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- Coates, Melissa
(författare)
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Visual ecology and functional morphology of Cubozoa (Cnidaria)
- 2003
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Ingår i: Integrative and Comparative Biology. - : Oxford University Press (OUP). - 1557-7023 .- 1540-7063. ; 43:4, s. 542-548
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Tidskriftsartikel (refereegranskat)abstract
- Jellyfish belong to one of the oldest extant animal phyla, the Cnidaria. The first Cnidaria appear in the fossil record 600 million years ago, preceeding the Cambrian explosion. They are an extremely successful group present in all marine environments and some freshwater environments. In contrast to many animal phyla in which vision is a primary sense Cnidarians do not, generally, employ image forming eyes. One small class stands alone: the Cubozoa. Cubomedusae are commonly known as box jellyfish. They possess image forming eyes (Coates et al., 2001) which certainly evolved independently from other metazoans. Cubomedusae therefore offer a unique perspective on the evolution of image forming eyes. This literature review collects, into one place, what is known about: the multiple eye types of box jellyfish, cubomedusan life history and ecology, and the sensory and neural systems of box jellyfish. Here I discuss how these features set cubomedusae apart from scyphomedusae and hydromedusae. Knowledge in these areas is sparse; the work done to date inspires increased efforts.
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| 2. |
- Kelber, Almut, et al.
(författare)
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Colour vision in diurnal and nocturnal hawkmoths
- 2003
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Ingår i: Integrative and Comparative Biology. - : Oxford University Press (OUP). - 1557-7023 .- 1540-7063. ; 43:4, s. 571-579
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Tidskriftsartikel (refereegranskat)abstract
- Diurnal and nocturnal hawkmoths (Sphingidae, Lepidoptera) have three spectral types of receptor sensitive to ultraviolet, blue and green light. As avid flower visitors and pollinators, they use olfactory and visual cues to find and recognise flowers. Moths of the diurnal species Macroglossum stellatarum and the nocturnal species Deilephila elpenor, Hyles lineata and Hyles gallii use and learn the colour of flowers. Nocturnal species can discriminate flowers at starlight intensities when humans and honeybees are colour-blind. M. stellatarum can use achromatic, intensity-related cues if colour cues are absent, and this is probably also true for D. elpenor. Both species can recognise colours even under a changed illumination colour.
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| 4. |
- Halanych, K. M., et al.
(författare)
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Unsegmented annelids? Possible origins of four lophotrochozoan worm taxa
- 2002
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Ingår i: Integrative and Comparative Biology. - 1540-7063. ; 42:3, s. 678-684
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Tidskriftsartikel (refereegranskat)abstract
- In traditional classification schemes, the Annelida consists of the Polychaeta and the Clitellata (the latter including the Oligochaeta and Hirudinida). However, recent analyses suggest that annelids are much more diverse than traditionally believed, and that polychaetes are paraphyletic. Specifically, some lesser-known taxa. (previously regarded as separate phyla) appear to fall within the annelid radiation. Abundant molecular, developmental, and morphological data show that the Siboglinidae, which includes the formerly recognized Pogonophora and Vestimentifera, are derived annelids; recent data from the Elongation Factor-1alpha (EF-1alpha) gene also suggest that echiurids are of annelid ancestry. Further, the phylogenetic origins of two other lesser-known groups of marine worms, the Myzostomida and Sipuncula, have recently been called into question. Whereas some authors advocate annelid affinities, others argue that these taxa do not fall within the annelid radiation. With advances in our understanding of annelid phylogeny, our perceptions of body plan evolution within the Metazoa are changing. The evolution of segmentation probably is more plastic than traditionally believed. However, as our understanding of organismal evolution is being revised, we are also forced to reconsider the specific characters being examined. Should segmentation be considered a developmental process or an ontological endpoint?
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