Sponges are more closely related to us than some animals with a nervous system:
A recent study challenges the idea that evolution always leads to increased complexity in animals. By analyzing gene arrangements on chromosomes, researchers sought to understand the evolutionary relationships between species.
The study found that sponges, which lack muscles and a nervous system, are more closely related to humans than comb jellies, which possess both traits. This contradicts the assumption that complexity determines evolutionary proximity. The research suggests two potential explanations: either sponges and other simple animals lost nerves and muscles over time, simplifying their body plans, or nerves and muscles evolved independently in different lineages.
Further investigation, such as studying the nerve and muscle cells of comb jellies in a lab, is needed to differentiate between these possibilities. The study underscores the complexity of animal evolution and challenges existing notions of evolutionary relationships based on traits and complexity.
Journal Reference:
Schultz, Darrin T., Haddock, Steven H. D., Bredeson, Jessen V., et al. Ancient gene linkages support ctenophores as sister to other animals [open], Nature (DOI: 10.1038/s41586-023-05936-6)
(Score: 3, Insightful) by HiThere on Thursday May 18, @08:35PM (2 children)
Divergent groups can as easily lose features as gain them over evolutionary time. Sponges live a life that doesn't require muscles, so they lost them. This isn't surprising, but is rather to be expected. Consider all the different varieties of blind cave fish. That's a lot shorter period of separation, so more of the eyes remain, but in some of them the retina is just gone. I expect that there are some that have become essentially eyeless rather than just blind.
So for sponges to lack features that other descendants of the comb jellies capitalized on and developed isn't something that should be unexpected.
Javascript is what you use to allow unknown third parties to run software you have no idea about on your computer.
(Score: 2) by Spamalope on Friday May 19, @02:47AM
Exactly. 'Old' lineages have survived multiple mass extinction events, and those filter out organisms wasting calories on unneeded function. We see many instances of losing function, just not these two core ones that require an extreme adaptation to lose.
(Score: 0) by Anonymous Coward on Friday May 19, @11:48PM
Oh, look, the internet experts are here. Oh, goody.
(Score: 3, Funny) by Runaway1956 on Thursday May 18, @09:36PM (3 children)
Nearly half the people I know always have their hands out, wanting money, food, clothes, drink, a car, free transportation, a new phone, it goes on, and on, and on . . . .
Abortion is the number one killed of children in the United States.
(Score: 2) by legont on Friday May 19, @03:16AM
Let me translate...
Most of the time nothing progresses, but rather stagnates or regresses outright. That's 99% of the time.
Every now and than there is a jump. It can happen anywhere and from anything. The bottom line, the idea of linear progress is bull. For example, most of the time people leaved worse than their parents. It was a few precious years when progress was made.
Going back to the USA, no income increase for male workers since 1980.
"Wealth is the relentless enemy of understanding" - John Kenneth Galbraith.
(Score: 0) by Anonymous Coward on Friday May 19, @11:57PM (1 child)
Actually inbred, the #1 killer of children in the US is gun violence.
(Score: 1) by Runaway1956 on Saturday May 20, @12:51AM
Liar - you made zero attempt to check your propaganda. https://www.childstats.gov/americaschildren/mortality.asp [childstats.gov]
Abortion is the number one killed of children in the United States.