Review sheet for Mendelian genetics through human evolution WARNING: I have tried to be complete, but I may have missed something. You are responsible for all the material discussed in class. This is only a guide. 1) Mendelian genetics Why do we call this section Mendelian genetics? Who was Gregor Mendel? What did he do? What was he trained in? (Know the basics about Mendel, as presented in class). What organism did Mendel study? What characteristics of this organism did he examine? How did Mendel come to his conclusions? What do P, F 1, and F 2 mean? What four hypotheses did Mendel develop? Make sure you understand these. How can these be used to explain Mendel's results? How do we get purple flowers in F 1 when we start with pure breeding purple and white parents? How do we get 3 purple to 1 white flower when we cross these F 1 offspring? Again, what do Mendel's four hypothesis have to do with this? How do they explain what happened? What is dominant? recessive? heterozygous? homozygous? phenotype? genotype? Obviously, you need to know what alleles and genes are to explain any of this. Where are alleles anyway? If P = purple and p = white, what would Pp look like? PP? pp? How many gametes can an individual flower make if it is PP? pp? Pp? How can we use this to figure out the number of different kinds of offspring that can result? What is a Punnet square and how can we use it to answer the last question? What is a phenotype ratio? A genotype ratio? How are they different? Can we figure out the phenotype from the genotype? The genotype from the phenotype? Explain. What do we mean when we say Mendel cheated a bit? Suppose we look at two traits at the same time. If we start with a pure breeding P generation (e.g., YYRR x yyrr), what do we get in F 1? What do we get in F 2?
What is a testcross? What do we need to know before we can answer the question about F 2? Answer: we need to know whether or not the genes for color (e.g., Yor y) and texture (e.g., Ror r) are on the same chromosome or on different chromosomes. What we are saying is that we need to know if the genes for color and texture are on the same or different chromosomes. If they are on different chromosomes, what do we expect in F 2? If they are on the same chromosomes, what do we expect in F 2? (What ratios do we expect? Why?) What is the law if independent assortment? When is it true? Know how coat colors in Labradors work. How do Mendel's hypotheses explain two traits at a time? How can we use a testcross to determine whether or not an individual organism is homozygous or heterozygous? You don't need to know anything about probability except that it's another way of solving genetics problems. What are some simple human genetic traits that follow a dominant/recessive realtionship? Is a dominant allele always more common? How can pedigrees be used to determine an individual's genotype? See particularly the deafness example in your text book. What is a carrier? Know the examples of genetic diseases we discussed in class Why is Huntington's disease so horrible? Why can inbreeding increase the probability of getting a genetic disease? Know the example we went over in class. What is incomplete dominance and how does it differ from co-dominance? We gave examples of each in class. Be familiar with these examples. What happens when we have more than two alleles? How do human blood types work? Are A & B codominant or incompletely dominant? What is a universal donor? Universal recipient? What is pleiotropy? Which example did we use for pleiotropy? What is polygenic inheritance (multiple genes controlling the same trait)? What example did we give in class? What is epistasis?
2) DNA What are some of the issues that come with genetic testing? What happens when the law of independent assortment does not apply? Make sure you understand why we get a 3:1 ratio if purple and long (see example we discussed) are on the same chromosome (and red and short on the homologous chromosome). Technically, we do get a few exceptions to the 3:1 ratio - crossing over! How does crossing over work, and how can we use crossing over to map genes? What is it about Fruit flies and genetics? Make sure you understand the fruit fly example. How is sex determined in humans? In other animals? What are sex linked traits? What is the difference between men and women (in humans)? Why are sex linked traits more important in men than in women (particularly if they're a recessive disease)? What are some examples of sex-linked diseases? What are the three parts making up a nucleotide? Which four nitrogenous bases are used by DNA? RNA? What are the rules for pairing (i.e., which nucleotide can pair with which)? Who first discovered DNA? What holds the two strands of DNA together? How does DNA replicate? What enzyme is used to do this? How is exact duplication ensured (i.e., which nucleotide can pair with which)? What are bubbles? How is replication sped up? How many nucleotides can be replicated in mammals? In bacteria? What steps are involved as one moves from DNA to a protein. What is transcription? Translation? What are the steps in making mrna? What about the genetic code? How was it discovered? How does this code for the 20 different amino acids? What is a codon?
3) Evolution What is a start or stop code? How does this work? How is mrna converted into a protein? What is the role of trna? What do ribosomes do? What part of the ribosome does the mrna attach to? What is the difference between the large and small subunits? How does the protein actually grow? How many different kinds of trna are there? What is the potential effect of changing just one nucleotide? Which example did we use to illustrate this? What is base substitution? Deletion? Addition? What can cause mutations? Are most mutations beneficial? Harmful? Have no effect? What is a virus? How does it work? What is the difference between an RNA and DNA virus? Why are some viruses more dangerous than others (i.e., which part of the body does the virus attack?) How does the AIDS virus work? Do viruses infect organisms other than humans? What are plasmids? How can we use plasmids to our advantage? So what is evolution? What is the definition of evolution? Please don't confuse the definition with evidence (things like fossils, etc.). Who was Linnaeus? What did he do? Who was Lamarck? What did he propose? What were the problems with his evolutionary theory? Who was Cuvier? What did he discover about fossils? What was his theory about fossils of animals no longer living in his location? What is paleontology?
Who were Hutton and Lyell? What is gradualism? Uniformitarianism? What did these concepts imply about the earth? Know Darwin's short biography as presented in class (all the details!). What book did he publish? Who provided the impetus to Darwin to finally publish this book? (Who was Wallace?) So what was Darwin's great contribution? What is natural selection? What are the main points of natural selection? Who was Malthus? What was Mendel's role in this? What evidence do we have for evolution? How do antibiotic and insecticide resistance demonstrate evolution? What is the fossil record? How do fossils form? Do they always form in rock? How does this provide evidence of evolution? What is comparative anatomy? What are homologous structures? Analogous? What is convergent evolution? Know some examples of homologous and analogous structures. Make sure you understand the why bird and bat wings are analogous, but the bones making up the wings are homologous. What evidence for evolution does embryology provide? Biochemistry. What is biogeography? What is artificial selection? How can DNA be used to establish relationships between living organisms? How is this similar to natural selection? Who (or what) does the selecting in artificial selection? What about camouflage? Adaptation? Mimicry? What are these and how do they provide evidence for evolution? What is the role of genetics in evolution? Remember: how do we define evolution?
What happens to a recessive lethal allele? Does it's frequency in the population go up or down? Know the Hardy-Weinberg equations. How can we use Hardy-Weinberg to figure out the percentage of the population that might be a carrier for a genetic disease? Be able to solve very simple problems using Hardy-Weinberg (no problems on the exam will require the use of a calculator). What are the rules for Hardy-Weinberg equilibrium? How can we use these rules to demonstrate evolution? (We will almost always violate one of the rules, and thus cause evolution). What is the source of new alleles? Where do they come from? What is the raw material for evolution? What is sexual selection? Why can it generate silly characteristics? What is the trade off between sexual selection and natural selection? What is speciation? What is a species? What prevents two different species from producing viable (fertile) offspring? What is allopatric? Sympatric? Which type of speciation is more common? Why? Why can island chains sometimes lead to a rapid explosion in the total number of species? Finally, what is a theory in the scientific sense? Are biologists arguing about evolution? If so, what are they arguing about? Did humans evolve from apes? 4) Human evolution Why or why not? (make SURE you understand this last bit - it's the source of much confusion among non-biologists). Primates - where did they come from? What are some characteristics of primates? Why do we have some of the characteristics that we do (e.g., why do we have excellent vision and lousy smell)?
Be aware that there is a lot of controversy amongst biologists about the exact shape of the human family tree. Know what was presented in class. You should know the basics (age of the fossils (if given), size of brain (if given), major characteristics) of each of the following: Sahelantropus tchadensis Ardipithecus ramidus Australopithecus anamensis Australopithecus afarensis Australopithecus africanus Australopithecus robustus & boisei Homo habilis Homo erectus Homo heidelbergensis Homo sapiens (incl. neanderthals) Know how these fit into the human family tree - which were ancestors to humans? Which were dead ends? Make sure you know what each species is known for: (e.g., H. erectus is the first species for which we have evidence of fire).