Search results for "evolutionary"
showing 10 items of 4392 documents
Walter Zimmermann and the Growth of Phylogenetic Theory
1992
seminal theoretical paper, "Arbeitsweise der botanischen Phylogenetik und anderer Gruppierungswissenschaften" ("Methods of botanical phylogenetics and other grouping sciences"), first published in 1931. In this paper, Zimmermann clearly ex? pressed many of the underlying principles of phylogenetic systematics?ideas that were later taken up by Hennig and formed the core of his theory. Zimmermann also focused attention on several basic meth?
Assessing divergence time of Spirulida and Sepiida (Cephalopoda) based on hemocyanin sequences
2011
Abstract The phylogenetic position of the mesopelagic decabrachian cephalopod Spirula is still a matter of debate. Since hemocyanin has successfully been used to calibrate a molecular clock for many molluscan species, a molecular clock was calculated based on this gene with special attention to the cephalopod genera Spirula and Sepia. The obtained partial sequence comprising ca., one third (3567 bp) of the complete gene is similar to that of Sepia officinalis. The molecular clock was calibrated using the splits of Gastropoda–Cephalopoda (ca. 550 ± 50 mya) and Heterobranchia–Vetigastropoda (ca. 380 ± 10 mya). The resulting hemocyanin-based molecular clock is stable, and the estimated diverge…
Ontogenetic and phylogenetic diversification of the hooded staminode in Marantaceae
2010
The flowers of Marantaceae are known for their unique pollination mechanism mediated by an explosive style movement. The mechanism is based on the highly modified elements of the inner androecial whorl, i.e., the single half-fertile anther and the fleshy and hooded staminodes. We investigated 67 species across 24 genera to elucidate which parts of the hooded staminode are shared by all species, thus likely under strong selection pressure, and which are allowed to vary. We treated hooded staminodes as character syndromes and grouped them based on gross similarities. We identified characters underlying the similarity and investigated their diversity and developmental pathways. All hooded stam…
A new combination in Mononeuria (Caryophyllaceae)
2018
The nomenclatural change Mononeuria caroliniana comb. nov. is proposed on the basis of molecular phylogenetic results analyzing the nuclear internal transcribed spacer.
Combining ontogenetic and evolutionary scales of morphological disparity: a study of early Jurassic ammonites
2007
SUMMARY Two major research themes in Evolutionary Developmental Biology and in Paleobiology, respectively, have each become central for the analysis and interpretation of morphological changes in evolution: the study of ontogeny/ phylogeny connections, mainly within the widespread and controversial framework of heterochrony; and the study of morphological disparity, the morphological signal of biodiversity, describing secular changes in morphospace occupation during the history of any given clade. Although enriching in their respective fields, these two themes have remained rather isolated to date, despite the potential value of integrating them as some recent studies begin to suggest. Here…
Genetics on Invasive Species
2002
Genetic markers are especially appropriate to reveal historical processes, as for example regarding biological invasions. Phylogenetic and population genetic methods enable to identify the taxa involved in an invasion (native and non-native species) and often lead to the perception of multiple or cryptic invasions. Phylogeographic and multi-locus approaches have been developed to assign individual invaders to potential source populations. The results may have implications for management measures. However, little is known about the genetic architecture of newly colonised populations. We introduce here genetic models for colonisations in linear habitats like rivers or coastlines. The expectat…
Molecular phylogeny of Metazoa (animals): monophyletic origin.
1995
The phylogenetic relationships within the kingdom Animalia (Metazoa) have long been questioned. Focusing on the lowest eukaryotic multicellular organisms, the metazoan phylum Porifera (sponges), it remained unsolved if they evolved multicellularity independently from a separate protist lineage (polyphyly of animals) of derived from the same protist group as the other animal phyla (monophyly). After having analyzed genes typical for multicellularity (adhesion molecules/receptors and a nuclear receptor), we present evidence that Porifera should be placed in the kingdom Animalia. We therefore suggest a monophyletic origin for all animals.
BoltzmaNN: Predicting effective pair potentials and equations of state using neural networks
2019
Neural networks (NNs) are employed to predict equations of state from a given isotropic pair potential using the virial expansion of the pressure. The NNs are trained with data from molecular dynamics simulations of monoatomic gases and liquids, sampled in the NVT ensemble at various densities. We find that the NNs provide much more accurate results compared to the analytic low-density limit estimate of the second virial coefficient and the Carnahan-Starling equation of state for hard sphere liquids. Furthermore, we design and train NNs for computing (effective) pair potentials from radial pair distribution functions, g(r), a task that is often performed for inverse design and coarse-graini…
Synchronised gravitational atoms from mergers of bosonic stars
2020
If ultralight bosonic fields exist in Nature as dark matter, superradiance spins down rotating black holes (BHs), dynamically endowing them with equilibrium bosonic clouds, here dubbed synchronised gravitational atoms (SGAs). The self-gravity of these same fields, on the other hand, can lump them into (scalar or vector) horizonless solitons known as bosonic stars (BSs). We show that the dynamics of BSs yields a new channel forming SGAs. We study BS binaries that merge to form spinning BHs. After horizon formation, the BH spins up by accreting the bosonic field, but a remnant lingers around the horizon. If just enough angular momentum is present, the BH spin up stalls precisely as the remnan…
Learning can be detrimental for a parasitic wasp
2021
Animals have evolved the capacity to learn, and the conventional view is that learning allows individuals to improve foraging decisions. The parasitoid Telenomus podisi has been shown to parasitize eggs of the exotic stink bug Halyomorpha halys at the same rate as eggs of its coevolved host, Podisus maculiventris, but the parasitoid cannot complete its development in the exotic species. We hypothesized that T. podisi learns to exploit cues from this non-coevolved species, thereby increasing unsuccessful parasitism rates. We conducted bioassays to compare the responses of naïve vs. experienced parasitoids on chemical footprints left by one of the two host species. Both naïve and experienced …