1. History of Evolutionary Thought
1.1. Early Thoughts on Origins + Human Evolution
1.1.1. Ancient Greek Essentialism: The greeks believed that creatures were in their "ideal forms"
1.1.2. Middle Ages: Many believed the Earth was static and young.
1.2. Major realizations that caused humans to think more! These realizations were brought on by the Age of Explorations
1.2.1. Extinction: We found animals who existed in the past but are now gone. What events caused this?
1.2.2. Human Variation: So many different humans around the world!
1.2.3. Earth's Age: Research into sedimentation and uniformitarianism showed us that the world is older than we thought.
1.3. Scientific Revolution and Discoveries:
1.3.1. Comte de Buffon, James Hutton, Charles Lyell, and Robert Hooke studied the Earth, the planet's layers, geology, and sedimentation to research how old our planet is. This research led them to discover fossils of extinct species.
1.3.1.1. Extinction mostly results from evolutionary forces rather than violent geological events. However, some catastrophes such as earthquakes or volcanic eruptions have led to extinction.
1.3.2. Many scientists, like John Ray, organized species to find if they had common ancestors. Ray searched for a "divine organization" of species. Carolus Linmeaus gave us the system we use today, which organizes animals into kingdom, phylum, class, order, family, genus, and species.
1.4. Evolutionary Thought
1.4.1. Erasmus Darwin researched our traits are carried down from generation to generation. He believed all life came from a "single living filament"
1.4.2. Chevalier de Lamark took Darwin's hypothesis even further to say that actions that we take during our life can cause new traits in the body. Then, these traits as well can be transferred!
1.4.3. Charles Darwin, thanks to 4 influences, was highly successful in teaching the world about evolution
1.4.3.1. 1. Uniforitariansim and the discoveries on the Earth's past caused Darwin to think deeply about how changes in the environment for millions of years caused species to evolve and adapt.
1.4.3.2. 2. On his voyage of the Beagle, Darwin discovered many varieties of fishes in the Galapagos Archipelago. He noticed how these finches had differences in their beaks, and linked this to environmental adaptation.
1.4.3.3. 3. Studying artificial selection, Darwin studied how we can affect which animals mate with one another.
1.4.3.4. 4. Darwin was heavily influenced by Thomas Malthus, who believed the Earth would become too populated and not be able to sustain life. Darwin thought this might lead to natural selection.
1.4.3.4.1. Darwin's theory on Natural Selection: Darwin saw that species have high potential in fertility and can grow exponentially. This, however, is held back by natural resource limits. Because of natural resource limited, some variations of a species might be better suited for survival than other variations. The variants that survive are able to pass down their traits to future generations.
1.4.4. After Darwin
1.4.4.1. Scientific progress after Darwin has allowed us to discover that variation is very random. Mutations begin at a small, individual level. Later, they will spread throughout a larger population if the variation is suitable. The environment MUST change, or else creatures stay stagnant.
2. Evolution in Humans
2.1. The Process:
2.1.1. Bipedalism developed more than 6 million years ago. It's important to recognize that apes have bipedalism as well!
2.1.2. Objects used to manipulate environments were developed about 2.6 million years ago. It's important to recognize that chimps can make simple tools!
2.1.3. Large Brains + speech developed 2 million years ago
2.1.4. Organized Hunting developed about 1.8 million years ago, but once again, it's important to remember chimps eat pigs!
2.1.5. Symbolic thinking developed 100 thousand years ago!. We were able to recently domesticate plants + animals only 11,000 years ago!
2.2. Biological Variation
2.2.1. Before C. Darwin, many theories were made on the origin of our physical differences.
2.2.1.1. The preformation hypothesis is a religious belief that all humans were created at the beginning of time by God, including appearance. This theory does not take into account the passing down of variation from parents.
2.2.1.2. Many people before Darwin believed in the blending of fluids. This recognized that traits carry over but did not explain how new variations could emerge.
2.2.2. Gregor Mendel created the laws of inheritance to communicate how organisms pass down traits to their offspring.
2.2.2.1. Each organisms has DNA, the code that defines who we are. This code is made of genes, which are located on chromosomes at different loci. Genes are defined by alleles. Alleles make up our genotypes. DNA can be found on chromosomes.
2.2.2.1.1. DNA allows humans to stably preserve genetic message. DNA's replicability ensures inheritance.
2.2.2.1.2. This code is made of genes, which are located on chromosomes inside our cells at individual spots called loci. Each cell has 23 pairs of chromosomes.
2.2.2.1.3. Our genes are made up of alleles. Each gene is determined by the combination formed between two alleles. What determines this combination is the genetic makeup our parents had. We label this combination our genotype. If our genotype has a direct influence on our physical appearance, than we also say that the genotype caused a phenotype to appear. A phenotype is an observable trait!
2.2.2.1.4. Lab 1 allowed me to explore how genotypes are developed. Using Mendelian genetic charts, I mapped out possible genotypes that an individual might obtain from their parents.
2.3. Evolutionary Forces
2.3.1. Mutation is a permanent alteration in DNA. It occurs vary randomly in response to the environment.
2.3.2. Natural Selection usually occurs whenever a variation affects the fitness of an individual.
2.3.3. Sexual selection is a force that occurs when an individual's trait directly appeals to someone.
2.3.4. The founder effect, also called a bottleneck effect, occurs when an event like a mass migration decreases the original population.
2.3.5. Gene Flow is when an individual with unique traits migrates to a different area.
2.3.6. Genetic Drift occurs when certain alleles and genotypes disappear over time due to decline in fitness.
2.4. Evolutionary Processes
2.4.1. Evolution works on discrete and continuous traits
2.4.1.1. Mendelian traits are discrete. They are controlled by alleles at one locus.
2.4.1.2. Polygenic traits are continuous, meaning they are controlled by alleles from more than 1 genetic locus
2.4.1.3. It's important to remember that evolution is homologous. This means that evolution "tinkers" with not just our genetic code, but other species as well. Humans, birds, and lizards all have a humerus. Goosebumps is something all mammals have.
2.5. Adapting
2.5.1. Adaptating allows us to respond to stressors.
2.5.2. Adaptation allows us to maintain homeostasis. This is the internal environment of an organism within acceptable healthy range.
2.5.3. Genetic adaptation occurs at a population level and involves natural selection. Genetic adaptation is inherited and not reversible.
2.5.4. Developmental adaptation occurs at an individual level during growth and development. The capacity to obtain a trait is inherited, but the actual trait is not. This is not reversible.
2.5.5. Acclimatization adaptation occurs at an individual level and is not inherited. The capacity to change is also not inherited. It is reversible. An example would be tanning.
2.5.6. Cultural adaptations involve the development of serials to cope with environment.
2.5.7. Adapting in the Cold and Heat
2.5.7.1. Being in the cold requires more energy, so many have genetic adaptations inherited from generations who've lived in higher, colder environments. These traits include short, squat bodies, wide noses, and raised metabolism. Bergman's Rule says that populations + species of larger mass are found in colder environments + species of smaller mass are in warmer regions. Allen's Rule says that populations in cold environments have smaller appendages than those found in warmer regions.
2.5.7.2. Acclimatization in the cold involves shivering. This is efficient and involves simply muscle movement. It creates body heat. Vasoconstriction is another adaption that makes blood vessels more narrow. It reduces blood flow, therefore retaining heat.
2.5.7.3. When in a high altitude, the human body experiences many stressors including UV radiation, poor nutrition, and coldness. This causes a high infant mortality, delayed birth and maturation rates, and a "barrel-chest". In the short term, this causes increased blood pressure but in the long term increase red blood count.
3. Common theme: All these developments were adaptations over time to the changing environment. The fact that chimps and apes share some of these traits shows how evolution is non-linear. Man, chimps, and apes all share a common ancestor. This is homology!
4. What Evolution IS and IS NOT
4.1. It is NOT Lamarckian. You can not "try" to evolve.
4.2. It is NOT random. It does happen for a reason!
4.3. It is NOT a linear progression.
4.4. It is NOT goal oriented.
4.5. It IS a genetic process that takes generations.
5. Lab 1
5.1. Lab 1 allowed me to explore how the 4 forces of evolution affect a population's genotypic and phenotypic identity. For example, I transferred one individual to a new population to understand gene flow better. Over time, I saw the population develop the same traits that the one individual had.
6. Lab 2
6.1. Lab 2 allowed me to apply the evolutionary forces that I researched in Lab 1 and apply them to the spread of real genetic variations that occurred in real life. I looked at the spread of the sickle cell allele (HbS) in Africa, which gave individuals to ability to defend themselves against malaria. The HbS allele entered a genetic pool which was heavily dominated by the HbA (normal red blood cell) allele. Individuals who were homogenous HbA/HbA and homogenous HbS/HbS struggled against fighting malaria. HbA/HbA individuals did not have any protection against Malaria, and HbS/HbS individuals essentially had too much sickle-cell protection that their bodies were being damaged. In the end, natural selection played out and the HbA/HbS genotype was the most fit!
7. BOTH Lab 1 and Lab 2 allowed me to research how evolutionary forces can cause significant change at a biological level across a population. This change at a biological level is reflected in a group's phenotypes and is necessary for fitness in a changing environment.
8. Taking a look at blood types is a good way to analyze how forces such as genetic drift and gene flow affect the spread of a set of genotypes. The B allele is common in Central Asia and sub-Saharan Africa, but is less common in the Americas + Australia.
9. Interesting Fact: In the Middle Ages, Archbishop James Usher said the Earth was created on 4004 BC. To him, the Earth was very new!
10. Interesting fact: Mendel first performed his inheritance tests with peas!
11. Dimensions of Anthropology
11.1. Cultural Anthropology
11.1.1. Studies the culture of present day societies. Many engage in ethnography, which is the collection of qualitative data about culture. This often takes place in non-western localities.
11.2. Linguistic Anthropology
11.2.1. Study of construction + use of language. Many engage in Sociolinguistics, which is how social contexts influence the way people use language.
11.3. Biological Anthropology
11.3.1. This is a study of the past + present, including human biological evolution and present bio-cultural variation.
11.4. Archaeological Anthropology
11.4.1. Studies past societies usually through material remains (artifacts).
12. Race + Racism
12.1. Common Misconceptions: 1. Humans naturally sort into different race. 2. Different races differ in obvious ways. 3. Differences in races reflect underlying genetic differences
12.2. Race is a cultural category made by society, rather than a biological reality.
12.2.1. Social Construction of Race
12.2.1.1. The United States is a hypo-descent society. This means that the children between members of different races are automatically placed in a minority group. Some countries like Brazil have hyper-descent, meaning that children are the status of the majority. All of this shows how the concept of race is used mainly to keep in place hierarchies of power.
12.3. Race + Biology
12.3.1. Some people believe that race = subspecies. This is not true. Humans are a monotypic species, meaning there are no subspecies. We are not a polytypic species
12.3.2. At a biological level, the only thing happening is our adaptation to the environment. That is all. In the end, we are all still Homo sapiens.
12.3.2.1. Light/Dark skin is geographically correlated.
12.3.2.1.1. Our skin pigment is a response to solar radiation. Melanin blocks UV rays, and our body produces more melanin when it is stimulated by sunlight. With more melanin, our body is able to produce folate, which is needed to develop DNA and keep our body's strong. When closer to the equator, ou body reacts to this selective pressure by creating more melanin. When farther away, our body holds back on developing lots of melanin.
12.3.3. Our small genetic variations correlate mainly with geographic distance, NOT with continent of origin.
12.3.3.1. Human variation today is a result of thousands of years of dispersal. All of us share common ancestors mainly from Africa.
12.4. Failing to live rationally due to cognition biases
12.4.1. Due to a variety of biases we have, we sometimes fail to think rationally about race and ethnicity. This leads to racism
12.4.1.1. Common Cognition biases - Social Diversity Bias: put forward opinions that we believe will be well-received by others. Confirmation Bias: We favor ideas that confirm our expectations. Motivated cognition: Belief that positive outcomes are more likely than they really are. Sunk Cost Fallacy: Because we invested on it, we keep doing what we've been doing long after it stopped being promising. In-Group Bias: We believe members of our group are more intelligent than others. Apophenia: we see patterns in noise/chaos. Halo effect: Opinions of famous individuals are more respected. False Consensus effect: We tend to overestimate how many people agree with us. Attentional bias: We consider fact to be more likely the more often we have heard of it. Bias Blind Spot: the belief that we are not biased.
12.5. Essentialism and Biological Determinism:
12.5.1. Prior to the age of exploration, there was little interest in race.
12.5.2. The Age of exploration brought about a number of classifications for the diverse amounts of people Europeans met with.
12.5.2.1. Linnaeus in the 1700's labeled races into subspecies.
12.5.2.2. In the 1700s, many believed in monogenism. This is the belief that all humans depended from Adam and Eve. Over time, humans degenerated from a European origin.
12.5.2.3. Anthropometery in the 1800s allowed "scientists" to divide races based on objective "scientific" measurements.
12.5.2.3.1. Franz Boaz took cranial measurements in 18,000 immigrant families to differentiate them according to race.
12.5.3. In the 1900s, eugenics was found across the world, even in America.
12.5.3.1. America was the first country to legalize compulsory sterilization. These sterilization targeted mentally ill, physically deformed, blind, deaf, and native Americans.
12.5.3.2. in the 1950's, Carelton Stevens Coon created 50 "subspecies" of humans.
12.6. Racial theories have been used to justify...
12.6.1. Slavery, Colonization, Immigration restriction, forced sterilization, and genocide.