In The Origin of Species (1859) Darwin challenged many of the most deeply-held beliefs of the Western world. Arguing for a material, not divine, origin of species, he showed that new species are achieved by "natural selection." The Origin communicates the enthusiasm of original thinking in an open, descriptive style, and Darwin's emphasis on the value of diversity speaks more strongly now than ever. As well as a stimulating introduction and detailed notes, this edition offers a register of the many (...) writers referred to by Darwin in the text. (shrink)

The aim of this study is an analysis of the possible adaptive consequences of delivery of low birth weight infants. We attempt to reveal the cost and benefit components of bearing small children, estimate the chance of the infants’ survival, and calculate the mothers’ reproductive success. According to life-history theory, under certain circumstances mothers can enhance their lifetime fitness by lowering the rate of investment in an infant and/or enhancing the rate of subsequent births. We assume that living in a (...) risky environment and giving birth to a small infant may involve a shift from qualitative to quantitative production of offspring. Given high infant mortality rates, parents will have a reproductive interest in producing a relatively large number of children with a smaller amount of prenatal investment. This hypothesis was tested among 650 Gypsy and 717 non-Gypsy Hungarian mothers. Our study has revealed that 23.8% of the Gypsy mothers had low birth weight (<2,500 g) children, whose mortality rate is very high. These mothers also had more spontaneous abortions and stillbirths than those with normal weight children. As a possible response to these reproductive failures, they shortened birth spacing, gaining 2–4 years across their reproductive lifespan for having additional children. Because of the relatively short interbirth intervals, by the end of their fertility period, Gypsy mothers with one or two low birth weight infants have significantly more children than their ethnic Hungarian counterparts. They appear to compensate for handicaps associated with low birth weights by having a larger number of closely spaced children following the birth of one or more infants with a reduced probability of survival. The possible alternative explanations are discussed, and the long-term reproductive benefits are estimated for both ethnic groups. (shrink)

With the discovery of conditioned reflexes by I. P. Pavlov, the possibilities for experimenting, following the example set by the classical, exact sciences, were made available to the behavioral sciences. Many psychologists hoped that the component parts of behavior had also been found from which the entire, multifaceted cosmos of behavior could then be constructed. An experimentally oriented psychology subsequently developed including the influential school of behaviorism. This first text on human ethology presents itself as a unified work, even though (...) not every area could be treated with equal depth. For example, a branch of ethology has developed in the past decade which places particular emphasis on ecology and population genetics. This field, known as sociobiology, has enriched discussion beyond the boundaries of behavioral biology through its stimulating, and often provocative, theses. After vigorous debates between behaviorists, anthropologists, and sociologists, we have entered a period of exchange of thoughts and a mutual approach, which in many instances has led to cooperative projects of researchers from different disciplines. This work offers a biological point of view for discussion and includes data from the author's cross-cultural work and research from the staff of his institute. It confirms, above all else, the astonishing unity of mankind and paints a basically positive picture of how we are moved by the same passions, jealousies, friendliness, and active curiosity. The need to understand ourselves has never been as great as it is today. An ideologically torn humanity struggles for its survival. Our species, does not know how it should compensate its workers, and it experiments with various economic systems, constitutions, and forms of government. It struggles for freedom and stumbles into newer conflicts. Population growth is apparently completely out of hand, and at the same time many resources are being depleted. We must consider our existence rationally in order to understand it, but certainly not with cold, calculating reason but with the warm feeling of a heart concerned for the welfare of later generations. (shrink)