hummingwolf (![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png)
hummingwolf) wrote2003-08-21 09:21 am
hummingwolf) wrote2003-08-21 09:21 am
Entry tags:
News link of the morning
This brainless mud worm is a long-lost relative of human beings, scientists have discovered.
It appears the slug-like creature found living at the bottom of a Swedish lake shares its ancestry with people.
It does not have a brain or even sex organs and scientists are baffled about how the Xenoturbella procreates....
"We have now been able to show that, amongst all of the invertebrates that exist, Xenoturbella is one of our very closest relatives.
Edit: Scientists previously thought it belonged to the same group as bivalve molluscs because it carried mollusc eggs, but in fact it had eaten them.
According to Nature:
It is the most primitive existing member of the group to which humans belong, called the deuterostomes, the authors argue. "It tells us what we evolved from 500 million years ago," says Telford. Deuterostomes include mammals, fish, starfish and worms.
The creature's rocky road to recognition began with its discovery more than 80 years ago. It's lack of recognizable features - it has no separate mouth or anus and no body cavity - led to its first labelling as a primitive flatworm.
Subsequent studies related it to acorn worms and starfish, because of similarities in its diffuse nerve network and outer epidermal layer. Then, in 1997, it received the lamentable mollusc moniker.
A preference for sludgy sea habitats makes Xenoturbella difficult to find, so researchers can only guess at their numbers. "Quite possibly, they're everywhere," says Telford, "but they're not the sort of thing you trip over on a beach."
I love following scientific research, I really do.
It appears the slug-like creature found living at the bottom of a Swedish lake shares its ancestry with people.
It does not have a brain or even sex organs and scientists are baffled about how the Xenoturbella procreates....
"We have now been able to show that, amongst all of the invertebrates that exist, Xenoturbella is one of our very closest relatives.
Edit: Scientists previously thought it belonged to the same group as bivalve molluscs because it carried mollusc eggs, but in fact it had eaten them.
According to Nature:
It is the most primitive existing member of the group to which humans belong, called the deuterostomes, the authors argue. "It tells us what we evolved from 500 million years ago," says Telford. Deuterostomes include mammals, fish, starfish and worms.
The creature's rocky road to recognition began with its discovery more than 80 years ago. It's lack of recognizable features - it has no separate mouth or anus and no body cavity - led to its first labelling as a primitive flatworm.
Subsequent studies related it to acorn worms and starfish, because of similarities in its diffuse nerve network and outer epidermal layer. Then, in 1997, it received the lamentable mollusc moniker.
A preference for sludgy sea habitats makes Xenoturbella difficult to find, so researchers can only guess at their numbers. "Quite possibly, they're everywhere," says Telford, "but they're not the sort of thing you trip over on a beach."
I love following scientific research, I really do.
no subject
Oh, right. The BBC. I should have known. :)
I'd like to know just what criteria determines our relation to the creature.
I also would love to live to see the day when things like this are disproved and make us all go "wow, what the heck were we thinking?"
no subject
no subject
Oh, study of this creature sounds like a comedy of errors to me. I like it!
no subject
no subject
no subject
*laughs* Which at least is a point in the favor of L.L. Bean.