The Evidence for Evolution Exploring modern science’s most eloquent theory

The Nature of Science Methodological vs. Metaphysical Naturalism Why Methodological Naturalism? 1. It Works! 2. Denying it Breaks the Scientific Method

The Nature of Science Three Criteria 1. Methodological Naturalism 2. Falsification 3. Predictability

Science Vs. Religion? NOMA -> Non-Overlapping Magisterium the magisterium of science covers the empirical realm: what the Universe is made of (fact) and why does it work in this way (theory). The magisterium of religion extends over questions of ultimate meaning and moral value. These two magisteria do not overlap, nor do they encompass all inquiry (consider, for example, the magisterium of art and the meaning of beauty).

History of Evolutionary Thought Lucretius (1st Century BC) Many were the monsters also that the earth then tried to make, springing up with wondrous appearance and frame…Whatever you see feeding on the breath of life, either cunning or courage or at least quickness must have guarded and kept it from its earliest existence…But those to which nature gives no such qualities, so that they could neither live by themselves at their own will, nor give some usefulness for which we might suffer them to feed under our protection and be safe, these certainly lay at the mercy of others for prey and profit, being hampered by their own fateful chains, until nature brought that race to destruction.

History of Evolutionary Thought Charles Lyell (19th Century) Uniformitarianism - The principle that the same scientific laws and processes are constant throughout space and time. Applied to geology, this meant that the geological column was built up gradually over time.

History of Evolutionary Thought Charles Darwin (1859) On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life In the struggle for survival, the fittest win out at the expense of their rivals because they succeed in adapting themselves best to their environment. I have called this principle, by which each slight variation, if useful, is preserved, by the term Natural Selection.

The Darwinian Mechanism As many more individuals of each species are born than can possibly survive; and as, consequently, there is a frequently recurring struggle for existence, it follows that any being, if it vary however slightly in any manner profitable to itself, under the complex and sometimes varying conditions of life, will have a better chance of surviving, and thus be naturally selected. From the strong principle of inheritance, any selected variety will tend to propagate its new and modified form.

The Darwinian Mechanism Natural Selection - The process whereby organisms better adapted to their environment tend to survive and produce more offspring

The Darwinian Mechanism Natural Selection + Variation = Evolution What is the source of variation?

The Darwinian Mechanism Lamarckism - The idea that an organism can pass on characteristics that it acquired during its lifetime to its offspring (also known as heritability of acquired characteristics).

The Darwinian Mechanism The Neo-Darwinian Synthesis 1. All evolutionary phenomena can be explained in a way consistent with known genetic mechanisms and the observational evidence of naturalists. 2. Evolution is gradual: small genetic changes, recombination ordered by natural selection. Discontinuities amongst species (or other taxa) are explained as originating gradually through geographical separation and extinction (not saltation). 3. Selection is overwhelmingly the main mechanism of change; even slight advantages are important when continued. The object of selection is the phenotype in its surrounding environment. 4. The primacy of population thinking: the genetic diversity carried in natural populations is a key factor in evolution. The strength of natural selection in the wild was greater than expected; the effect of ecological factors such as niche occupation and the significance of barriers to gene flow are all important. 5. In paleontology, the ability to explain historical observations by extrapolation from micro to macro-evolution is proposed. Historical contingency means explanations at different levels may exist. Gradualism does not mean constant rate of change.

The Darwinian Mechanism In Simpler Terms... Natural Selection + Random Mutations = Evolution

Evidence for Evolution 1. Experimental Evidence 2. The Fossil Record 3. Biology 4. Genetics

1.) Experimental Evidence Evidence for the Neo-Darwinian Mechanisms Evidence for Speciation 1. New Species in the Lab Fruit Flies 2. New Species Observed in the Wild

2.) Fossil Record Geological Column - Ordering of the fossil record into distinct periods. Different ranges of time are associated with particular strata of rocks.

2.) Fossil Record Transitional Forms 1. Archaeopteryx

Bird-Like FeaturesDinosaur-Like Features ‣ Wings ‣ Wishbone ‣ Flight Feathers ‣ Partially Reversed Toe ‣ Jaws with Sharp Teeth ‣ Three Fingers with Claws ‣ Long, Bony Tail ‣ Hyper-extensible Second Toe ‣ Various Skeletal Features

2.) Fossil Record Transitional Forms 1. Archaeopteryx 2. Tiktaalik

Fish-Like FeaturesFishapod-Like FeaturesTetrapod-Like Features ‣ Fish Gills ‣ Fish Scales ‣ Limb bones and joints (including fish-like fins instead of toes.) ‣ Ear Region ‣ Tetrapod Rib Bones ‣ Tetrapod Mobile Neck ‣ Tetrapod Lungs

2.) Fossil Record Transitional Forms 1. Archaeopteryx 2. Tiktaalik 3. Homo Erectus

3.) Biology Homology Homology - Any similarity between characteristics that is due to shared ancestry.

3.) Biology Homology Homology - Any similarity between characteristics that is due to shared ancestry. Vestigial Structures 1.Whale Legs 2.Wings on Emus and Other Flightless Birds 3.Human Appendix Vestigial Structures - Homologous characters of organisms which have seemingly lost all or most of their original function in a species through evolution.

4.) Genetics Pseudogenes Synteny Blocks Pseudogenes - Defunct relatives of known genes that have lost their protein-coding ability or are otherwise no longer expressed in the cell. Often called “Junk DNA.” Syteny Blocks - Similar regions where unrelated genes are found in the same order on chromosomes of different organisms.

Intelligent Design? Michael Behe -> Darwin’s Black Box Irreducible Complexity - A system composed of several well-matched, interacting parts that contribute to the basic function, wherein the removal of any one of the parts causes the system to effectively cease functioning.

Intelligent Design? H Allen Orr An irreducibly complex system can be built gradually by adding parts that, while initially just advantageous, become- because of later changes - essential. The logic is very simple. Some part (A) initially does some job (and not very well, perhaps). Another part (B) later gets added because it helps A. This new part isn’t essential, it merely improves things. But later on, A (or something else) may change in such a way that B now becomes indispensable. This process continues as further parts get folded into the system. And at the end of the day, many parts may all be required.

Conclusion Evolutionary Theory is well-supported by the evidence and forms the backbone of scientific biology today.

Questions?