Chapter 8 Launchpad Questions and Answers Graded A

Chapter 8 Launchpad Questions and Answers Graded A The appropriate unit for defining and measuring genetic variation is the population Define adaptation refers both to the processes by which organisms become better matched to their environment and to the features of an organism that make it more fit than other individuals Why is the fossil record an incomplete record? 1. the soft parts of an organism almost always decay rapidly and completely after death 2. only a few environments demonstrate reduced forces of decomposition resulting in the preservation of the organism's hard parts (i.e., teeth, bones) What do you need to establish to prove that natural selection is operating in a population? 1. variability for a trait 2. heritability of that trait 3. differential reproductive success based on that trait radiometric dating is useful in conjunction with the study of the fossil record because: it allows a determination not only of the relative ages of different fossils, but their absolute ages as well Which method is most likely to give rise to a large population of smaller-than-average dogs after 20 generations? 1) start with a large population of dogs varying in sizes 2) when selecting the dogs to breed in order to generate a new generation, choose dogs in the lowest 20% in body size 3) repeat this for multiple generations An organism's fitness is measured by: -relative to other genotypes/phenotypes in the population -only for a specific environment -by reproductive success -for a given point in time the amino acid chains making up hemoglobin in different species differ depending how long it has been since the species last shared a common ancestor What supports the best idea that the frequency of recessive alleles do not decrease over time? Using Hardy-Weinberg equilibrium, it can be demonstrated that X allele frequencies will always produce the same genotype frequencies, retaining the allele frequencies What are important reasons that natural selection does not lead to perfect organism? -environments change quickly, natural selection may be too slow to adapt an organism in a population to the constantly "moving target" of the environment -variation is created by random processes and natural selection can only "work" with the variations that show up -there are often multiple alleles for a trait; each allele may represent an equally fit "solution" to the challenges of the environment How would you best describe worldwide views before and after Darwin? BEFORE: God created all living things AFTER: Over time, species evolved, but it all started with one organism Which of the following is considered a result of a natural selection? Adaption Name the selection: Turkeys have been selected based on increased size of their breast muscles Stabilizing selection What are examples of homologous and analogous structures? Homologous = a human arm and a bat wing Analogous = flying mammal and a flying insect Define radiometric dating makes it possible to determine the absolute age of fossils