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1.
Learned bird songs evolve via cultural evolution, with song patterns transmitted across generations by imitative learning. In Darwin''s finches of the Galápagos Islands, males learn songs from their fathers, and song types can be maintained across multiple generations. However, little is known about the time frame over which specific song types are preserved, in the face of copy errors and corresponding modifications to song structure. Here we investigate cultural evolution in songs of male Geospiza fortis, at Academy Bay, Santa Cruz Island, comparing songs recorded in 1961 by R. Bowman (20 individuals) to those recorded in 1999 by J. Podos (16 individuals). For each individual, we characterized four timing and six frequency parameters, and assessed inter-individual variation in song structure using multivariate analysis. Several 1961 song types persisted into 1999, some with remarkable fidelity. Variation among song types was extensive during both years, and we detected no changes in 10 vocal parameters across the sampling period. These results illustrate temporal continuity in a culturally acquired trait, and raise questions about mechanisms that promote stability in song structure. 相似文献
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The classical case of character release: Darwin's finches (Geospiza) on Isla Daphne Major, Galápagos
P. T. BOAG P. R. GRANT 《Biological journal of the Linnean Society. Linnean Society of London》1984,22(3):243-287
The history of how Darwin's medium ground finch (Geospiza fortis) on Isla Daphne Major, Galápagos became a textbook example of character release is reviewed. Four hypotheses for the evolution of the intermediate-sized Daphne fortis are examined, including genetic drift/founder effect, hybridization with the small ground finch (G'. fuliginosa) , food supply (or local adaptation hypothesis) and character release in allopatry.
Modern data suggest that genetic drift is unlikely to have been important, due to inadequate isolation and over-riding selection and introgression on Daphne. All three remaining hypotheses have probably played a role. Hybridization with G. fuliginosa occurs, although it cannot counteract the selection pressures seen during our study. Local adaptation has also occurred, with natural selection changing the relative frequencies of fortis phenotypes in response to changes in Daphne food supplies. The selection resulted from correlations between the size of seeds available, feeding behaviour and morphology. However, recent phenotypic tracking has resulted in larger, not smaller phenotypes. There is also evidence for character release in the form of diet expansion by G. fortis during periods of food shortage, and indirect evidence for interspecific competition between fortis and the cactus ground finch (G. scandens). The Daphne fortis phenotype probably represents a balance between introgression with fuliginosa, selection for larger body size in dry years and selection for smaller body size in wet years. The simple textbook account of a character shift caused by the accidental absence of competitors should be qualified to reflect the ecological complexity of the situation. 相似文献
Modern data suggest that genetic drift is unlikely to have been important, due to inadequate isolation and over-riding selection and introgression on Daphne. All three remaining hypotheses have probably played a role. Hybridization with G. fuliginosa occurs, although it cannot counteract the selection pressures seen during our study. Local adaptation has also occurred, with natural selection changing the relative frequencies of fortis phenotypes in response to changes in Daphne food supplies. The selection resulted from correlations between the size of seeds available, feeding behaviour and morphology. However, recent phenotypic tracking has resulted in larger, not smaller phenotypes. There is also evidence for character release in the form of diet expansion by G. fortis during periods of food shortage, and indirect evidence for interspecific competition between fortis and the cactus ground finch (G. scandens). The Daphne fortis phenotype probably represents a balance between introgression with fuliginosa, selection for larger body size in dry years and selection for smaller body size in wet years. The simple textbook account of a character shift caused by the accidental absence of competitors should be qualified to reflect the ecological complexity of the situation. 相似文献
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Grant PR Grant BR Keller LF Markert JA Petren K 《Evolution; international journal of organic evolution》2003,57(12):2911-2916
Studies of inbreeding and interspecific hybridization are generally pursued separately with different metrics. There is a need to integrate them because they have the common goal of seeking an understanding of the genetic and ecological basis of fitness variation in populations. We use mean expected heterozygosity as an axis of variation on which to compare the fitness of inbreeding and hybridizing Darwin's finches (Geospiza scandens and G. fortis) relative to the fitness of matched outbred controls. We find that relative fitness of inbred finches is less than one in the 1991 cohorts of both species. Inbreeding depression is stronger in the species (G. scandens) with the lower genetically effective population size. Relative fitness of hybrids (backcrosses) in the same cohort of G. scandens is greater than one. Evidence of heterosis in G. fortis is mixed. Thus the two interbreeding species displayed somewhat different fitness patterns under the same set of environmental conditions. Hybridization may enhance fitness to different degrees by counteracting the effects of inbreeding depression, by other additive and nonadditive genetic effects, and by producing phenotypes well suited to exploit particular ecological conditions. 相似文献
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Phylogenetic relationships and morphological diversity in Darwin's finches and their relatives 总被引:4,自引:0,他引:4
Burns KJ Hackett SJ Klein NK 《Evolution; international journal of organic evolution》2002,56(6):1240-1252
Despite the importance of Darwin's finches to the development of evolutionary theory, the origin of the group has only recently been examined using a rigorous, phylogenetic methodology that includes many potential outgroups. Knowing the evolutionary relationships of Darwin's finches to other birds is important for understanding the context from which this adaptive radiation arose. Here we show that analysis of mitochondrial DNA sequence data from the cytochrome b gene confirm that Darwin's finches are monophyletic. In addition, many taxa previously proposed as the sister taxon to Darwin's finches can be excluded as their closest living relative. Darwin's finches are part of a well-supported monophyletic group of species, all of which build a domed nest. All but two of the non-Darwin's finches included in this clade occur on Caribbean islands and most are Caribbean endemics. These close relatives of Darwin's finches show a diversity of bill types and feeding behaviors similar to that observed among Darwin's finches themselves. Recent studies have shown that adaptive evolution in Darwin's finches occurred relatively quickly. Our data show that among the relatives of Darwin's finches, the evolution of bill diversity was also rapid and extensive. 相似文献
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Comprehensive long-term studies of isolated populations provide valuable comparative data that may be used to evaluate different methods for quantifying the relationship between genetic diversity and fitness. Here, we report on data collected from large and well-characterized cohorts of the two numerically dominant species of Darwin's finches on Isla Daphne Major, Galápagos, Ecuador - Geospiza fortis and G. scandens. Multilocus microsatellite (SSR) genetic diversity estimates (heterozygosity and d2) and pedigree-based estimates of the inbreeding coefficient (f) were compared to each other and to two fitness components: lifespan and recruitment. In the larger sample of G. fortis, heterozygosity (H) was correlated with both fitness components, but no relationship was detected in the smaller sample of G. scandens. Analyses of the inbreeding coefficient detected highly significant relationships between f and recruitment, but no relationship between f and overall lifespan. The d2 statistic showed no relationship to either fitness component. When the two SSR-based estimators were compared to f, d2 was correlated with f in G. fortis in the predicted direction, while in G. scandens the relationship was positive. Multilocus heterozygosity was correlated with f in G. fortis but not in the G. scandens sample. A pedigree simulation demonstrated that the variation in true autozygosity can be large among individuals with the same level of inbreeding. This observation may supplement the interpretation of patterns relevant to the local (locus-specific) and general (genome-wide) effects hypotheses, which have been proposed to explain the mechanism responsible for associations between genetic diversity and fitness. 相似文献
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Raymond L. Neubauer 《Evolutionary ecology》1999,13(4):365-380
Two way choice tests show a preference of female zebra finches for male songs four standard deviations longer than normal
song. Further tests show the ontogeny of this preference to parallel song learning in general as well as a preference for
songs with entirely heterogeneous notes compared to songs with four note repeats. These findings are discussed in relation
to a theory of the evolution of bird song from bird calls due to female preferences for longer, more complex vocalizations.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
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P. T. Boag 《Journal of Zoology》1984,204(3):413-441
Seven widely used avian external morphological measurements were examined, mainly in Geospiza fortis and G. scandens on Isla Daphne Major, Galapagos. Geospiza grow more slowly than other "finches", and smaller Geospiza species grow relatively more slowly than larger Geospiza . Weight, wing chord and tarsus grow quickly, while bill characters grow more slowly. This pattern of relative growth (dynamic allometry) is reversed in the static allometry of adults, where bill characters, particularly bill depth in G. fortis , display strong, positive allometry with respect to weight, wing and tarsus. Static allometric patterns help explain differences in the size, shape and relative variability of different characters in adults, as well as the results of multivariate analyses such as principal components or canonical variates. Several different multivariate techniques arrange five Geospiza populations in a consistent two-dimensional morphological space, with a major axis of overall "body-size", and a minor axi of "bill-pointedeness". An alternative analysis of dynamic and static allometry is also provided, based on multivariate techniques. 相似文献
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Beak shape in Darwin's ground finches (Geospiza) is emblematic of natural selection and adaptive radiation, yet our understanding of the genetic basis of beak shape variation, and thus the genetic target of natural selection, is still evolving. Here we reveal the genomic architecture of beak shape variation using genomewide comparisons of four closely related and hybridizing species across 13 islands subject to parallel natural selection. Pairwise contrasts among species were used to identify a large number of genomic loci that are consistently related to species differences across a complex landscape. These loci are associated with hundreds of genes that have enriched GO categories significantly associated with development. One genomic region of particular interest is a section of Chromosome 1A with many candidate genes and increased linkage. The distinct, pointed beak shape of the cactus finch is linked to an excess of intermediate frequency alleles and increased heterozygosity in significant SNPs, but not across the rest of the genome. Alleles associated with pointier beaks among species were associated with pointier‐beaked populations within each species, thus establishing a common basis for natural selection, species divergence and adaptive radiation. The adaptive genomic landscape for Darwin's finches mirrors theoretical expectations based on morphological variation. The implication that a large number of genes are actively maintained to facilitate beak variation across parallel populations with documented interspecies admixture challenges our understanding of evolutionary processes in the wild. 相似文献
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Dynamic gene expression in the song system of zebra finches during the song learning period
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Christopher R. Olson Lisa K. Hodges Claudio V. Mello 《Developmental neurobiology》2015,75(12):1315-1338
The brain circuitry that controls song learning and production undergoes marked changes in morphology and connectivity during the song learning period in juvenile zebra finches, in parallel to the acquisition, practice and refinement of song. Yet, the genetic programs and timing of regulatory change that establish the neuronal connectivity and plasticity during this critical learning period remain largely undetermined. To address this question, we used in situ hybridization to compare the expression patterns of a set of 30 known robust molecular markers of HVC and/or area X, major telencephalic song nuclei, between adult and juvenile male zebra finches at different ages during development (20, 35, 50 days post‐hatch, dph). We found that several of the genes examined undergo substantial changes in expression within HVC or its surrounds, and/or in other song nuclei. They fit into broad patterns of regulation, including those whose expression within HVC during this period increases (COL12A1, COL 21A1, MPZL1, PVALB, and CXCR7) or decreases (e.g., KCNT2, SAP30L), as well as some that show decreased expression in the surrounding tissue with little change within song nuclei (e.g. SV2B, TAC1). These results reveal a broad range of molecular changes that occur in the song system in concert with the song learning period. Some of the genes and pathways identified are potential modulators of the developmental changes associated with the emergence of the adult properties of the song control system, and/or the acquisition of learned vocalizations in songbirds. © 2015 Wiley Periodicals, Inc. Develop Neurobiol 75: 1315–1338, 2015 相似文献
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Joris Soons Anthony Herrel Annelies Genbrugge Peter Aerts Jeffrey Podos Dominique Adriaens Yoni de Witte Patric Jacobs Joris Dirckx 《Philosophical transactions of the Royal Society of London. Series B, Biological sciences》2010,365(1543):1093-1098
Darwin''s finches have radiated from a common ancestor into 14 descendent species, each specializing on distinct food resources and evolving divergent beak forms. Beak morphology in the ground finches (Geospiza) has been shown to evolve via natural selection in response to variation in food type, food availability and interspecific competition for food. From a mechanical perspective, however, beak size and shape are only indirectly related to birds'' abilities to crack seeds, and beak form is hypothesized to evolve mainly under selection for fracture avoidance. Here, we test the fracture-avoidance hypothesis using finite-element modelling. We find that across species, mechanical loading is similar and approaches reported values of bone strength, thus suggesting pervasive selection on fracture avoidance. Additionally, deep and wide beaks are better suited for dissipating stress than are more elongate beaks when scaled to common sizes and loadings. Our results illustrate that deep and wide beaks in ground finches enable reduction of areas with high stress and peak stress magnitudes, allowing birds to crack hard seeds while limiting the risk of beak failure. These results may explain strong selection on beak depth and width in natural populations of Darwin''s finches. 相似文献
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Male zebra finches normally learn their song from adult models during a restricted period of juvenile development. If song models are not available then, juveniles develop an isolate song which can be modified in adulthood. In this report we investigate the features of juvenile experience that underly the timing of song learning. Juvenile males raised in soundproof chambers or in visual isolation from conspecifics developed stable isolate song. However, whereas visual isolate song notes were similar to those of colony-reared males, soundproof chamber isolates included many phonologically abnormal notes in their songs. Despite having stable isolate songs, both groups copied new notes from tutors presented to them in adulthood (2.7 notes per bird for soundproof chamber isolates, 4.4 notes per bird for visual isolates). Old notes were often modified or eliminated. We infer that social interactions with live tutors are normally important for closing the sensitive period for song learning. Lesions of a forebrain nucleus (IMAN) had previously been shown to disrupt juvenile song learning, but not maintenance of adult song for up to 5 weeks after surgery. In this study, colony-reared adult males given bilateral lesions of IMAN retained all their song notes for up to 4–7.5 months after lesioning. However, similar lesions blocked all song note acquisition in adulthood by both visual and soundproof chamber isolates. Other work has shown that intact hearing is necessary for the maintenance of adult zebra finch song. We infer that auditory pathways used for song maintenance and acquisition differ: IMAN is necessary for auditorily guided song acquisition—whether by juveniles or adults—but not for adult auditorily guided song maintenance. © 1993 John Wiley & Sons, Inc. 相似文献
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Peter R. Grant B. Rosemary Grant 《Biological journal of the Linnean Society. Linnean Society of London》1997,60(3):317-343
Three species of Darwin's Finches hybridize on the Galapagos island of Daphne Major. We examined mating patterns to determine if hybrids exhibit mate preferences. Geospiza fortis x G. scandens F1 hybrids backcrossed to both of the parental species, whereas all backcrosses bred with the parental species to which they were most related, or with hybrids. Paternal song was shown to be the crucial factor determining the mating pattern of G. fortis x G. scandens F1 hybrids and their offspring. Song is culturally inherited, transmitted faithfully from father to son (with few exceptions) as a result of an imprinting-like process. Size also contributes to the choice of mates. G. fortis x G. scandens F1 hybrid females paired with large G. scandens -like G. fortis males. G. fortis x G. fuliginosa F1 hybrids paired negatively assortatively with respect to the size of their G. fortis mates. Non-random mating of hybrids based on song, a non-generic trait, has interesting evolutionary consequences. Song characteristics and nuclear and mitochondrial genes flow from G. fuliginosa into the G. fortis population, whereas the direction of transfer of genetic and song information between G. fortis and G. scandens depends on which song was sung by the father of the hybrids. 相似文献
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Charles E. Taylor John T. Brumley Richard W. Hedley Martin L. Cody 《Bioacoustics.》2017,26(3):259-270
Many birds have songs with variable structure and sequences. In earlier studies, we characterized some features from the song structures of California Thrashers (Toxostoma redivivum). In the Thrashers, there were a large number of phrase types, dozens to hundreds and the songs that were sequences of these many phrases were not random, but show some structure referred to as syntax. For example, a syntactic rule might be that phrase type A can be followed by phrase type B, but not type C. We, along with others, have assumed that syntax is an important feature of songs. This paper describes an experimental attempt to determine that syntax is important to California Thrashers by recording the reaction of territorial thrashers to playbacks of other thrasher songs, some of which obeyed the syntax rules we had discovered while others violated those rules. We also obtained video recordings of their behaviour near the playback speakers. We observed differences in the reactions to the birds that heard these two types of playbacks. Resident males reacted to either playback type, but more strongly when the original order was preserved. We observed difference in their behavioural response to correct or altered syntax. This indicates that the syntax of their songs is perceived in territorial defence by the birds. 相似文献
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Dean Ansell Robert D. Magrath Tonya M. Haff 《Ethology : formerly Zeitschrift fur Tierpsychologie》2020,126(12):1098-1110
Territorial songbirds often match the song features or singing patterns of rivals, commonly as an aggressive signal. Most studies of song matching have been on Northern Hemisphere species with short lifespans and high song rates, but vocal matching is predicted to be affected both by longevity and territorial stability. We studied song matching in males of the white-browed scrubwren, Sericornis frontalis, a long-lived, sedentary, territorial Australian songbird. We quantified natural song rate and diversity, and then conducted three playback experiments to test: (a) whether males match by song type; (b) how they respond physically and vocally to territorial intrusion; and (c) whether they match by song length, and use it as an agonistic signal. Males naturally had very low song rates, singing on average less than three times per hour, and moderate repertoires, with an estimated mean of 17.5 song types for individual males. Males did not engage in extended counter-singing bouts. The first experiment showed that males matched the song type of immediate neighbours almost 90% of the time, if that type was in their repertoire. The remaining experiments revealed that song-type matching was an aggressive signal; males responded more aggressively to, and were more likely to match, playback simulating a neighbour's territorial intrusion than song from their shared boundary. Males did not match songs by length, but they produced longer songs after simulated intrusion. Males also responded more aggressively to playback of longer songs that simulated intrusion, but less aggressively to longer songs from the territory boundary. Overall, we show that sedentary, long-lived songbirds with low song rates, can use song-type matching as an aggressive signal to communicate with neighbours and intruders. Song length had a different role in communication, possibly related to individual quality or territory ownership. 相似文献
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Sita M. ter Haar Wiebke Kaemper Koen Stam Clara C. Levelt Carel ten Cate 《Proceedings. Biological sciences / The Royal Society》2014,281(1796)
Vocal acquisition in songbirds and humans shows many similarities, one of which is that both involve a combination of experience and perceptual predispositions. Among languages some speech sounds are shared, while others are not. This could reflect a predisposition in young infants for learning some speech sounds over others, which combines with exposure-based learning. Similarly, in songbirds, some sounds are common across populations, while others are more specific to populations or individuals. We examine whether this is also due to perceptual preferences for certain within-species element types in naive juvenile male birds, and how such preferences interact with exposure to guide subsequent song learning. We show that young zebra finches lacking previous song exposure perceptually prefer songs with more common zebra finch song element types over songs with less common elements. Next, we demonstrate that after subsequent tutoring, birds prefer tutor songs regardless of whether these contain more common or less common elements. In adulthood, birds tutored with more common elements showed a higher song similarity to their tutor song, indicating that the early bias influenced song learning. Our findings help to understand the maintenance of similarities and the presence of differences among birds'' songs, their dialects and human languages. 相似文献