When fecundity does not equal fitness: evidence of an offspring quantity versus quality trade-off in pre-industrial humans

Maternal fitness should be maximized by the optimal division of reproductive investment between offspring number and offspring quality. While evidence for this is abundant in many taxa, there have been fewer tests in mammals, and in particular, humans. We used a dataset of humans spanning three generations from pre-industrial Finland to test how increases in maternal fecundity affect offspring quality and maternal fitness in contrasting socio-economic conditions. For ‘resource-poor’ landless families, but not ‘resource-rich’ landowning families, maternal fitness returns diminished with increased maternal fecundity. This was because the average offspring contribution to maternal fitness declined with increased maternal fecundity for landless but not landowning families. This decline was due to reduced offspring recruitment with increased maternal fecundity. However, in landowning families, recruited offspring fecundity increased with increased maternal fecundity. This suggests that despite decreased offspring recruitment, maternal fitness is not reduced in favourable socio-economic conditions due to an increase in subsequent offspring fecundity. These results provide evidence consistent with an offspring quantity–quality trade-off in the lifetime reproduction of humans from poor socio-economic conditions. The results also highlight the importance of measuring offspring quality across their whole lifespan to estimate reliably the fitness consequences of increased maternal fecundity

On ecological conceptualizations of perceptual systems and action systems

This article examines Gibson's concept of perceptual system and Reed's concept of action system. After discussing several assumptions underlying these concepts, the ontological status of these systems is considered. It is argued that perceptual systems and action systems should be conceptualized neither as parts of an animal's body nor as softly (temporarily) assembled devices; rather, they are best understood as animals' abilities to achieve functional relationships, that is, as dispositional properties. This conceptualization entails that these systems are relatively permanent properties of the animal that are causally supported by, though not identical to, anatomical substrates. Further, it entails that it is the animal that perceives and acts, not its perceptual and action systems

Arquitetura, anatomia e histoquímica das folhas de Gomphrena arborescens L.f. (Amaranthaceae) Architecture, anatomy and histochemistry of the leaves of Gomphrena arborescens L.f. (Amaranthaceae)

As folhas de Gomphrena arborescens L.f., nativa do Cerrado, são utilizadas contra dismenorréia na medicina popular. As investigações morfológica, anatômica e histoquímica das folhas visam fornecer elementos para taxonomia, para controle de qualidade de drogas e identificação microscópica de fitoterápicos. Folhas foram coletadas em Brasília, DF, nas áreas de Cerrado do Centro Olímpico da Univesidade de Brasília e na Reserva Ecológica do IBGE. Foram efetuadas análises morfológicas, anatômicas e histoquímicas. Os estudos de arquitetura foliar, densidade estomática e de vênulas terminais foram efetuados em folhas diafanizadas, apresentando médias de 42,39&plusmn;15,50 estômatos mm-2 e 11,7&plusmn;3,55 vênulas terminais mm². As folhas apresentaram duas formas de tricomas tectores. O mesofilo bilateral apresenta tecido clorenquimático disposto radialmente à bainha parenquimática completa que envolve os feixes vasculares, características da síndrome Kranz associada ao ciclo fotossintético C4. O amido concentra-se na bainha parenquimática. As folhas são ricas em celulose, drusas de oxalato de cálcio, proteínas, lignina e outros compostos fenólicos, entre eles os flavonóides. As folhas apresentam morfologia variável, mas o padrão anatômico e de venação são constantes.<br>Leaves of the Brazilian Cerrado plant Gomphrena arborescens L.f. are used against dismenorea in popular medicine. The morphological, anatomical and histochemical investigation aims to help taxonomy, quality control of drugs and microscopical identification of phytotherapics. The leaves have been collected in Brasília, DF, in the Olympical Center of the University of Brasilia and in the Ecological Reserve of IBGE. The leaf architecture, stomatal and veinlet densities have been studied in clarified leaves, presenting average of 42,39&plusmn;15,50 stomata mm² and 11,7&plusmn;3,55 veinlet mm-2. Leaves presented two forms of tector trichomes. The bilateral mesophyll surrounds the complete bundle sheat, features of the Kranz syndrome associated with C4 photosynthetic pathway. The starch is concentrated in the bundle sheat cells. Leaves are rich in cellulose, calcium oxalate druses, proteins, lignin and other phenolic compounds, such as flavonoids. Leaves present variable morphology, but steady pattern of anatomy and veination