Information landscapes and sensory ecology of the Cambrian Radiation

Paleobiology ◽  
2010 ◽  
Vol 36 (2) ◽  
pp. 303-317 ◽  
Author(s):  
Roy E. Plotnick ◽  
Stephen Q. Dornbos ◽  
Junyuan Chen
Keyword(s):  
Marine Environment ◽  
Animal Movement ◽  
Energy Content ◽  
Sensory Systems ◽  
Transport Processes ◽  
Sense Organs ◽  
Spatial Complexity ◽  
Major Transitions ◽  
History Of ◽  
Signal Sources

Organisms emit, detect, and respond to a huge array of environmental signals. The distribution of a given signal is dependent, first of all, upon the original spatial distribution of signal sources, thesource landscape.The signal sources can be fixed or moving and their output can be stable or ephemeral. Different sources can also occupy the same general spatial location, such as insects living on a host plant. The emitted signals are modified by relevant transport processes, which are often strongly scale and environment dependent. Chemical signals, for example, are propagated by diffusion and turbulence. The resulting complex, three-dimensional, and dynamic distribution of signals in the environment is thesignal landscape;it is the environment of potentially available information in which sensory systems function and have evolved. Organisms also differ widely in what signals they can actually detect; the distribution of signals that an organism can potentially respond to is itsinformation landscape.Although increasing the kinds and specificity of signals that can be detected and processed can lead to improved decision making, it almost always comes at an increased cost. The greater the spatial and temporal complexity of the environment, the greater are the costs of incomplete information and the more advantageous is the development of improved information-gathering capabilities. Studies with simulation models suggest how variability in the spatial structure of source and signal landscapes may control patterns of animal movement that could be represented in the trace fossil record. Information landscapes and the corresponding sensory systems should have evolved in concert with major transitions in the history of life. The Ediacaran to Cambrian interval is one of the most intensively studied periods in the history of life, characterized by the profound environmental and biological changes associated with the bilaterian radiation. These include the advent of macroscopic predation, an increase in the size and energy content of organisms, and the transition in seafloors from laminated matgrounds to mixgrounds produced by the development of macroscopic infaunal bioturbation. The overall effect of these transitions was to markedly increase the spatial complexity of the marine environment. We suggest that this increased spatial complexity, in turn, drove the evolution of macroscopic sense organs in mobile bilaterians, leading to their first appearance during the Cambrian. The morphology and distribution of these sense organs should reflect the life habits of the animals that possessed them. Our overall hypothesis was that there was a “Cambrian Information Revolution,” a coevolutionary increase in the information content of the marine environment and in the ability of and necessity for organisms to obtain and process this information. A preliminary analysis of the Maotianshan Shale (Chengjiang) biota indicates that the distribution of eyes and antennae in these animals is consistent with predictions based on their life habit.

The Major Transitions in Evolution

1997 ◽  
Author(s):  
John Maynard Smith ◽  
Eors Szathmary
Keyword(s):  
Full Range ◽  
Evolution Of Cooperation ◽  
Major Transitions ◽  
Insect Societies ◽  
Wide Range ◽  
Major Transition ◽  
Life Itself ◽  
History Of ◽  
Emergence Of Cooperation ◽  
Multicellular Organisms

Over the history of life there have been several major changes in the way genetic information is organized and transmitted from one generation to the next. These transitions include the origin of life itself, the first eukaryotic cells, reproduction by sexual means, the appearance of multicellular plants and animals, the emergence of cooperation and of animal societies, and the unique language ability of humans. This ambitious book provides the first unified discussion of the full range of these transitions. The authors highlight the similarities between different transitions--between the union of replicating molecules to form chromosomes and of cells to form multicellular organisms, for example--and show how understanding one transition sheds light on others. They trace a common theme throughout the history of evolution: after a major transition some entities lose the ability to replicate independently, becoming able to reproduce only as part of a larger whole. The authors investigate this pattern and why selection between entities at a lower level does not disrupt selection at more complex levels. Their explanation encompasses a compelling theory of the evolution of cooperation at all levels of complexity. Engagingly written and filled with numerous illustrations, this book can be read with enjoyment by anyone with an undergraduate training in biology. It is ideal for advanced discussion groups on evolution and includes accessible discussions of a wide range of topics, from molecular biology and linguistics to insect societies.

scholarly journals Neurophysiology goes wild: from exploring sensory coding in sound proof rooms to natural environments

2021 ◽  
Vol 207 (3) ◽  
pp. 303-319
Author(s):  
Heiner Römer
Keyword(s):  
Sensory System ◽  
Sensory Systems ◽  
Natural Environments ◽  
Sensory Coding ◽  
Noise Levels ◽  
Sensory Physiology ◽  
Sound Localisation ◽  
Physical Environments ◽  
History Of ◽  
Adaptive Behaviours

AbstractTo perform adaptive behaviours, animals have to establish a representation of the physical “outside” world. How these representations are created by sensory systems is a central issue in sensory physiology. This review addresses the history of experimental approaches toward ideas about sensory coding, using the relatively simple auditory system of acoustic insects. I will discuss the empirical evidence in support of Barlow’s “efficient coding hypothesis”, which argues that the coding properties of neurons undergo specific adaptations that allow insects to detect biologically important acoustic stimuli. This hypothesis opposes the view that the sensory systems of receivers are biased as a result of their phylogeny, which finally determine whether a sound stimulus elicits a behavioural response. Acoustic signals are often transmitted over considerable distances in complex physical environments with high noise levels, resulting in degradation of the temporal pattern of stimuli, unpredictable attenuation, reduced signal-to-noise levels, and degradation of cues used for sound localisation. Thus, a more naturalistic view of sensory coding must be taken, since the signals as broadcast by signallers are rarely equivalent to the effective stimuli encoded by the sensory system of receivers. The consequences of the environmental conditions for sensory coding are discussed.

scholarly journals The origin and early radiation of terrestrial vertebrates

2001 ◽  
Vol 75 (6) ◽  
pp. 1202-1213 ◽  
Author(s):  
Robert L. Carroll
Keyword(s):  
Fossil Record ◽  
Early Carboniferous ◽  
Late Devonian ◽  
Lower Carboniferous ◽  
Major Transitions ◽  
Terrestrial Vertebrates ◽  
History Of ◽  
Paleozoic Tetrapods ◽  
Early Radiation ◽  
Ways Of Life

The origin of tetrapods from sarcopterygian fish in the Late Devonian is one of the best known major transitions in the history of vertebrates. Unfortunately, extensive gaps in the fossil record of the Lower Carboniferous and Triassic make it very difficult to establish the nature of relationships among Paleozoic tetrapods, or their specific affinities with modern amphibians. The major lineages of Paleozoic labyrinthodonts and lepospondyls are not adequately known until after a 20–30 m.y. gap in the Early Carboniferous fossil record, by which time they were highly divergent in anatomy, ways of life, and patterns of development. An even wider temporal and morphological gap separates modern amphibians from any plausible Permo-Carboniferous ancestors. The oldest known caecilian shows numerous synapomorphies with the lepospondyl microsaur Rhynchonkos. Adult anatomy and patterns of development in frogs and salamanders support their origin from different families of dissorophoid labyrinthodonts. The ancestry of amniotes apparently lies among very early anthracosaurs.

scholarly journals Science & the Senses: Perceptions & Deceptions

2012 ◽  
Vol 74 (3) ◽  
pp. 145-149 ◽  
Author(s):  
William D. Stansfield
Keyword(s):  
Science Education ◽  
Confirmation Bias ◽  
Sensory Systems ◽  
Sense Organs ◽  
Cognitive Error ◽  
Biology Textbooks ◽  
Sensory Signals ◽  
Scientific Investigations ◽  
Human Tendency ◽  
Derived Data

Science requires the acquisition and analysis of empirical (sense-derived) data. Given the same physical objects or phenomena, the sense organs of all people do not respond equally to these stimuli, nor do their minds interpret sensory signals identically. Therefore, teachers should develop lectures on human sensory systems that include some common examples of sensory limitations, variations, deficiencies, malfunctions, and diseases (as discussed herein) because they have important implications for conducting scientific investigations, science education, and introspection that are seldom included in biology textbooks. Students need to be made aware of the human tendency to self deception in order to avoid the cognitive error of confirmation bias.

The Ecology and Management of Wood in World Rivers

2003 ◽  
Keyword(s):  
Spatial Patterns ◽  
General Framework ◽  
River System ◽  
Field Studies ◽  
Transport Processes ◽  
River Networks ◽  
Spatial And Temporal Patterns ◽  
History Of ◽  
World Rivers ◽  
Trapping Sites

<em>Abstract.</em>—A landscape perspective of wood in world rivers accounts for spatial and temporal patterns of sources of wood from streamside forests, processes of wood delivery to channels, transport of wood through river networks, and trapping sites of wood. Amounts of wood in a river system also depend on productivity of forests in source areas and decomposition rates. Collectively, these factors determine the amount and arrangement of individual pieces and accumulations of wood through a river network, which, in turn, affect ecological, geomorphic, social, and other features of rivers. Research to date deals with subsets of these components of wood in rivers, but there has been limited development of a general framework for wood in river networks. This chapter considers a framework for examining the arrangement of wood in river landscapes and how it may reflect the history of spatial patterns and timing of wood input and redistribution. Field studies provide examples of different spatial patterns and architectures of wood accumulations. Wood accumulations are shaped by input processes, trapping sites, and transport processes. Reaches in river networks may switch from wood patterns dominated by one set of controls to another because of gradual or abrupt input and redistribution. A framework for future studies and management includes interpretation of these different controls through time and over river networks.

Gender differences in substrate utilization during submaximal exercise in endurance-trained subjects

2002 ◽  
Vol 282 (2) ◽  
pp. E435-E447 ◽  
Author(s):  
Carsten Roepstorff ◽  
Charlotte H. Steffensen ◽  
Marianne Madsen ◽  
Bente Stallknecht ◽  
Inge-Lis Kanstrup ◽  
...  
Keyword(s):  
Oxygen Uptake ◽  
Energy Content ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Substrate Utilization ◽  
Peak Oxygen Uptake ◽  
Submaximal Exercise ◽  
Activity Level ◽  
Relative Contribution ◽  
History Of

Substrate utilization across the leg during 90 min of bicycle exercise at 58% of peak oxygen uptake (V˙o 2 peak) was studied in seven endurance-trained males and seven endurance-trained, eumenorrheic females by applying arteriovenous catheterization, stable isotopes, and muscle biopsies. The female and male groups were matched according toV˙o 2 peak per kilogram of lean body mass, physical activity level, and training history of the subjects. All subjects consumed the same diet, well controlled in terms of nutrient composition as well as energy content, for 8 days preceding the experiment, and all females were tested in the midfollicular phase of the menstrual cycle. During exercise, respiratory exchange ratio (RER) and leg respiratory quotient (RQ) were similar in females and males. Myocellular triacylglycerol (TG) degradation was negligible in males but amounted to 12.4 ± 3.2 mmol/kg dry wt in females and corresponded to 25.0 ± 6.0 and 5.0 ± 7.3% of total oxygen uptake in females and males, respectively ( P < 0.05). Utilization of plasma fatty acids (12.0 ± 2.5 and 9.6 ± 1.5%), blood glucose (13.6 ± 1.5 and 14.3 ± 1.5%), and glycogen (48.5 ± 4.9 and 42.8 ± 2.1%) were similar in females and males. Thus, in females, measured substrate oxidation accounted for 99% of the leg oxygen uptake, whereas in males 28% of leg oxygen uptake was unaccounted for in terms of measured oxidized lipid substrates. These findings may indicate that males utilized additional lipid sources, presumably very low density lipoprotein-TG or TG located between muscle fibers. On the basis of RER and leg RQ, it is concluded that no gender difference existed in the relative contribution from carbohydrate and lipids to the oxidative metabolism across the leg during submaximal exercise at the same relative workload. However, an effect of gender appears to occur in the utilization of the different lipid sources.

scholarly journals The Sense-organs and Perceptions of Fishes; with Remarks on the Supply of Bait

1890 ◽  
Vol 1 (3) ◽  
pp. 225-256 ◽  
Author(s):  
W. Bateson
Keyword(s):  
Natural History ◽  
Sense Organs ◽  
Marine Animals ◽  
Practical Solution ◽  
Biological Association ◽  
Marine Biological ◽  
Marine Biological Association ◽  
History Of ◽  
Insight Into

The Council of the Marine Biological Association appointed me, in 1889, to make observations on the perceptions of fishes, and especially on those which constitute the modes by which they hunt for and recognise their food. It was suggested that this subject should be treated in as wide a manner as possible, and in accordance with this suggestion I have endeavoured to utilize any opportunities which presented themselves of getting an insight into the natural history of marine animals. In addition to this I have also made some experiments towards the practical solution of the bait question, both by making artificial baits, and by endeavouring to preserve materials which are already in use for bait.

scholarly journals Assessment of Acoustic Coherent Doppler and Cross-Correlation Techniques for Measuring Near-Bed Velocity and Suspended Sediment Profiles in the Marine Environment

2002 ◽  
Vol 19 (3) ◽  
pp. 367-380 ◽  
Author(s):  
Kyle F. E. Betteridge ◽  
Peter D. Thorne ◽  
Paul S. Bell
Keyword(s):  
Suspended Sediment ◽  
Marine Environment ◽  
Cross Correlation ◽  
Sediment Concentration ◽  
Transport Processes ◽  
Sediment Flux ◽  
Doppler Velocity ◽  
Acoustic Doppler Velocimeter ◽  
Flow Measurements ◽  
The Cross

Abstract The simultaneous measurement of current flow and suspended sediment concentration in the marine environment is central to the study of sediment transport processes. In view of this, two acoustic approaches for measuring flow were tested in a tidal estuary to assess their capabilities in this environment. A coherent Doppler velocity profiler and a cross-correlation velocity profiler were assessed using conventional current meters and a commercially available acoustic Doppler velocimeter. Mean velocity profiles were obtained up to a range of 1.47 m in 0.046-m range bins over a number of flood tides. The measurements compared well with the reference instruments and regression analysis produced gradients close to unity. Turbulent velocities measured with the coherent Doppler profiler were comparable with turbulent fluctuations measured with the acoustic Doppler velocimeter. The cross-correlation velocity profiler was shown to be unable to measure turbulent velocities. The backscattered signals received on the cross-correlation transducers were also used to compute the sediment concentration profiles using an explicit solution to the acoustic backscatter equation. Combining the concentration and flow measurements enabled sediment flux profiles to be obtained, the results of which compared favorably with flux measurements obtained from the conventional current meters and pumped sampling.

scholarly journals The function of the ampullae of Lorenzini, with some observations on the effect of temperature on sensory rhythms

1938 ◽  
Vol 125 (841) ◽  
pp. 524-553 ◽  
Keyword(s):  
Lateral Line ◽  
Cranial Nerves ◽  
Effect Of Temperature ◽  
Comprehensive Treatment ◽  
Lateral Line System ◽  
Sense Organs ◽  
Line System ◽  
Ampullae Of Lorenzini ◽  
History Of ◽  
Relationship Of

The recognition of the morphological and developmental relationship of the vertebrate auditory organ and the lateral-line system of fishes and aquatic Amphibia rests on the foundation of a large volume of com­ parative researches. The main outlines of this generalization were already laid down forty years ago, and Cole’s work on the cranial nerves and lateral sense organs of fishes (1898) contains a comprehensive treatment of the history of the subject. The acustico-lateral or neuromast system embraces, in addition to the labyrinth and the lateral-line canals, the pit organs found to a greater or less extent in most fishes, the vesicles of Torpedo , and the ampullary canal system of Selachians and Holocephali. Concerning these Cole wrote: “The history of our knowledge of the phylogeny of the sensory canals is coincident with three discoveries—the discovery that the‘mucus’ canals contain sense organs, the discovery of Savi’s vesicles, and the dis­covery of the ampullae of Lorenzini.... We now know that all three types belong to the lateral line system, and I shall suggest that they represent three stages in the development of a canal—the most superficial condition, represented by the pit organs and Savi’s vesicles; the full development, represented by the canal; and the intermediate type, forming neither a Savi vesicle nor yet a canal, represented by the ampullae of Lorenzini” (p. 187). This conception has remained valid to the present day. The ampullae of Lorenzini, with which I am here principally concerned, are briefly described in current text-books as transitional or specialized neuromasts, and the implication always is that structurally and functionally they do not differ significantly from the neuromasts of the lateral-line canals. For example, in their recent exhaustive treatise on the vertebrate nervous system Kappers, Huber and Crosby (1936) state with reference to the lateral-line canals, the Savi vesicles and the ampullae of Lorenzini: “thus in the various animals there is a transition between an open and a closed system for perceiving vibrations" (p. 438).

Sign in / Sign up

Export Citation Format

Share Document