We are pleased to announce that Dr Donald Prothero, a research associate at the Natural History Museum of Los Angeles County, USA, has been appointed as the PalAss Exceptional Lecturer for 2023/24.
How do animals respond to climate change? Lessons from the prehistoric birds and mammals of La Brea Tar Pits
Conventional evolutionary theory views organisms as responsive to their environments on rapid timescales, and able to readily change size or shape due to selection pressures (as exemplified by the famous case of Galápagos finches). However, since 1863, it has been well established that Pleistocene animals and plants show limited change in response to recent glacial-interglacial cycles. Rancho La Brea tar pits in Los Angeles, California, preserve a large and diverse fauna from many well-dated deposits, spanning 37,000 years. Pollen evidence shows that climate changed from oak-chaparral about 37 ka to snowy piñon-juniper-ponderosa pine forests during the peak glacial about 18 ka, then returned to the modern chaparral since the glacial-interglacial transition. We have studied all the sufficiently abundant mammals (dire wolves, saber-toothed cats, giant lions, Harlan’s ground sloths, camels, bison and horses) and all the common birds (28 species, ranging from eagles, hawks, vultures, condors, owls, to yellow-billed magpies, ravens and Western meadowlarks). We found complete stasis in size and robustness as measured by the major limb bones in all 28 species. There was no significant response even at 20 ka to 18 ka, during the peak glacial period, when climate and vegetation were very different at La Brea. The larger species might be so wide-ranging and versatile that they would not respond to environmental changes, but this is inadequate to explain stasis in even the smallest birds, such as meadowlarks and burrowing owls. While the Galápagos finch model suggests rapid morphological change in response to environmental change, the fossil record shows that such small-scale changes are transient and do not accumulate to result in speciation.
Dr Donald R. Prothero - 2023/24 PalAss Exceptional Lecturer
Rancho la Brea Tar Pool: palaeoart from 1921 by Charles R. Knight for AMNH mural decorations in hall of the Age of Man. Image in the public domain.
Want Donald to visit your institution?
We now invite interested institutions to apply to host Donald via the Association’s website. Please provide a timeframe (between September 2023 and May 2024) during which you would like Donald to give a lecture at your institution. The list of interested institutions will be forwarded to Donald on 1st June 2023, although any applications from institutions submitted after this date will still be considered depending on the remaining time and budget. The Association will pay for any reasonable travel costs incurred by the Exceptional Lecturer in visiting each of the host institutions (up to a maximum of £500 per lecture). The host institutions are expected to cover costs for accommodation (where necessary) and hospitality.