evidence for evolution story: where did we come from? you may be tested on all the material in this...

Evidence for Evolution

Story: Where did we come from?

You may be tested on all the material in this powerpoint

Kansas State Board of Education

• 1999 this school board adopted new statewide standards

• Missing was the Theory of Evolution

• In 2000 there was a backlash

• Some lost their jobs

• Theory of Evolution was added once again to the curriculum

Kansas State Board of Education - part 2

• In 2004 many ousted members were reelected

• They adopted a different approach• They mandated the teaching of ‘alternatives

to evolution’

• Other lawmakers in other regions of the US have also interjected their views into the teaching of evolution

Why the upheavals

• The root issue is the discussion of human existence and origins

• Who are we?• Where did we come from?• Many religions include a key part about how humans

were designed by an intelligent supernatural being• In contrast, evolutionary theory argues we descended

from ancient apes• The courts have consistently upheld the constitution and

outlawed the teaching of religious beliefs at school

Implications

• The Kansas State School Board argued that the Theory of Evolution represents a religious view too!

• One that rejects the actions of a higher power• The same board voted to allow the teaching

of evolution provided the teachers discussed ‘gaps’ in the theory and offered alternative explanations for these gaps

• Is this acceptable - both are a matter of faith• Or is this a dangerous trend in US education?

What is evolution?

• Has two different meaning for biologists– 1) A process

• Evolution means change - Biological evolution means change in the characters of a population over generations.

• These changes MUST occur at the genetic level– Inherited characters (i.e. head lice example) = evolution– Change in US women's dress size from 8 to 14 over the

past 50 years = no evolution

– Most people accept that this process occurs• Aristotle was incorrect - he said species had never

changed

What is evolution?

• Has two different meaning for biologists– 2) A theory - The Theory of Evolution

• It is unfortunate that the word theory has a completely opposite meaning to the nonscientist verses that formulated by scientists.

• It gives the notion of a ‘best guess’

– DEFINITION - All species present on Earth today are descendants of a single common ancestor, and all species represent the product of millions of years of microevolution via natural selection and other modes of evolutionary change.

Common Descent

• Nearly every biologist accepts that modern species evolved from ancient ones

• HOWEVER, recent polls of Americans show that 50% of them do not believe that modern species evolved from common ancestors!

Common Descent is a fact!

• When Darwin published his book, most Europeans believed that special creation was fact - that God created all species during the 6 days of genesis– As stated in the first book of the Bible - Genesis– It states that little has changes since that time -

under 10,000 years ago– The same basic belief is shared by Judaism & Islam

Compare

• Special Creation vs Common Descent• Special creation involves a supernatural entity - this

makes it impossible to test by standard observation involving the material universe

• The scientific method cannot be applied to a supernatural entity

• One can test some assertions of special creation– 10,000 years– No change in species ever - the static model hypothesis

More than two hypothesis

• Other hypothesis - somewhere between the two we have been considering exist also -

• Transformation hypothesis – Species can change over time

• Separate hypothesis – Separate common ancestors which can

give rise to different species

All acceptable

• More polls indicated that American citizens

• have about equal belief in all 4 of these hypothesis

• as equally reasonable explanations for the origin of biological diversity

Kansas Board and the citizen

• Most non-scientists believe that the board was right in 1999– It was right to outlaw the teaching of

evolution, to balance between the different theories

• Most non-scientists believe that the board was right again in 2005– Trying to be fair in allowing the

consideration of all other hypothesis

All is not equal

• Most scientists do not consider that the different hypothesis are equal

• They base this view on all the current testable evidence

• …lets consider this evidence with respect to a very important debate… Are humans really related to apes?

Morphology

• Carl von Linne - (Carolus Linnaeus) - Swedish doctor

• Classified all known life forms into biological diversity based on form

• He proposed a two part name• He also formulated a classification system• Linnaeus was himself a believer in the

Creation hypothesis

Evidence from homology

• Similar observable features should similar anatomical and genetic material

• This is what is being discovered…

• Comparative Anatomy– The concept of homology– Similarity of characteristics that has

resulted from common ancestry

Anatomy

• Most plausible explanation is– Each species inherited the basic structure

from the same common ancestor– The process that cause evolution led to

their unique modification in each group