Evolution and Society
Evolution and society
Creationism
Over 40% of Americans believe that the human species was created directly by a god
Most in Europe, Australia, etc. accept evolution
Evolution and religion
Evolution conflicts with a literal interpretation of the bible
Many believe that the bible contains symbolic truths, not literal ones
Many deeply religious people believe in evolution
– Theistic evolution – evolution driven by a divine hand
– Pope John Paul II in 1996 affirmed evolution
Intelligent design
Movement that asserts itself as science
Belief that life is too complex to have formed “by chance”
Many believe that intelligent design should be given equal time with evolution in science classes
– Is intelligent design science?
What is science?
Science is a process for producing knowledge
Science depends on making precise observations of natural phenomena and on formulating rational theories to make sense of those observations
Science reduces our tendency to rely on emotional reactions and unexamined assumptions
Science
Science searches for testable evidence that cultural and religious traditions do not
Scientists do not accept proposed explanations until there is substantial evidence to support them
Science
Science is a process of testing hypotheses about the material world using evidence and natural laws
Scientists are always skeptical and provisional, even of evolution
Intelligent design is not testable and is therefore not science
Evolution has been tested and supported by evidence for the past 150 years
Hypothesis and theory
An hypothesis is a conditional explanation
After systematic testing, scientists either accept or reject the hypothesis
When a large amount of evidence and many tests support a hypothesis and a majority of experts have reached general consensus, we call it a scientific theory
What is the evidence for evolution?
Fossil record
– Has gaps, but even with gaps, data from the fossil record match the predictions of evolution
Evidence for evolution
Phylogenetic and comparative studies
– Molecular and morphological phylogenies match
– Universal features in all organisms, e.g. L-isomer amino acids and DNA
– Intermediate species
Evidence for evolution
Genes and genomes
– Molecular evolution is showing commonalities in all species
– Mechanisms for new genes to arise
– Molecular clocks match phylogeny and fossil record
Evidence for evolution
Biogeography
– Distribution of species correspond to geologic events
Evidence for evolution
Evolution in action
– Grants’ studies on Darwin’s finches
– Endler’s studies on guppies
– Speciation in fruit flies
– Natural selection
– Etc., etc., etc!
Fallacies of intelligent design
What about inferior design?
– Panda’s thumb
– Vestigal structures
Arguments of creationism
Evolution cannot be observed
Evolution cannot be proved
Evolution is not a scientific hypothesis because it is not testable; no possible observations can refute it
The orderliness of the universe is evidence of intelligent design
Arguments of creationism
Evolution of greater complexity violates the second law of thermodynamics, which holds that entropy increases
It is almost infinitely improbable that even the simplest life could arise from non-living matter
Mutations are harmful and do not give rise to complex new adaptive characteristics
Arguments of creationism
Natural selection eliminates unfit mutants, rather than creating new characters
Chance could not produce complex structures
Complex adaptations such as wings, eyes and biochemical pathways could not have evolved gradually because the first stages would not have been adaptive
Arguments of creationism
If an altered structure, such as the long neck of a giraffe, is advantageous, why don’t all species have that structure?
If gradual evolution had occurred, there would be no phenotypic gaps among species and classification would be impossible
Arguments of creationism
The fossil record does not contain any transformational forms representing the origin of major new forms of life
The fossil record does not objectively represent a time series because strata are ordered by their fossil contents, and then are assigned different times based on the assumption that evolution has occurred
Arguments of creationism
Vestigal structures are not vestigal, but functional
The classic examples of evolution are false
Disagreements among evolutionary biologists show that Darwin was wrong
There are no fossil intermediates between humans and apes
Arguments of creationism
As a matter of fairness, alternative theories, such as supernatural creation and intelligent design should be taught so that students can make their own decisions
Practical application of evolution
Health and medicine
Agriculture and natural resources
Environment and conservation
Understanding nature and humanity