Post reply

Reply to the message by David Turell

Name:

E-mail: (optional, won't be displayed directly)

Leave this field empty:

Homepage: (optional)

Leave this field empty:

Location: (optional)

Remember me (cookie)

Category:

Subject:

Formatting help

skip to input

format text bold: [b]bold text[/b]
format text italic: [i]italic text[/i]
insert hyperlink: [link=http://example.com/]link text[/link] / [link]http://example.com/[/link]
set text color: [color=#rgb]colored text[/color]
font size: [size=small]small text[/size]; [size=large]large text[/size]
insert list: [list][*]list item[/list]
insert image: [img]http://example.com/image.jpg[/img]; left: [img=left]http://example.com/image.jpg[/img]; right: [img=right]http://example.com/image.jpg[/img]; thumbnail: [img=thumbnail]http://example.com/image.jpg[/img]; thumbnail left: [img=thumbnail-left]http://example.com/image.jpg[/img]; thumbnail right: [img=thumbnail-right]http://example.com/image.jpg[/img]

:-)
;-)
:-P
:-D
:-|
:-(

Message:

> They sit on the sea floor and have compound eyes like insects on tentacles for protection:
> 
> https://www.sciencedaily.com/releases/2017/08/170801094325.htm
> 
> "Scientists examining the multiple eyes found on the tentacles of fan worms have discovered they evolved independently from their other visual systems, specifically to support the needs of their lifestyle.
> 
> "Fan worms live in tubes on the seafloor. From their heads, the worms extend feather-like tentacles up out of their tubes to sift the water for food particles and aid in respiration.
> To protect themselves from predators, fan worms have evolved a variety of unusual compound eyes on their tentacles that act like shadow or motion detectors, alerting the worm to danger and triggering a rapid hiding response to encroaching objects in the water.
> 
> "Superficially, some of these eyes resemble those of crustaceans or insects, but their photoreceptor cells are structurally and functionally distinct.
> 
> "Researchers from Lund University in Sweden used transcriptomic sequencing to examine the genes expressed in these eyes from a species of fan worm collected on the Great Barrier Reef, Megalomma interrupta.
> 
> "This sequencing approach identifies nearly all gene transcripts expressed in a given piece of tissue. They identified a number of genes that produce light-sensitive cellular signalling components such as opsins and g-proteins in the fan worm's eyes, which they compared with others known from across the animal kingdom.
> 
> ***
> 
> "It seems that the eyes on the tentacles of fan worms evolved independently from all other visual systems in order to support the needs of their unusual filter-feeding lifestyle.
> 
> "'Many questions remain about the evolution and function of these eyes.
> 
> "'Due to their unique evolutionary history and neural circuitry these eyes could offer many clues about the emergence of new sensory systems and how the first eyes may have arisen.'"
> 
> Comment: As dhw points out, developing life forms appear to have the capability of adaptation to special needs. God given?