Symmetry, Locomotion, and the Evolution of an Anterior End: A Lesson From Sea Urchins

Grabowsky, Gail L.

doi:10.1111/j.1558-5646.1994.tb05300.x

Cited by 13 publications

(4 citation statements)

References 16 publications

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“…Like most animals, our robots are bilaterally symmetrical. We built this constraint into our robots because bilateral symmetry is known to help with forward locomotion 20 . The lefthand 2 × 4 × 3 = 24 resting voxel lengths are reflected on the other, righthand side of the midsagittal line, yielding 24 independent resting lengths.…”

Section: Resultsmentioning

confidence: 99%

How morphological development can guide evolution

Kriegman

Cheney

Bongard

2018

Sci Rep

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Organisms result from adaptive processes interacting across different time scales. One such interaction is that between development and evolution. Models have shown that development sweeps over several traits in a single agent, sometimes exposing promising static traits. Subsequent evolution can then canalize these rare traits. Thus, development can, under the right conditions, increase evolvability. Here, we report on a previously unknown phenomenon when embodied agents are allowed to develop and evolve: Evolution discovers body plans robust to control changes, these body plans become genetically assimilated, yet controllers for these agents are not assimilated. This allows evolution to continue climbing fitness gradients by tinkering with the developmental programs for controllers within these permissive body plans. This exposes a previously unknown detail about the Baldwin effect: instead of all useful traits becoming genetically assimilated, only traits that render the agent robust to changes in other traits become assimilated. We refer to this as differential canalization. This finding also has implications for the evolutionary design of artificial and embodied agents such as robots: robots robust to internal changes in their controllers may also be robust to external changes in their environment, such as transferal from simulation to reality or deployment in novel environments.

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Section: Resultsmentioning

confidence: 99%

How morphological development can guide evolution

Kriegman

Cheney

Bongard

2018

Sci Rep

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“…The complementarity of sensing to locomotion is an ancient pattern stretching back to the early appearance of the bilateral animal body plan. In this body plan, bilateral symmetry, which often [22] includes high forward mobility along the midline axis, is closely coupled with a clustering of sensory organs around the head. All vertebrates and most other highly mobile animals such as insects feature this body template.…”

Section: Codesign Of Body Plan Sensor Geometry Control and Mementioning

confidence: 99%

Designing Future Underwater Vehicles: Principles and Mechanisms of the Weakly Electric Fish

MacIver

Fontaine

Burdick

2004

IEEE J. Oceanic Eng.

142

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Future underwater vehicles will be increasingly called upon to work in cluttered environments and to interact with their surroundings. These vehicles will need sensors that work efficiently at short range and be highly maneuverable at low speed. To obtain insights into principles and mechanisms of low-speed operation in cluttered environments, we examine a fish that excels in this regime, the black ghost knifefish Apteronotus albifrons. This fish hunts in dark or turbid water using a short-range self-generated electric field to sense its surroundings. Coupled with this unique mode of sensing is an unusual ribbon fin propulsion system that confers high multidirectional maneuverability at low speeds. To better understand the relationship between body morphology and common maneuvers of this fish, we utilized an idealized ellipsoidal body model, Kirchhoff's equations, and an optimal control algorithm for generating trajectories. We present evidence that common fish trajectories are optimal, and that these trajectories complement the sensory abilities of the fish. We also discuss prototypes of the sensing and propulsion systems of the fish with a view to providing alternative approaches for underwater vehicle design where high maneuverability in geometrically complex environments is needed.

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“…is the mean vector angle, g is the angle of the undirected axis of the grand mean; angles were given in degrees which forward they preferably proceed (Parker 1936;Grabowsky 1994). This was conWrmed here.…”

Section: Discussionmentioning

confidence: 98%

Do regular sea urchins show preference in which part of the body they orient forward in their walk?

2012

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Regular sea urchins, which have pentaradial symmetry, have been believed to show no preference in which part of the body forward they proceed with. Through use of circular statistics, we show that the regular sea urchin Hemicentrotus pulcherrimus had no preference with respect to what body part, as determined by Lovén's system, should be anterior in locomotion. The sea urchins, however, preferably proceeded with the body part, which had contacted with the aquarium walls at rest, forward. When the contact part was artiWcially altered, the body part facing forward in the following proceeding changed accordingly: the animals walked with the part that had contacted last forward. The biological signiWcance of this behavior was discussed in relation to the aggregation formation and homing behavior.

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Symmetry, Locomotion, and the Evolution of an Anterior End: A Lesson From Sea Urchins

Cited by 13 publications

References 16 publications

How morphological development can guide evolution

How morphological development can guide evolution

Designing Future Underwater Vehicles: Principles and Mechanisms of the Weakly Electric Fish

Do regular sea urchins show preference in which part of the body they orient forward in their walk?

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