today
9 a.m. Historic Archaeology Lab Opportunity HSU Behavior and Social Sciences Building
read >10:30 a.m. The Mighty Diamonds (reggae) Humboldt Brews
read >noon Free Multi-Level Yoga Class Humboldt Wellness Center
read >1:30 p.m. Josephine Johnson (folk/soul) Has Beans
read >4 p.m. K-8 After School Drawing Space Humboldt Wellness Center
read >5 p.m. Tuesday Music Cafe Arkley Center for the Performing Arts
read >6 p.m. Pacific Union School Fundraiser for 8th Grade Trip Cher-Ae-Heights Casino
read >6 p.m. The Grass Band Mad River Brewing Company
read >6 p.m. Our Pathways to Health: Fortuna Sequoia Springs Assisted Living Facility
read >6:30 p.m. Open Mic with Sky Miller Old Town Coffee & Chocolates
read >7 p.m. North Coast Jazz Six Rivers Brewery
read >7 p.m. Open Jam Blondies Food And Drink
read >7:30 p.m. The Marriage of Bette and Boo Van Duzer Theatre
read >8 p.m. North Group Sierra Club Adorni Recreation Center
read >9 p.m. Blues Night Jambalaya
read >9 p.m. Karaoke/Dance Party The Playroom
read >10 p.m. Progressive Drink Night with DJ Dub Cowboy Sidelines
read >previous columns
July 17, 2008
Si, PV and LED
Silicon, PhotoVoltaics and Light Emitting Diodes are of growing importance. ...
read >July 10, 2008
Pupal Memories
I remember watching a chick emerge from an egg. It ...
read >July 3, 2008
Lagoons and Beaches
Lagoons Shelter Cove Much of our coastal topography is generated ...
read >Photos
Arms Race & Species
By Don Garlick
Herpetology, the study of amphibians and reptiles, sheds much light on the nature of evolution. Consider the range of body plans and lifestyles among salamanders (amphibians with tails). They commonly hatch from eggs in water or moist places, though a few species give birth to live young. Some are confined to water and use external gills. Some metamorphose into land crawlers and breathe with lungs. Surprisingly, most require neither gills nor lungs, but exchange gases through moist skin and mouth membranes. A local lungless species has such small legs that it resembles a tiny snake. The nine-inch Pacific Giant Salamander devours banana slugs. A Japanese salamander is almost six feet long.
Salamanders with drier skin are called newts. The Rough-skinned Newt (photo), ranging from Santa Cruz to Alaska, has a particularly toxic skin. If ingested, it can paralyze and kill several humans. That "tetrodotoxin" also occurs in Pufferfish and Blue-ringed Octopuses. In those marine animals, at least, the toxin is produced by symbiotic bacteria.
Garter Snakes have evolved an immunity to tetrodotoxin. It is clear that predation has driven newts to become increasingly toxic, and snakes to become increasingly immune. It's an example of co-evolution and a natural arms race. Moreover, after eating a newt, toxin resides in a snake's liver for weeks, undoubtedly affording it some protection from birds. On Vancouver Island, newts and snakes have avoided the chemical arms race. Canada is just more peace-loving.
An insight into speciation is provided by lungless Ensatina Salamanders, whose young, hatched from eggs under damp wood, resemble tiny adults. Several sub-species range southward on both sides of the Central Valley (map). Neighboring sub-species readily interbreed and blend, except those at the southern extreme of the range. These remain distinct because their hybrids have reduced vigor. Biologists consider the southern-end members to represent two different species.
Another example of a "ring species," demonstrating the gradual origin of species by increasing geographic separation, is provided by sea gulls: Gradual changes through 360 degrees around the Arctic Ocean culminate in two distinct species in northern Europe.
Be kind to salamanders -- our ancestors resembled them just 360 million years ago.
I thank Prof. Sharyn Marks of H.S.U. for correcting my errors.



















1. Don Garlick:
Aug. 20, 6:51 p.m.
The map caption is wrong (added by webmaster). Ensatina Salamanders are not Rough-skinned Newts.
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