Evidence of Great Biocrises in the Field and the Drawer

Life on our planet has been a constant series of cataclysmic events, and we are more suitable for extinction than a trilobite or a reptile. So we will vanish. There’s no doubt in my heart. –Werner Herzog

Griffithidella doris, Lake Valley Formation, New Mexico
Griffithidella doris, Lake Valley Formation, Mississippian Period, New Mexico. A series of biocrises in the Late Devonian Epoch whittled trilobite diversity down to only four families by the opening of the Carboniferous (Mississippian) Period. Smaller trilobite is 1.0 cm long.

Extinction must frequently be on the mind of many trilobite collectors. Every species of once-living thing in their cabinets has been extinct for hundreds of millions of years. What’s more, the diversity of specimens in those cabinets reflects the steady background rate of extinction as well as the mass extinction events sprinkled throughout the Paleozoic Era.

Most noticeable, perhaps, is how the Late Devonian events shape a fossil collection. The Lower Devonian drawers are chock full, the Upper Devonian drawers are sparse, and (unless you’ve made a concerted effort), the late Paleozoic drawers have ample space for additional specimens!

Other transitions are just about as apparent. Ordovician drawers stuffed with asaphids, for example, bear little resemblance to the Silurian drawers—no doubt reflecting the big trilobite die-off at the end of the Ordovician Period.

Megistaspidella triangularis, Kunda level, Ordovician Period, St. Petersburg region, Russia
Megistaspidella triangularis, Kunda level, Ordovician Period, St. Petersburg region, Russia. The Megistaspidae is a group containing large, spectacular shovel-nosed forms. Megistaspids are confined to Lower and Middle Ordovician rocks. Trilobite is about 13 cm long.

Each of the five major mass extinction events of the Phanerozoic, no doubt, looked different to the organisms experiencing them, from cataclysmic bolide impacts to seas draining away or becoming choked with organic detritus . . . .

As a natural history enthusiast who spends a great deal of time in the field (mostly photographing birds), I accept the concept of the Anthropocene, the Age of Man. I also accept that we are experiencing the the sixth great (anthropogenic) mass extinction event of the Phanerozoic Eon. I have no doubt that the fossil record of the future will show evidence of a geologically instantaneous extinction event dating to . . . now.

Older Holocene terrestrial strata will record a diverse vertebrate fauna, and nearshore marine strata will preserve reef facies bristling with invertebrates. Younger Anthropocene strata will show a much decreased biodiversity and a much greater abundance of cow, pig, chicken, human, and dog bones interlaced with scrap metal, broken concrete, and plastic debris!

One more subtle aspect of the unfolding anthropogenic extinction event, I think, is the human importation of often destructive exotic species into many parts of the world.

And now for a bit of shameless self-promotion . . . .

Save the Date (January 18, 2017): A New Two Shutterbirds Presentation at the Houston Audubon Nature Photography Association (HANPA)

Prothonotary Warbler on bottlebrush, Catholic Cemetery, Dauphin Island, Alabama
Looking for a Sweet Treat: Prothonotary Warbler on Bottlebrush, Catholic Cemetery, Dauphin Island, Alabama. Bottlebrushes are Australian plants, but birds everywhere love them because of the copious nectar and pollen they produce. Sweet calorie-rich nectar must be a wonderful treat after a grueling trans-Gulf of Mexico flight! Canon EOS 7DII/600mm f/4L IS (+1.4x TC). High-speed synchronized fill-flash.

Exotics Gone Native!

Synopsis: Human-introduced exotic plants and animals are all around us, and many of them are doing nicely, thank you very much. It’s sometimes hard not to notice them while out photo-birding. The proliferation of these organisms can be troubling to nature lovers, particularly eco-purists. Are these foreign organisms adversely affecting our native plants and wildlife? And if so, how badly? Are some helpful to our native species? Certainly some, like bottlebrush, are helpful to the bird photographer! Whatever your stance on exotics, perhaps the healthiest thing to do is treat them as just another opportunity to experience new species in the wild—even if they are out of place. In this talk, Chris Cunningham will share images of some frequently encountered exotic species and discuss their place in our native landscape. (Note: If this topic is too upsetting, Chris and Elisa will share and some images of native wild birds from their most recent outings to West Texas, the Coastal Bend, and central New Mexico, too!)

Time and Place: 7:00 PM, January 18, 2017 at the Edith L. Moore Nature Sanctuary, 440 Wilchester Blvd., Houston TX 77079. For additional details, please see the Houston Audubon HANPA website.

©2016 Christopher R. Cunningham. All rights reserved. No text or images may be duplicated or distributed without permission.