Study of more than 200 species suggests that the anatomical differences among birds are as big as those among other vertebrates of comparable taxonomic rank The result is notable because, for more than 100 years, many biologists have believed that birds are more uniform anatomically than other classes of vertebrates Furthermore, assessment of biochemical and geological evidence suggests that the time scale for bird evolution could be quite short Hence, birds may share with placental mammals the distinction of having had a high rate of anatomical evolution, compared to that in lower vertebrates The rate appears to have been very high in songbirds and higher primates and extremely high in the genus Homo In an attempt to explain such contrasts in rates of anatomical evolution, we advance the hypothesis that in higher vertebrates, behavior, rather than environmental change, is the major driving force for evolution at the organismal level This hypothesis predicts accelerated anatomical evolution in species composed of numerous mobile individuals with the dual capacity for behavioral innovation and social propagation of new habits Consistent with this hypothesis, we demonstrate a correlation between relative brain size and rate of anatomical evolution in land vertebrates

https://www.pnas.org/content/pnas/80/14/4394.full.pdf

Birds, behavior, and anatomical evolution

In exploring the possible experiential canalization of development, it was found that the mallard duck embryo's contact call plays a canalizing role in species-specific perceptual development. When mallard ducklings were prevented from hearing the contact call, they were susceptible to developinga preference for an extraspecific maternal call over the mallard maternal call. Exposure to the contact call prevented the ducklings from developing a preference for the extraspecific maternal call. Thus, normally occurring experience, in concert with genetic and other activities, can canalize behavioral development. Canalizing influences account for developmental stability, so that what we think of as normal or typical for a species repeats itself generation after generation. In order for evolution to occur, through genetic mutation or otherwise, the canalizing influences associated with normal development must be overcome. Canalization is thus a conservative feature of development that prevents evolution from occurring in a ready fashion. My preced ing article (Gottlieb, 199 la)established the theoretical framework for examining the possibility that normally occurring experience can canalize behavioral development. The present article presents empirical evidence for the experiential canalization of species-specific maternal attachment. The present hypothesis is that normally occurring experience helps to achieve species-specific development by making the developing organism unresponsive to extraspecific influences. For example, if the mallard duck (Anas platyrhynchos) embryo is devocalized, the usually highly selective response to the mallard maternal call is weakened: After hatching, the duckling is as responsive to a chicken (Galfus gallus) maternal call as to a mallard maternal call in a simultaneous-choice test (Gottlieb, 1978). Exposing otherwise devocalized embryos to a recording of mallard embryo contact vocalizations causes them to show the usual preference for the mallard call versus the chicken call in the postnatal test (Gottlieb, 1985). Exposure to other types of sibling vocalizations in embryo, or exposure to the contact call after hatching, is ineffective, so the kind of experience and the timing of the experience are highly specific. If the experiential canalization hypothesis is correct, embryonic devocalization should make the mallard embryo and hatchling more susceptible to exposure to an extraspecific maternal call, assuming that the contact vocalization is acting as a canalizing or buffering experience. With the necessary control groups, five experimental conditions are necessary to test the canalization hypothesis, as indicated in Table 1. In Table 1, X indicates the predicted preference and X—-X indicates prediction of no preference. The two most critical

/pdf/experiential-canalization-of-behavioral-development-results-3d4c4hdqcn.pdf

Experiential canalization of behavioral development: results

http://bartos.agrobiology.eu/publications/pdf/Bartos_1990_.pdf

Horns, Pronghorns, and Antlers

Scientists are not always remembered for the ideas they cherished most. In the case of the French biologist Jean-Baptiste Lamarck, his name since the end of the nineteenth century has been tightly linked to the idea of the inheritance of acquired characters. This was indeed an idea that he endorsed, but he did not claim it as his own nor did he give it much thought. He took pride instead in advancing the ideas that (1) nature produced successively all the different forms of life on earth, and (2) environmentally induced behavioral changes lead the way in species change. This article surveys Lamarck's ideas about organic change, identifies several ironies with respect to how his name is commonly remembered, and suggests that some historical justice might be done by using the adjective "Lamarckian" to denote something more (or other) than a belief in the inheritance of acquired characters.

https://www.genetics.org/content/genetics/194/4/793.full.pdf

Lamarck, evolution, and the inheritance of acquired characters.

The paper reflects on a study which explored the role of spirituality in the lives of women during the first year after being diagnosed with breast cancer. The study utilised a qualitative method (hermeneutic phenomenology) designed to provide rich and thick understanding of women's experiences of breast cancer and to explore possible ways in which spirituality may, or may not, be beneficial in enabling coping and enhancing quality of life. The paper draws on the thinking of David Hay and Viktor Frankl to develop a model of spirituality that includes, but is not defined by, religion and that has the possibility to facilitate effective empirical enquiry. It outlines a threefold movement - inwards, outwards and upwards - that emerged from in-depth interviews with women who have breast cancer. This framework captures something of the spiritual movement that women went through on their cancer journeys and offers some pointers and possibilities for better and more person-centred caring approaches that include recognition of the spiritual dimension of women's experiences for the management of those with breast cancer.

Gabriel W. Lasker

Papers

The living stream