bio 301m exam 2 study guide

bio 301m exam 2 study guide - 1. 2. 3. Study Guide, Exam 2...

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Study Guide, Exam 2 Spring 2012 1. Half life - pg 477 -Example at study session: Half life of N14 is 50,000  is 6.25% of that isotope left in this organism (it is important to  understand that the isotope is incorporated, as well as the  normal form of the element. The problem will most likely ask  how old the fossil is.  100/2 = 50/2 = 25/2 = 12.5/2 = 6.25/2  200,000 2. Fossil record- 423, 432, 474-475,423,478- 479,490(horses),477, 490 -a primary source of data about the evolutionary  history of many organisms.Although imperfect, the fossil  record provides our only direct information about life in the  past.  -The 300,000 described fossil species represent less  than 1% of all the species that have ever lived. Several  factors make the fossil record incomplete.  -The fossil record also allows scientists to see how  structures were modified as they became adapted for  specialized uses (see Figure 19.3 in Section 19-1b).  Moreover, fossils chronicle the proliferation and extinction of  evolutionary lineages and provide data on their past  geographical distributions. -The first fossil is 3.8 billion years old; the initial  atmosphere had no oxygen, the earth was not oxygenated  until 2 billion years ago because of photosynthesis 3. Hardy-Weinberg 436,437,438-439
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- An evolutionary rule of thumb that specifies the  conditions under which a population of diploid organisms  achieves genetic equilibrium. -The Hardy–Weinberg Principle Is a Null Model That  Defines How Evolution Does Not Occur (. ..even though it  does.) - equilibrium is possible only if  all  of the following  conditions are met No mutations are occurring. The population is closed to migration from other populations. The population is infinite in size. All genotypes in the population survive and reproduce equally well. Individuals in the population mate randomly with respect to genotypes 4. Natural selection 423-424, 428, 446-448, 447-449, 420, 440  - 444 - (not referred to in terms of individualism) *” Alleles that increase the likelihood of survival and the reproductive output of the individuals that carry them become more common in subsequent generations.” Natural selection alters phenotypic variation in three ways (Figure 20.9).  Directional selection increases or decreases the mean value of a trait, shifting it  toward a phenotypic extreme. Stabilizing selection increases the frequency of the  mean phenotype and reduces variability in the trait (Figures 20.10 and 20.11).  Disruptive selection increases the frequencies of extreme phenotypes and  decreases the frequency of intermediate phenotypes (Figure 20.12). 5.
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This note was uploaded on 03/20/2012 for the course BIO 301M taught by Professor Jasper during the Spring '08 term at University of Texas at Austin.

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bio 301m exam 2 study guide - 1. 2. 3. Study Guide, Exam 2...

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