Andre poses some interesting questions to Nick Matzke. I thought I’d start a thread that might help him find some answers. I’ll have first go :
Yes please can we get a textbook on Macro-evolution’s facts!
I’ll make it easy for you;
1.) I want to see a step by step process of the evolution of the lung system.
Google Scholar: evolution of the lung sarcopterygian
2.) Step by step process of the evolution of the heart.
3.) Step by step process of the sexual reproductive system.
Well, there are rather a lot of sexual reproductive systems, but this might get Andre started:
Google Scholar: evolution of dioecy
4.) When did survival of the fittest kick in? With the first single cell organism or later? How did they know that survival is key?
This one just needs a little thought, rather than google. “Survival of the fittest kick[s] in” as soon as you have any population of self-replicators that replicate with heritable variance in reproductive success in the current environment. This is a matter of straightforward logic:
IF a population of self-replicators replicate with less-than perfect fidelity
AND IF some variants are better at self-replicating than others (tend to have more viable offpring)
THEN the variants that self-replicate better will become more prevalent.
This conclusion is sometimes referred to as the “survival of the fittest” (survival down the generations), and sometimes “natural selection”. So the answer to Andre’s question is this: We do not yet know just how simple a self-replicator had to be in order to fulfil the two conditions necessary for Darwinian evolution (aka natural selection), but we do know that wherever those two conditions are present, Darwinian evolution will be the near-inevitable result. Current thinking is that the earliest Darwinian-capable self-replicators were probably a combination of self-replicating polymers enclosed in expandable and divisible lipid vesicles.
5.) How does natural selection select? If something is not in the search space how does it find stuff that is not there? Or has everything always been there?
Well “natural selection” is a figure of speech. “Artificial selection” is selection of traits by artifice – by human breeders who desire particular traits in their livestock or plants. So in “artificial” selection, the traits that promote successful reproduction are those that please the breeder, who then breeds from those individuals. In nature the traits that promote successful reproduction are simply those that facilitate breeding in the natural environment, hence Darwin’s use of the analogous term natural selection.
I think the “search space” metaphor has to be used with caution. There is no Mother Nature who is “searching” for an ideal organism. Rather, traits that best fit an organism to reproduce in a specific environment are the ones that become most prevalent in a persisting population. This is so obviously true that some people think it is tautologous. It is not, but it is syllogistic.
However, if Andre’s question is about how the variants that confer those beneficial traits come about: I think there is a considerable misunderstanding about this. Most traits are polygeneic, and the degree to which they are present or absent (e.g. spots; feathers; light-detection capacity) is governed by a whole host of DNA sequences, most of which regulate the process by which an infant becomes an adult, and each of which have many alleles. So, for sexually reproducing species anyway, I think it’s misleading to think of specific variants as producing brand new traits – better to think of variance as a kind of constant drip-feed into the gene pool, most variants being neutral and propagating simply by drift; while “selection” operates in any given environment by means of those organisms who inherit the most beneficial cocktail of variants spreading their particular inheritance more generously than those who inherit a less beneficial cocktail. So in that sense, the “search” in every generation is simply for the optimum (in the current environment) allele set of those currently available. Ten generations on, the set of possibilities will be slightly different, as will the current environment, so the population tends to “move” towards the distribution of alleles that works best of the options available. It’s as though chocolate manufacturers kept on adding new chocolates to their boxes at whim, and removing others, and every so often, one particular selection takes the fancy of the customers (more truffles; fewer caramels) and suddenly the manufactureres of the boxes with lots of truffles and hardly any caramels experience much higher demand. Thank goodness those green pralines have almost dropped out of the chocolate gene pool.
6.) If Random mutations are 90% bad most of the time why are we here? is 1% good enough to go from a single cell to a complex organism such as a human? Is this scientifically possible?
Mutations (whether you call them “random” or not depends on what you mean by “random” – most are probably the result of really quite highly deterministic processes, and certainly some kinds of mutations are far more probable than others) are not “90% bad most of the time”. The vast majority are near-neutral. However, in a poorly adapted population (perhaps one subject to rapid climate change) a larger percentage will tend to be beneficial than in a well-adapted population (one in a stable environment) so in the latter, more will tend to be “worse” than “better”. And yes, a small percentage is enough – it’s not the percentage that matters, so much as the frequency of near-neutral mutations, and the rate of environmental change.
7.) How did the feathers evolve?
Lots of literature on this. Try:
Google Scholar: evolution of feathers
8.) How did animals evolve from cold blooded to warm blooded?
Again, google scholar is your friend:
Google Scholar: evolution of thermal regulation warm-blooded
Your most valuable scientific facts will be greatly appreciated.
You are very welcome!
And good luck with your searches 🙂 I’m sure some others will be along shortly to put me right/supplement your reading/explain more clearly.