Ch. 7 Flashcards
What is the focus of microevolution?
Microevolution: subfield of evolution are studies that devotes attention to short term evolutionary changes that occur within a given species over relatively few generations of ecological time.
Sometimes involves what’s called ecological time, or the pace of time as experienced by organisms living in and adapting to their ecological settings
Briefly describe the modern evolutionarily synthesis?
What other term has been used for the modern revolutionary synthesis?
A new way of thinking about evolution that combined Darwinian natural selection ideas about heredity.
Neo-Darwinism
Identify the three nesting concepts that underlie argument by evolutionarily biologists.
•Species are reproductively isolated from other species
•Species can’t produce fertile offspring with other species
•Species occupy a specific niche in nature 
What is the most important measure of membership in our species
The ability of human beings from anywhere in the world to interbreed successfully is the most important measure of membership in our species. 
Identify the two groups of polymorphous variants
1st group, Polymorphic alleles, accounts for most genetic variation across populations. Populations differ not because they have mutually exclusive sets of alleles but because they possess different proportions of the same set of alleles. 
2nd group, Private polymorphisms, includes a oils that are found in the genotypes of Sam, but usually not all, members of a particular population. 
Briefly describe how the ABO blood group reflects polymorphic alleles
ABO blood groups: polymorphic alleles A, B, and 0 are found in all human populations, but the frequency of each allele differs from population to population.
Briefly describe how the Diego antigen is an example of a private polymorphism.
How does this render the traditional western concepts of race biologically and genetically meaningless?
Genetically determined blood cell antigen known as Diego antigen. Occurs only an Asian and African populations, although 60 to 90% of the members of these populations do not have it 
There is not a simple line that can be drawn to distinguish groups of humans based on their genetic make up.
Geneticist Richard Lewontin (1972) demonstrated That more genetic variation could be found within conventionally identified racial groups then could be found between them. 
This means that the boundaries set to defined human races have been culturally imposed on shifting and unstable clusters of alleles. 
”Genetic variation in human populations is mostly a matter of differences in the relative proportions of the same sets of alleles”: what is the gradual intergradtion of genetic variation from population population called? 
Clines.
The distribution of particular field types shifts graduate from place to place across populations as the frequencies of some alleles increase well those of others decrease or stay the same. Can be represented on a map.
Briefly describe Abu El-Haj’s (2007) concerns with some bio medical researchers using information about racial groups genetics to stand in for genetic information particular individuals who consider themselves to be members of those particular groups.
Outline Abu El-Haj’s (2007) two reasons why this biomedical use of race does not reflect scientific racism. Briefly describe concerns with the development and distribution of the drug BiDil in the United States. (I.e., What was it designed to treat and which group did it target).
What was the circular argument around claiming the drug was proven to work?
?
First, the old race concept focussed on the classification of phenotypes, whereas the new race concept classifies genotypes. As a consequence of changing historical understandings of sickle cell anaemia in North America. Sickle cell anaemia was identified as a disease of black people— or people with African ancestors. But later, it’s cause was traced to molecular genes: the presence of an abnormal sickling hemoglobin allele at a particular locus on a genome. Second, 19 century race science aimed to discover how many races existed and to assign all individuals to their true race. The commercial technologies used by biomedical researchers to distinguish human populations in terms of the continents from which their ancestors personally came. But all assume that everyone has a mixed ancestry of some kind; the goal is to measure how much of which ancestry markers are present in each population, thereby determining with the degree of risk the members of a population face for genetic diseases associated with particular ancestors. 
The drug trial involved only self identified African-American subjects, which the FDA agrees is a highly imperfect but useful proxy. The FDA admits that other individuals besides self identified African-Americans might will benefit from BiDil, but this was not demonstrated by the A-HeFT drug trial because all of the participants were African-American. In other words, the drug was proven only to work on African-Americans because it was only tested on African-Americans.
Identify and defined the four evolutionarily processes.
Natural selection, mutation, gene flow, and genetic drift
Sum up how the HbS allele conveys evolutionarily advantage within malaria environments.
The HbS allele conveys a higher resistance to malaria people. People exposed to malaria have a better chance of resisting the parasite if their haemoglobin genotype is HbA/HbS rather than the normal HbA/HbA.
Thus, in regions of the world where malaria is common, having the HbS allele is advantageous to survival; not surprisingly, it is in the same regions that the HbS allele appears in its highest frequencies.
This is an example of a balanced polymorphism, in which the heterozygous genotype is fitter than either of the homozygous genotypes. HbS allele changes the structure of the blood cells enough to inhibit malaria parasites but not enough to cause sickle cell anemia. 
Define gene flow and genetic drift.
What forms may genetic drift take?
Gene flow: the exchange of genes that occurs want to get some population experiences a sudden expansion due to in-migration of outsiders from another population of species.
Genetic drift: random changes in gene frequencies from one generation to the next due to a sudden reduction in population size as a result of disaster, disease, or the out-migration of a small sub group from a larger population.
Briefly describe how genetic drift has been studied in relation to the French Canadian population of Quebec
Approximately 6 million people, most of whom are descendants of approximately 808,500 French settlers who arrived in new France in the period from the early 17th century to the late 18th century. The availability of both genomic and Genealogical data from the population has allowed researchers to distinguish several founder events and establish related indices. 
They have found evidence that the various migrations of these settlers and their early descendants lead to a series of regional founder effects, the generic implications of which are reflected in the geographical distribution of certain genetic diseases among French Canadians in Quebec today. 
Where do most biologists and anthropologists agree the most intense selective pressures our species face comes from?
The most intense selection pressures are species face come from disease organisms that target our immune systems and from human made environmental threats, such as pollution and the ozone hole. 
Briefly some of how disease patterns changed as human social organization shifted from living in small foraging groups to settling in towns and cities with poor sanitation
When our ancestors were living in small foraging bands, they were susceptible to chronic parasitic infections, such as pinworms, and disease is transmitted from animals.
After the domestication of plants and animals, however human diets changed. Populations expand, individuals had more frequent contact with one another, and the stage was set for the rise and spread of endemic diseases (I.e., diseases particular to a population) that could persist in a population without repeated introduction from elsewhere.
It was this endemic diseases that had devastating impact on the populations of indigenous people in North America during colonization, creating the current limited genetic variety among the population.
