnitude in terms of complexity to even come close to thousands of millions of years of evolution.

as to your other question:
Why didn't life on Earth reach an evolutionary dead end? Is Earth rare in this sense?

more correct to say it hasn't yet - evolution hasn't stopped and it could be argued that climate change will require it to speed up over the next millenium. Since we know nothing about evolution on other planets it is impossible to have a comparator to events on earth.

(posted in General Biology)

see
http://www.ncbi.nlm.nih.gov/pubmed/19822534

agreed.

however since invertebrates have muscles but not bones could it not be argued that muscles developed first

You can relax! I am sure this a combination of forming and dissociating lipid micelles and protein aggregation caused by the warming of the light below the stage and brownian motion.

not all eukaryotic genomes have been sequenced so we can't say for sure. Certainly the fugu (puffer fish) genome has very few and very small introns. I suspect that all eukaryotes have some introns - they are fundamental to splicing and gene regulation.

agreed. leaving aside the fat conetnt of blood which would make fermentationvery difficult, the volumes of blood needed would be huge!

sorry I don't think we can help you. surely the two are by definition already related!

http://www.askabiologist.org.uk/answers … p?id=15021
the answer is the same - there are multiple genes involved in these events and their inheritance patterns are mostly unknown.

(posted in Genes, Genetics and DNA)

a few points to note:
1. homeobox genes code for proteins that are transcription factors (TFs), each of which will bind to enhancer regions of other down-stream genes. each TF can therefore regulate the expression of multiple other genes - in terms of their levels, sites and timings. As said above this is not a binary on/off - the complete opposite is true and exquisite and subtle levels of regulation are possible between tissues, timings during development and differing genes.
2. the sequences in those downstream genes that are bound and thus regulated by the TFs can be within, up or downstream from those genes and in some cases may be hundreds of kilobases away - in other words long range regulation.
3. hox genes arose as a small number of primordial genes which were duplicated and then diverged. That is why often they are present as clusters rather than spread out over the whole genome. as above point 2 they can then regulate genes a long way away.

(posted in Birds)

onl;y time will tell but 5 days is a long while for the eggs not to be incubated.

see below - probably a weaver or scorpion fish.
http://www.agrino.org/fishing/htmldocs/sltwtrfish.html

its a great question and there is no easy answer I'm afraid.

The variable missing from your post is the hundreds of millions to billions of years of evolution that have finely honed the various pathways you describe in a system.

At the start of every unoptimised system there will be a point where it will still work a bit and give a read out. Tweak 5 bits of the system each by say 2-5% it works a whole heap better. make that hundreds or thousands of components in a complex biological system and optimisations over hundreds of millions of years then it works to close to a peak of optimisation.

Then as you say there are constant mutations that decrease the effectiveness a bit and occasionally are so catastrophic that the pathway stops or drops below a minimum level of effectiveness. That leads to disease, foetal malformation or death.

To put it another way in massively well optimised system there is enough headroom to tolerate some degree of failure - most of the time.

(posted in Evolution)

Agreed and one additional point to emphasise - failure of fertilisation and/or development when sperm and ova are mixed from different species is NOT just because of differencing number of chromosomes between the two species.

There will be a myriad of proteins and immune processes that are for want of a better word "incompatible" betweeen the species that will stop fertilisation and/or development occurring.

you have answered your own question! the definition you provide is correct so the simple answer is no, only during foetal development. That said organ maintenance, turnover and in some cases repair can occur throughout life.

see
https://en.wikipedia.org/wiki/Oviparity

(posted in Fossils)

yes it looks to be the upper part of a deer skull.

I doubt it. I think it more likely the original tree had largely died and a number of roots survived and are now growing upwards through the inside of the trunk towards the light.

(posted in General Biology)

agreed.

Which modules you do duirng your degree programme counts for very little in the longer term. The key things are to enjoy what you are doing (which as a by-product makes it easier to learn and thus do well in exams) and to aim for the very highest marks in your final exams. That is what will make the difference when you then apply for Masters or PhD programmes for post-graduate studies.

see
http://biology.kenyon.edu/courses/biol1 … 5/code.gif

take the number of possible codons for each amino acid and multiply them together - total 128.

see
https://en.wikipedia.org/wiki/Smog

Carbon dioxide is a major contributor to global warming/climate change. it is not a major part of smog.

(posted in Genes, Genetics and DNA)

All cells from all organisms within a species have the same genome (with minor organism to organism differences that are called polymorphisms).

sorry but no-one seems to know the answer to your question.

gender identity is poorly understood and very difficult to study, as opposed to genetic/chromosomally encoded gender. the interactions with societal pressures and norms add further layers of complexity that are very difficult to separate. That said, the majority of those who wish to, or do, change their gender identify are aware of being born into the wrong body from a very early age The supposition therefore is that gender identify is imprinted early in development and will inevitably be dependent on both genetic and local hormonal factors.

see
https://en.wikipedia.org/wiki/Gender_id … _formation

other than e-mailing all relevant university departments and maybe pharmaceutical/biotech companies in a realatively wide area to where you live, I can't think of anything else I'm afraid.

sorry no-one seems to know the answer to your question.

(posted in Mammals)

sorry no-one seems to know the answer to your question.

(posted in Fossils)

sorry no-one seems to know the answer to your question.

mitosis and meiosis are both incredibly well conserved in almost all higher organisms studied. given the degree of evolutionary time that has passed to optimise these processes there will be few if any pressures for change. most if not all mutations will tend to make the processes less efficient and this will be selected against.

That said, it is possible that one or more new mutations might arise at some point in the future that could make the processes more efficient.

(posted in Plants & Fungi)

Q1. once the human body had largely decomposed it would release nitrogen and nutrients so I would assume the plants would grow better.

Q2. an absence of air/oxygen will significantly inhibit decomposition

posting here is not the way to get an internship. you need to identify the labs you wish to visit, find out what issues there may be regarding visa and the many financial questions such as who will pay. Then send a copy of your CV with a formal letter of request to the head of the lab you wish to visit.

there is no "up and down" for a single iron ion in the context of its position in a protein.

(posted in Evolution)

agreed so answer Daniel's question - no there aren't 2 separate processes. there is only random mutation that may confer a selective advantage or disadvantage that is then selected for or against depending on the new trait/phenotype and the specifics of what is driving the selection.

(posted in Fossils)

sorry no-one seems to know the answer. The spherical indentations (bubbles when the rock was molten) make me think this is more likely to be rock rather than bone/fossil.

(posted in Genes, Genetics and DNA)

No it is not possible. Points to note:

1.  it is not technically nor ethically possible to clone humans at present
2. the genes that determine fish gills are largely unknown so can't just be "slipped in". any sort of genetic engineering in humans is legally forbidden worldwide leaving aside the ethics of it
3. grapes with or without seeds are NOT genetically engineered - they are bred for those characteristics over very many generations.

see below. In addition most scientists agree that life arose independently multiple times.
http://www.askabiologist.org.uk/answers … p?id=10761
https://en.wikipedia.org/wiki/Evidence_ … on_descent

no one knows for sure but it is thought that the black and yellow stripes are to warn other animals (including humans) that they are dangerous. That is why people get alarmed when they see any flying insect with black and yellow stripes. The hover fly for example has black and yellow stripes. People are scared of them, even though they are completely harmless.

also note, not all bees and wasps are black.yellow they can be other colours as well.

This is a UK site so its unlikely we will have direct experience of this. from my reading of the scientific literature the hydrogen peroxide will definitely release the cellular contents and measurements of those MC toxins can rise over 10 fold. There is no reason to think the H2O2 will destroy these toxins. see

https://www.google.co.uk/url?sa=t&r … getps6ptEg

there are some plants hundreds if not thousands of years old.

for animals the simple answer is that the longer the animal lives the greater the number of somatic mutations that occur which in turn lead on to disease and poor survival. From a species point of view having a relatively quick turn over with reproduction early on in life is efficient and provides a survival advantage.