Transcript Document

Evolution and
Natural Selection,
Anthropologically
All cites from Lavenda
and Schultz (2012):
Anthropology: What Does
it Mean to be Human?
VIEWS OF NATURAL WORLD
BEFORE EVOLUTION
Ideas from the Bible & Greek
philosophy (LS:31)
Greeks: enduring world
Bible: Earth was young
October 23, 4004 B.C. (36-37)
Shared Essentialism, unchanging world
species have essences, unchanged since
creation (31)
“Cowness”
Great Chain of Being (LS:32)
NEW MATERIAL EVIDENCE (LS:33)
Fossils of extinct species
Similar but different from existing
Catastrophism versus
Uniformitarianism (33)
Revise essentialism
Species change over time
Older earth (LS:37)
NEW IDEAS
Transformational Evolution, Lamarck (LS:35)
 Panda’s “Thumb”
 Giraffes
 Use the thumb, stretch the neck, passed along
Mechanism of Natural Selection, Darwin
and Alfred Russel Wallace
 Variation
 Heredity
 Differential reproduction
 Competition for resources
Drastically oversimplified view
of thoughts
about
evolution, circa
19th century
Animals
Man
Evolution joined
the “links” on
the Great Chain
of Being but did
not change
underlying idea
NATURAL SELECTION
THEN AND NOW
After originally talking about “descent
with modification,” Darwin borrows
Spencer’s “survival of the fittest” phrase
BIG MISTAKE
No such thing as absolute fitness (LS:39)
Fitness in an always-changing
environment
Adaptation & Exaptation (LS:39)
GENETICS, THEN AND NOW
At Darwin’s time, pangenesis or blended
inheritance (LS:39)
Mendel
Genetics: disproves pangenesis
Inheritance preserves variation as individual
units
Very complex, not just one gene/trait (41-49)
Latest research on importance of genetic
switches
Genes just one part of developing organism
NICHE CONSTRUCTION (LS:50-52)
Genes are dynamic in an environment
Organisms alter the environment
Beaver dams
Birds, rodents, algae
Human activity
Unintentional alterations
Those alterations can change conditions
of selection for the next generation
Organisms move to different habitats (52)
SEXUAL SELECTION
Sexual selection: people (and other
creatures) choose mates
Blue eyes or red feathers are not necessarily
indicators of fitness
Agency: Actions like moving, altering the
environment, selecting mates can
reshape evolutionary processes (LS:53)
Doesn’t mean we can do whatever we
want or control consequences
REVISITING GREAT
CHAIN OF BEING
Evolution is not a march to the better and
better
 Within an environment, environment always changing
and in dynamic interaction with organisms (LS:39)
 Adaptive in one environment, maladaptive in others
 Humans are not inevitable result or pinnacle (53)
Evolution doesn’t always “work”
 99.999% of once-existing species are extinct (53)
Not a path from simple  complex
 Sometimes simpler is more adaptable to changes
THEM
U
S
THEM
Chimpanzees
Bacteria
Monkeys
Mice
Humans
Horses
Bacteria
Elephants
US
Worms
Lions
U
S
INVITATION
“The study of evolution in contemporary
biology is very lively” (LS:53)
A method, not an answer
Invitation to
 Debate, ongoing questions, understanding evidence
 Not to a dogmatic cult
Accepting that debate doesn’t mean losing
religion
 But it may mean losing the dogmatic cult