“A single cilium is made up of some 600 protein pieces—more than many other cellular structures.”
“A single cilium is made up of some 600 protein pieces—more than many other cellular structures.”
Primary cilia (non-motile) act like antennae, sensing the external environment. Filled with proteins that amplify the signal, they act as a communications hub for the cell.
During development, motile cilia direct the liver on the right side of the body and the heart on the left.
Cilia sweep the airways clean of mucus by moving in concert in a wave-like motion.
Motile cilia direct the female egg to the uterus. An extra-long cilium propels a sperm cell toward the egg. (This is called a flagellum but does not work the same as the rotary flagellum found in bacteria.)
Motile cilia direct the female egg to the uterus. An extra-long cilium propels a sperm cell toward the egg. (This is called a flagellum but does not work the same as the rotary flagellum found in bacteria.)
Cilia “circulate the fluid needed for proper brain function.”
“More than a dozen rare but serious genetic disorders stem from cilia glitches.”
Reporter Amber Dance did not discuss how these organelles might have evolved. Instead, she reported that scientists at Brandeis University are trying to imitate them.
This article was true to form: mentions of evolution are inversely proportional to the detail of complexity discussed. Biochemist Michael Behe made cilia an example of irreducible complexity in his first book Darwin’s Black Box, and discussed them in more mind-boggling detail in his second book, The Edge of Evolution. Make the design inference: (1) Cilia are composed of multiple interacting parts, all of which must be present for the cilium to work. (2) Removal or damage to a single part destroys the cilium and results in serious disease to the organism. Charlie, where are you?
This article was true to form: mentions of evolution are inversely proportional to the detail of complexity discussed. Biochemist Michael Behe made cilia an example of irreducible complexity in his first book Darwin’s Black Box, and discussed them in more mind-boggling detail in his second book, The Edge of Evolution. Make the design inference: (1) Cilia are composed of multiple interacting parts, all of which must be present for the cilium to work. (2) Removal or damage to a single part destroys the cilium and results in serious disease to the organism. Charlie, where are you?
Some evolutionary papers are filled with verbs like arose, emerged, and originated. Do these convey scientific understanding, or are they veils concealing ignorance? Is it like saying “abracadabra” to say something “arose” by evolution? A recent paper about sophisticated metabolic enzymes in plants is a case in point.
Some evolutionary papers are filled with verbs like arose, emerged, and originated. Do these convey scientific understanding, or are they veils concealing ignorance? Is it like saying “abracadabra” to say something “arose” by evolution? A recent paper about sophisticated metabolic enzymes in plants is a case in point.
In a paper by Weng, Philippe and Noel in Science (29 June 2012: Vol. 336 no. 6089 pp. 1667–1670; DOI: 10.1126/science.1217411), the magic starts right in the title: “The Rise of Chemodiversity in Plants.” It rose to a crescendo throughout the overture to evolution’s uncanny power to bring things forth out of nothing.1 In the following excerpts, the magic words, hedging words and personifications are highlighted in bold:
The Emergence of Metabolism
The Emergence of Metabolism
New metabolic branches continuously arose throughout land-plant evolution.…
Since its origin as a fundamental property of the cell, metabolism is generally regarded as having evolved toward increasing order and catalytic efficiency.…
Primary metabolism likely arose from promiscuous primeval metabolic reactions and evolved toward greater catalytic precision and efficiency. Specialized metabolism likely emerged from primary metabolism.
Even deleterious changes appearing in one paralog may be tolerated and not eliminated by selection, when the other paralog contributes to fitness. In such cases, the evolution of advantageous activities can now be favored in new environments.
.…increased catalytic promiscuity likely molded the evolution of specialized enzymes.
.…increased catalytic promiscuity likely molded the evolution of specialized enzymes.
Once a duplication-derived progenitor emerged, mutations may have loosened the energetic interdependencies.…
For instance, the evolution of rosmarinic acid biosynthesis in Lamiaceae herbsarose from gene duplication of a BAHD acyltransferase.
The emergence of rosmarinic acid synthase (RAS) in Lamiaceae likely followed substrate permissiveness of its evolutionary progenitor HCT, a more conserved enzyme ubiquitous in land plants.
By exploiting the broader substrate recognition of ancestral DFR, I. gesnerioidesevolved a red flower color.…
After a gene-duplication event, one gene copy likely was selected for increased activity toward this substrate, resulting in the emergence of a new metabolic step.…
