Download Nothing in biology makes sense except in the light of evolution

Nothing in biology makes sense except in the light of evolution
Dobzhansky, 1973
Definitions
In science, laws and theories are related but separate
Different types of scientific knowledge
Laws: statements or generalizations made about natural
phenomena
Law of Natural Selection
Organisms with adaptations that allow them and their offspring to
thrive in an environment will survive, others will eventually die out
Law of Gravity
Math equation, demonstrates how gravity works under ideal
conditions and with things of “large” mass (anything above an
molecule in size)
Mass of one object * Mass of second object
Gravity = Universal ________________________________________
Constant
Square of distance between two objects
Fg = G [m1 * m2 / r2 ]
Theories: explanation of for how the law works
Theory of Evolution
Change over time
Explains how natural selection works
Theory of Gravity
Does not exist, no one not even Einstein could explain how gravity
actually works, especially at the atomic and subatomic levels
Evolution and Darwin
Historical Evidence
600 BCE
 Anaximander, credited with coming up with the primary tenets
of evolution
 Determined that creatures from the sea were forced to come
ashore, and evolved into land creatures
345 BCE
 Plato writes that all life represents the imperfect replica of a
perfect heavenly model
 (In other words, living things are not perfect and are able to
change over time.)
340 BCE
 Aristotle observes that dolphins and whales come to the surface
for air, fish do not. Therefore, dolphins must once have lived
on land.
Early 18th C (1700’s)
 Geological and fossil evidence for change over time is
discovered, discussed and published by many geologists and
early paleontologists.
 There was no good explanation of the mechanisms for that
change
Observational Evidence (Darwin)
 HMS Beagle (1831 – 1836)
 Made numerous observations, hated boat trips and tried to get
off as often as he could.
 In South America looked at living armadillos and compared
them to fossil evidence.
 Compared living organisms to fossil evidence: human bones,
mollusk shells, ferns, etc
 Galapagos: made observations of animal behavior as well as
appearance
 Finches were used to determine the mechanism of evolution
o An original finch population came from the West Coast of
South America and settled on the islands
 Finches found on the West Coast of South America
do not have a lot of genetic differences
o These finches spread out over time
o Random genetic mutation allowed some finches to
survive in “microclimates” while others died
 Ones with larger beaks break apart harder seeds
 Smaller beaks eat smaller seeds
 Vampire finches
o Eventually they “drifted” genetically apart and are
separate sub species
o Over time they could develop into completely separate
species of birds (thousands to millions of years)
Historical, Cultural and Social Influence
 Alfred Russel Wallace (1858)
o Traveled to Indonesia and made his own biological
observations
o Came to the same conclusions as Darwin, wrote to
Darwin to get Darwin’s opinion
o Darwin honored Wallace’s contribution (today seen as
equals)
o Work gave Darwin the push to publish
Experimental Evidence
Darwin
 Took 20 years of writing and experimenting before he
published (1859, Origins of the Species)
 One example:
o Took seeds and immersed them in sea water over
different time periods to see if the seeds could germinate
o Were seeds able to make it to Galapagos from S. America
(yes)
Current Evidence
 Surtsey: Volcanic island near Iceland a current “living
laboratory”
o Didn’t exist until 1964
 Genetic Research
o Look at DNA and can compare genes
o Find out how many genes we share with different species
 98% the same a chimpanzees
o Also demonstrates the immense differences that can
occur with so few genes
 Bacterial and Viral drug resistence
o Exposed to antibiotic and antiviral drugs
o Only one surviving bacteria or virus needs to develop an
immunity
o Will pass trait onto offspring
o New strain of bacteria or virus that current medicine will
not kill