Week 8 Bio
Week 8 Bio Bio 111
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This 11 page Class Notes was uploaded by Sierra Taylor on Monday February 29, 2016. The Class Notes belongs to Bio 111 at California Polytechnic State University San Luis Obispo taught by Eric Noel in Winter 2016. Since its upload, it has received 76 views. For similar materials see General Biology in Biology at California Polytechnic State University San Luis Obispo.
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Date Created: 02/29/16
2/22: Midterms were passed back to students, class average of 82% iClicker Questions and Answers 1. Gene “A” is a recessive sexlinked trait. What is the genotype of the father? #5, Xa, Y 2. Female first cousin in the youngest generation’s genotype is the one not certain of based on the pedigree shown. a word problem would always tell you if the trait is sex linked or if it is a recessive/dominant allele 3. Male has type A blood, female has type O, their son has type O, what is the genotype of the mom and dad? Mom: OO, Dad: AO Both A and B are dominant blood types over O, in order to have a genotype that has a phenotype of O, genotype must be OO A and B are also codominant, creating the blood type AB (7.11) Multigene Traits How are continuously varying traits such as height influenced by genes? Polygenetic traits: a trait that is influenced by many different genes Additive effects: the more genes we add together that are going to contribute to a trait, the more complex the trait becomes. what happens when the effects of alleles from multiple genes all contribute to the ultimate phenotype. (7.12) One gene now influences multiple traits Pleiotropy: one gene, many effects ex: hemoglobin in sickle cell anemia effects both the oxygen carrying capacity of red blood cells as well as immunity to malaria (capability of red blood cells contracting malaria) HbA HbA (homozygous dominant) normal red blood cells, vulnerable to malaria HbS HbA (heterozygous) – half normal red blood cells, half sickle cells, has sickle cell anemia but is still capable of living and breathing, for the most part immune to malaria (they can be effected but not to extent of death) HbS HbS (homozygous recessive) – all sickle cells, immune to malaria (7.13) Why are more men than women color blind? Sex linked traits differ in their patterns of expression in males and females. Men inherit color blindness from their mom because color blindness is a sex linked trait carried on the X chromosome. (Figure 7.25) Women: XX – can have one dominant allele that masks the effect of the recessive allele Men: XY To be color blind… Men: only have to inherit the allele from the X chromosome of their Mom, they have only one X chromosome so they have no chance of inheriting a dominant allele that can mask their recessive allele. Women: must inherit a recessive allele from both parents (homozygous recessive) (7.14) Cause of malepatterned baldness? Modern Approach: Balding men commonly share DNA sequences on their X chromosome. What does that tell us about whom they inherit that DNA from? Research suggests baldness caused by sexlinked gene that codes for an androgen receptor (more receptors on the X chromosome). Males always inherit malepatterned baldness from their mother. You can know this be looking at your Mom’s Dad as to whether you will be bald if you’re a male. (7.15) Environment effects: identical twins are not identical. Genes interact with their environment to produce physical characteristics. Like diet, Genes do not “code” for physical characteristics. ex. Siamese cats and Himalayan bunnies; both carry a heat sensitive enzyme that deactivates when temperature is elevated cause light pigmentation, but when activated in the cold will cause dark pigmentation on the tail, nose, ears and feet. Experiment done was strapping an ice pack to a Himalayan bunny and watching a dark patch of fur develop where the ice pack was placed. Ch.8 Evolution and Natural Selection Darwin’s dangerous idea: evolution by natural selection (both fact and theory) (8.12) Organisms in a population can become better matched to their environment through natural selection Adaptations increase fitness. Evolution: a genetic change in population. Natural selection: the consequence of certain individual organisms in a population being born with characteristics that enable them to survive better and reproduce more than the offspring of other individuals in the population. ex: 1. Bats greater ear because they live in the dark and are blind therefore they need to listen for predators. 2. Peppered moths: before the industrial revolution all peppered moths were lighter in color (looked as though they are peppered), 98% white phenotype but after the 2 decades of IR an opposite effect occurred where 98% were the black phenotype, this occurred because of all the coal burned turning the trees black so the white moths on the black trees got eaten by predators so natural selection allowed black moths to reign leading to a dramatic change in phenotype in order to aid survival in the new and changed environment. Workshop Notes If a homozygous female who is not color blind has children with a male who is color blind, what percentage of their sons will be color blind? What percentage of their daughters will be color blind? Answer: 0% for both sons and daughters. A cross between redflowered snapdragons and whitecolored snapdragons produces offspring with pink flowers, showing incomplete dominance. Let R= red, W= white. Suppose a pink flowered plant is crossed with a pinkflowered plant. Answer: Possible genotypes and phenotypes are RR (red), WW (white), and RW (pink). The ratio of the offspring that will have pink flowers is ½, and the percept of offspring that will have red flowers is 25%. A man with type AB blood is married to a woman with type O blood. They have 2 natural children and 1 adopted child. Which child is adopted? Answer: The child with blood type O because A and B are both dominant alleles so no type O offspring are produced according to the Punnett Square. How is height a polygenic trait? Answer: Because genes on chromosome 15 and others all effect the trait of height. How can the gene hemoglobin provide us an example for pleiotropy? Answer: Because it effects both the oxygen carrying capacity of red blood cells as well as the capability to become immune to malaria. If a male with color blindness (sexrelated variety) and a female with normal vision have a color blind son, what can you infer about the parents? Answer: The mother was a carrier for color blindness. Susan, a mother with type B blood, has a child with type O blood. She claims that Craig, who has type A blood, is the father. He says no. Further blood tests reveal Craig is AA. What does the judge rule? Answer: Craig is right and doesn’t have to pay child support. A colorblind man and a woman with normal vision whose father was colorblind have a son. Color blindness in this case is caused by an Xlinked recessive gene. If only the male offspring are considered, the probability that their son is color blind is 50%. Multiple effects of a single gene is known as pleiotropy. What is the difference between incomplete dominance and codominance? Answer: In incomplete dominance the offspring do not exhibit the traits of either parents, while in codominance, the offspring exhibit the traits of both parents. A woman with type B blood and a man with type A blood could have children with which phenotypes? Answer: A, B, AB, or O What is the significance of androgen receptors and male patterened baldness? Who do bald males inherit that trait from and why? Answer: Androgen receptors means that there are more receptors on the X chromosome so the recipient who shows greater amounts of androgen receptors has the link to be bald. They inherit from their Mom’s because of the androgen receptor being located on the X chromosome. Why do diet CocaCola cans advertise that they contain phenylalanine? Answer: Because people with defective enzymes can’t digest phenylalanine and if they have this disorder then the accumulation of phenylalanine can become toxic. How is phenylketonuria related? Answer: It is the name of the disorder with the defective enzymes. 2/24: Look at PolyLearn for 14 Final Exam Short Answer Questions, he will be picking 15 of these exact questions for the Final Exam iClicker Questions and Answers: Which parents would have the possibility of producing a daughter who is colorblind? –XrY and XrXR a girl who is colorblind must have a homozygous recessive genotype of rr, or XrXr The impact of a single gene on more than one characteristic is called pleiotropy. ex. hemoglobin effects both sickle cell anemia and immunity to malaria polygenic inheritance is multiple genes effecting one trait, ex. height Phenylketonuria (PKU) is a genetic disorder that causes the inability to convert phenylalanine to tyrosine (which are two different types of amino acids) If you have PKU you have a nonfunctional phenylalanine hydroxylase enzyme that will not convert phenylalanine to tyrosine. (8.12) Continued… Increased fitness means the organism has a higher probability of passing its’ genes to the next generation of offspring. How much is a gene aiding an organism’s survival will depict whether the trait is needed, meaning whether the gene is needed. Natural selection decides this. ex. Galapagos finches: food supply and beak size. Darwin noticed a relationship between food supply, time of year, and beak size. 2 Beak Sizes 1. Dry years, large hard seeds, big beaks 2. Wet years, small soft seeds, smaller beaks Researchers found that the average beak size fluctuated according to the food supply and environment. Factors that Prevent Populations from Progressing Inevitably toward Perfection 1. Environments change quickly 2. Variation is needed as the raw material of selection 3. There may be multiple different alleles for a trait, each causing an individual to have the same fitness Artificial Selection Animal breeders and farmers are making use of natural selection when they modify their animals and crops through selective breeding. Since the differential reproductive success is determined by humans rather than by nature, this type of natural selection is also called artificial selection. ex. Cows Male cow that makes a lot of milk, resides in SLO Female cow that makes a lot of milk, resides in Nebraska Humans bring both cows together to mate them and produce offspring that will also make lots of milk. Red Delicious Apple Began as a weed on an Iowa Farm Directional Selection The average value for the trait increases or decreases. ex. peppered moth, went from peppered phenotype to black phenotype which was a dramatic change turkey breast size: farmers take the turkeys with larger breasts and mate them with others with larger breast, therefore the population of smaller breast turkeys decreases and the larger breast turkeys increase Stabilizing Selection Individuals with intermediate phenotypes are the most fit. ex. human baby birth weight less than 7 pounds: health complications between 79 pounds: healthy baby greater than 10 pounds: health complications Disruptive Selection Individuals with extreme phenotypes experience the highest fitness and those with intermediate phenotypes have the lowest. ex. salmon small: good because they can sneak into the beds and fertilize eggs medium: bad because they are easily visible and will be beaten up by the big salmon before they can fertilize the eggs. big: good because they can easily beat up other fish (8.17) Natural selection causes evolution of complex traits and behavior ex. fast and slow learning mice, after around 6 generations of breeding fast w/ fast and slow w/slow, the fast mice only made ½ the mistakes that the slow mice made. Can copot traits for new functions. Functional shifts of structures serving a purpose. ex. Insect wings, little (provide warmth), medium (provide more warmth and some aerodynamic benefits), long (can provide warmth and flight) 1 function (warmth) led to another function (flight) (8.21) Molecular biology reveals that common gene sequences link in all life forms Estimates of evolutionary relatedness made from: 1. Comparative Anatomy 2. The Fossil Record 3. Embryology gills in embryotic stage 4. Radiometric dating Molecular Clocks ex. Hemoglobin, protein: alpha and beta chains (146 amino acids long, what we are comparaing) Human; 146 AA Monkey: 138 AA Dog: 114 AA Bird: 101 AA Lamprey: 21 AA The longer 2 species have evolved on their own, the greater amount of differences. Theory: human and monkeys share a common ancestor. Workshop Notes What are the four mechanisms of evolution? 1. Genetic Drift (random change of alleles) 2. Mutation 3. Natural Selection 4. Migration (emigration/immigration) List the three conditions of natural selection. The trait has to be heritable, variation, and the phenotype must cause reproductive success. Describe how bacteria evolve to resist antibiotics. Natural selection selects and allows alleles for antibiotic resistant enzymes to survive and reproduce (also due to mutations in the bacteria’s DNA) Define fitness. The ability to pass down your genes to the next generation (or your offspring). What factors prevent populations from progressing towards perfection? 1. Variation is essential for natural selection. 2. Environments are changing rapidly. 3. Multiple alleles can cause the same fitness. Provide an example of natural selection improving a complex trait. Trait of intelligence throughout mice. Researchers bred slow learners with slow learners and fast learners with fast learners and they saw over 6 generations that the fast learning mice had only made ½ the mistakes that the slow learning mice had made, showing that overtime the intelligence trait in the fast learning mice had improved. A population of birds experiences a random change in allele frequencies, over time making a greater percentage have black beaks as opposed to yellow beaks. Has evolution occurred? YES Fitness is a measure of the reproductive output of an organism. Conditions necessary for natural selection include variation, heritability, and differential reproductive success. After a group of individuals migrates from one population to another, only the population they join experiences a change in their allele frequencies FALSE Natural selection can, on occasion, lead to perfect organisms FALSE Provide and explain an example where a structure’s purpose can change over evolutionary time due to evolution: Flies wings were first used as a form of warmth (they looked like little nubs), as they evolved into a medium length they aided warmth furthermore but also provided a few aerodynamic benefits, then they evolved more so to be long and provide both warmth and the function of flight. Directional selectins favors the intermediate phenotype FALSE Baby birth weight is a good example of stabilizing selection TRUE Insect wings were originally evolved for flight FALSE Why might the fossil record not be the best method of documenting the process of natural selection? The most abundant organisms of the time are the ones usually preserved, soft parts of organisms are replaced by minerals, only certain environments provided the optimum conditions for fossilization, and organisms with bones, shells, exoskeletons, or other hard parts were the most likely to be preserved. The longer the time period two species have been evolving on their own, the greater the number of genetic differences between them. 2/26: BIO Alternative Final on Tuesday of Finals Week. iClicker Questions and Answers Primordial insect wings were first used for thermoregulation. As size increased they could be used for flight Ch.9 Evolution and Behavior: cooperation, selfishness, altruism; behaviors are traits that can evolve (9.1) Behavior has adaptive value appetite, we like FroYo because our appetite craves sugar and fat; we don’t eat dirt because it has very little nutritional value. Animals should maximize energy consumed and minimize energy used. Ancestral humans who preferred fatty foods were less likely to starve; calories were heard to come by, fat was easiest and readily available. EnergyEfficient Feeding Behavior has Evolved feeding off of juiciest, most appealing food shore crabs preferentially choose mussels that provide the most energy relative to the effort it takes to open the shell. Why have taste preferences? directly effect fitness living and reproducing require energy maxima energy and essential nutrients NATURAL SELECTION CAN SHAPE FEEDING BEHAVIOR. Scope of Animal Behavior courtship and mate choice cooperation, alliance building and sociality competing for food and avoiding predators migration and navigation behavioral control of body temperature (9.2) Innate Behaviors Innate behaviors instincts ex. male stickleback (fish), red bellies for mating session, when they see other red fish bellies they become extremely aggressive/violent Requires no learning; ex. gees, Mom’s will retrieve lost eggs (or any object) (9.3) Learned Behaviors Learning: involves behaviors that are altered and modified over time in response to past events. ex. monkeys, once exposed to the fear of snakes they then become fearful of snakes language acquisition in humans Human babies are more fearful of snakes but not of guns, why? Evolutionary change cannot always keep up with a rapidly changing environment. (9.5) Kindness Altruistic behavior: behaviors that come at a cost to the individual doing the behavior while benefitting the recipient. ex. Australian social spider Mom liquefies after birth and let her babies eat her live. Darwin’s Theory Natural selection generally works to produce selfish behavior. Altruism appearing behavior is common (looks alike but its not) 1. Kin selection: kindness towards relatives 2. Reciprocal altruism: kindness towards unrelated individuals ex. ground squirrel, Mom comes out when predators are present and alerts family, cares about her own genes in offspring and her legacy, not really her family members (kin selection) ex. vampire bats with vomit blood in order to feed friends, waiting for others to return the favor (reciprocal altruism) charitable acts can give us pleasure, can be evolutionarily maladaptive, we argue it’s the right thing to do with it makes us feel good, Darwin argues altruism because of past favor system but incentive has changed. Workshop Notes What are the four mechanisms of evolution? 1. Genetic drift random change of alleles 2. Mutation 3. Natural Selection 4. Migration (emigration/immigration) Whar are the three conditions for natural selection? 1. the trait has to be heritable 2. phenotype must cause reproductive success 3. variation Describe how bacteria evolves to resist antibiotics. Natural selection allowed for antibiotic resistant enzymes to survive and reproduce. Define fitness: the ability to pass down your genes to the next generation, or your offspring What factors prevent populations from progressing toward perfection? 1. Variation is essential for natural selection 2. Environments always change 3. Multiple alleles cause the same fitness Provide an example of natural selection improving a complex trait. Learning fast/slow for mice. A population of birds experiences a random change in allele frequencies, over time making a greater percentage of the population have black beaks as opposed to yellow beaks. Has evolution occurred? –YES Fitness is the measure of the reproductive output of an organism. Conditions necessary for natural selection are variation, heritability, and differential reproductive success. Provide an example for which a structure’s purpose can change over evolutionary time due to evolution. Flies wings were first used as a form of height and then as they evolve and elongated they became utilized for flight. Baby birth weight is a good example of stabilizing selection. The longer the time period two species have been evolving on their own, the greater the number of genetic differences between them.
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