Question
What are alternative theories to Darwinian evolution that explain our observations in biology?
Answer
Shan Kothari's answer is excellent.
I'll just add one point to it. Stuart Kauffman at the Santa Fe Institute has been trying to come up with such a theory for a couple of decades now. See At Home in the Universe for his approach.
It is suggestive, but not entirely convincing. It isn't an alternative to Darwinism so much as a sort of build on it using more basic properties of complex systems, the mathematics of graphs, self-organized criticality and so forth.
There are basically two things you can add to Darwinism to model more phenomenology: throw in ideas from thermodynamics (which many in the "chaos theory" era tried to do with ideas like "dissipative systems") and throw in ideas from pure mathematics. Von Neumann was the first to really figure out this basic idea, via his work on Universal Constructor self-replicating automata and results showing that open-ended evolution required injection of randomness from the outside into a computing system. There are various results about this sort of math (about how minimally complex a system needs to be to be self-replicating, etc.... self-replication is central to this question because it basically is a view of all evolution as signal transmission without corruption over time... evolution tries to find increasingly noise-resistant signals in a way)A simple illustration of the role of pure mathematics is the way properties of prime numbers can affect species' phenotypes, as in the case of the 17 year cicada cycle.
Early days yet, but this is a promising line of work to build on Darwinism. It should bring in good models of irreversibility and increasing complexity.
I'll just add one point to it. Stuart Kauffman at the Santa Fe Institute has been trying to come up with such a theory for a couple of decades now. See At Home in the Universe for his approach.
It is suggestive, but not entirely convincing. It isn't an alternative to Darwinism so much as a sort of build on it using more basic properties of complex systems, the mathematics of graphs, self-organized criticality and so forth.
There are basically two things you can add to Darwinism to model more phenomenology: throw in ideas from thermodynamics (which many in the "chaos theory" era tried to do with ideas like "dissipative systems") and throw in ideas from pure mathematics. Von Neumann was the first to really figure out this basic idea, via his work on Universal Constructor self-replicating automata and results showing that open-ended evolution required injection of randomness from the outside into a computing system. There are various results about this sort of math (about how minimally complex a system needs to be to be self-replicating, etc.... self-replication is central to this question because it basically is a view of all evolution as signal transmission without corruption over time... evolution tries to find increasingly noise-resistant signals in a way)A simple illustration of the role of pure mathematics is the way properties of prime numbers can affect species' phenotypes, as in the case of the 17 year cicada cycle.
Early days yet, but this is a promising line of work to build on Darwinism. It should bring in good models of irreversibility and increasing complexity.