Arete

Actually, functioning natural ecosystems are imperative to human survival, as they form the basis of natural systems we rely upon for things like the water cycle, carbon cycle, nutrient cycling etc and so on, all of which are critical to you and I having basics like air to breathe and clean water to drink. So the question, as CharonY put is "what is the minimum species required to keep natural systems functioning?" Given that only ~10% of species on earth are actually known, the answer to that question is an emphatic "We don't know." In addition to a lack of knowledge regarding the minimum number of species required to maintain the basic level of ecosystem functioning, redundancy in the system - i.e. organisms which both perform the same basic task in maintaining ecosystem function allows it to survive fluctuations which may cause the extinction of one but not the other. So there's an exceptionally strong argument from a utilitarian point of view for maximizing biodiversity without any need to invoke the intrinsic value of ofthe forms of life on the planet. You wouldn't build a water treatment plant, power station or hospital without redundant backup systems and you wouldn't build an investment portfolio with no diversity to account for potential failures, so why would you limit the diversity of natural ecosystems that you critically depend on?

No worries. Many of us spend several years studying full time just to catch up on the known research and concepts, so it's not a trivial task to try and evaluate the existing evidence. It's exceptionally admirable to actually try rather than dismissing it all out of hand.

This is subjective, as it is my take on how I view the definition of certain proposals in my own scientific writing but: Speculation - an idea/explanation/etc still in the process of formulation and prior to any proof of concept - a back of the envelope, down at the pub kind of idea. Hypothesis - an idea/explanation/etc which has proof of concept, but no experimentally viable support as of yet - the kind of idea you can design an experiment to test. Theory - a hypothesis which has been supported by one or more experimentally viable studies. As for observed evolution, Journals like: Evolution, Trends in Ecology and Evolution, the Journal of Evolutionary Biology, Molecular Phylogenetics and Evolution, Journal of Molecular Evolution, Molecular Ecology, Journal of Biogeography etc and so on are dedicated to publishing peer reviewed, empirically supported studies in evolutionary biology. As such, experimental tests, which support the fundamental principles of the modern theory of evolution and explore details thereof, are published by the hundreds every month. This makes the modern theory of evolution one of the most well supported scientific theories there is. Further to SwansonT's peppered moth example, well supported studies have linked reproductive isolation to genetic divergence between related species e.g. http://onlinelibrary...1096.x/abstract and http://www.sciencema...8/5847/95.short, changes in phenotype to changes in genotype e.g. http://www.plosbiolo...al.pbio.1000363 and http://www.nature.co...ng.2007.70.html, environment to changes in phenotype and genotype e.g. http://www.nature.co...ature07285.html and http://www.cell.com/...092867408001141, etc and so on. Basically - saying "You've never observed speciation so therefore you have no proof it happens." is akin to saying "You didn't see that oak tree in your front yard grow from an acorn so you can't prove that it did."

This is another intellectual dishonesty. It's called "Guilt by association" http://www.nizkor.org/features/fallacies/guilt-by-association.html. The fact Dawkins might use the term and you dislike his books is not a valid counter-argument, it's a sidestep. Arumentum ad Ignoratum - or the argument from incredulity - has been around a lot longer than Dawkins - "Another way that Men ordinarily use to drive others, and force them to submit their Judgments. And receive the Opinion in debate, is to require the Adversary to admit what they alledge [sic] as a Proof, or assign a better. And this I call Argumentum ad Ignorantum" – John Locke. 1690. An essay in Human Understanding Book IV.

There's no mechanistic distinction between "micro" and "macro" evolution - you're just describing the same process over different periods.

You can't prove that the sun will rise tomorrow either. You can theorize that the earth and the sun are both spheres, the earth revolves around the sun whilst simultaneously spinning, meaning that for approximately 12 hrs tomorrow, the sun will be visible from the point on earth on which you stand. Based on theory and past events, we can be pretty sure that it will rise tomorrow. We can, in a similar fashion be reasonably certain, given the prima facie evidence that the organisms represented in the fossil record were capable of reproduction.

I'm a PhD student in evolutionary biology. I don't "believe" in Evolution per se - I believe in the most parsimonious explanation of observations. Currently, the best supported theory is that organisms diversify due to the accumulation of random genetic mutations resulting in differential phenotypes. A diverse array of environmental pressures mean that some phenotypes are able to reproduce and therefore pass their genetic information to the next generation better than others. As environments are complex, temporally and spatially dynamic, a number of phenotypes can be simultaneously successful. This theory has been tested in a scientific framework countless times, with even more replications, by thousands of people all over the globe and not once has there been a result which significantly rejects the fundamental principles of the theory. That's an exceptionally large body of support... however if you or someone else could find an empirically supported alternative that better explains our large body of observations, demonstrate that it works and how it works - it would mean all us evolutionary biologists would have a fair bit of hat eating to do, but on the flip side it would make it a very interesting time to be working in the field. It seems you're tangling up a few anti-evolution arguments in one. The first - the argument of irreducible complexity. The wing is actually a good example of how the argument of irreducible complexity is flawed as there are several extant - gliding possums, gliding lizards, gliding seed pods, parachuting spiders, jet propelled squid, flying fish, etc and so on... and extinct - Longisquama, Archaeopteryx, Microraptor etc. where intermediatory methods of flight are selectively advantageous. A membrane, or inefficient flapping wing which allows you to get to the next fruit bearing tree or remain airborne longer than something intent on eating you - even if it's a controlled fall more or less, is better than none at all in certain environments. Next - argumentum ignoratum. You don't comprehend how a gliding structure can evolve into a flapping wing and thus conclude it cannot be done. This is an argument from incredulity - and thus a logical fallacy. If we look at the evolution of bird wings for e.g. the shoulder and elbow joints are residual from that limb being first a leg, then an forelimb. When furnished with a plane of feathers, bending and straitening that limb can generate lift. As such, the manipulation of the limb is residual - a happy coincidence for the bird and speculatively - a reason for their exceptional evolutionary success.

What sort of loci are you looking at, and what sort of sampling have you undertaken (as in population level - across phyla)?

As with almost all good scientific questions, the answer is yes, and no... generally, organisms can be divided into autotrophs - those which can fix inorganic carbon into complex organic compounds and heterotrophs - those which can't. Autotrophs can be further divided into photoautotrophs - those which use photosynthesis (plants, algae, phytoplankton, cyanobacteria etc) and chemolithoautotrophs - those which are able to synthesize organic carbon compounds using chemical reactions - these are exclusively microbial and support communities like the deep sea vent systems. In addition to these, "radiotrophic" fungi was found surviving inside the Chernobyl nuclear reactor and is theorized to have been harnessing energy from radiation. Heterotrophs can be divided into organotrophs - animals, bacteria, fungi etc which get their resources from complex organic compunds produced by other organisms. Photoheterotrophs, such as purple and green bacteria can sythesize ATP using light but build require organic compounds to create structures. Then there's mixotrophs - some sulfur bacteria which can do both. So in the typical macro scale ecosystems we tend to observe and think of, the basis of energy production is photosynthesis of organic compounds by photoautotrophs, which are then used by all the organotrophs which eat them, but a variety of other systems demonstrate that photosynthesis is not a requirement for the evolution of life. edit - spelling fail

It's a decorator or brachyuran crab, however there's some difficulties in identifying specific species and you may well need the specimen in hand to key it out - which continued instabilities in the taxonomy of the group might make difficult... sorry for the lack of a straightforward answer. These guys might be able to assist: http://www-eve.ucdavis.edu/stachowicz/decorator.shtml Interestingly, the trait has been "lost" and "gained" numerous times throughout the group.

Phenotypic evidence, such as endothermy, lungs rather than gills, vestigial legs, hair, lack of scales, placental young etc and so on strongly suggest that cetaceans (whales & dolphins) are mammals and genetic evidence evidence is in support : - Maureen A. O'Leary and Jonathan H. Geisler (1999) The Position of Cetacea within Mammalia: Phylogenetic Analysis of Morphological Data from Extinct and Extant Taxa Systematic Biology Vol. 48, No. 3 (Sep., 1999), pp. 455-490 - Springer MS, Stanhope MJ, Madsen O, de Jong WW (2004) Molecules consolidate the placental mammal tree. Trends Ecol Evolut 19:430–438 The process by which they came to physically resemble fish is called convergent evolution, whereby similar environmental conditions select for similar traits in organisms with different ancestors, which leads to distantly related organisms having similar appearances.

Hi, I'm currently in the latter stages of my PhD, alternating between procrastination/avoidance (hence my presence here), writing up and looking for postdocs. I work primarily in genetics/evolutionary biology on a range of things such as species tree reconstruction, adaptive diversification/species processes and population genetics.