Ariel Chipman - Academia.edu (original) (raw)
Papers by Ariel Chipman
Frontiers in Ecology and Evolution, 2023
The stable isotopes composition of chemolithoautotrophic cave ecosystems is known to differ from ... more The stable isotopes composition of chemolithoautotrophic cave ecosystems
is known to differ from epigenic caves. Here we show that in addition,
dead carbon (devoid of 14C), is utilized and transferred throughout this
ecosystem, rendering it unsuitable for radiocarbon dating. The connectivity
of the Ayyalon Cave ecosystem with the surface is studied, along with its
sources of energy and carbon, as well as the interconnections between
its constituents. We use isotopic evidence to show that its ancient resilient
ecosystem is based on an underground food web depending on rich biomass
production by chemolithoautotrophic nutrient supplies, detached from
surface photosynthesis. Carbon isotopic values indicate that: (1) the microbial
biota use bicarbonate from the groundwater (23.34 pMC [% of modern
carbon]) rather than the atmospheric CO2 above the water (71.36 pMC); (2)
the depleted 14C signal is transferred through the entire ecosystem, indicating
that the ecosystem is well-adapted and based on the cave biofilm which is
in turn based on groundwater-dissolved inorganic carbon. Incubation of
Ayyalon biofilm with 14C-labelled bicarbonate indicates uptake of the radiolabeled
bicarbonate by sulfur-oxidizing proteobacteria Beggiatoa, suggesting
that these sulfur-oxidizing microorganisms use the water-dissolved inorganic
carbon for chemolithoautotrophic carbon fixation. Organic matter in the
cave is much lighter in its stable nitrogen and carbon isotopes compared with
respective surface values, as expected in chemolithoautotrophic systems. This
evidence may be applicative to subsurface voids of ancient Earth environments
and extraterrestrial systems.
BMC evolutionary biology, 2015
Our understanding of the early evolution of the arthropod body plan has recently improved signifi... more Our understanding of the early evolution of the arthropod body plan has recently improved significantly through advances in phylogeny and developmental biology and through new interpretations of the fossil record. However, there has been limited effort to synthesize data from these different sources. Bringing an embryological perspective into the fossil record is a useful way to integrate knowledge from different disciplines into a single coherent view of arthropod evolution. I have used current knowledge on the development of extant arthropods, together with published descriptions of fossils, to reconstruct the germband stages of a series of key taxa leading from the arthropod lower stem group to crown group taxa. These reconstruction highlight the main evolutionary transitions that have occurred during early arthropod evolution, provide new insights into the types of mechanisms that could have been active and suggest new questions and research directions. The reconstructions sugge...
Evolutionary Developmental Biology of Invertebrates 5, 2015
Journal of Zoological Systematics and Evolutionary Research, 2009
Integrative and Comparative Biology, 2006
PLoS biology, 2014
Myriapods (e.g., centipedes and millipedes) display a simple homonomous body plan relative to oth... more Myriapods (e.g., centipedes and millipedes) display a simple homonomous body plan relative to other arthropods. All members of the class are terrestrial, but they attained terrestriality independently of insects. Myriapoda is the only arthropod class not represented by a sequenced genome. We present an analysis of the genome of the centipede Strigamia maritima. It retains a compact genome that has undergone less gene loss and shuffling than previously sequenced arthropods, and many orthologues of genes conserved from the bilaterian ancestor that have been lost in insects. Our analysis locates many genes in conserved macro-synteny contexts, and many small-scale examples of gene clustering. We describe several examples where S. maritima shows different solutions from insects to similar problems. The insect olfactory receptor gene family is absent from S. maritima, and olfaction in air is likely effected by expansion of other receptor gene families. For some genes S. maritima has evolv...
The Journal of experimental zoology, Jan 15, 2001
Differences in nuclear DNA content in vertebrates have been shown to be correlated with cell size... more Differences in nuclear DNA content in vertebrates have been shown to be correlated with cell size, cell division rate, and embryonic developmental rate. We compare seven species of anuran amphibians with a three-fold range of genome sizes. Parameters examined include the number and density of cells in a number of embryonic structures, and the change in cell number in the CNS during development. We show that genome size is correlated with cell proliferation rate and with developmental rate at different stages of embryonic development, but that the correlation between genome size and cell size is only evident at later stages. We discuss the evolution of genome size in amphibians. Our discussion takes into account data that reportedly support two conflicting hypotheses: the "skeletal DNA" hypothesis, which claims a selective role for differences in genome size, and the "junk DNA" hypothesis, which claims that differences in genome size are a random result of the acc...
Journal of Experimental Zoology, 2000
Journal of experimental zoology. Part B, Molecular and developmental evolution, Jan 15, 2003
Constraints are factors that limit evolutionary change. A subset of constraints is developmental,... more Constraints are factors that limit evolutionary change. A subset of constraints is developmental, and acts during embryonic development. There is some uncertainty about how to define developmental constraints, and how to formulate them as testable hypotheses. Furthermore, concepts such as constraint-breaking, universal constraints, and forbidden morphologies present some conceptual difficulties. One of our aims is to clarify these issues. After briefly reviewing current classifications of constraint, we define developmental constraints as those affecting morphogenetic processes in ontogeny. They may be generative or selective, although a clear distinction cannot always be drawn. We support the idea that statements about constraints are in fact statements about the relative frequency of particular transformations (where 'transformation' indicates a change from the ancestral condition). An important consequence of this is that the same transformation may be constrained in one ...
Frontiers in Ecology and Evolution, 2023
The stable isotopes composition of chemolithoautotrophic cave ecosystems is known to differ from ... more The stable isotopes composition of chemolithoautotrophic cave ecosystems
is known to differ from epigenic caves. Here we show that in addition,
dead carbon (devoid of 14C), is utilized and transferred throughout this
ecosystem, rendering it unsuitable for radiocarbon dating. The connectivity
of the Ayyalon Cave ecosystem with the surface is studied, along with its
sources of energy and carbon, as well as the interconnections between
its constituents. We use isotopic evidence to show that its ancient resilient
ecosystem is based on an underground food web depending on rich biomass
production by chemolithoautotrophic nutrient supplies, detached from
surface photosynthesis. Carbon isotopic values indicate that: (1) the microbial
biota use bicarbonate from the groundwater (23.34 pMC [% of modern
carbon]) rather than the atmospheric CO2 above the water (71.36 pMC); (2)
the depleted 14C signal is transferred through the entire ecosystem, indicating
that the ecosystem is well-adapted and based on the cave biofilm which is
in turn based on groundwater-dissolved inorganic carbon. Incubation of
Ayyalon biofilm with 14C-labelled bicarbonate indicates uptake of the radiolabeled
bicarbonate by sulfur-oxidizing proteobacteria Beggiatoa, suggesting
that these sulfur-oxidizing microorganisms use the water-dissolved inorganic
carbon for chemolithoautotrophic carbon fixation. Organic matter in the
cave is much lighter in its stable nitrogen and carbon isotopes compared with
respective surface values, as expected in chemolithoautotrophic systems. This
evidence may be applicative to subsurface voids of ancient Earth environments
and extraterrestrial systems.
BMC evolutionary biology, 2015
Our understanding of the early evolution of the arthropod body plan has recently improved signifi... more Our understanding of the early evolution of the arthropod body plan has recently improved significantly through advances in phylogeny and developmental biology and through new interpretations of the fossil record. However, there has been limited effort to synthesize data from these different sources. Bringing an embryological perspective into the fossil record is a useful way to integrate knowledge from different disciplines into a single coherent view of arthropod evolution. I have used current knowledge on the development of extant arthropods, together with published descriptions of fossils, to reconstruct the germband stages of a series of key taxa leading from the arthropod lower stem group to crown group taxa. These reconstruction highlight the main evolutionary transitions that have occurred during early arthropod evolution, provide new insights into the types of mechanisms that could have been active and suggest new questions and research directions. The reconstructions sugge...
Evolutionary Developmental Biology of Invertebrates 5, 2015
Journal of Zoological Systematics and Evolutionary Research, 2009
Integrative and Comparative Biology, 2006
PLoS biology, 2014
Myriapods (e.g., centipedes and millipedes) display a simple homonomous body plan relative to oth... more Myriapods (e.g., centipedes and millipedes) display a simple homonomous body plan relative to other arthropods. All members of the class are terrestrial, but they attained terrestriality independently of insects. Myriapoda is the only arthropod class not represented by a sequenced genome. We present an analysis of the genome of the centipede Strigamia maritima. It retains a compact genome that has undergone less gene loss and shuffling than previously sequenced arthropods, and many orthologues of genes conserved from the bilaterian ancestor that have been lost in insects. Our analysis locates many genes in conserved macro-synteny contexts, and many small-scale examples of gene clustering. We describe several examples where S. maritima shows different solutions from insects to similar problems. The insect olfactory receptor gene family is absent from S. maritima, and olfaction in air is likely effected by expansion of other receptor gene families. For some genes S. maritima has evolv...
The Journal of experimental zoology, Jan 15, 2001
Differences in nuclear DNA content in vertebrates have been shown to be correlated with cell size... more Differences in nuclear DNA content in vertebrates have been shown to be correlated with cell size, cell division rate, and embryonic developmental rate. We compare seven species of anuran amphibians with a three-fold range of genome sizes. Parameters examined include the number and density of cells in a number of embryonic structures, and the change in cell number in the CNS during development. We show that genome size is correlated with cell proliferation rate and with developmental rate at different stages of embryonic development, but that the correlation between genome size and cell size is only evident at later stages. We discuss the evolution of genome size in amphibians. Our discussion takes into account data that reportedly support two conflicting hypotheses: the "skeletal DNA" hypothesis, which claims a selective role for differences in genome size, and the "junk DNA" hypothesis, which claims that differences in genome size are a random result of the acc...
Journal of Experimental Zoology, 2000
Journal of experimental zoology. Part B, Molecular and developmental evolution, Jan 15, 2003
Constraints are factors that limit evolutionary change. A subset of constraints is developmental,... more Constraints are factors that limit evolutionary change. A subset of constraints is developmental, and acts during embryonic development. There is some uncertainty about how to define developmental constraints, and how to formulate them as testable hypotheses. Furthermore, concepts such as constraint-breaking, universal constraints, and forbidden morphologies present some conceptual difficulties. One of our aims is to clarify these issues. After briefly reviewing current classifications of constraint, we define developmental constraints as those affecting morphogenetic processes in ontogeny. They may be generative or selective, although a clear distinction cannot always be drawn. We support the idea that statements about constraints are in fact statements about the relative frequency of particular transformations (where 'transformation' indicates a change from the ancestral condition). An important consequence of this is that the same transformation may be constrained in one ...