The reason why nature, I assume you're talking biologically, is complex is because  life has undergone over almost 3 billion years of evolution in which each organism is pressured in harsh competition and only the fittest survived leading inevitably to complexity, and life is diverse because diversity allows a higher probability to survive due to access to new resources. Macroevolution is merely speciation which we've observed in our lifetime. Microevolution and Macroevolution use the same mechanisms. Microevolution is changes within a species(variations in humans) while Macroevolution is changes between species(the different species of finches in the galapagos) both which have been observed numerous times. What you're against is how long the earth has been around. As for the notion that science is bias, science is constantly challenging theories, hypothesis, and laws to see if they are compatible with nature. The reason why evolution, gravity, and atomic theory don't seem to be in much threat in the scientific community is because they are both very large portions but both very consistant to the evidence. What is being challenged everyday is the more specific details like why did our ancestors become bipedal, why did the neanderthals become extinct, which atomic model is the most accurate, etc. Because evolution has been proven, scientists base how to cure diseases with evolution. Saying this is bias is like saying that people designing airplanes are biased about gravity. We use scientific facts/theories/laws currently known to discover new scientifc facts and if those new facts are incompatible with the current facts/theories/laws, then those current theories/laws need to be revised. If the theory cannot be revised it must be discarded and a new theory/law must replace. Since the Origin of Species, the theory of evolution has been revised due to discovery of inheritence, DNA, organelles, but every single discovery has been 100% compatible with evolution, and that's why evolution is a fact.

A. Macro and micro evolution  are exactly the same mechanism, but to a different scale. What exactly made you think micro evolution was acceptable, but macro evolution comes from a "crackpot", when it's exactly the same thing? For my further argument read my rebuttals to Dsister.

B. You have shown that you do not understand the scientific process at all. A scientific theory is not the same as the common use of the word theory. When the term theory is used in science it means that it is the best explanation of an aspect of nature from the available evidence. A scientific theory has to be substantiated by facts drawn from evidence and  it has to be falsifiable so the theory can become better refined, or even disproven (but to disprove a scientific theory you have to account for the evidence the theory is built on, which for both micro and macroevolution is a lot). In other words, a scientific theory is more or less fact.

C. The fact that you have said a scientific theory is untouchable is baffling to me to be quite frank. Scientific theories are constantly changing to adapt to the evidence available.

It really doesn't. Trust me on this one.

Oh woah. I usually don't take part in these kinds of discussion because they frustrate me (the people not the subject) but one would have to be rather close-minded and rather ignorant/uninformed not to accept evolution as the best answer.

It's okay to believe in God or whatever but that doesn't mean evolution is "a lie".

I think it's not respecting who you are if you deny evolution.

Evolution is just so obviously true. I mean it's everywhere around us and it doesn't need a lot to see it.

Micro and Macro while fairly similar aren't exactly the same, and it isn't a matter of size or time scale. Microrganisms are well lets be fair aren't that slick in how they go about mutation. Hell it isn't even all that random. They often just pick up garbage they find lying around. Many of them when they find a piece of genetic code just incorporate it into their bodies. Doesn't matter where it comes from. You can literally bleed into a petry dish and in a week come back, and test the bacteria, and you will find human genes in their genome. The mutation isn't so much random with some bacteria, as it is driven by instinct. They naturally diversify even in the absence of radiation, or replicating errors. Many of them seem to even be fairly oblivious to their DNA.

This isn't a critique of Evolution. Just being fair here, because I know the creationists are basically ignorant about the terms they use in a vain effort to refute the evidence. Basically the plethora of bugs in the biosphere, aren't evolving at all as most people would understand evolution. Idiotically the creationist lobby just latched on to a defense that conceded a point they didn't need to concede. Pretty damning proof that they know they are full of it in my opinion.

Bacteria just mutate constantly as a survival mechanism. They aren't changing over time in response to the environment so much as they are mutating prior to environmental change. By constantly changing shit up they are basically ahead of the game. Unlike in Macro Evolution it isn't a try and fail venture. All outcomes are equally desirable. Further more it isn't even a linear progression. The bacteria just mutate in circles. They aren't getting more complex, or coming up with massively new mechanisms. Think of it more like changing clothing over and over and over again.

Don't get me wrong it is proof positive of Natural Selection. Just not in the way that the creationists obviously thought that it was. Had they just actually read rather then skimmed. They would have seen a logical counter argument. Beyond oh shit mutation making different things we are so fucked. Mutation in microbes isn't about random change so much as it is a active survival mechanism. Take a pond full of bacteria today, and test them against a pond full of bugs from three hundred million years ago, and you would find bugs with the exact same DNA. No it isn't that they did not change, but that they have gone full circle billions of times.

The fact that Bacteria basically don't give a shit about the genetic code they take in has been a boom for science, and frankly for industry. You can put any genes you like in the bugs, and you can have them churning out all sorts of drugs, and industrial chemicals. Kind of ironic that the study of Natural Selection is probably going to lead to cheaper drugs that can treat thousands of conditions in the future, because Microbes don't give a shit like their bigger cousins.

Just trying to keep it a little fair, and before Creationists make the argument for the sake of reason do a little reading on this subject. Seriously don't be so handicapped that a believer in Natural Selection has to present you with a logical defense to your side of the equation. Stop hiding in the corner.

Whats your explanation for fossils of different species that go back for hundreds of millions of years?

If your answer is that every 100,000 years Jesus kills every living thing on Earth and then creates slightly different living things, then don't expect me to reply.

Why does it have to be either God or evolution. Most evolutionists believe in a supernatural being so they are not incompatible. As for more faith in evolution that God(I assume you are talking about Creationism), it's not even close. Evolution is more proven than even Gravity. What is it that makes you reject Evolution? If it's religious issue, I cannot help because we will get nowhere with bias. If it's a natural observation, than ask and I will do my best to answer.

First of all, creationism only holds it's ground as a philosophical/religious hypothesis and nothing more due to the obvious lack of any scientific evidence. Even looking at things that way, it's still kind of incoherent when you stop to think about it. Which kind of God would enjoy a static creation when he could make much more? Which one would you prefer if you had the power to make your room be filled with roses - clap hands and have them all appearing at one instant or see the seeds growing and developing all the way to full-grown plants and blooming flowers in some twenty seconds?

Secondly, evolutionism is often misinterpreted as "taking a step forward". There is no such thing as evolution on that sense. No linear walk toward perfection. Nature is often redundant and every single organism is far from optimal (I explained about some skeletal human issues on the bipedalism topic already) which however does not keep life from being the most fascinating thing in the whole universe, of course. Genetic diversity comes by random change alone and organisms eventualy born more suited to the enviroment survive, giving a false impression of continuous adaptation and improvement. That's were Jean-Baptiste, also known as chevalier of Lamarck, failed. Darwin too, by the way, for he actually didn't know about genes and such and used Lamarck's laws of adaptive forces to explain diversity, as himself states on his magnum opus, the Origin of the Species. That's why today we talk about neo-Darwinism instead of only Darwinism.

So, a certain kind of bacteria do not develop resistance to a certain antibiotic even though it seems so at a first glance. The naturally resistant ones were just selected and passed their genes to the offspring.

You can only talk about more or less adapted and more or less complex, the later of which does not automatically mean imediate success towards ever-changing nature. Look at the molluscs, considered much less "evolved" than mammals and still a hundred times more successful than mammals considering number of species. Let alone insects...

To say the truth none ever observed speciation...

Honestly, in terms of "none ever observed" stuff, I'd say religion is far ahead of science