User:HighFlyingFish/sandbox

In the wild

The Siamese Tiger originates from the Chao Phraya river basin in the center of Thailand. Unfortunately the fish is completely extinct in the wild. The last know sighting was over 5 years ago. The fish has been over fished for the aquarium trade and more extensively for the dinner plate. In its last years big Pulchers were fetching about 1000 Dollars U.S and being sold to rich customers in restaurants. The Department of Fisheries in Thailand(DOF) has a captive breeding program, but success has been limited so far.^{[citation needed]}

See also

• List of brackish aquarium fish species

References

External links

• Secrets of the Datnoids Tigerfish

_______________________________________________________________________________________________________________________________________________________________ Stored, in order to find secondary review sources as they come up

Advantages over the traditional RNA world hypothesis

The RNA world hypothesis postulates that RNA alone was initially the first form of chemical replicator (and hence of life), since it is capable of providing a template that can be copied, and catalyzing the reactions which would copy said template. It is often argued that, since RNA is responsible for synthesizing proteins in modern biology, RNA must have preceded proteins, and natural selection must have eventually favored protein synthesis amongst early RNA molecules. However, all lab generated molecules that preform any of the functions that an RNA replicator would need to do are different from anything found in naturally occurring ribosomes.^[6] Moreover, studies have suggested that it would take an extremely long time for RNA to develop a sufficiently high fidelity (i.e. reliability of replication) for the biological evolution of RNA to occur, possibly requiring multiple universes for such an event to be likely.^[7] Urzyme catalysts would considerably increase the rate of replication, hence making the Peptide-RNA world a more probable explanation for the origin of life.^[8]

Criticisms

The idea of a peptide-RNA world has been criticized for several reasons. First, it is unlikely that the two complex molecules would arise together at the same place, at the same time to produce a reaction. Second, the synthesis of complex proteins is preformed by RNA catalysts in ribosomes, indicating that that RNA must have synthesized these proteins in the last common ancestor, even if smaller protein building blocks may have been present before. Indeed, using libraries of RNA sequences and SELEX it is possible to fill many of the gaps between functions modern RNAs preform and those that the molecules of an RNA world would have preformed.^[9]

References

Arguments for this view

In contemporary cells RNA polymerase (an enzyme which produces RNA) is a protein, but RNA directs the function of protein biosynthesis.^[5][6] All lab generated molecules that preform any of the functions that an RNA replicator would need to do are different from anything found in naturally occurring ribosomes, so it appears that the interdependence of proteins and RNA is something that appeared early in the evolution of life.^[7] Enzymes serve to catalyze RNA self-replication, which is otherwise slow and unreliable, with some studies suggesting that it would take an extremely long time for RNA to develop a sufficiently high fidelity (i.e. reliability of replication) for the biological evolution of RNA to occur without enzyme catalysts, possibly requiring multiple universes for such an event to be likely.^[8] Proteins could help speed up RNA self replication and selection for increased fidelity.

Criticisms

The idea of a peptide-RNA world has been criticized for several reasons. First, it is unlikely that the two complex molecules would arise together at the same place, at the same time to produce a reaction. Second, the synthesis of complex proteins is preformed by RNA catalysts in ribosomes, indicating that that RNA must have synthesized these proteins in the last common ancestor, even if smaller protein building blocks may have been present before. Indeed, using libraries of RNA sequences and SELEX it is possible to fill many of the gaps between functions modern RNAs preform and those that the molecules of an RNA world would have preformed.^[9]

References

{{Origin of life} {{Molecular-cell-biology-stub}

[[Category:Origin of life] [[Category:Biology theories]

Xenoturbella Westbladi

In 1999 Israelsson examined specimens held at the Swedish Museum of Natural History and concluded that a small subset of them must belong to another species.^[1] This population differed from specimens Israelsson identified with X. Bocki in its small size (12 mm at most), pink coloration (in contrast to yellow-white coloration identified for X. Bocki) and positioning of gametes and sperm.Israelsson believed there was evidence of internal fertilization in this set of specimens. He named the species after Westblad, who collected the specimens. The specimens come from coarser and shallower habitats in the same range as X. Bocki. American scientist Greg Rouse and collegues sequenced mitochondrial DNA from specimens identified with both species and on the basis of this, determined that the two populations were the same species, declaring X. Westbladi to be a junior synonym to X. Bocki.^[2]

References

• Escobar L., M., Ota, R., Machado‐Allison, A., Andrade‐López, J., Farias, I., & Hrbek, T. (2019). A new species of Piaractus (Characiformes: Serrasalmidae) from the Orinoco Basin with a redescription of Piaractus brachypomus. Journal Of Fish Biology. doi: 10.1111/jfb.13990

[[Category:Serrasalmidae] [[Category:Fish of South America] [[Category:Fish described in 2019]

{{Characiformes-stub}

Entomology

Globulus derives from the latin word for a small ball or sphere.

Distribution

This species is found exclusively in marine environment.^[3] It prefers tropical habitats, no deeper than 60 minutes. It is a benthic organism, found on continental shelves and inshore habitats. It has bene collected throughout the Indian ocean and west and central Pacific Ocean. It is found off the shores of north Australia, the Phillippines, south Japan, China, New Caledonia, Indonesia and the Bay of Bengal. In the fossil record, specimens have only been found in recent strata.

Ecology

This species consumes plants, including both macro and microalgae.^[4] This species is nocturnal. It will often attach small objects like algae, stone or polyps into its spines.

Use by humans

This species often appears in the aquarium trade.^[4] This species is considered reef safe, meaning it will not harm coral and other invertebrates. It is considered delicate.