Chalky

Apparently it's possible to be immortal (if you're a jellyfish). Story on the BBC here

You could try looking up an event called the Palaeocene-Eocene Thermal Maximum which is a global warming event that happened some time ago on Earth. One theory is that large amounts of methane were released. As Essay said however, methane doesn't last very long in the atmosphere (about 12 years) so you need a VERY large source if you want to sustain large amounts for any period of time (it does convert to CO2 however, which would sustain elevated global temperatures).

Try this. You need to work out your last common ancestors, which are your Great-grandparents (their grandparents). Thus you are 1st cousins once removed.

"Do" I or "would" I?

You said it yourself: you assumed that the mean was 1. Is it? If we only consider the Earth, then yes. But what about other planets? Consider Mercury, Venus and Mars as well. We currently have no evidence for life on them. Assuming that this is true, then your mean is already down to 0.25. What about all the other planets in the solar system? The galaxy? The universe? Our mean potentially becomes very small. There's also an equation called the Drake Equation which may be of use to you.

Depends how long it takes the wave to reach you. If the earthquake is close, as in Japan, then yes, but everywhere else around the Pacific had quite a lot of warning.

Try Lane, Allen and Martin (2010) How did LUCA make a living? Chemiosmosis in the origin of life for a slightly unconventional viewpoint on the origin of life. Lane and Archibald (2008) cover horizontal gene transfer in eukaryotes, but +1 on Stefan's suggestion for Google scholar.

As I understand it, the paper can be paraphrased in over simplified manner as: Consider a hypothetical example where a species has 10 members which live in a 10 km2 area (for simplicity lets assume that they are evenly distributed). Then we have 1 animal per 1 km2. So we only need to survey 1 km2 to "discover" the species. However, to determine if the species is extinct, we need to examine the entire 10 km2. So it is much easier to discover a species than to show it is extinct. So mathematically the maximum overestimate of extinction might be 160%, but (without knowing more about ecology I can't really say) it is probably less.

If you cross the International Date Line on the stroke of midnight on the 20th May, you will find yourself in the 22nd. Doomsday averted.

I was writing an essay today about ecology, and realised that I didn't actually know what it meant. What sort of areas of science does is cover? Is classification of organisms included?

Did anyone else here about this. Made me chuckle.

Well, there's a lot of debate about how the extinction happened in the first place. But the ocean is quite a sensitive system. If we look at the oceans today, rising atmospheric CO2 is making them more acidic. Every time El Nino happens in the Pacific, the current flow reverses direction and causes marine life to die off South America. Add in a massive catastrophic event like a meteorite or a big volcanic eruption and the effects on the oceans could be massive.

There's a fascinating (and at times quite acrimonious) debate on this and related issues between Stephen J Gould of Harvard University, and Simon Conway Morris of Cambridge University. Gould argues that we arose completely by chance and that "if the tape of life were replayed" intelligence would not necessarily have arisen, because evolution is so random and easily influenced by minute events (i.e. the butterfly effect). Conway Morris says that Gould is completely wrong and points to convergent evolution. This is the independent evolution of the same traits in completely separate lineages (for example, flight in insects, bats, pterosaurs and birds). He uses this (and quite a few other examples) to suggest that intelligence is a natural endpoint of evolution. This debate is still ongoing and nobody really knows the answer. As with all endmember views, the answer probably lies somewhere in the middle. Would life have evolved on another planet? That depends on how similar you think alien life has to be to that on planet Earth. I've been reading a little about the subject recently and it basically comes down to how you define life.

But is there just one way of synthesising life, whatever you define that as?

Soft tissue has (supposedly) been found in a T. Rex skeleton. http://en.wikipedia.org/wiki/Tyrannosaurus#Soft_tissue I don't remember much about the original papers but the scientists matched it quite closely to birds. Whether or not it was original or later contamination is another matter...

If you want to go into science, do lots of maths and physics, regardless of your eventual aim. It's much easier to switch from a mathematical to a more conceptual science than vice versa. However, all sciences involve an element of maths at their highest level, so being taught "conceptually" (my experience with subjects like biology) doesn't prepare you for the top end of that science.

Bear in mind that the Yucutan Peninsula is a relatively tectonically stable area in CONTINENTAL crust. It is very hard to either create or destroy continental crust so plate tectonics is relatively unimportant in this case. (Oceanic crust is being continuously created at ocean ridges and destroyed at subduction zones, but the impact crater is not in oceanic crust). As large areas of the continents are old Precambrian shields (i.e. before 500 million years ago) and the Chicxulub meteorite is only 65 million years old, it's entirely plausible that the impact crater is still there. The reason we don't see our planet littered with craters (like the moon) is the active sedimentary cycle, which will erode the rim of the crater and infill the hollow with sediment. This will remove any evidence of the crater being seen from the surface. However, the different densities of sediments vs crust mean that the crater will show up on gravity surveys.

Some evolutionary biologists think that convergence is a significant feature of evolution. For example, why do so many metazoan groups develop camera eyes independently? Camera eyes Based upon this (and other examples), is there a fundamental determinism to evolution? Personally I don't think so, but it all depends on your view of variation as a random process and the nature of the selection that acts upon it.