Reddit mentions of Evolution, the Extended Synthesis (The MIT Press)

What part of evolution? Common ancestry is as solid as anything in biology. The role of natural selection is more controversial these days. Some people (e.g., Dawkins) think natural selection is absolutely central; the only way you can get complexity in the natural world. Others (e.g., Stuart Kauffman, Mary Jane West-Eberhard) think the role of natural selection has been overstated. They emphasize things like development, self-organization, etc.

EDIT: Just to make it clear if it wasn't, when I say the role of natural selection in evolutionary theory is becoming more disputed, I am not talking at all about Intelligent Design. Kauffman, West-Eberhard, and the rest are thoroughly committed to a naturalistic, scientific understanding of complexity in the natural world. If you'd like to learn more, check out Stuart Newman's page for his articles, Mary Jane West-Eberhard's page for her articles, Stuart Kauffman on PubMed, Gerd Müller's page for his articles, and the collection of articles in Evolution: The Extended Synthesis.

The main tenets of Darwin's ideas, mainly the idea that evolution occurs because of natural selection on variations, has stayed the core of evolutionary theory. However, the processes and scope of evolutionary theory have expanded dramatically and have done away with some of the assumptions that Darwin held. As Timizle and civilizedanimal have mentioned, Darwin was operating in a world that didn't know about Mendelian inheritance so many of his theories on how variation occurred are often very wrong. Darwin had a brilliant understanding to the What, but he didn't have the evidence to explain the How.

Darwin, and most evolutionary biologists through the 1960s, thought that evolution was only the result of slow, gradual change selected upon by natural selection. However, there are growing bodies of evidence, mostly from epigenetics and Evo-Devo (Evolutionary developmental biology) that evolution can occasionally happen in larger jumps and also take some different paths than gradual genetic change. As is the usual disclaimer, these Wikipedia articles are not definitive science texts, but good introductions to the topics.

A good book that opened my eyes to how much evolutionary theory has advanced beyond the basic concepts of Darwinism was Evolution: The Extended Synthesis. It gives a great account of the last 30-40 years of evolutionary biology written by scientists who are active today. It can get a little technical at times, but a decent understanding of the basics of evolution should be enough to understand almost all of it.

https://www.amazon.com/Evolution-Extended-Synthesis-MIT-Press/dp/0262513676

As one commenter has already pointed out, this kind of thing has been going on for a long time. Sometimes it's punctuated equilibrium, sometimes it's niche construction, sometimes it's group selection, and sometimes it's epigenetics, but debates about whether we need an extended synthesis to accomodate 'new' mechanisms of evolution are nothing new. In fact, go back fifty years and you'll find it was the hot topic of biology (see [G.C. Williams' Adaptation and Natural Selection] (http://press.princeton.edu/titles/558.html)).

That being said, it's important not to give the people defending these ideas short shrift (not saying anyone here is). There's a lot of impressive empirical and philosophical work meant to show the traditional framework can't readily accomodate the processes above, i.e. that they lead to new predictions and explanations which weren't really available before, so they can't be dismissed lightly.

Here's some resources to shed light on your question:

• Massimo Pigliucci did a write-up on the topic, responding to [Jerry Coyne's criticism of the extended synthesis idea] (https://whyevolutionistrue.wordpress.com/2009/02/16/are-we-ready-for-an-extended-evolutionary-synthesis/), [here] (http://rationallyspeaking.blogspot.ca/2009/02/jerry-coyne-and-extended-evolutionary.html) (Pigliuicci is a big supporter of the EES)
  
• [Pigliucci's An Extended Synthesis for Evolutionary Biology] (http://www.biol.uw.edu.pl/empseb2010/images/artPigliucci2.pdf) is a classic
  
• [Evolution: The Extended Synthesis] (http://www.amazon.ca/Evolution-Extended-Synthesis-Massimo-Pigliucci/dp/0262513676), edited by Pigliucci, is another good source
  
• Not by a philosopher, but [Gould's Structure of Evolutionary Theory] (http://www.hup.harvard.edu/catalog.php?isbn=9780674006133) is a good source for the history of the modern synthesis v. extended synthesis and of course his [punctuated equilibrium] (http://evolucion.fcien.edu.uy/Lecturas/GouldyEldredge1993.pdf), as well as other ideas meant to motivate revising the synthesis (some of which the architects of the synthesis, like Ernst Mayr, explicitly denied)
  
• Elliot Sober is a huge proponent of group selection, which is one of the things people say the Modern Synthesis came to ignore and so needs to be updated in light of. His and David Sloan Wilson's [Unto Others] (http://www.amazon.ca/Unto-Others-Evolution-Psychology-Unselfish/dp/0674930479) is a good source on this.
  
• For an alternative perspective to Sober's, check out the [Illusory Riches of Sober's Monism] (http://joelvelasco.net/teaching/167win10/kitcher%20etal%2090%20-%20the%20illusory%20riches%20of%20sobers%20monism.pdf) by Phil Kitcher, Kim Sterelny, and Ken Waters. Sober replies to them in [The Poverty of Pluralism] (http://joelvelasco.net/teaching/167win10/The%20Poverty%20of%20Pluralism%20-%20A%20Reply%20to%20Sterelny%20and%20Kitcher.pdf).
  
• Again not philosophers, but John Maynard Smith and Eors Szathmary deal with the major transitions in evolution (which are often treated from a multi-level perspective) from the gene's eye point of view in the [Major Transitions in Evolution] (http://www.amazon.ca/Major-Transitions-Evolution-Maynard-Smith/dp/019850294X)