Unequal Chances: Family Background and Economic Success

Is the United States "the land of equal opportunity" or is the playing field tilted in favor of those whose parents are wealthy, well educated, and white? If family background is important in getting ahead, why? And if the processes that transmit economic status from parent to child are unfair, could public policy address the problem? Unequal Chances provides new answers to these questions by leading economists, sociologists, biologists, behavioral geneticists, and philosophers. New estimates show that intergenerational inequality in the United States is far greater than was previously thought. Moreover, while the inheritance of wealth and the better schooling typically enjoyed by the children of the well-to-do contribute to this process, these two standard explanations fail to explain the extent of intergenerational status transmission. The genetic inheritance of IQ is even less important. Instead, parent-offspring similarities in personality and behavior may play an important role. Race contributes to the process, and the intergenerational mobility patterns of African Americans and European Americans differ substantially. Following the editors' introduction are chapters by Greg Duncan, Ariel Kalil, Susan E. Mayer, Robin Tepper, and Monique R. Payne; Bhashkar Mazumder; David J. Harding, Christopher Jencks, Leonard M. Lopoo, and Susan E. Mayer; Anders Björklund, Markus Jäntti, and Gary Solon; Tom Hertz; John C. Loehlin; Melissa Osborne Groves; Marcus W. Feldman, Shuzhuo Li, Nan Li, Shripad Tuljapurkar, and Xiaoyi Jin; and Adam Swift.family background, economic success, education, status, public policy, inequality, genetic inheritance, intergenerational mobility

Online and clicker quizzing on jargon terms enhances definition-focused but not conceptually focused biology exam performance

Mastery of jargon terms is an important part of student learning in biology and other science, technology, engineering, and mathematics domains. In two experiments, we investigated whether prelecture quizzes enhance memory for jargon terms, and whether that enhanced familiarity can facilitate learning of related concepts that are encountered during subsequent lectures and readings. Undergraduate students enrolled in neuroanatomy and physiology courses completed 10-minute low-stakes quizzes with feedback on jargon terms either online (experiment 1) or using in-class clickers (experiment 2). Quizzes occurred before conventional course instruction in which the terms were used. On exams occurring up to 12 weeks later, we observed improved student performance on questions that targeted memory of previously quizzed jargon terms and their definitions relative to questions on terms that were not quizzed. This pattern occurred whether those questions were identical (experiment 1) or different (experiment 2) from those used during quizzing. Benefits of jargon quizzing did not consistently generalize, however, to exam questions that assessed conceptual knowledge but not necessarily jargon knowledge. Overall, this research demonstrates that a brief and easily implemented jargon-quizzing intervention, deliverable via Internet or in-class platforms, can yield substantial improvements in students\u27 course-relevant scientific lexica, but does not necessarily impact conceptual learning

Evolution of the patellar sesamoid bone in mammals

The patella is a sesamoid bone located in the major extensor tendon of the knee joint, in the hindlimb of many tetrapods. Although numerous aspects of knee morphology are ancient and conserved among most tetrapods, the evolutionary occurrence of an ossified patella is highly variable. Among extant (crown clade) groups it is found in most birds, most lizards, the monotreme mammals and almost all placental mammals, but it is absent in most marsupial mammals as well as many reptiles. Here, we integrate data from the literature and first-hand studies of fossil and recent skeletal remains to reconstruct the evolution of the mammalian patella. We infer that bony patellae most likely evolved between four and six times in crown group Mammalia: in monotremes, in the extinct multituberculates, in one or more stem-mammal genera outside of therian or eutherian mammals and up to three times in therian mammals. Furthermore, an ossified patella was lost several times in mammals, not including those with absent hindlimbs: once or more in marsupials (with some re-acquisition) and at least once in bats. Our inferences about patellar evolution in mammals are reciprocally informed by the existence of several human genetic conditions in which the patella is either absent or severely reduced. Clearly, development of the patella is under close genomic control, although its responsiveness to its mechanical environment is also important (and perhaps variable among taxa). Where a bony patella is present it plays an important role in hindlimb function, especially in resisting gravity by providing an enhanced lever system for the knee joint. Yet the evolutionary origins, persistence and modifications of a patella in diverse groups with widely varying habits and habitats—from digging to running to aquatic, small or large body sizes, bipeds or quadrupeds—remain complex and perplexing, impeding a conclusive synthesis of form, function, development and genetics across mammalian evolution. This meta-analysis takes an initial step toward such a synthesis by collating available data and elucidating areas of promising future inquiry