Oct 20, 2020 10:37 PM
(This post was last modified: Oct 21, 2020 03:01 AM by C C.)
Why does evolution keep turning different species into crabs?
https://www.syfy.com/syfywire/evolution-...into-crabs
EXCERPT: . . . The studied species all developed the same basic “crab-like habitus,” or basic outer structure that defines their body, despite having differing evolutionary ancestors. With some degree of specific variation, they all evolved similar hardened shells, in the same familiar broad, flat shape. But in a first discovery for the scientific world, the study even found that their internal anatomical structures — things like the vascular and nervous systems — also began to arrange themselves similarly over time.
The process by which this keeps happening, according to the study, is carcinization — literally, according to its Greek etymology, the crab-ifying of species. Researchers believe that, despite local differences, the reasons carcinization occurs are all physical: time, temperature, gravity, and the similar conditions of life in shallow aquatic reaches all converge — time and time again, it seems — to take a perfectly good original crustacean and pressure it into becoming more crab-like... (MORE - details)
Memories can be injected & survive amputation & metamorphosis
http://nautil.us/blog/-memories-can-be-i...amorphosis
EXCERPT: . . . But if memories aren’t stored in synaptic connections, where are they stored instead? Glanzman’s unpopular hypothesis was that they might reside in the nucleus of the neuron cell, where DNA and RNA sequences compose instructions for life processes. DNA sequences are fixed and unchanging, so most of an organism’s adaptability comes from supple epigenetic mechanisms, processes that regulate gene expression in response to environmental cues or pressures, which sometimes involve RNA. If DNA is printed sheet music, RNA-induced epigenetic mechanisms are like improvisational cuts and arrangements that might conduct learning and memory.
Perhaps memories reside in epigenetic changes induced by RNA, that improv molecule that scores protein-based adaptations of life. Glanzman’s team went back to their aplysia and trained them over two days to prolong their siphon-withdrawal reflex. They then dissected their nervous systems, extracting RNA involved in forming the memory of their training, and injected it into untrained aplysia, which were tested for learning a day later. Glanzman’s team found that the RNA from trained donors induced learning, while the RNA from untrained donors had no effect. They had transferred a memory, vaguely but surely, from one animal to another, and they had strong evidence that RNA was the memory-transferring agent.
Glanzman now believes that synapses are necessary for the activation of a memory, but that the memory is encoded in the nucleus of the neuron through epigenetic changes. “It’s like a pianist without hands,” Glanzman says. “He may know how to play Chopin, but he’d need hands to exercise the memory.”
The work of Douglas Blackiston, an Allen Discovery Center scientist at Tufts University, who has studied memory in insects, paints a similar picture... (MORE - details)
https://www.syfy.com/syfywire/evolution-...into-crabs
EXCERPT: . . . The studied species all developed the same basic “crab-like habitus,” or basic outer structure that defines their body, despite having differing evolutionary ancestors. With some degree of specific variation, they all evolved similar hardened shells, in the same familiar broad, flat shape. But in a first discovery for the scientific world, the study even found that their internal anatomical structures — things like the vascular and nervous systems — also began to arrange themselves similarly over time.
The process by which this keeps happening, according to the study, is carcinization — literally, according to its Greek etymology, the crab-ifying of species. Researchers believe that, despite local differences, the reasons carcinization occurs are all physical: time, temperature, gravity, and the similar conditions of life in shallow aquatic reaches all converge — time and time again, it seems — to take a perfectly good original crustacean and pressure it into becoming more crab-like... (MORE - details)
Memories can be injected & survive amputation & metamorphosis
http://nautil.us/blog/-memories-can-be-i...amorphosis
EXCERPT: . . . But if memories aren’t stored in synaptic connections, where are they stored instead? Glanzman’s unpopular hypothesis was that they might reside in the nucleus of the neuron cell, where DNA and RNA sequences compose instructions for life processes. DNA sequences are fixed and unchanging, so most of an organism’s adaptability comes from supple epigenetic mechanisms, processes that regulate gene expression in response to environmental cues or pressures, which sometimes involve RNA. If DNA is printed sheet music, RNA-induced epigenetic mechanisms are like improvisational cuts and arrangements that might conduct learning and memory.
Perhaps memories reside in epigenetic changes induced by RNA, that improv molecule that scores protein-based adaptations of life. Glanzman’s team went back to their aplysia and trained them over two days to prolong their siphon-withdrawal reflex. They then dissected their nervous systems, extracting RNA involved in forming the memory of their training, and injected it into untrained aplysia, which were tested for learning a day later. Glanzman’s team found that the RNA from trained donors induced learning, while the RNA from untrained donors had no effect. They had transferred a memory, vaguely but surely, from one animal to another, and they had strong evidence that RNA was the memory-transferring agent.
Glanzman now believes that synapses are necessary for the activation of a memory, but that the memory is encoded in the nucleus of the neuron through epigenetic changes. “It’s like a pianist without hands,” Glanzman says. “He may know how to play Chopin, but he’d need hands to exercise the memory.”
The work of Douglas Blackiston, an Allen Discovery Center scientist at Tufts University, who has studied memory in insects, paints a similar picture... (MORE - details)