| 1. |
|
|
| 2. |
- Bok, Michael J., et al.
(författare)
-
Here, There and Everywhere : The Radiolar Eyes of Fan Worms (Annelida, Sabellidae)
- 2016
-
Ingår i: Integrative and Comparative Biology. - : Oxford University Press (OUP). - 1540-7063 .- 1557-7023. ; 56:5, s. 784-795
-
Tidskriftsartikel (refereegranskat)abstract
- Fan worms (Annelida: Sabellidae) possess some of the strangest eyes in nature. Their eponymous fans are composed of two sets of radiolar tentacles that project from the head up out of the worm's protective tube into the water column. Primarily used for respiration and feeding, these radioles are also often involved in photoreception. They display a surprising diversity of eyes of varying levels of sophistication, ranging from scattered single ocelli to compound eyes with up to hundreds of facets. These photoreceptors could represent a relatively recent evolutionary development to cope with a sessile, tube-dwelling lifestyle, and the primary cerebral eyes (haplessly positioned within the tube most of the time) amount to little more than minute pigment cups with scant visual potential. The radiolar eyes on the other hand, appear to function as visual burglar alarms for detecting looming predators and eliciting a startle response for the worm to rapidly retreat within its fortified tube. Despite sometimes resembling arthropod compound eyes, the radiolar photoreceptors have many canonically vertebrate-like physiological characteristics. Considering the unusual and apparently recently evolved nature of the fan worm radiolar photoreceptors, these animals are an excellent case for examining the emergence of novel visual systems, the development of rudimentary visually guided behaviors, and the function of distributed sensory systems. Here, we review over 100 years of investigations into the anatomical diversity of sabellid radiolar photoreceptors and eyes in an evolutionary and functional context. We provide new information on radiolar eye structure in several species of fan worms, and we attempt to organize the various eye types and ocellar structures into meaningful hierarchies. We discuss the developmental, evolutionary, and functional significance of the radiolar eyes and highlight areas of future interest in deciphering their unique nature.
|
|
| 3. |
- Colley, Nansi Jo, et al.
(författare)
-
Photoreception in Phytoplankton
- 2016
-
Ingår i: Integrative and Comparative Biology. - : Oxford University Press (OUP). - 1540-7063 .- 1557-7023. ; 56:5, s. 764-775
-
Tidskriftsartikel (refereegranskat)abstract
- In many species of phytoplankton, simple photoreceptors monitor ambient lighting. Photoreceptors provide a number of selective advantages including the ability to assess the time of day for circadian rhythms, seasonal changes, and the detection of excessive light intensities and harmful UV light. Photoreceptors also serve as depth gauges in the water column for behaviors such as diurnal vertical migration. Photoreceptors can be organized together with screening pigment into visible eyespots. In a wide variety of motile phytoplankton, including Chlamydomonas, Volvox, Euglena, and Kryptoperidinium, eyespots are light-sensitive organelles residing within the cell. Eyespots are composed of photoreceptor proteins and typically red to orange carotenoid screening pigments. This association of photosensory pigment with screening pigment allows for detection of light directionality, needed for light-guided behaviors such as positive and negative phototaxis. In Chlamydomonas, the eyespot is located in the chloroplast and Chlamydomonas expresses a number of photosensory pigments including the microbial channelrhodopsins (ChR1 and ChR2). Dinoflagellates are unicellular protists that are ecologically important constituents of the phytoplankton. They display a great deal of diversity in morphology, nutritional modes and symbioses, and can be photosynthetic or heterotrophic, feeding on smaller phytoplankton. Dinoflagellates, such as Kryptoperidinium foliaceum, have eyespots that are used for light-mediated tasks including phototaxis. Dinoflagellates belonging to the family Warnowiaceae have a more elaborate eye. Their eye-organelle, called an ocelloid, is a large, elaborate structure consisting of a focusing lens, highly ordered retinal membranes, and a shield of dark pigment. This complex eye-organelle is similar to multicellular camera eyes, such as our own. Unraveling the molecular makeup, structure and function of dinoflagellate eyes, as well as light-guided behaviors in phytoplankton can inform us about the selective forces that drove evolution in the important steps from light detection to vision. We show here that the evolution from simple photoreception to vision seems to have independently followed identical paths and principles in phytoplankton and animals, significantly strengthening our understanding of this important biological process.
|
|
| 4. |
- Hart, M. W., et al.
(författare)
-
Selection on coevolving human gamete recognition genes
- 2016
-
Ingår i: Integrative and Comparative Biology. - Simon Fraser Univ, Burnaby, BC V5A 1S6, Canada. Arizona State Univ, Tempe, AZ 85287 USA. Univ Chicago, Chicago, IL 60637 USA. Uppsala Univ, Uppsala, Sweden.. - 1540-7063 .- 1557-7023. ; 56, s. E84-E84
-
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
|
|
| 5. |
- Natesan, D., et al.
(författare)
-
Airflow mediated antennal positioning in flying hawkmoths
- 2016
-
Ingår i: Integrative and Comparative Biology. - Natl Ctr Biol Sci, Bangalore, Karnataka, India. KTH, Stockholm, Sweden.. - 1540-7063 .- 1557-7023. ; 56, s. E159-E159
-
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
|
|
