(1938 – 2011)
An American biologist and notorious for giving out about the Neo-Darwinian version of our current dogmatic and blinkered view of evolution. She is famous in her own right for coming up with the origin of complex cells hypothesis which she says resulted in further complexity and diversity due to merging of simple cellular life-forms (a form of symbiosis). She was also married to Carl Sagan (who is famous for popularising the science behind the COSMOS). This is what Richard Dawkins says about her theory:
“I greatly admire Lynn Margulis’s sheer courage and stamina …
This is one of the great achievements of twentieth-century evolutionary biology, and I greatly admire her”.
(Excerpt from the Third Culture: Beyond the Scientific Revolution by John Brockman 1995, Chapter 7) 
Here’s what Margulis says about Dawkins and his elk:
“Neo-Darwinists say that new species emerge when mutations occur and modify an organism. I was taught over and over again that the accumulation of random mutations led to evolutionary change __ led to new species. I believed it until I looked for evidence”
(Teresi 2011, p. 68 from an Interview in Discover Magazine) 
Here’s another quote:
“Mutations, in summary, tend to induce sickness, death, or deficiencies. No evidence in the vast literature of heredity changes shows unambiguous evidence that random mutation itself, even with geographical isolation of populations, leads to speciation”.
(Margulis & Sagan 2003, Acquiring Genomes: A Theory of the Origins of the Species, p. 29) 
And yet another quote:
“When evolutionary biologists use computer modeling to find out how many mutations you need to get from one species to another, it’s not mathematics—it’s numerology”.
Ammendment to reference: apologies – I had referenced this previously as: Margulis: Science’s Unruly Earth Mother, in Science 19 April 1991) . It is actually from (Teresi 2011, p. 71 from an Interview in Discover Magazine) 
“[…] Then how did one species evolve into another? This profound research question is assiduously undermined by the hegemony who flaunt their correct solution. Especially dogmatic are those molecular modelers of the tree of life who, ignorant of alternative topologies (such as webs), don’t study ancestors. […], they correlate computer code with names given by authorities to organisms they never see! Our zealous research, ever faithful to the god who dwells in the details, openly challenges such dogmatic certainty.”
Margulis – The President of American Scientist Magazine (2006 The Phylogenetic Tree Topples)