Biological Anthropology
Franz Boaz
"father of American anthropology" Supported holistic approach to understanding humanity Developed idea of cultural relativism He and his students founded many of the major US anthropology departments
Gregor Mendel
- Austrian monk with training in math and botany - Published "Experiments in Plant Hybridization" in MID 19th CENTURY - >30 years between publication and recognition - This work would become the basis for understanding genetic heredity - Grew and studied pea plants - Observed traits disappear and then reappear in later generations - Adds to Darwin's ideas by explaining how traits are transferred from one generation to the next Mendelian traits-traits related to a single locus or gene.
Charles Lyell
- British lawyer and geologist - Wrote Principles of Geology - Challenged Cuvier and Catastrophism - Uniformitarianism - HIs views were radical at the time because he suggests that the earth is much older than previously estimated (much more than ~6000 years) and that Life forms may change! Observed processes of erosion in river banks Concluded: The earth has always been subject to slow gradual changes God not involved
What did people believe in before the mid-19th century?
- European scholars believed that God made all of the earth's creatures and that the earth was a few thousand years old - They believed in the Great Chain of Being
Jean-Baptiste Lamarck
- French naturalist (soldier, biologist, academic) - Proposed the theory of inheritance of acquired characteristics His goal: - To explain biological variation - The law of use and disuse \ - Postulated interaction between environment and organism - Inheritance of acquired characteristics = "Lamarckianism" or transformational evolution * Lamarck identified an important link between the environment and the organism
Georges Cuvier
- French naturalist and zoologist who observed fossils of extinct creatures, and the appearance of new forms - Catastrophism - His views were radical at the time because he challenged story of creation; and the Great Chain of Being
Continuous Distribution
- Humans have thousands of genes = countless phenotypic outcomes - Certain phenotypes are more common in some populations Phenotypic traits grade imperceptibly from one member of the population to the next
Where in the world do we see the process of Natural Selection at work?
- In populations affected by both sickle cell anemia (genetic) and malaria (mosquito-borne parasite) ex: Sickle cell trait buffers against disease
Natural Selection
- Low frequency for a gene that causes a specific trait in the population - Individuals with the trait more likely to produce offspring for whatever reason ex: Milk tolerance is higher among populations where dairy farming became common ex: Sickle Cell Allele
Charles Darwin
- Origin of the Species published in THE MID 19th CENTURY - Darwin shied away from explicitly suggesting his ideas applied to the human species - Even so, religious backlash, social and political upheaval followed his publication What's next? - Additional evidence was needed to support (or refute) Darwin's hypotheses - Mechanism for passing biological variations to offspring not clear
Gene Flow
- Population expansion due to migration of outsiders from another population - Increased variation within populations - Decreased variation between populations- WHY? The distinctness of each population reduces--no variation
Carolus Linnaeus
- Swedish botanist - Understood species to be separate and unchanging --> Did not challenge pre-existing views of the world - Life's work devoted to classifying and naming things - Making sense of relationships using genus/species nomenclature = taxonomy
Principles from Mendel's Pea Experiments
- Units of inheritance are discrete particles (called factors - now known as alleles/genes) - Particles do not blend ...but particles can be: --> Dominant - a particle that masks the effect of another (Y) --> Recessive - a particle that is masked by another (y) -Principle of Segregation: An individual gets one particle for each trait from each parent -Principle of Independent Assortment: Inheritance of one particle for one trait does not determine which particle you will inherit for another trait
Uniformitarianism
-Explaining past changes to the Earth's surface by reference to causes now in operation -Changes in life forms are as gradual as changes to the earth's surface
What is mutation?
-Random changes in the genetic code -Produces new allele -May have effects on phenotype (or not)
Why do biological anthropologists study non-human primates?
-To better understand evolutionary forces -Studying nonhuman primates opens a window into our evolutionary past -To save non-human primates from the threat of extinction
Why is Darwin famous?
1) First to convince people of species transmutation (change) 2)First to conceive of evolution as branching tree of life 3)First to explain mechanism for evolutionary change, Natural Selection . HOWEVER... No one bought it at the time, so he was not famous for this until later.
How did Darwin explain biological diversity?
1) Principle of Variation: - All individuals within a species vary from one another - Members of a population are not exact replicas of one another - Variations are random 2) Principle of Heredity: - Offspring inherit variations from their parents 3) Principle of Natural Selection: - Some variations are helpful when an environment changes (e.g., competition for food/water resources) - Individuals with those variations are more likely to survive and reproduce
Classifying Primates
1) Prosimians 2) Anthropoids New World Monkeys Old World Monkeys Lesser Apes Great Apes Humans 3) Defining Characteristics: (Location/habitat Skeletal/body features Social Behaviors)
What is Natural Selection?
1) There is variation in the population. 2) That variation is heritable 3) Resources are finite, leading to competition. 4) There is differential fitness (reproductive success) in the population associated with the aforementioned heritable variation and resource competition. Overall, a two step process First, the production of variation (Random) Second, the selection of variation (Non-Random)
Sickle Cell Allele demonstrates...
1. Balanced polymorphism Maintenance of two (or more alleles) in a population due to the selective advantage of the heterozygote 2. Biocultural evolution Cultural and environmental change Genetic change
Scientific Method
A continual process of testing and refining hypotheses. Evidence (asking questions & demanding evidence) Observation (collecting empirical evidence [data]) Generalization (finding patterns & relationships) Testing (prediction vs. reality) Continued testing (refining explanations & correcting errors) Hypotheses must be falsifiable Hypotheses are supported, not proven Methods should be systematic and explicit so they can be duplicated Well tested hypotheses become theories (e.g., evolution)
Adaptation
A trait that increases the fitness (reproductive success) of an organism Measured in terms of: Differential survivorship (mortality) Differential reproduction (fertility) Produced by natural selection within the context of a particular environment Environments can change Not all adaptations are "perfect"
The Great Chain of Being
All organisms exist in a universal hierarchical ladder Linear (simple to complex) with continuity Unchanging (Fixity of Species) Humans at top but below gods & angels
Allele
Allele-one variant of a gene
Biological Anthropology
Also called physical anthropology Focused on the evolution of and variation in human morphology, physiology, and genetics Includes: Paleoanthropology Skeletal Biology and Osteology Paleopathology and Bioarchaeology Forensic Anthropology Primatology Human Genetics Human Biology
Robert Malthus
An Essay on the Principle of Population: human population size can't increase indefinitely because of limited resources
What worldviews influenced early ideas about the natural world prior to the 18-19th centuries ?
Ancient Greek philosophy God created all individual species Judeo-Christian understanding The world is not very old James Ussher (Irish Archbishop) calculated the age of the earth to be about ~6000 years old Taken as fact
Theorists and their Timeline
Ancient: Judeo-Christian teachings Greek Philosophy Prior to mid-19th century: Linnaeus, Cuvier, Lyell, Lamarck Late 19th century: Mendel and Darwin
Paleopathology and Bioarchaeology
Bioarchaeology: The study of human remains in an archaeological context Paleopathology: The study of diseases in ancestral human populations
Biological Evolution
Biological Anthropologists rely on evolutionary theory in order to explain human origins, human biology, skeletal anatomy, genetics, etc.
Is evolution slow or fast
Both the fossil record seems slow, but we can observe change in the finches within our lifetime Rate of evolutionary change is dependent on: Generation time Mutation rate Strength of selection
Genetic Inheritance (What is Polygenic Inheritance?)
Controlled by two or more than two genes (usually by many different genes at different loci on different chromosomes) ex: height, weight, skin color
What makes anthropology unique?
Cross-cultural understanding Evolutionary theory Studies social phenomena from a scientific perspective Interaction between biology and culture The study of human populations and cultures in evolutionary, historical, and comparative frameworks. General Characteristics: Holistic in nature, Interested in understanding the range of human variation, often involves fieldwork Want to be explanatory, not just descriptive
Darwin could not explain
Darwin could not explain: How traits were inherited Proposed that offspring inherited traits from both parents (blending) How variation originated and was maintained Overall missing Molecular biology -Mendelian genetics -Cell replication and division -DNA
The Anthropological Perspective: Field-based
Data collection involves direct contact with the people, sites, artifacts, skeletal remains or animals of interest What does the field look like? - Depends on the discipline of anthropology. NOTE: "The field" will look different for archaeologists, cultural anthropologists, and linguistic anthropologists. Not all biological anthropologists do fieldwork--labs
What are alleles?
Different versions of genes (have different effects) Each parent has 2 alleles for a trait (one on each chromosome, at the same location) Offspring gets only 1 allele from each parent
Genetics
Different versions of the same gene are called alleles (Mendel's particles) Found at the same location on a chromosome pair An individual receives two alleles (one from each parent) but donates only one allele to an offspring
Dominant
Dominant- an allele that confers the visible phenotype in homozygous dominant or heterozygous individuals (yellow)
Biological anthropology timeline
Early work dedicated to documenting human variation- particularly with respect to measuring physical form Practiced anthropometry & especially craniometry Much early work dedicated to describing discrete racial types First identifiable hominin discovered in Neander Valley, Germany in 1856 When discovered, was unclear whether represented an ancient human or a different human-like species now extinct 1859 Publishes "Origin of Species" In 1871 publishes "Descent of Man and Selection in Relation to Sex", which argues that humans evolved from common ancestor with other apes Darwin's theory of evolution underpins modern biological anthropology although our understanding of evolution has advanced Boaz Refuted idea of cranial shape as predetermined and undermined notions of essentialist differences in cranial type by race/nationality Neo-Darwinian Synthesis - Sherwood Washburn (1951) Synthesized genetics, anatomy, ecology, and behavior with evolutionary theory Building a new biocultural synthesis: 1998 Allan Goodman and Thomas Leatherman. Biocultural anthropology: The study of the interaction between biology and culture, which plays a role in most human traits.
Falsifiability
Evidence supporting and not supporting a theory
Evolution
Evolution is the change in frequency of a gene (trait) in a population over multiple generations
If Lamark's Hypothesis was correct...
Fundamental error: Evolutionary change does not occur during the lifetime of an individual Breakthrough: Recognizing that relationships exist between an organism and its environment
Gene
Gene -section of DNA that has an identifiable function
Where are genes found?
Genes are segments of DNA (deoxyribonucleic acid) DNA is 'packaged' in chromosomes Humans have 46 chromosomes (23 ♀ and 23 ♂)
Anthropological genetics
Genetic change as the underlying foundation for evolutionary change: genetic structure, inheritance patterns, and species relationships
Genotype
Genotype-one individual's allele combination (Aa)
Catastrophism
Georges Cuvier --> Observed extinct species in the fossil record Concluded: In the past, the earth experienced sudden, short-lived, violent events (e.g., floods) Linked to God
Why is the theory of evolution important to Anthropologists?
Helps us to explain human origins, human biology, skeletal anatomy, genetics, etc.
Heterozygous
Heterozygous- two different alleles (Aa)
Homozygous
Homozygous-two of the same allele (AA or aa)
What is Biocultural Evolution?
Human biology and human culture interact in complex ways to influence processes of evolution
Biocultural Evolution
Human biology and human culture interact in complex ways to influence processes of evolution *"Cultural Evolution" = idea rejected by many Anthropologists
What exactly is a primate?
Large brains relative to body size Grasping hands with opposable thumbs/toes -Nails, fingerpads Skull features including: -Forward-facing eyes -Enclosed/partially enclosed bony eye orbits -Inner ear protected by bone (petrosal bulla) Generalized teeth and body plan Single offspring; infant dependency Learned social behaviours
Prosimians
Lemurs (Madagascar), Lorises (Africa, Asia), Tarsiers (SE Asia) Tooth Comb--except tarsiers--they have tiny bodies , large eyes and feet
Genetic Inheritance (What is Linkage?)
Linkage genes sit close together on the same chromosome and are more likely to be inherited together then genes found in different chromosomes.
What Medel Didn't Know...
Linkage: More than one gene on the same chromosome is passed on together during cell division Crossing over: Part of one chromosome breaks off and re-attaches to another chromosome during cell division Pleiotropy: Occurs when one gene influences two or more seemingly unrelated phenotypic traits Polygenic Inheritence When many genes affect one trait Physical traits that have polygenic inheritance are influenced by more than one gene and typically display a continuous distribution E.g., range in heights, weights, skin colours, fingerprints, etc.
Locus
Locus-physical location of a gene on a chromosome
Challenges of 4 subfields
Making research accessible to individuals from different sub-fields Holism sounds great, but can be difficult in practice Requires collaboration among many different types of specialists
Why did it take so long for Mendel's ideas to be recognized?
Mendel not well- connected to the scientific community Published in obscure journal intended for horticulturalists Only able to duplicate his results in some but not all plants Became too busy as the head of his monastery Scientific community still reeling from Darwin's publication
Mendel's Pea Experiments Resulted in Three Key Findings
Mendel used the term "particles" to describe how a trait was passed from parent to offspring Particles = genes (different forms of a gene = alleles) 1) Principle of Segregation An individual gets one particle from each parent 2) Principle of Dominance A dominant particle will mask the effect of a recessive particle 3) Principle of Independent Assortment Inheritance of one particle for one trait does not determine which particle you will inherit for another trait
Anthropoids
New World Monkeys Found in the Americas Mexico, Central + South America Tree dwelling Key Features: Small body size Three premolar teeth Some have prehensile tails Old World Monkeys E.g., macaques, baboons Found in Africa, Asia and Middle East Variety of environments Key Features: Ischial callosities 2 premolars + double ridged molar teeth Lesser Apes E.g., Gibbons Found in Southeast Asia Tree dwelling Key Features: Long arms (brachiators) Monogamous Most vocal primates Great Apes E.g., chimpanzee, bonobo, gorilla, orangutan
Does the environment have to change?
No. Random variation will occur in the population regardless of the environment
What does it mean to embrace cultural relativism?
Non-judgmental approach to examining beliefs and behaviours (no one culture is superior to another) Promoting understanding of cultural practices, particularly those that "outsiders" might find puzzling, incoherent, or troubling
Great Apes
Orangutan Largely solitary Large bodied (males weigh up to twice that of females)~200lbs for males Once mature, offspring disperse from mother's territory Endangered: <70 000 left in the wild Gorillas Largest primates (up to 200 kg) Sexual dimorphism =larger males Live in groups (from a few to a few dozen) Both males and females emigrate out of the group Endangered <80 000 left in the wild Chimpanzees Our closest living relatives Large groups of males and females living together Females emigrate Tool use and hunting behaviours Bonobos Live in large communities Hypersexual behaviour for conflict resolution; social cohesion Females achieve dominance
Niche construction
Organisms (including humans) actively modify their environment or move to new ones This may change the "selection pressures" experienced by the organism Organisms are vulnerable to the consequences
Macroevolution
Origins of new species and diversification across millions of years of geological time
Genetic Inheritance (What is Crossing over?)
Part of one chromosome breaks off and re-attaches to another chromosome during cell division This process of recombustion mixes up or shuffles the allele types found on a given chromosome
Phenotype
Phenotype-one individual's observed characteristic (yellow)
Bottleneck Effect
Population is suddenly reduced in size ex: violent change in physical environment, widespread disease
Darwin's Three Principles
Principle of Variation-All individuals within a species vary from one another (random, not always perceivable) Principle of Heredity-Offspring inherit variations from their parents Principle of Natural Selection-Some variations are helpful when an environment changes (e.g., competition for food/water resources) Individuals with those variations are more likely to survive and reproduce
Genetic Drift
Random changes in gene frequencies from one generation to the next
Recessive
Recessive- an allele that confers the visible phenotype only in homozygous recessive individuals (green)
Darwin's Context on Evolution
Recognition of deep time Geological evidence of an old Earth Increased exploration and discovery of ancient monuments Discovery extinct animals Earlier evolutionary ideas but: Most speculative not scientific Most with no mechanism of change No common descent
Science
Science is self-correcting Science is suited to address questions about what happened in the physical and natural universe Science is not suited to address questions outside of the physical and natural universe Biological Anthropologists rely on evolutionary theory and the scientific paradigm The scientific method starts with observations/ideas, leads to a hypothesis, data gathering and testing, and finishes with evidence for or against the hypothesis As anthropologists we understand the kinds of questions that science can and cannot address, and respect other ways of knowing The intellectual and practical activity encompassing the systematic study of the structure and behavior of the physical and natural world through observation and experiment
artifical selection
Selection by humans for breeding of useful traits from the natural variation among different organisms
What is culture?
Shared patterns of learned behaviors, beliefs and ways of understanding The characteristics and knowledge of a group of people (e.g., language, religion, cuisine, social habits, music, arts, etc.) Material artifacts and structures created and used by the group
Microevolution
Short term changes that occur within a given species over a "short" time period Among Human Populations... - Shifting gene frequencies - Human populations differ because they possess different proportions of the same set of alleles (not because they have completely different genes)
homologous traits
Similar structures, but often with different functions Indicative of common ancestry
How do gene frequencies change?
THE FOUR FORCES OF EVOLUTION: Mutation Natural Selection Gene Flow Genetic Drift
Applied Anthropology
Taking anthropological concepts and applying them to make a difference at the local level
Human Biology
The study of biological variation in modern populations and how it is adapted to and influenced by ecological and social factors.
Forensic Anthropology
The study of human remains applied to a legal context
Cultural Anthropology
The study of human societies, especially in a cross-cultural context
lingusitc anthropology
The study of language, its history and use; also called anthropological linguistics
Archeology
The study of the material culture of past peoples Material Culture: physical evidence of a culture in the form of objects or architecture
Primatology
The study of the non-human primates and their anatomy, genetics, behavior, and ecology
Skeletal Biology and Osteology
The study of the skeleton and the patterns and processes of human growth, physiology, and development Anthropometry: Measurement of the human body
What does it mean to take a comparative approach?
To look at a situation from all perspectives, and see all the different across different countries or cultures
Expatation
Trait that originally evolved independent of its current function
Theory
When a hypothesis has been tested and retested over many years using different methods Highly reliable (...but can still open to interrogate ex: Evolutionary Theory
Polygenic Inheritence
When many genes affect one trait Physical traits that have polygenic inheritance are influenced by more than one gene and typically display a continuous distribution E.g., range in heights, weights, skin colours, fingerprints, etc.
Genetic Inheritance (What is Pleiotropy?)
When one gene influences two or more seemingly unrelated phenotypic traits
What is a balanced polymorphism?
When the heterozygous trait is the preferred state bc it gives you the best chance of survival in a given population
Discontinuous variation
a variation in a characteristic in which individuals show two, or a few, traits with large differences between them
Darwin Came Up With His Ideas
because the Galapagos has a lot of biodiversity and the finches are an example of Adaptive radiation: diversification of one founding species into multiple species & niches
Four subfields of anthropology
biological anthropology, archaeology, anthropological linguistics, and cultural anthropology
vestigial structures
remnant of a structure that may have had an important function in a species' ancestors, but has no clear function in the modern species.
Paleoanthropology
the study of the history of ancestral humans and their primate kin through the fossil record
continous variation
variation in a population showing an unbroken range of phenotypes rather than discrete categories
