Week 2

Evolutionary context

effects of evolutionary forces on human variation, broad geographic and temporal scope

Holistic approach

consider biology/culture/environment, belive cannot separate humans biologically from their culture

Evolution

process, dynamic series of events, change in biological constitution of an organism

macroevolution

large scale change (fossil), speciation

microevolution

smaller scale change to gene/allele frequences over generations, adaptation

Pre Darwin view of natural world

static and unchanging, product of grand design, typological thinking, difficulty in understanding/explaining variation/change

Essentialism

traced to plato, fixed forms exist perfect and unchanging, difference are accidents

Aristotle

elaborated on essentialism, similarities and difference could be used to arrange life in single line (great chain of being)

The great chain of being

framework for interpreting the world, every living thing linked in single line (no gaps/felxibilty/extinction), differed from those above/below by least possible difference,ranking-higher closer to divine ideals (angels), separated humans by sex/race

Carolus Linnaeus

modern biological taxonomy (classification), essentialist, reorganized the great chain of being, grouping based on similarites/differences, recognized close similarities but didnt suggest evolutionary relation, depicted human as part of nature (controversy), published Systena Naturae

modern taxonomy classification system

kingdom, phylum, class, order, family, genus, species

Primate traits (linnaeus classification)

opposable thumb/big toe, nail not claws, fingertips/toes have pads rich in nerve ending and dermal ridges (sensitivity and friction)

Systema Naturae

by Carolus linnaeus, revise with increasing diversity from exploration,classified human diversity using subspecies call human varieties

Linnaeus human varieties

American (reddish), European (white), Asiatic (yellow), negro (black)

linnaeus basis for human varieties

skin colour, face form, skull shape, stature, hair form, nose shape, behavioural attributes/social customs (biodeterminism)

Johann Blumenbach

classified human 5 races (Caucasoid, Monogoloid, American, Ethiopian, Malayan), essentialist but environment (diet/climate/social class) account for smaller variation within race

Blumenbach basis for races

skin colour, hair form, facial characteristics (idea of degeneration via exposure to stressors), skull shape and measurment (Craniometry) (regarded as resistant to influence)

Jean baptiste de Lamark

changes in evolutionary thinking, challenges concept of fixity of species, examines interation between environment and biology to explain change/variation,believed changed to better suit it environment, Transformational evolution, suggest fossils were ancestors, creator gve ability to change with the changing world

Transformational evolution

organism in species change physically in response to change/new environmental demands

lamark laws of transformation

law of use/disuse, law of inheritance of aquired characteristics

law of use and disuse

feature of an organism could be strengthened/enhanced by use and weaken/disappear through disuse

law of inheritance of aquired characteristics

changes which occurred in an organism lifetime could be passed to its offspring

Charles Darwin and ALfred russel wallace

observed geographical variation in organism in form of species divsersity, idea that variatiion result of different species emerging through descent with modification

Charles darwin influences and background

Charles lyell’s Principle of geology (nautral forces reshape earth), modification through artifical selection (pigeon breeder),Thomas Malthus’ Essay on the princple of population (Competition for scarce resources)

On the origin of Species by Mean of Natural Selections or Preservation of Favoured Races in the Struggle for Life

written by charles darwin, published November 1959 (he was 50)

Thomas Malthus

english clergyman/political economist, concered declinging living conditions, percieved inherent conflict (nature reproduces quicker then resources do), faminie/poverty result from overpopulation and resource depletion, population growth lead to struggle for life (competition)

Variational evolution

biological variation is present in population, varaition best suited/adapted for enviroment has greater chance of survival, greater chance survival = greater chance of reproducing (passing on those traits)

Natural selection

slow and gradual process, population over generations, concept of fitness

measurment of fitness

Differential mortality (survive to reproduction age), Differential fertility (reproduce)