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Results for “cliff environment”

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PubMed2025

Genome sequencing and population genetics provide insights into local adaptation of Opisthopappus species on cliff environments of Taihang Mountains.

Local adaptation represents a pivotal theme in evolutionary biology. The Opisthopappus genus, comprising Opisthopappus longilobus and O. taihangensis, thrives on the cliffs of the Taihang Mountains. During their evolutionary history, two species are hypothesized to have locally adapted to their cliff habitats. In the present study, we employed a combined approach of whole-genome sequencing of O. taihangensis and population genomic analysis from both species to gain deeper insights into their patterns of local adaptation. Our results revealed that the expansive genome of O. taihangensis (3010.18 Mb), a consequence of a whole-genome duplication (WGD) event, coupled with a high proportion of repetitive sequences (82.70%), was postulated as one of its adaptive strategies. A clear differentiation between O. taihangensis and O. longilobus was observed, with the two species diverging approximately 17.57 million years ago (Mya), with O. longilobus serving as the ancestor. Since their divergence, limited gene flow was observed between the two species. Post-divergence, the effective population sizes of both species expanded, yet underwent a dramatic reduction at approximately 0.07 Mya. Furthermore, a total of 798 adaptive genes were identified, of which 207 overlapped with expanded genes, and eight genes were found to be under positive selection. These genes primarily regulated the growth and development of both species via pathways such as oxidation-reduction and ubiquitin-proteasome, enabling them to withstand climate changes. These findings provide profound insights into the local adaptation of Opisthopappus species to the cliff environments and offer valuable clues for further exploring the local adaptation among various cliff-dwelling organisms.

Adaptation, Physiological↗

PubMed1976

Duration of early visual experience and visual cliff behavior of chicks.

Visual cliff behavior was studied in 120 chicks as a function of 22, 46, 70, 94, or 118 hr of rearing in a deep or shallow environment. Preference for the deep side of the visual cliff increased directly with duration of depth-rearing but was uninfluenced at any duration of shallow-rearing. Although qualitative differences existed in the behaviors of those shallow- and deep-reared chicks which crossed the cliff, the loss of depth avoidance by the latter group appeared to be specific to the rearing and testing apparatus.

Animals↗

PubMed1977

Situational effects on the identification of emotions in children.

Naive judges were asked to observe infants independently and judge their emotions at 5 sec intervals under three different conditions. Two experiments were conducted to produce the different conditions. In Experiment I, 9- and 12-month-old infants of both sexes (N = 40) were exposed to a series of situations each designed to provoke a specific emotion (Condition 1). Although the judges were not informed as to which emotion each situation sought to provoke, one may assume that they received clues from the situations themselves. In Experiment II, 13- to 17-month-old infants of both sexes (N = 16) were individually placed on a large table (8' X 6') on which they could explore or play in the presence of their mothers (Condition 2). The judges were tota-ly without guidelines as to what emotion to expect. For Condition 3 in the same experiment the table was transformed into a visual cliff, and the judges were told that the generally expected emotion was fear. The judges reached significant agreement for the emotions of interest and anger in Conditions 1, 2, and 3; for distress only in Condition 1; for joy only in Condition 3; and no agreement for fear in any condition.

Anger↗

PubMed1986

Acoustic adaptations for parent-offspring recognition in swallows.

We have used field and laboratory studies to investigate acoustic adaptations for parent-offspring recognition in two closely related pairs of swallows: (a) bank swallow (Riparia riparia) and northern rough-winged swallow (Stelgidopteryx serripennis), and (b) cliff swallow (Hirundo pyrrhonota) and barn swallow (Hirundo rustica). Cross-fostering and playback experiments show that bank swallow and cliff swallow parents recognize their offspring by voice while rough-winged swallow and barn swallow parents do not. We argue that this species difference is due to an evolutionary history of strong selection for recognition in bank swallows and cliff swallows, which live in large, dense colonies, and of weak or no selection for recognition in rough-winged swallows and barn swallows, which live solitarily or in small groups. We consider two possible acoustic adaptations which may underlie the observed species difference. First, the "signature" calls of cliff swallow and bank swallow chicks appear to be more individually distinctive than the homologous calls of rough-winged swallows and barn swallows. This conclusion is supported by a sonographic analysis of among- and within-individual call variation: The information content of bank swallow and cliff swallow calls is considerably greater than that of rough-winged swallow or barn swallow calls. We also discuss our more recent work on the hypothesis that the colonial swallow species are better able to discriminate these sorts of auditory stimuli. We conclude with the caution that auditory specializations may be unnecessary given the signature call adaptation and the general capabilities of the avian ear.

Animal Communication↗