Evolution and Natural Selection, Anthropologically

All cites from Lavenda and Schultz (2012): Anthropology: What Does it Mean to be Human?

Ideas from the Bible & Greek philosophy (LS:31)

Greeks: enduring worldBible: Earth was young

October 23, 4004 B.C. (36-37)Shared Essentialism, unchanging worldspecies have essences, unchanged since creation (31)“Cowness”

Great Chain of Being (LS:32)

VIEWS OF NATURAL WORLD

BEFORE EVOLUTION

Fossils of extinct speciesSimilar but different from existing

Catastrophism versus Uniformitarianism (33)

Revise essentialismSpecies change over timeOlder earth (LS:37)

NEW MATERIAL EVIDENCE (LS:33)

Transformational Evolution, Lamarck (LS:35)Panda’s “Thumb”GiraffesUse the thumb, stretch the neck, passed along

Mechanism of Natural Selection, Darwin

and Alfred Russel WallaceVariationHeredityDifferential reproductionCompetition for resources

NEW IDEAS

Man

Animals

Drastically over-simplified view of thoughts about evolution, circa 19th century

Evolution joined the “links” on the Great Chain of Being but did not change underlying idea

After originally talking about “descent with modification,” Darwin borrows Spencer’s “survival of the fittest” phrase

BIG MISTAKENo such thing as absolute fitness (LS:39)

Fitness in an always-changing environment

Adaptation & Exaptation (LS:39)

NATURAL SELECTIONTHEN AND NOW

At Darwin’s time, pangenesis or blended inheritance (LS:39)

MendelGenetics: disproves pangenesisInheritance 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

GENETICS, THEN AND NOW

NICHE CONSTRUCTION (LS:50-52)

Genes are dynamic in an environmentOrganisms alter the environmentBeaver damsBirds, rodents, algaeHuman activityUnintentional alterationsThose alterations can change conditions of selection for the next generation

Organisms move to diff erent habitats (52)

SEXUAL SELECTION

Sexual selection: people (and other creatures) choose matesBlue 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 GREATCHAIN OF BEING

Evolution is not a march to the better and betterWithin 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 complexSometimes simpler is more adaptable to changes

BacteriaMonkeys

Chimpanzees

Humans

US

Mice

THEM

US

Humans

Citrus fruits

Flies

US

Bananas

Bacteria

THEM

US

Lions

Worm

s

Bact

eri

a

U S

Hors

es

Ele

phants

TH

EM

INVITATION

“The study of evolution in contemporary biology is very lively” (LS:53)

A method, not an answerInvitation to

Debate, ongoing questions, understanding evidence

Not to a dogmatic cultAccepting that debate doesn’t mean losing religionBut it may mean losing the dogmatic cult