• Transitional Turtle and Root Fossils

    The fossil evidence for evolution long ago accumulated to the point of being totally conclusive. That said, even more has been uncovered recently, and is it fascinating! Via ScienceDaily:

    “There are a couple of key features that make a turtle a turtle: its shell, for one, but also its toothless beak. A newly-discovered fossil turtle that lived 228 million years ago is shedding light on how modern turtles developed these traits. It had a beak, but while its body was Frisbee-shaped, its wide ribs hadn’t grown to form a shell like we see in turtles today.” (Link)

    Another fascinating transition has also been uncovered, this one involving transitional root fossils in plants. Professor Dolan (who was involved in this research) remarked “I really want to find out where root caps came from. They seemed to have appeared out of thin air. They are very important in extant roots; the root cap is important to protect the root as it pushes through the soil and it is the site where roots detect gravity. How did these ancient roots manage without a cap to provide these functions?”

    The answer: “The fossil analysis reveals that the meristems of A. mackiei lack both root hairs and caps — they are covered instead by a continuous layer of surface tissue. This structure makes these roots unique among the vascular plants.” (Link)

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    Article by: Nicholas Covington

    I am an armchair philosopher with interests in Ethics, Epistemology (that's philosophy of knowledge), Philosophy of Religion, Politics and what I call "Optimal Lifestyle Habits."

    2 comments

    1. • Given that microevolution is observable.

      When engaging a “Darwin-Doubter”, my rule of thumb is to establish that an intelligible dialogue on microevolution is possible before entering the realm of current–theory per evolution/natural-selection as the origin of species.

      Cf. “Examples of microevolution”. evolution.berkeley.edu.

      House sparrows were introduced to North America in 1852. Since that time, the sparrows have evolved different characteristics in different locations. Sparrow populations in the north are larger-bodied than sparrow populations in the south. This divergence in populations is probably at least partly a result of natural selection: larger-bodied birds can often survive lower temperatures than smaller-bodied birds can. Colder weather in the north probably selects for larger-bodied birds. . . . sparrows in colder places are now generally larger than sparrows in warmer locales.

    2. Bobrovskiy, Ilya; Hope, Janet M.; Ivantsov, Andrey; Nettersheim, Benjamin J.; Hallmann, Christian; Brocks, Jochen J. (2018). “Ancient steroids establish the Ediacaran fossil Dickinsonia as one of the earliest animals”. Science. 361 (6408): 1246–1249. doi:10.1126/science.aat7228. ISSN 0036-8075.

      [Abstract] The enigmatic Ediacara biota (571 million to 541 million years ago) represents the first macroscopic complex organisms in the geological record and may hold the key to our understanding of the origin of animals. Ediacaran macrofossils are as “strange as life on another planet” and have evaded taxonomic classification, with interpretations ranging from marine animals or giant single-celled protists to terrestrial lichens. Here, we show that lipid biomarkers extracted from organically preserved Ediacaran macrofossils unambiguously clarify their phylogeny. Dickinsonia and its relatives solely produced cholesteroids, a hallmark of animals. Our results make these iconic members of the Ediacara biota the oldest confirmed macroscopic animals in the rock record, indicating that the appearance of the Ediacara biota was indeed a prelude to the Cambrian explosion of animal life.

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