Penny Higgins - Storyteller • Artist • Scientist
Combining Science and Joyful Creativity
Leslie, 2014, Impacts of phylogenetic nomenclature on the efficacy of the U.S. Endangered Species Act: Conservation Biology, v. 29, p. 69-77
What’s it about?
7\\\\\4iiiiikkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkk89000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000Oa
What’s it about?
The author here discusses several of the various concepts for defining species and the reasons why scientists would use one over another.Continue reading “Making Sense of Species Concepts – #365papers – 2018 – 41”
de Queiroz, 2007, Species concepts and species delimitations: Systematic Biology, v. 56, 879-886.
What’s it about?
Species is a difficult concept in biology, even if it seems straightforward. The author of this paper shows that it really is as simple as it seems, but the means of distinguishing one species from another. The problem isn’t in the definition of species but in the distinction among species.Continue reading “Defining and Distinguishing Species of Organisms – #365papers – 2018 – 40”
What’s it about?
In mammals, each vertebra is a single bone. However, these apparently singular bones are actually composed of several bones that are sutured together. This paper explores the individual bones that get fused together, and their origins in the transitional forms between fish and terrestrial tetrapods (four legged animals, e.g. amphibians, reptiles, birds, and mammals).Continue reading “Putting Together the Tetrapod Vertebra – #365papers – 2018 – 39”
What’s it about?
Recently, there has been great discussion about the extraction of proteins from fossils. This paper outlines various methods, and their strengths and weaknesses, for extracting proteins from ancient bones.Continue reading “Methods for Extracting Proteins from Fossils: Paleoproteomics – #365papers – 2018 – 38”
What’s it about?
Isotopes of oxygen and hydrogen from water can give us insights into the altitude at which that water fell to the ground as rain. Some of this water can become incorporated into volcanic glass (in ash), preserving the isotopic values of the original water.Continue reading “Using Glass to Estimate Altitude – #365papers – 2018 – 37”
What’s it about?
The first billion years or so of Earth’s existence was marked by repeated bombardment of the planet by various asteroids, and even planetessimals. It is thought that this bombardment would superheat the Earth’s surface and kill any life that may have started to develop there. This study shows that, while the heating was extreme, there were still places that were protected from life-killing heat.Continue reading “Did Bolide Bombardment Kill Life on Earth More Than Once? – #365papers – 2018 – 36”
What’s it about?
The Endangered Species Act exists to protect species from extinction. However, the means by which we define ‘species’ can affect what groups of organisms get this protection. The ‘textbook’ definition of species (populations of organisms that interbreed naturally and have living and fertile offspring) is what most people think of. This is known as the Biological Species Concept. But what about sub-species, or isolated populations of organisms (such as the Florida panther)?
Modern phylogenetics, including cladistics, allows species to be defined using molecular data and focuses more on dividing organisms into the smallest, distinct populations, which are likely to be reproductively isolated.Continue reading “How Definitions of Species Affect Conservation – #UREES270 – 2018”
What’s it about?
The authors observed the decay to two very similar organisms: amphioxus (Branchiostoma), a chordate, and the ammocoete larva (Lampetra), a vertebrate. It was observed that the distinctive characters that distinguish vertebrates from other chordates very quickly decay after death, resulting in both amphioxus and the ammocoete appearing to be merely stem chordates. Continue reading “Why Can’t We Tell If a Chordate Is a Vertebrate in the Fossil Record? – #365papers – 2018 – 35”
What’s it about?
Modern horses have a single obvious hoof on each lef, which is representative of the third digit – equivalent to our middle finger. The fossil record shows that horses evolved from three-toed ancestors, which themselves evolved from four-toed ancestors, which even further back, came from five-toed ancestors.
In modern horses, the remnants of digits 2 and 4 (our index and ring fingers) are evident as tiny splint bones fused to the cannon bone (third metacarpal or metatarsal) of the leg. The authors use study of limbs of adult, full-term fetal, and early fetal horses. They trace the positions of nerves and blood vessels in the legs of horses, as well as consider the articulation between the horse’s toe bones and carpal-metacarpal joints to show that modern horses retain parts of all five of the original toes that their deep ancestors possessed.Continue reading “Horses Have Five Toes on Each Foot – #365papers – 2018 – 33”
Penny Higgins - Storyteller • Artist • Scientist