What topic of focus unifies all the fields of anthropology?
the study of humankind through a comparative perspective
What are the four fields of anthropology?
cultural anthropology (modern human societies), archaeology (prehistoric human population and societies), linguistics (construction, use, and form of language) and biological (human evolution, variation, and adaptations)
comparison and study of language use in specific cultural contexts
study of material remains of human activity
study of living primate biology and behavior
study of a population's skeletons for clues to their health and adaptations
study of the evolution of human anatomy and behavior in the fossil record
judeo-christian idea of an intelligent "watchmaker" with a complex plan for creation
What was the concept of fixity of species?
each species was initially created in the same form we find it in today, tying into the idea of stasis and a fixed and unchanging world
What is the Great Chain of Being?
life is a series of creations reflecting increasingly perfect organisms, from the most lowly forms to humans, angels, and God
What contribution did John Ray and Carolus Linnaeus make to classification of organisms and understanding our place in nature?
Ray defined the terms species and genus and laid groundwork for taxonomy based on physical appearance; Linnaeus created binomial nomenclature, added the terms class and order and put humans into the classification system
How did people interpret the fossil record in the early 17th and 18th centuries?
fossils were considered "sports of nature" or mythical creatures and were interpreted biblically; later studies infer that fossils found in bottom layers are older, Cuvier and Buffon look at fossils over long timespans and say that the environment influenced which fossils lived where
Explain the difference between Lamarckian and Darwinian theories of evolution
Lamarckian theory was based around the idea that successful activity patterns affected animal physiology and were passed on through inheritance of acquired, pregenetic characteristics; Darwinian theory based on the idea of natural selection and descent with modification, that animals with advantageous characteristics survive to pass on their traits to the next generation, and these traits become more common in the population over time
How did Lyell, Malthus and Wallace influence Darwin's ideas of evolution?
Lyell — demonstrated the great age of the earth and geological structures, argued for "deep time" and the concept of geological change occurring over slow increments; Malthus — idea that reproduction is constrained by resources, helping Darwin realize the concept of resource competition; Wallace — inadvertently discovered the logic of natural selection at the same time, prompting Darwin to publish first
What is selective breeding and how did it help Darwin formulate his idea of natural selection?
choosing animals with the most attractive traits to breed so that their offspring will have a higher chance of having those traits; watching breeders select for marbled meat in cows, Darwin realized that what breeders do intentionally might also occur naturally because of environmental constraints
What is the difference between intentional and inadvertent natural selection?
both are artificial, caused by human interference; intentional is done to produce offspring with desired traits (dog breeding for show, cow breeding for food) while inadvertent occurs as a result of human effects on the environment changing what traits are advantageous (peppered moths and industrial melanism)
What is differential reproduction?
the process by which organisms that are better adapted to their environments tend to survive longer and pass on the advantageous trait they carry to the next generation with a higher frequency, causing a growth in the trait over generations
organisms that are better fitted, or suited, to their environment will be more likely to survive and have greater reproductive success
Does evolution necessarily mean progress? Is the evolution of species on earth more like a tree or a bush? Why?
evolution is not progress or hierarchical steps to greater perfection or complexity, but a gradual accumulation of changes that make a species better suited to an environment; organisms are all just as evolved, just to their own niche, and increasing complexity is merely a side effect of expanding into more specific niches; therefore, evolution is not hierarchical or progressional like a tree, but expansive like a bush
Are chimpanzees trying to evolve to become humans? Why or why not?
no; organisms do not strive to achieve new forms, but to stay the same despite changing conditions; the evolutionary change chimpanzees can undergo is constrained by their current form, but not directed towards any specific form, such as a human
What is the difference between stabilizing, directional and disruptive selection? Give an example of each.
stabilizing — the most advantageous trait is somewhere in the mean, so over time the species moves towards an average, staying how it is and limiting variety so that it can continue to fit into the environment (similar size and coloration in a species); directional — population shifts towards a new mean, environmental shift causes one extreme of a trait to become more successful, and the population moves towards that before stabilizing (becoming faster, smarter, sharper claws); disruptive — population shifts towards two extremes due to a disadvantage in the mean trait, eventually differentiating over time (sexual dimorphism, males favor fighting while females favor caring for young)
What is differential reproductive success?
the difference in the amount of offspring left behind by different individuals of a species; individuals that are more suited to the environment will have greater reproductive fitness and leave more offspring, passing on their advantageous trait, while those less suited will leave behind less children and have less reproductive success
What are chromosomes? How many chromosomes in humans?
long strings of DNA, containing genes, that are coiled around proteins and found in cell nuclei; humans have 46 chromosomes (23 pairs)
What is a gene? What is an allele? Give an example.
gene — portion of DNA that code for a specific functional product, usually proteins, through codons (groups of three nucleotide bases); alleles are alternate forms of a gene that can be dominant or recessive. example: in a gene affecting human earwax, one allele codes for dry wax, while the other codes for wet wax.
What is the significance of the experiments done by Gregor Mendel in the mid-1800s? What did we learn about patterns of inheritance from Mendel?
demonstrated the particulate and combinatorial nature of inheritance, providing a basic explanation for the vehicle of inheritance; realized that inheritance is dictated by two separate forms of a gene, one dominant and one recessive, the former of which can drown the other out; also that alleles separate into different gametes, allowing each parent to pass on a single allele to the offspring, and that different traits are passed on independently of each other
What is the difference between mitosis and meiosis?
mitosis — occurs in somatic cells, used for growth and repair, involves one division and produces two identical, diploid daughter cells; meiosis — occurs in gametes, used for reproduction, involves two divisions and produces four unique, haploid daughter cells
When does crossing over occur? What happens during crossing over?
occurs during prophase I of meiosis, when the chromosomes have formed and are next to each other in the cell; the ends of homologous chromosomes swap, creating four new chromatids that are a mix of both parents' genetic information, and allowing for more varied offspring
How do independent assortment and recombination (crossing over) contribute to genetic variation?
independent assortment — genes on different chromosomes will be passed on independently from each other, allowing infinite different combinations of mother's and father's genes in gametes; crossing over creates chromosomes that are a mix of the parents' genetic information; both processes generate offspring with a mix of traits from both parents, increasing variation
2n; having two sets of chromosomes (each chromosome is part of a homologous pair); found in somatic cells
n; only having one set of each type of chromosomes; found in gametes
the specific position or location of a gene on a chromosome; genes in different loci will be affected by independent assortment
homologous chromosome autosomal inheritance
normally inherited; crossing over and independent assortment, random assignment to gametes occurs; one chromosome of each homolog is contributed by both the mother and the father
condition in which both alleles for a gene are expressed in the phenotype (i.e. a cow being both red and white); most genes express some degree of codominance
traits that are coded for by genes located on the X chromosome; because males only possess one X chromosome, there is no possibility for dominance masking, and sex-linked recessive phenotypes are more commonly expressed, causing genetic disorders
a change in a DNA base pair; can cause a change in the corresponding codon, amino acid, and protein, causing a new trait to arise; only source of new genetic variation!
What is meant by the term "carrier" with regard to sex-linked traits? Why is the male more frequently affected in sex-linked traits than females?
"carrier" is a female who has the recessive allele on one of her X chromosomes, but not the other; because of this, she does not exhibit the trait, but can pass on the allele to her sons, who will exhibit it; because males only have one X chromosome, any recessive alleles that cause the trait will be exhibited because there is no dominant allele to mask it
What causes color blindness?
a mutation in one of the 3 genes, located on the X chromosome, that codes for color sensitivity in cones; a mutation in 1+ of these genes creates reduced light sensitivity and different color perception
What is hemophilia and how is it inherited?
blood disorder in which a mutated form of the enzyme essential to the function of clotting factor thrombin is produced, causing reduced clotting and excess bleeding; inherited via the X chromosome, making it a sex-linked trait
What is the additive effect in polygenic traits
the greater number of genes that have the allele coding for a specific trait, the stronger the trait will appear in the phenotype (i.e. more dark skinned alleles create a darker skin color)
What causes genetic mutations?
basic mechanical errors in/during replication; chemical/radiation damage to DNA
What amino acid in the diet is involved in the enzymatic reaction that leads to the production of melanin?
What causes albinism?
a mutation in any of the genes that synthesize the enzyme that converts dietary phenylalanine to melanin; causes a homozygous recessive loss of enzymatic function due to mutations at one of two loci, knocking out the whole sequence and preventing pigmentation
How are gene flow and genetic drift potent forces in evolution?
gene flow — mixing of genes between different populations, alters allelic frequencies and adds variation in breeding populations; genetic drift — statistical sampling effects produce a random selection of genes to be passed on, 50% of each parent's genome is randomly lost, reducing variety; having more offspring reduces the effects of genetic drift by allowing a higher chance of the complete genome being passed on
What is founder effect and what is a bottleneck in a founder population?
founder effect — when a new population is drawn from a small sample of the original population; causes a genetic bottleneck if the founder population makes up a small percentage of the original group — the new population has reduced genetic variation to choose from