Evolutionary Biology Intro: Boas, Hrdlicka & History - Prof. G. Listi, Study notes of Introduction to Cultural Anthropology

Download Evolutionary Biology Intro: Boas, Hrdlicka & History - Prof. G. Listi and more Study notes Introduction to Cultural Anthropology in PDF only on Docsity! 09/10/2010 I. Physical Anthropology –  The study of human biological evolution and of human biocultural variation. The study of humans as biological creatures past and present, and of other primates.  Franz Boas (1858 – 1942) o The father of American Anthropology. The original four field approach person. o He trained others. o Believed it was important to encompass all aspects of being human. o “Human societies are best understood from as many angles as possible.”  Ales Hrdlicka (1869 – 1943) o Very interested in the human skull. o He started the American journal of physical anthropology. o He founded the American Association of physical anthropologists. II. History of Evolutionary Thought  Charles Darwin o Four of his ideas have profoundly affected our ideas of the natural world.  Evolution  The concept that humans/species can change/evolve.  Adaptive Radiation  Out of one species will branch many related species.  Gradualism  The idea that change occurs gradually/slowly over time.  Natural Selection  The environment influences life forms.  Middle Ages o Concepts  Order  Life was ordered; there is a hierarchy to life.  Stasis  Unchanging, static. o Religious Beliefs  There is a supreme being at the top of the natural order (God).  There is a Great Chain of Being (order/hierarchy). o Natural World  Fixity of Species  The world was created and once created, things didn’t change. The species were fixed.  Young Earth  The concept that the Earth was young. o Political System  Feudal System  Dominated by monarchies. An absolute ruler/king, at the top of the social order.  14th – 18th Centuries o Renaissance & Enlightenment o Graduated from school in 1831 and joined the scientific exploration to circle the globe (The Beagle) o Origin of the Species – 1859 (natural selection)  Natural Selection o “survival of the fittest” – those who are the most fit are going to be the ones who survive o Basic Processes:  Biological variation within a species  Competition – in nature it often happens that a species will reproduce faster than its resources. This leads to competition among individuals to get the resources.  Advantageous traits – those who have advantageous traits are going to be the ones who do better in the competition (win) and who reproduce.  Fitness – has to do with reproductive success; how many offspring you produce and rear to adulthood and then your offspring reproduce. Those with advantageous traits have a higher fitness.  Selective Pressure – any circumstance or phenomenon that effects the behavior or the fitness of an organism within a given environment.  It is often the environment or a circumstance in the environment.  Traits passed on – animals that have advantageous traits will survive, reproduce and pass the traits on. The ones without the advantageous traits will not survive or reproduce and those disadvantageous traits may end up dying out. Over time there will be a shift in the frequency of these traits. The advantageous traits will accumulate in the population and the disadvantageous will become less frequent and eventually die out.  New Species – over time if enough changes have occurred to where the descended population is different from the original, you may have a new species. o Contrast Darwin to Lamarck  Natural selection is saying that originally you have biological variation in the length of giraffe necks. Something happens in that environment and the leaves on the lower branches of the trees become depleted. The giraffes with the shorter necks cant reach the food and end up dying out. The giraffes with longer necks can reach the higher leaves and they will pass this trait onto their offspring. Overtime there will be more long necks o Examples of Natural Selection  Peppered Moths  Variety of moths that lived in England. In the 18th century there was a grey variety and a black variety of these moths. Grey variety was more common – they were well camouflaged when the landed on trees. Over time the grey moths became less common and black became more common. The industrial revolution changed the environment with the pollution that was produced from the factories. It killed the lichen on the trees and darkened the tree bark.  Medium Ground Finches  Natural variation occurs in the beak side – some have longer, larger beaks and others have shorter beaks. Prior to the 1970s, the most frequent was the shorter, smaller beak (food source was a smaller seed). In the mid 1970s there was a drastic change where the size of the beak in medium ground finches increased rapidly. IN the early to mid 1970s there was a drought and the seeds that the birds preferred to eat were killed and the finches had to eat harder, larger, and thicker seeds for food. Eventually the drought ended and there was a shift back to the smaller beak size.  Antibiotic Resistance  EX: multidrug-resistant Tuberculosis (MDR TB) and Methieillin-Resistant Staphylococcus aureus (MRSA)  Inheritance o Heredity  Homunculus – a little person who was fully form was present in the sperm cell  Blending Inheritance – proposed that within the reproductive organs were tiny particles called “Gemmules”. These particles represented different body parts or organs. During fertilization gemmules from the parents would meet up during fertilization and that is what would form the individual. The offspring would then be a blend of the parental traits.  Cells (the basic unit of life – all complex life forms have billions of cells):  Prokaryotic  Relatively simple life forms, have no nucleus  EX: bacteria  Eukaryotic o Can result in mental retardation, malformed lungs o Mendelian Genetics  Gregor Mendel – monk in the 1850s and 60s who experimented with pea plants. He chose 7 different traits having to do with the position of the flower, color, shape of pea, shape of pods ext. In order to see how the plants offspring was passed on. He crossed various combinations and followed them out through multiple generations.  In the first generation, one of the traits appeared to be lost – all offspring were tall or yellow.  Then Mendel allowed the first generation to cross each other. What he found was that the more frequent trait appeared in most of the plants again, but the trait that seemed to be lost reappeared in some of the plants (3 to 1)  Genetic Principles (suggested by Mendel)  Law of segregation  Two alleles for any given trait are inherited, one from each parent. During gamete production, only one of the two alleles will be present in the egg or the sperm. This showed that the offspring was not a result of blending genes.  Gene/allele  Gene – sequence of DNA that codes for some function  Allele – an alternate form of a gene  Dominant/recessive – a dominant gene is one that is expressed in the presence of another different allele. A recessive allele is one that is not expressed in the presence of another different allele. o Just because an allele is dominant doesn’t mean that it is better, it just means that it is expressed when another allele is present. It also doesn’t meant that it is more frequent  Locus – the location of a gene or an allele on a chromosome  Homozygous/heterozygous (“hmz”/ “htz”) o Homozygous – two copies of the same allele (TT) capital T is dominant, lower case t is reccesive o Heterozygous – different alleles present (Tt)  Genotype/phenotype o Genotype is referring to the genetic makeup; the pair of alleles coding for the trait (TT) o Phenotype is the physical description of the trait (tall)   Punnent Squares  A method of determining how the parental alleles are going to combine in the offspring. It will show you the possible genotypes and phenotypes  In the following table, the genotype is Tt and the phenotype is tall. All offspring will be tall with Tt. T T t Tt Tt t Tt Tt TY Ty tY ty TY TTYY TTYy TtYY TtYy Ty TTYy TTyy tTyy tTyy tY TtYY TtYy ttYY ttyY ty TtYy Ttyy ttYy ttyy  Sickle Cell Allele  Caused by mutation that causes the hemoglobin molecule to deform, which ultimately causes the red blood cells to deform.  Balanced Polymorphism (Heterozygote Advantage) – The maintenance of two or more alleles in a population due to the selective advantage of the heterozygote.  Taysachs with Tuberculosis  Sickle Cell Anemia with Malaria o Human Variation  “Voyages of Discovery” – 1500s-1700s  Monogenism  All humans descended from a single, original pair (Adam & Eve) but the single differences that you saw in humans was due to environmental variation.  Polygenism  Humans descended from multiple original pairs from different parts of the worlds.  Early Studies (18th – early 19th centuries)  Descriptive/classifying  Mid 19th century:  Biological determinism – behavioral attributes such as intelligence or morals are governed by or associated with biological traits. This says that just because you look a certain way will determine how smart you are or how moral you are. o Race  Common definitions:  Species  Cultural/ethnic identity  Religious Identity  Physical characteristics  Often called “Ethnicity”, “Ancestry”  Problems with organizing people into groups  Racism  No reliable way to distinguish groups of people  Entire populations that cannot be categorized  Generic variation  Geneisists are finding that there is more generic variation within races than between different races.  “Race from the Anthropological Perspective:  One polytypic species  Geographically patterned phenotypic variation  Cultural affiliation with biological effects o Human Variation  Human Response to Environmental Stress  Cultural  Ex) Dressing warmly when its cold outside.  Acclimatization (“physiological”)  Can occur any time your body is stressed, its reversible.  Ex) Sunburn or sun tan  Developmental  Responses to stress that happens during the periods of growth and development. Not reversible.  Ex) Increased chest size in children that are raised in high altitudes.  Genetic (population)  Inherited, not reversible.  Ex) skin color  Purpose: Maintain Homeostasis  The ability of an individual to maintain an internal equilibrium. o Temperature Extremes  Heat  Vasodilation – capillaries near the surface of your skin dilate which increases the blood flow outward towards the surface of your skin.  Sweating  Cold  Vasoconstriction  When the capillaries near the skin surface constrict, and it reduces blood flow towards the skin and keeps blood in your organs.  Shivering  A response to cold to help warm your body up.  BMR (Basal Metabolic Rate)  Populations that live in cold environments tend to have a higher BMR that people who live in hot environments.  Bergmann’s and Allen’s Rules  Suggests there is a relationship between your body size and climate/temperature.  Bergmann’s rules say that within a species, body size increases as distance from the equator increases.  Allen’s rules suggest that within a species, limb length will decrease as distance from the equator increases. o Solar Radiation and Skin Color  Skin pigmentation (“Pigment Protection Hypothesis”)  People who live in equatorial regions have darker skin, whereas people who live farther north have lighter skin.  All humans have the same number of melanocytes, but the size of the melanin granules and the amount produced is what differs.  People who had the highest amount of melanin had the best fitness 09/10/2010 III. 09/10/2010 IV.