Human Biological Variation Midterm

Human Adaptation: Homeostasis and Stressor

adaptations that allow them to change and survive in different environments, the ability to maintain homeostasis is an adaptive success homeostasis (maintain/restore stable internal physiological environment within tolerable limits) stressor (disruption of normal functioning and interferes with homeostasis)

Hardy Weinberg theory of genetic equilibrium: principles and utlity

allele and genotype frequencies in a population must remain constant or are in equilibrium from generation to generation unless specific disturbing influences are introduced

The "eternal triangle": Genotype, Phenotype, and Culture (Paul Baker)

attempts to understand the causes for phenotypic differences in the biology and behavior of human populations phenotype should be conceived as interaction between genotype, physical environment, and culture

phenotypic plasticity and reaction norms

based on the mechanimsm associated with phenotypic plasticity (ability of single genotype to generate a range of phenotypes in response to environmental conditions)

point mutation

change in 1 base pair of DNA

histone methylation

chemical cahnges in chromatin structure that lead to how DNA strands are wrapped around a histone protien

Describing vs. classifying human variation

classification schemes in biology of human diversity as "race" we describe/categorize people based on skin color

exons

coding DNA, transcribed by mRNA and involved in protein synthesis

structural gene

coding sequences code for proteins, which are constructed by amino acids (collagen, enzymes)

haplotypes

combinations of genes or nucleotides in close proximity and inherited as a linked unit

stress and health

direct physio effect through activation of stress response and indirect effects through health relatd behaviors

problem of evolutionary convergence

distantly related populations are similar for certain traits if they evolved under the same selctive pressures

great chain of being

early classifications used this system of the universal heirarchical ladder (implied or explicit rank order of superiority from euro--> asian-->american-->black)

developmental origins of health and disease (DOHaD)

environmental events occurring during sensitive developmental periods that can induce effects on human biology that persist into adulthood

epigenetics

epigenetics (differences in how DNA is read without changes in the DNA itself) epigentic mechanisms 1. DNA methylation 2. Histone methylation

fetal origins moderl (david barker)

fetal undernutition/ permanent physiological programming --> developmental response--> low muscle, insulin resistance, high visceral fat, hypertension--> increased cardiovascular and metabolic disease risk in adulthood

general objectives and timing of developmental plasticity

fine tune an individuals physiology during development to match the local ecological conditions, induce long term adjustments in bio structure and function of the phenotype

Altman bonobo research

foraging in east african dump--> increased size, earlier sexual maturity, enhanced sexual dimorphism

mitochondrial DNA

found in mitochondria, maternally inherited, high mutation rate, high copy number in each cell

isolation by distance

high gene flow btwn geographic close populations human genetic diversity form geographic clines (people tend to be more genetically similar to people who line near them then 2 people who live father away0

Samuel Morton: Cranial Measurement

hypothesis: difference among race particularly among brain size (intellectual capabilites) 1. brain capacity order: english, chinese, SE asian, american indian, african thoughts at the time 1.humans could be divided into fixed number of race 2.moral intellectual capabilities not evenly distributed among races 3.mental capabilites are associated with certain racial features

primate foundations of developmental plasticity

increased bio flexibility in primate systems with long lifespan and slow growth, physio flexability allows enviro tracking

frameshift mutation

insertion or deletion of DNA that leads to misreading of codon

biological programming (david barker)

insult experience during a senstive time of development can affect the growth and organization of specific biological systems

nondisjuntion mutation

lack of seperation between homogolous chromosomes during meiosis when combined with a normal gamete--> leads to extra chromosme

developmental plasticity

long term, irreversible changes that result from exposure to environmental stressors during growth and development

classic markers

mendellian inheritance, protein polymorphisms ex. blood groups

synthetic theory of evolution

merging of natural selection and genetics through mutation

DNA mathylation

methyl groups attach to regions adjacent to specific gene promoters

introns

most non-coding DNA

polygenic

multigene inheritence, traits infleunce by the actions of two or more genes and often produce variation

genetic switches

not actually genes but sections of the DNA that turn nearby genes on/ off

population thinking

not typology

SNP's

occur bz of alteration in single nucleotide via point mutation

polymorphism

occurrance in a discrete gene trait of two or more genetic variations

how race becomes biology: Gravlee's biocultural approach

overfocus on genetics so.... 1. consider multple levels of analysis 2. use developmetnal and life course perspectives 3.look at individual levels of racism 4.look at institutionalized racism

hardy weinberg breakdown

p= frequency of the dominant p^2 = homozygous dominant (RR) q= frequency of the recessive q^2 = homozygous recessive (rr) 2pq= frequency of Rr (heterozygous Rr)

hardy weinberg equation

p^2 +2pq +q^2 = 1 (p+q=1)

Functional Adaptations: Acclimitization and developmental acclimitization/ plasticity

phenotypic changes during the lifetime of an individual to help maintain homeostasis in response to a stressor

anthropometry

physical measurement of the human form

acclimitization

provides important buffering mechanisms to maintain internal stability (homeostasis)

regulatory gene

regulate the timing and expression of other genes, turns DNA on or off ex. HOX gene (highly structured genes that control sequential patterns during development)

Herbert Spencer: social darwanism

scientific racism of applying evolution framework to describe social evolution competition to survive to maintain and improve characteristics of human racial groups

pleitrophy

single gene inheritence that affeccts differet traits

craiometery

size and shape 1. cephalic index (breadth/depth of skull) 2. facial form (progmatic [projecting midface], or orthognathic [straight faced])

Stephen J Gould

the mismeasure man thought morton manipulated data to inform hypothesis on brain size reflected intelligence subconciously

population genetics

the study of how frequency and distribution of alleles, genotypes, and phenotypes within and between populations focus on the change in the genetic composition of populations over time and geographical space

complex or polygenic traits

traits whose properties are controlled by many genes

gene- environment interactions

typically not based on a one-to-one correspondence bwteen genes and expression of traits ex. Tooth crowding and malocclusion (result from changes in diet and food prep, softer food reduces stress on chewing muscles, reducing the underlying bone)

How to address the question of "Are we still evolving?"

until recently no, however yes because of the evolution of food production (malaria, sickle cell, lactose, skin color) evolution is not just natural selection, there are multiple factors (mutation, gene flow, genetic drift, natural selection)

transcription and translation

DNA--> RNA--> amino acids--> proteins

Johann Blumenbach

"father of physical anthropoloy" defined the classical race in 1795 1. 4 group scheme of geography (europeans, asian, american, african) 2. 5 group scheme of physical characteristic (caucasion: white, mongolian:yellow, ehtiopian:black, american:red, malayan: brown) studies skeletal morphology--> the field mves toward focus on the skull and the era of measurement and explicit hierarchy begins

Francis Galton: eugenics

"race improvement" and controlled selective breeding sterillization and anti-immigrant movement natural selection in species as away to improve/control hereditary traits

Modes of biological adaptations (Gabriel Lasker)

* Gabriel Lasker proposed in 1969 science paper that stated 1. human biology has a repertoire of adaptive processes or "modes" that allow for adjustment to environmental change 2. humans must cope with ecological change that occurs on multiple levels and timescales

early scientific approaches to human variation

1. Carolus Linneaus 2. Johann Blumenbach

Types of human adaptation: Cultural/behavioral and biological

1. cultural/ behavioral tools, tech, language, medicine, subsistence strategy and diet, aspects of culture can be adaptive by increasing survival and fitness 2. biological

3 modes that allow for adjustment to environmental change

1. darwinian or genetic adaptors 2. acclimitization 3. developmental plasticity

human genetic variation and the concept of race

1. human genetically extremely homogenenous 2. human racial classification based on diff criteria are nonconcordant (diff traits= diff clustering) 3. evolutionary convergence

hardy weinberg 5 condition

1. matins is random with respect to the trait being studies 2. mutation is not occurring at the locus being studied 3. the population is infinite which limits the possibility of random genetic drift 4. no migration in or out of the population, thus no gene flow 5. natural selection is not acting on the trait being studied

Key events leading to fall of race concept

1. modern synthesis 2. sherwood washburn "the new physical anth" 3. population thinking 4. Human developmental plasticity and secular trends

monogenesis vs. polygenesis

1. mono -human race were the result from chances in a single origin 2. poly -races were seperate bio species and emphasized heirarchy (multiple humans with diff species: race)

Rise of Race concept

1. most early studies of human variation were focused on description and classification not understanding 2. physcial anthro begins as technique to describe an classify modern humans 3. early studies of human var shaped european colonialism and ethnocentricism 4. evolutionary theor provides a framework for understanding human var, early attempts were problemative

evolutionary forces shaping genetic variation

1. mutaiton 2. gene flow (increased genetic variation within populations and decreased genetic variation between populations) 3. genetic drift (decreased genetic variation within populations and increased genetic variation between populations) 4. natural selection

key factors to stress and health

1. percieved lack of control 2. lifestyle inconguity 3. lack of social support 4. inability to acheive full social engagement

Types of genetic and DNA markers

1. polymorphisms 2. classic parkers 3. complex or polygeneic traits 4. SNP's 5. Haplotypes

Genetic/Darwinian Adaptations

1. reflects natural selection, developed over many generations (measured through fertility and mortality) 2. expected when enviromental stressors due present over long period of time, stressors cant be buffered using other means limits the ability to make future changes in physiology of morphology

continuous variation and nonconcordance

1. variation typically continuous in most traits of interest to those studying traits 2. nonconcordance (diff traits lead to diff pop groups, but they vary independently of each other--> thus choice is arbitrary)

carolus linneaus

1758 used a systematic attempt at assigning varieties of race (homo sapiens, hs. americanus, hs. europeous, hs asaiticus, hs ferus, hs montrous) used a form of biological determinism by traits like skin color, head size & shape, facial shape, geography, and percieve intelligence and behavior to categorize

modern synthesis

1930/40's started with synthetic theory of evolution, and bridged macro and micro evolution turing the focus onto populations focus on pop: watched variabel populations to see that change in allele/gene frequencies over generational time and populations evolve not individuals

Sherwood Washburn: the new physiccal anth

1951 sought to bring physical anth into the realm of modern synthesis by changing perspective and moving from methods and classsification to processes of mechanization of evolutionary cahnge unifying theoretical framework for understanding human variation and change through time

Frank Livingstone: "On the non-existence of human races"

1962 suggests the focus on clinal variation in geography other then the unchanging view of discrete racial groups is inconsistent with out knowledge of human adaption and evolutionary change

Richard Lewontin: patterning of genetic variation

1972 looked at allele frequencies within and wout of populations to understand genetic change of variation 1. variation btwn races (10) 2. variation brwn pop (5) 3. variation within pop (85) race no longer valid because variation in the population is the highest

human developmental plasticity: franz boas and secular trends

Franz boas 1. Immigration studies 1912 2. elements from environment effect growth and development, the plasticity of the human , not just in weight and height but also in cranial shape (facilitated the demise of the race concept because markers that were once thought as set were not plastic) secular trend 1. change in phenotype occur over generational time

general adaptation syndtrom

Hans Seyle the ability to return to homeostasis unless ongoing stress then exhaustion