• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 1
  • Tagged with
  • 2
  • 2
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

The biology of South African Bryde's whales

Penry, Gwenith S. January 2010 (has links)
The biology of South African Bryde’s whales (Balaenoptera brydei/edeni), with a focus on the inshore form, was investigated through estimates of abundance and survival rate, seasonality of occurrence and variation in mitochondrial and nuclear DNA. Photographs, sightings data and biopsy samples were collected in Plettenberg Bay, on the south-east coast of South Africa. Additional genetic material was obtained from the Iziko South African Museum, Marine and Coastal Management, and the Port Elizabeth Museum. Mark-recapture methods applied to photo-identification data were used to estimate abundance and survival rate. Estimates of abundance ranged from 130 to 250 (CV = 0.07 - 0.38) and the estimated annual survival rate was 0.93 (CV = 0.047, 95% CI = 0.852 - 1.0). Seasonal increases in the encounter rate and number of individual whales were observed during summer and autumn, with a peak in April, which corresponded to increased feeding activity and larger average aggregation sizes. Chlorophyll-a, sea surface temperature and wind speed were all significant factors in explaining the variability in the occurrence of whales. No seasonality in the occurrence of calves was detected. Mitochondrial DNA control region sequences (685bp) were compared to published sequences. This confirmed the offshore form as Balaenoptera brydei and the inshore form as closely related to B.brydei, possibly at the sub-specific level, but excluded it as B.edeni. Phylogenetic analyses support complete separation between the two forms. The use of 10 polymorphic microsatellite loci revealed no population structure among the inshore samples (FST = 0.006). Pairwise estimates of relatedness found most individuals to be unrelated, with only a few distant relatives detected.
2

Systematics and phylogeography of the genus Tigriopus (Copepoda, Harpacticoida, Harpacticidae) in the basin of the Mediterranean Sea

Vecchioni, Luca 23 March 2021 (has links)
[ES] El género de copépodos Tigriopus Norman, 1869 se distribuye en todo el mundo en piscinas costeras de rocas y actualmente se considera que incluye 15 especies válidas. Tigriopus fulvus (Fischer, 1860), con su subespecie Tigriopus fulvus adriaticus Van Douwe 1913 y Tigriopus fulvus algiricus Monard 1935, actualmente se informa que ocurren en el área mediterránea, pero actualmente se desconoce la diversidad real del género. Nuestro objetivo fue evaluar la identidad real de las poblaciones mediterráneas de Tigriopus y dilucidar su taxonomía y patrón de diversidad genética. Para alcanzar estos objetivos, utilizamos dos enfoques diferentes. El primero, basado en la morfología, donde las posibles diferencias morfológicas entre muestras topotípicas de Tigriopus fulvus s.s. y muestras topotípicas de las dos subespecies fueron investigadas. Un segundo, sobre una base molecular, donde se secuenciaron fragmentos de dos genes de ADN mitocondrial (subunidad I de citocromo c oxidasa, COI y subunidad de ARN ribosómico pequeño, 12S) y un gen de ADN nuclear (28S) para ser usados como marcador de referencia. En este marco, se utilizaron enfoques taxonómicos moleculares, como el descubrimiento automático de brechas de código de barras (ABGD), bPTP (procesos de árbol de Poisson bayesianos) y la relación K / ¿, para investigar la existencia de las supuestas subespecies de Tigriopus a través de la identificación de Operacional Unidades Taxonómicas (OTU). Nuestros datos sugieren la presencia de una sola especie caracterizada por una notable estructura genética basada en la geografía en toda el área de estudio. El patrón de diversidad observado se atribuye tentativamente aquí a una fuerte monopolización de los estanques de rocas por parte de los primeros inmigrantes que los alcanzan. Sin embargo, tal monopolización se ve interrumpida periódicamente por los eventos de extinción locales, que son frecuentes en los hábitats intrínsecamente inestables de las piscinas de rocas Aquí proponemos para este patrón el nombre de "monopolización periódica" ("Clockwork monopolization"). / [CA] El género de copépodos Tigriopus Norman, 1869 se distribuix en tot el mon en piscines costeres de roques i actualment se considera que inclou 15 especies valides. Tigriopus fulvus (Fischer, 1860), en la seua subespecie Tigriopus fulvus adriaticus Van Douwe 1913 i Tigriopus fulvus algiricus Monard 1935, actualment s'informa que ocorren en l'area mediterranea, pero actualment se desconeix la diversitat real del género. Nostre objectiu fon evaluar l'identitat real de les poblacions mediterranees de Tigriopus i dilucidar la seua taxonomia i patrón de diversitat genetica. Per a alcançar estos objectius, utilisem dos enfocaments diferents. El primer, basat en la morfologia, a on les possibles diferencies morfologiques entre mostres topotípicas de Tigriopus fulvus s.s. i mostres topotípicas dels dos subespecies foren investigades. Un segon, sobre una base molecular, a on se secuenciaron fragments de dos gens d'adn mitocondrial (subunidad i de citocromo c oxidasa, coi i subunidad d'arn ribosómico menut, 12s) i un gen d'adn nuclear (28s) per a ser amprats com marcador de referencia. En este marc, s'utilisaren enfocaments taxonomics moleculars, com el descobriment automatic de breches de codic de barres (ABGD), bPTP (processos d'arbre de poisson bayesianos) i la relacio K/¿, per a investigar l'existencia de les supostes subespecies de Tigriopus a través de l'identificacio d'operacional unitats taxonomiques (OTU). Nostres senyes sugerixen la presencia d'una sola especie caracterisada per una notable estructura genetica basada en la geografia en tota l'area d'estudi. El patrón de diversitat observat s'atribuix tentativament aci a una forta monopolisacio dels safarejos de roques per part dels primers immigrants que els alcancen. No obstant, tal monopolisacio se veu interrompuda periodicament pels events d'extincio locals, que son freqüents en els hábitats intrinsecament inestables de les piscines de roques aci proponem per a este patrón el nom de "Monopolisacio Periodica" ("Clockwork Monopolization"). / [EN] The copepod genus Tigriopus Norman, 1869 is distributed worldwide in coastal rock-pools and it is currently considered to include 15 valid species. Tigriopus fulvus (Fischer, 1860), with its subspecies Tigriopus fulvus adriaticus Van Douwe, 1913 and Tigriopus fulvus algiricus Monard, 1935, are currently reported to occur in the Mediterranean area, but the actual diversity of the genus is currently unknown. We aimed to assess the actual identity of Mediterranean Tigriopus populations and to elucidate their taxonomy and pattern of genetic diversity. In order to reach these goals, we use two different approaches. The first, based on morphology, where the possible morphological differences among topotypical samples of Tigriopus fulvus s.s. and topotypical samples of the two subspecies were investigated. A second, on a molecular basis, where fragments of two mitochondrial DNA genes (cytochrome c oxidase subunit I, COI and small ribosomal RNA subunit, 12S) and a nuclear DNA gene (28S) were sequenced to be used as a reference marker. In this frame, molecular taxonomical approaches, such as Automatic Barcode Gap Discovery (ABGD), bPTP (bayesian Poisson Tree Processes) and K/¿ ratio, were used in order to investigate the existences of the alleged subspecies of Tigriopus through the identification of Operational Taxonomic Units (OTUs). Our data suggest the presence of a single species characterized by a noteworthy geographically-based genetic structure in the whole study area. The observed diversity pattern is tentatively ascribed here to a strong monopolization of the rock pools by the first immigrants that reach them. However, such a monopolization is periodically disrupted by local extinction events, which are frequent in the intrinsically unstable rock pool habitats. We propose the name "clockwork monopolization" for this pattern. / Vecchioni, L. (2020). Systematics and phylogeography of the genus Tigriopus (Copepoda, Harpacticoida, Harpacticidae) in the basin of the Mediterranean Sea [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/144122 / TESIS

Page generated in 0.0259 seconds