ANG 6930Proseminar in

Anthropology IIA: Bioanthropology

Day 2ANG 6930

Prof. Connie J. MulliganDepartment of Anthropology

This week

Science and Evolution Reading

The Human Species, Chpt 1(pp 12-29) and Chpt 4 Course packet

Park MA. 2005. Biological Anthropology, An Introductory Reader, Chpt 9 (pp 40-44), Natural Selection (1858), Charles R. Darwin and Alfred Russel Wallace

Mayr E. 1997. “What is science?” in This is biology: The science of the living world, pp 24-44. Cambridge: Harvard University Press

Scott EC. 1997. Antievolution and creationism in the United States. Annual Review of Anthropology 26:263-289

Talbot M. 2005. Darwin in the Dock. The New Yorker, pp 66-77 Berkman MB et al. 2008. Evolution and Creationism in America’s

Classroom: A National Portrait. PLoS Biology, 6:0920-0924

Next week Genetics and the development of evolutionary theory

Mendelian and molecular genetics Population genetics Evolutionary development biology (Evo Devo)

Reading The Human Species, Chpts 2 (Human genetics), 3 (Evolutionary

forces), 8 (Paleoanthropology) Course packet

Tattersall I. 2000. Paleoanthropology: The last half-century. Evolutionary Anthropology 9:2-16

Foley R. 2001. In the shadow of the modern synthesis? Alternative perspectives on the last fifty years of paleoanthropology. Evolutionary Anthropology 10:5-14

Carroll SB. 2003. Genetics and the making of Homo sapiens. Nature. 422:849-857

“Beyond Stones and Bones”, Newsweek, March 19, 2007. Topic and abstract for journal analysis is due

Journal analysis

Your topic (the relevant question(s) and which other subfield you will be examining) and an abstract (<200 words) including your search strategy (which journals are you using and why) is due at the beginning of class on Jan 21. In your abstract, describe the problem you are addressing and

some of the history of this issue. Be sure to specify your two additional journals, and why you chose them, as well as the other subfield of anthropology that you will be studying. I encourage you to discuss your topic with me in advance, in person or by email.

The final paper is due at our last class, Feb 18. Turn in your original (graded) abstract with the final paper

From last week

Current hot topics on humans

Top 10 mysteries about humans http://www.livescience.com/history/091026-top10-

origins-mysteries.html Top 10 things that make humans special

http://www.livescience.com/culture/091030-origins-top10-special.html

Anthropology

Important to remember that a strength of anthropology is its holistic approach What’s the difference between cultural anthropology and

sociology? What’s the difference between biological anthropology and

biology? Holistic view is not limited to the 4 anthropology subfields,

but any relevant field Many Anthro departments are splitting along subfield lines

Why do you think more anthropological research is not truly interdisciplinary? How could you make your research relevant to

someone outside your subfield?

Modified from Balaresque et al. 2007

Expansion out of Africa

Peopling of the

Americas

Domestication of the donkey

Origin and expansion of Semitic

speakers

Genetic and cultural components to ethnicity and health

Demography Migration/colonization

Out of Africa Peopling of New World

Population origins Semitic speakers

Admixture Puerto Ricans

Adaptation Natural selection

Skin color Agriculture/domestication Disease

Origin/intro to naïve pop’s Genetic/cultural risk factors

Balaresque et al. 2007

Chpt 1 - Science and Evolution

Development of evolutionary thought

Darwin and natural selection

Misconceptions about evolution

Science as a way of knowing

Science, evolution, and creationism

Landmarks in Euro-American Thought about Human Origins and Diversity

2000

1900

1800

1700

1600

1500

1400

1300

1200

1100

1000

Years A.D.

Darwin publishes On the Origin of Species

Age of European Exploration

Development of Evolutionary Thought Ancient roots – differences and origins Renaissance – empiricism and science 17th-18th centuries – naturalism 1800-1859 – Racial origins 1859-1900 – Evolution and racial origins 1900-1950 – Description and classification 1950-present – New Physical Anthropology

Pre-Darwinian Theories and Seeds of (R)evolution

Pre-Darwinian thought Ancient Greek philosophy

Static, unchanging view of the world Aristotle (384-322 B.C.) Greek philosopher and naturalist Historia Animalium describes similarities between man,

apes, and monkeys Differences attributed to position in the scala naturae (Great

Chain of Being)

Aristotle’s notion of scala naturae did not incorporate racial hierarchy Argued for environmental causes of variation

Wooly hair of Africans due to harsh, arid climate Straight hair of Thracians and Scythians due to moist air

Carolus Linneaus (1707-1778)

Swedish botanist and founder of taxonomy

Epitomized focus on description and classification

Systema Naturae (1735-1766)

Identified two-dimensional structure of nature, as opposed to one-dimensional “Great Chain”

Great Chain vs Linnaean Taxonomy

Source: Marks (1995) Human Biodiversity

Linnaeus’s Classification of Humans

Homo sapiens in order Primates

Four geographic varieties mix culture and biology H. sapiens europaeus H. sapiens asiaticus H. sapiens americanus H. sapiens afer

George Louis Leclerc, Comte de Buffon (1707-1788)

French naturalist Opposed Linnaeus

No unit higher than species Species comprise Great Chain

of Being Dismissed evolutionary

implications of Linnaean ideas Posited microevolution in

response to environment, but denied macroevolution

Buffon and Human Variation

Buffon rejected classification as goal of study, aimed to describe and explain diversity

Varieties of the Human Species (1749) How is variation patterned? What explains patterns of variation?

Buffon and Linneaus represent two strains of thought in 20th century anthropology

Georges Cuvier (1769-1832)

French zoologist and founder of paleontology

Embraced Linnaeus’s nested hierarchy, but not evolutionary implications

Best remembered for catastrophism Mass extinctions, repopulation

gives appearance of change Consistent with Biblical view

Jean Baptiste, Chevalier of Lamarck (1744-1829)

French aristocrat Regarded classification as

sterile and theorized about process of evolutionary change

Inheritance of acquired characteristics Organism altered during lifetime

by environment and behavior Change inherited by offspring

James Hutton (1726-1797)

Scottish geologist Developed principle of

uniformitarianism (1785) Same geologic processes

(erosion, continental drift) operate today as in the past

Earth has long history Supernatural theories not

required to explain history Earth’s geology shaped by

processes observable today e.g. Deep soils formed by the

weathering of bedrock over 1000s of years

Sir Charles Lyell (1797-1875)

Scottish geologist Promoted and extended

principle of uniformitarianism

Three-volume Principles of Geology (1830-1833)

Darwin – “I always feel as if my books came half out of Lyell’s brain.”

Charles Darwin (1809-1882)

Born into intellectual family in northern England

Enrolled in medicine, then graduated in theology

Joined HMS Beagle in 1831 as “unpaid gentleman scholar and naturalist”

Voyage of the HMS Beagle

Darwin and Wallace

Darwin outlined theory of natural selection in 1837

20 years later, young Wallace developed same theory

Darwin and Wallace co-presented at Linnaean Society of London (1858)

Darwin published On the Origin of Species a year later

Alfred Wallace1823-1913

Darwin’s observations

Much morphological variation Variation made sense in terms of

environment Creatures in cold climates had fur Birds in areas where insects live deep inside tree

trunks have long beaks

Darwin’s Postulates

Infinite ability of populations to grow, but finite ability of environments to support growth Malthus showed that the planet can not support

uncontrolled growth, i.e. a large percentage of offspring will die and Darwin helps provide the answer as to who will die

Within populations, organisms vary in ways that affect ability to survive and reproduce

Variations are transmitted from parents to offspring

Natural selection – evolution by variation and selective retention

An Example – Darwin’s Finches

Darwin identified multiple species of finches on Galápagos Islands, attributed special role in his thinking

Drought and Darwin’s Finches

Natural experiment– severe drought—tests Darwin’s postulates As food supply shrank,

finch population declined

Beak depth affected survival

Parents and offspring had similar beak depths

Darwin’s Finches

Directional selection Beak depth influences individual’s probability of survival Distribution of beak depth shifts to right due to selection

Darwin’s Finches

Balancing selection Selection maintains status quo when most common type is

best adapted Selection required to keep populations the same, not just to

change

Individual Selection

Selection arises from competition among individuals, not among populations or species

Example – individual reproductive success vs species’ survival

Selection may favor high individual fertility, even if population growth threatens survival of species

Evolution of Complex Adaptations

Small variations are important Continuous, not discontinuous traits important Complexity arises from accumulation of small random

variations Typing monkeys - “Methinks it is like a weasel.”

Chance of randomly typing monkeys reproducing Shakespeare - ~ 1 in a trillion. Same as chance of randomly producing a human eye in a single trial

Convergence - complex adaptations have evolved independently multiple times

Selection favors intermediate phenotypes

Selection of Intermediate Steps

Living gastropod mollusks illustrate intermediate steps between eye cup and camera-type eye

Rates of Evolutionary Change

14 living species in Galápagos

All descended from single species within last half million years

Evolution of Evolutionary Theory

Darwin could not explain how variation was maintained Assumed blending inheritance Could not explain evolution beyond original range

of variation

Acceptance of Darwinian mechanisms awaited rediscovery of Mendelian genetics

Modern Synthesis (1930-1950)

Evo-Devo (1980-present)

Science andCreationism

What is Science?

[Empirical science] is systematic description and classification of objects, events, [and] processes, and the explanation of those events and processes by theories that employ lawful regularities, all of the descriptive and explanatory statements employed being testable against publicly observable data.

O’Meara, 1989

Science Is…

Empirical

Systematic and explicit

Theoretical, explanatory, predictive

Self-critical, reflexive, based on testing

Public

Creationist Claims

“Evolution is only a theory” Actually, evolution is both a fact and a theory

Fact is “an observation that has been repeatedly confirmed and for all practical purposes is accepted as ‘true.’”

Theory is “a well-substantiated explanation of some aspect of the natural world that can incorporate facts, laws, inferences, and tested hypotheses.”

National Academy of Sciences

Creationist Claims

“Evolution is unscientific, because it is not testable or falsifiable.” Microevolution and macroevolution Fossil record and macroevolutionary hypotheses

“Living things must be products of intelligent design, because natural selection could not produce some complex beings.” Evolution of camera-type eye Convergence

Chpt 4 - Speciation and Phylogeny

Overview

Microevolution macroevolution Species concepts

Biological species Ecological species

Evolutionary forces Systematics, phylogeny, and taxonomy

Definitions

Microevolution Changes in allele frequencies over relatively short time

periods/small geographic ranges/small genomic ranges Evolution over short time periods Occurs in our lifetime, i.e. is observable to all of us

Macroevolution Changes in allele frequencies over relatively long time

periods/large geographic ranges/large genomic ranges Evolution over long time periods

Creationists have problem with macroevolution b/c they say we can’t directly observe macroevolution

We can’t do million year experiments, but we can make testable predictions, like in geology or astronomy

What Are Species? Species are real biological categories, not abstractions

Paleospecies are more abstract concepts

Controversy about how species are defined Biological species concept

Group of organisms that naturally interbreed and produce fertile offspring

Ecological species concept Natural selection plays important role in species differences Reproductive isolation not necessary

Species occupy different ecological niches, but are not necessarily physically isolated from each other

Phylogenetic species concept Some level of genetic variation is chosen to define different

species

Modes of Speciation

Anagenesis Cladogenesis

Phylogeny and Systematics

Phylogeny refers to evolutionary relationships among group of species, often depicted as a “family tree” What is the “outgroup” in this tree?

Systematics is construction of phylogenies

Taxonomy is use of phylogenies in naming and classification

Approaches to systematics

Evolutionary systematics Considers all homologous traits, primitive and derived Based on descent and overall similarity Complex algorithms to evaluate genetic distance or

coalescence and translate that relationship into a tree Cladistics

Argues that phylogenies should be constructed only on shared derived traits

Much simpler, less sophisticated and probably less realistic

Natural selection

Mechanism for evolutionary change favoring the survival and reproduction of some organisms over others because of their biological characteristics.

Requirements: Variation must exist a priori in order for natural

selection to act, i.e. natural selection does not create a variant but it ‘prefers’ it

Preferred variant/phenotype must act in such a way as to influence fitness of offspring, i.e. Alzheimer’s will not be selected against b/c it occurs late in life long after childbearing years

Misconceptions of evolution and natural selection

Bigger is better Newer is better Faster is better Natural selection always works Evolution has a direction or goal Natural selection always produces perfect structures All structures are adaptive Current structure reflect initial adaptations

Natural selection will solve every problem – Will natural selection solve problem of stress-based disease?

What is evolution?

From a genetic perspective, not phenotypic At the most basic, causative definition

What is evolution?

Changes in allele frequencies over time

What are the evolutionary forces that can change allele frequencies over time?

What are the evolutionary forces that can change allele frequencies over time?

Mutation Natural selection Genetic drift Gene flow

What are the evolutionary forces that can change allele frequencies over time? Mutation

Introduces a new variant, initially at very low frequency Natural selection Genetic drift Gene flow

What are the evolutionary forces that can change allele frequencies over time? Mutation

Introduces a new variant, initially at very low frequency Natural selection

Alleles that increase fitness exhibit an increase in freq Alleles that decrease fitness exhibit a decrease in freq Balancing selection/heterozygote advantage = heterogzygote has

selective advantage so frequencies of both alleles are selected to be in balance (sickle cell allele of hemoglobin protein)

Genetic drift Gene flow

What are the evolutionary forces that can change allele frequencies over time? Mutation

Introduces a new variant, initially at very low frequency Natural selection

Alleles that increase fitness exhibit an increase in freq Alleles that decrease fitness exhibit a decrease in freq Balancing selection/heterozygote advantage = heterogzygote has

selective advantage so frequencies of both alleles are selected to be in balance (sickle cell allele of hemoglobin protein)

Genetic drift Random change in allele frequency from generation to generation

Gene flow

What are the evolutionary forces that can change allele frequencies over time? Mutation

Introduces a new variant, initially at very low frequency

Natural selection Alleles that increase fitness exhibit an increase in freq Alleles that decrease fitness exhibit a decrease in freq Balancing selection/heterozygote advantage = heterogzygote has selective

advantage so frequencies of both alleles are selected to be in balance (sickle cell allele of hemoglobin protein)

Genetic drift Random change in allele frequency from generation to generation

Gene flow One individual moves into a new population and reproduces there

New genes are introduced into a population Gene flow makes 2 populations more similar No gene flow → reproductive isolation → genetic divergence → speciation

What are the evolutionary forces that can change allele frequencies over time?

Mutation Natural selection Genetic drift Gene flow In reality, all 4 forces, or a subset, can act at the

same time

Bioethics

Review of research involving human subjects

Federal regulations require that all research involving human subjects be approved by an IRB prior to the research

Institutional review board = IRB Virtually all universities and research institutes will have their own IRBs

Composed of professors/scientists who volunteer their time Must be research – anything commercial is not subject to same

regulations, e.g. if someone pays to have genetic typing performed or forensic case work or contract archaeology

Also excludes general medical practice, i.e. distinction between accepted and experimental therapy

What is a human subject?

A human subject is a living individual about whom a researcher obtains: Data through intervention or interaction w/ the individual Identifiable private information

IRB regulations do not cover: Dead persons – no protection for the sample of

someone who has died Samples that are already collected and that have no

identifying information (i.e. are anonymous)

Goal of IRB review

To safeguard the rights and welfare of human subjects participating in biomedical and behavioral research

Guided by the Belmont Report The Belmont Report

Ethical Principles and Guidelines for the Protection of Human Subjects of Research The National Commission for the Protection of Human Subjects of Biomedical and Behavioral ResearchApril 18, 1979

Written in response to past abuses of human subjects in biomedical research WWII

Abuses of concentration camp victims Tuskogee Syphilis Project

Gov’t sponsored study (1932-1972) that denied effective treatment for syphilis to 399 African-American men in order to document the natural history of the disease

Three basic principlesBelmont Report

Respect for persons Subjects must be given the opportunity to choose what will or will

not happen to them Principle of informed consent and the consent process (information,

comprehension and voluntariness) Beneficence

“do no harm” “maximize possible benefits and minimize possible harms” Extends to both investigator and society

Justice Requires that there be fair procedures and outcomes in the

selection or subjects, both individually and socially (no one asked to unfairly bear burdens)

Projects in which the study populations are intimately involved with the project

Iceland – National human genome project deCode Genetics, an Icelandic start-up genomics

company, spearheaded a project to map the genome of the Icelandic people as part of a larger medical database

African Ancestry project Provides DNA testing to determine indigenous African

paternal and maternal lineages among African Americans

deCode Genetics Iceland is ideal location for a genetic disease association study

Historically small population (~50,000 19th century & ~275,000 today) Relatively homogeneous and comparatively isolated

Disease candidate genes may be easier to identify Detailed genealogical records for generations Detailed medical records dating back to 1915

In 1998 Icelandic parliament passed a bill authorizing the construction of a national medical database

Lots of controversy, some detractors, but general Icelandic public seems to be in favor of project Informed consent as far as medical records goes was based on the

principle of presumed, rather than informed, consent, i.e. people had to specifically request that their medical records not be used

Many papers have identified genes involved in schizophrenia, heart attacks, asthma, pain, vascular disease, diabetes, etc

African Ancestry project

Motivated by African-Americans’ desire for more information about their ancestry There is only limited historical info

available for African-Americans prior to their enslavement

From 1619-1850, millions of indigenous west and central Africans were enslaved

Primarily from Senegal south through the Cape of Good Hope and north along eastern Africa to Cape Delgado

African Ancestry project, cont

Spurred by African Burial Ground project In 1991, human remains were uncovered from an 18th

century burial ground of enslaved African in lower Manhattan

African American community became a major contributor (both financial and intellectual) to a research project with these aims: What are the origins of the population? What was the physical quality of life in 18th century NYC? What can the site reveal about the biological and cultural transition

from African to African American identities?

My experiences

Panama Explaining my research to indigenous groups in Panama

Genetics is my way of understanding history Collecting trip in Panama w/ Panamanian colleague Different decision-making process How to inform an indigenous person about my research?

Yemen and Mongolia Different experience – completely positive and enthusiastic

Bottom line

Best research involves research subjects from the beginning and throughout project

Best research honors the beliefs and goals of the research subjects Don’t expect them to buy into “greater good” argument

because that is a standard of our culture, not all cultures Best research assumes that research subjects can

be educated about the research as long as you put yourself in their position

Discussion questions

Scientists and the general public Do scientists/the general public have a “right” to

learn about the human past? Do scientists/the general public have a

“responsibility” to learn about the human past? Individuals

Do individuals have a “responsibility” to participate in research for the common good?

Do individuals have a “right” to participate in research for the common good?