Search results for " selection"

Parasite Infection and Host’s Behavior

2010

Animal behavior and parasitism are more tightly linked, from an ecological and evolutionary point of view, than commonly thought. In the past 30 years, the growing field of evolutionary parasitology has tackled both proximate and ultimate answers to the following question: Why and how should the behavior of hosts exposed to the risk of a disease or that of parasitized hosts be altered? Altered behavior may simply be a symptom of disease without obvious connection with host resistance or parasite-transmission strategies. However, natural selection may have shaped behavior to avoid infection, get rid of parasites, or limit their pathogenicity. Alternatively, manipulative parasites may alter t…

1993

From his studies on Invertebrate animals and fossils in the vicinity of Paris, J.-B. de Lamarck (1744–1829) formulated a number of conclusions in his Zoological Philosophy [1] (1809), the first coherent theory of evolution. However, in contrast to commonly held belief, this was not based purely on speculation, but was progressively elaborated.

Should the teaching of biological evolution include the origin of life?

2010

The development of mainstream research on the origin of life as an outcome of Darwinian evolution is discussed. It is argued that prebiotic evolution and the origin of life should not be excluded from the syllabus and should be part of classes on biological evolution, and that the transition from non-living to living matter is best understood when seen as part of evolutionary biology. The wide acceptance of evolutionary approaches to the study of the emergence of life in European and Latin American countries is discussed.

1993

We have pointed out that the history of the giraffe’s neck served as an example to explain the theoretical concepts of transformism, proposed by J.-B. Lamarck, and of Darwin’s natural selection. However, at that time it had not been substantiated by palaeontological data. Since then, the record has furnished a number of fossils which enable us to reconstruct the major trends in the evolution of the giraffides of Africa, Asia, and Europe [1,2, 3] (Fig. 16.1; Appendix 16.1).

Morphological variation of the Oncocyclus irises (Iris: Iridaceae) in the southern Levant

2002

Morphological traits of Iris section Oncocyclus (Siems.) Baker in the southern Levant (Israel, Jordan, The Palestinian Authority and Sinai/Egypt) were analysed in order to clarify taxonomic relationships among taxa and the validity of diagnostic characters. Floral and vegetative characters were measured in 42 populations belonging to nine species during the peak of the flowering season in 1998‐2000. Pearson’s Coefficient of Racial Likelihood (CRL) was used to calculate morphological distances between populations. Twelve of the measured populations, distributed along the north-south aridity gradient in Israel, were further explored for morphological changes along the gradient. Cluster analys…

Productivity increases with variation in aggression among group members in Temnothorax ants

2011

Social insect societies are characterized not only by a reproductive division of labor between the queen and workers but also by a specialization of workers on different tasks. However, how this variation in behavior or morphology among workers influences colony fitness is largely unknown. We investigated in the ant Temnothorax longispinosus whether aggressive and exploratory behavior and/or variation among nest mates in these behavioral traits are associated with an important fitness measure, that is, per worker offspring production. In addition, we studied how body size and variation in size among workers affect this colony fitness correlate. First, we found strong differences in worker b…

Rapid growth of Atlantic salmon juveniles in captivity may indicate poor performance in nature

2011

Abstract The hatchery environment often favours completely different traits than natural selection in the wild. Consequently, hatchery-reared fish are usually larger and more aggressive than their wild counterparts. Increased growth rate and aggression are predicted to be beneficial in feeding competition in hatcheries, but not necessarily in nature, where food resources are spatially and temporally more variable. We compared the growth, condition and mortality of landlocked Atlantic salmon (Salmo salar L.) juveniles in a common hatchery environment and when feeding on natural prey in semi-natural channels. We found that the growth and survival probability of the fish in the hatchery was ne…

Mammalian nest predator feces as a cue in avian habitat selection decisions

2012

Breeding habitat selection is expected to be adaptive. Animals should respond to strong agents of natural selection, such as expected offspring mortality due to nest predators, in their settlement decisions. In birds, mammalian nest predators are a significant mortality source and birds are known to respond to their presence. However, the mechanism used by birds to perceive mammalian nest predators and estimate the nest predation risk remains unknown, in particular at larger spatial scales while comparing potential breeding habitat patches. We experimentally tested whether the farmland bird community can detect and perceive cues of a mammalian nest predator (urine and feces), and how this p…

An improved version of the Atlantic cod genome and advancements in functional genomics: implications for the future of cod farming

2016

Abstract Recent advancements within state-of-the-art genomic tools and the generation of the first version of the Atlantic cod genome (Star et al., 2011) have proven to be valuable resources, improving our understanding of this species’ biology. In this chapter we describe some aspects and implications of using these resources to identify genes and molecular pathways involved in Atlantic cod growth and development, as well as responses to nutritional changes, pathogens and other immune stimuli, and environmental stressors (e.g., temperature, stress, or pollutants). Additionally, we highlight the immunological puzzle of the Atlantic cod that lacks components of the adaptive immune system pre…

Multiplicity and history have a detrimental effect on survival in patients with T1G3 bladder tumors selected for conservative treatment.

2008

Purpose: In the absence of Tis tumor we assessed whether history and multiplicity have a detrimental effect on conservative treatment in carefully selected patients with T1G3 bladder carcinoma. Materials and Methods: Between January 1976 and December 1999, 165 select patients with T1G3 bladder tumors were conservatively treated with transurethral resection plus adjuvant intravesical therapy. Patients with concomitant or previous Tis, previous T1G3, tumor size greater than 3 cm and more than 3 lesions were excluded from analysis. Repeat transurethral resection was not routinely performed. However, cytology had to be negative for atypia before the start of adjuvant intravesical therapy. Resul…