Download 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