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Introduction to Natural Selection Natural selection posits that only a certain percentage of offspring born will survive to reproduce another generation. Individuals with certain genotypes will be more likely to survive, mate, and reproduce their genotypes in subsequent generations. Thus, natural selection acts upon individuals, whereas evolution occurs at the level of a population. There are [...] Altering Existing Genetic Variation Genetic drift is a change in in genetic variation due to chance changes in allele frequencies. For example, genetic drift may occur as a matter of luck; one phenotype may simply never meet a member of the opposite sex in order to mate and produce offspring. Genetic drift is not affected [...] Population geneticists primarily study allele and genotype frequencies. They use quantitative methods to analyze the frequency of alleles. For example, a population geneticist may study the frequency of certain patterns on the fur of wild cats, then will revisit the same population several generations later to find how the frequency of patterns has changed from [...] Species- a natural group that shares a distinct form Onset & Symptoms: Personality changes Treatments: Nothing known to slow or stop the decline Prevalence: 1 in 20,000 people Famous People with the Disease: Woody Guthrie Heritability & Environmental Factors: Caused by a dominant allele Individuals with Huntington’s Disease have one dominant Huntington’s allele and one normal allele. It is [...] Onset & Symtoms: Mental retardation Treatments: Specialized low-phenylalanine diet Prevalence: 1 in 10,000 people Famous People with the Disease: Unknown Heritability & Environmental Factors: Caused by a recessive allele PKU is caused by a recessive allele, meaning an individual must inherit two copies of the allele, one from each parent, in order [...] Ribosomes are the location where translation takes place. Prokaryotic cells do not have compartmentalized organelles, and thus need only one type of ribosome. They have one type of ribosome that translates the mRNA in the cytoplasm. In eukaryotic cells, however, there are different kinds of ribosomes in different organelles. The most abundant type of ribosome [...]
Article being discussed: Disinfectants may promote growth of superbugs. At first blush, it seems this article may be telling us a couple things we already know. Most people are aware of the superbug concept- that bacteria can become resistant to things that are supposed to kill them, because of the overuse of things [...] You will never think of the word “sniffer” in the same way again. Ok, you might, but still an interesting article that sheds light on some of the inner workings of the brain. New biosensors reveal workings of anti-psychotic drugs in the living brain. I’m not sure whether I should giggle or shake the hands of these researchers. Who thinks up experiments such as this? I certainly never thought of it. Can you imagine? Man walks into his doctor, complaining about his… ahem… libido. Or rather, the lack thereof. The doctor says, “No problem! We’ll just temporarily remove your [...] |
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