摘要:

Interclonal variation in six morphometric characters and in the onset and rate of capitulum production, together with inter‐and intra‐clonal variation in esterase zymograms was examined in each of the two obligately apomictic species,Taraxacum pseudohamatum(sectionHamata) andT. unguilobum(sectionNaevosa). Interclonal and interspecific variation in esterase zymograms was also examined within and between seven additional obligately apomictic species within the sectionHamata.WithinT. pseudohamatum, interclonal variation in the morphometric and electrophoretic characters was extensive; no variation was recorded in the onset and rate of capitulum production. WithinT. unguilobum, interclonal variation in the morphometric characters and in the onset and rate of capitulum production was recorded; five of the six clones electrophoretically assayed shared the same esterase zymogram but one of these clones contained an individual which exhibited an aberrant zymogram. Within the sectionHamata, considerable variation in esterase zymograms was recorded; this variation was both inter‐and intra‐specific although one zymogram predominated, being represented in each species and in 65% of the

ISSN:0024-4066    

DOI:10.1111/j.1095-8312.1985.tb00372.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

It is shown for binary (1, 0) data that there is a direct relationship between a new measure of predictivity in classification and the Simple Matching Coefficient. This predictivity measure is related to the variance of a cluster in phenetic space and to the mean variance of the proportion of 1 states in the members of the cluster. It can be considered a form of ‘squared predictivity’. Maximizing the measure leads to Variance Clustering, and if weighted by the number of cluster members, to Sums of Squares Clustering. The relations to the Unweighted Average Pair Group and Unweighted Centroid Pair Group methods are also elucida

ISSN:0024-4066    

DOI:10.1111/j.1095-8312.1985.tb00373.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

Beauchêne Island is the most isolated of the Falkland Islands archipelago and until the authors' visit there in 1980 little was known or published about the island and its biota apart from its avifauna. The first collections and identifications of various plant and invertebrate groups were made and a brief account of their ecology and interrelationships is given; many of the arthropods are first records for the Falkland Islands and some are new to science. More detailed information is presented for tussock grass (or tussac),Poa flabellata, which reaches a height of 3.5 m and covers two‐thirds of the island with a unique monospecific grassland. The underlying deep peat, in places reaching 13 m depth, was investigated and radiocarbon dates obtained at various levels through the profile, indicating that the grassland has existed virtually unchanged for 12 500 years. The status of the avifauna was assessed. The black browed albatross and rockhopper penguin colonies were counted reasonably accurately and calculated to contain up to 170000 and 300000 pairs, respectively. A population of about 250 striated caracaras was counted, together with 67 nests, possibly the largest concentration of these rare raptors anywhere. The recently discovered population of fairy prions was estimated at several thousand birds. Sea lions were not abundant and fur seals, once said to occur in large numbers on the island, were absent. The biological simplicity of the exceptionally uniform tussac ecosystem offers ideal conditions for testing ecological hypotheses, especially those related to trophodynamics and predator‐prey interrelationships, and its potential for research is emphasized. The importance of applying strict conservation measures to protect this unique island is stressed in view of the possible future economic development of the Falkland Isl

ISSN:0024-4066    

DOI:10.1111/j.1095-8312.1985.tb00374.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

The behaviour of individually marked melanic and typical forms ofAllophyes oxyacanthaewas followed in four successive tests in an apparatus comprising bark of three different reflectances. In samples of wild populations, melanics showed a moderate preference for dark bark, while typicals did not seem to prefer or avoid this substrate. However, in four of the eight families of known parentage tested, both melanics and typicals preferred to rest on dark bark. These four families were the progeny of dark typicals which had shown a preference for dark bark and were the families containing the darkest typicals. InA. oxyacanthaethe variation in resting behaviour is not therefore closely associated with the melanic allele but may be linked to a ‘dark typical’ allele which, together with other loci, produces polygenic darkening of the normal phenotype. The results withA. oxyacanthaeare compared with those obtained withBiston betulariaand other moth spec

ISSN:0024-4066    

DOI:10.1111/j.1095-8312.1985.tb00375.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

Book reviewed in this article:Biomass Utilization, edited by W. A. Cote.The Ecological Century: A Personal Appraisal, by E. B. Worthington.

ISSN:0024-4066    

DOI:10.1111/j.1095-8312.1985.tb00376.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY