Specific Points ‘Bout Evolution

• Each incremental step on the way towards the design of every complex structure must confer more advantage than the previous step along the way

• The Blind Watchmaker: Evolution has no plan or goal -it is controlled entirely by competition and is short-sighted

Each step along the way…(micro- vs. macro-evolution)

• “If it could be demonstrated that any complex organ [or structure] existed which could not possibly have been formed by numerous, successive, slight modifications, my theory would absolutely break down.” - Chuck

• Evolution by natural selection can easily explain slight changes in already existing complex structures, but what about their inception?

• First some easier structures, then some tough ones...

Flippers of Mammals

• Even in human populations there is variation in the amount of skin between digits of the hands and feet, often known a “webbed feet”

• This same variation could have existed in the sea mammal ancestor. If they were beginning to exploit the sea niche, more webbing would be more beneficial

• But no gill adaptation - Bummer...

Flight in Mammals

• How would mammals acquire the ability to fly? What behavior would it allow? What niche could be exploited?

• Bug eating mammals in trees

• Gliding ---> Flying (membranes)

Flight in Insects

• Sure, wings are highly beneficial, but how about all the precursors to wings?

• Would little nubs of wings help the “nubbed” enough to drive evolution towards larger nubs?

• What behavior? Which niche?

• Water insects

One true challenge to Darwinian Evolution: Biochemistry

• Biochemical reactions inside of cells are extremely complex.

• If they came about through Darwinian Evolution, each step along the way in their development must have been “fitter” than the previous one.

• Starting from the present and working backwards, we must be able to walk through a series of structures each less complex and less fit than the one closer to present day.

• For example, a music box...

The Mammalian Eye

• Argument #1: Could all of these pieces fall into place and interact in such complex ways by simple, incremental steps?

• In other words, is this irreducibly complex?

• A complexity quote from the book...

The Protein Clotting Cascade

The Cilial/Flagellar Motor

Argument #2: For a structure witha particular purpose, how couldthe previous structures have worked to generate an output thatrequires such complexity to workat all?

• Swimmer Analogy

• Any Mechanical System:take one piece out andthe thing don’t work at all

Darwin’s Black Box Conclusions

• Assumption #1: FALSE Each piece of the biochemical puzzle is not separate to begin with. E.g. nerve cells, signalling cascades, etc, etc. (music box example)

• Assumption #2: FALSE The structures and cascades did not always necessarily serve the purpose that they do now. Flagella, photocell, nerve cells, etc, etc. (music box example)

• Which leads us to...

The Blind Watchmaker: Fallacy #1 and #2 summed up

• Even though modern structures serve remarkable purposes, they weren’t created to fulfill those roles

• Each structure in the body of any animal must have come about by accident. If the mutation solved some problem, it stayed and changed the gene pool, if it didn’t then it was outcompeted in the gene pool.

• Evolution must be short-sighted. It deals only with the baby step that occurs away from the current position. Many of these steps can lead to complex structures that appear to be made for a purpose, but were not.

• Some quotes...

What’s wrong with this picture?

• “Evolution’s intent for us lies far beyond exercises of ‘mind over matter’ though we need to know of such capacities. Our job on earth is not to mutilate our earth matrix, but to nurture and maintain her as she nurtures and maintains us.” p. 179

• “Arthur Koestler…considered the fact that the left hemisphere has almost no connection with the balancing limbic system an error of evolution. I would point out it is a gamble of evolution’s but hardly an error.” p. 240

• “What use would be… half a lung?”

A Blindness Example:Flippers

Convergence #2: similar environments/ different parts of the world

Okay, Explain this Complex Structure in terms of Evolution

Okay, Explain This: Mammalian Ears

• Waves in our environ-ment tell us much

• Strong selection towards perception of waves

• Any delicate surface linked to activating a nerve cell will do

• All the rest are structural details

Cilia in the Cochlea (Hearing)

…in the Semicircular Canals (Balance)

…in the Nose (Olfaction)

The Selfish Gene

• Many think that animals act for the good of the species.

• Others think that animals act for the good of themselves.

• It turns out that animals act for the good of their genesgenes.

• In other words, “A human is just a genes way of making another gene…”

Explaining Cooperation and “Altruism”

• Female birds risk their own lives to save their offspring

• Vampire bats with extra blood feed the babies of neighbors

• Hyenas and Wild dogs let each other know when they’ve made a kill to share the food

• Bees sting an invader (and kill themselves in so doing) to save the hive

• Zebra and Giraffe sharing the watch at water hole