Sensation & Control

Sensation & Response without Nerves

Cnidaria: Cnidocyte discharge

Sensation & response without nerves

• Ctenophore apical organ

Sensation & Control: generalized insect ns

Mechanoreceptors

• Insect haltere 335 strain

receptors, 11 muscles – functions as a gyroscope, detecting slight changes in pitch, etc. transmitting to the brain, eyes, and some directly to wing pitch muscles

Crustacean Sensory Systems

• Lobster Statocyst

• Copepod median eye

Chemorecptors

• Molluscan Osphradium

• A) marine gastropod

• B) marine pelagic gastropod

Mixed sensory structures

• Insect Sensilla

Mixed Sensory Structures

• Cnidarian Rhopalium

Photosensory

• Annelid eyes

Photosensory

• Cephalopod camera eye

Photosensory

• Compound Eye Ommatidia dark/light adapted appositional & superpositional eyes

Photosensory

• Neural Superpositional eye

Nervous Systems

Nerve Net & Nerve Ring in Hydra oligactis

From: Koizumi 2007 Brain Behav Evol 69:151-159

Hydra Nerve Ring Function

Possible origin of a Central Nervous System?

From: Koizumi 2007 Brain Behav Evol 69:151-159

Central Nervous Systems

Squid Giant Axons

Crayfish escape reflex: fixed action pattern

• Tail flip

Processed ResponseMoth & Bat 1

• Sensory neurons with different thresholds

Processed ResponseMoth & Bat 2

Moth & Bat 3

• Comparisons of a1 signals from different sides and in relation to wing position.

• Responses

adjusted.

Processed response: problem solving

• Jumping Spider• Detour experiments

Processed Response: Learning – memory input

• Octopus

Cephalopod Responses

• Skin coloration I

Cephalopod Responses

• Skin coloration 2

• CNS control

Cephalopod Response

Skin coloration organized, along with skin texture and body posture, to create repeatable patterns

Bobtail Squid (Euprymna scolopes) Light Organ

• Light is provided by a luminous bacterial symbiont Vibrio fischeri

From: Nyholm and McFall-Ngai 2004 Nature reviews vol.2 August 2004

Bobtail Squid Light Organ II

• Young squid must pickup symbiont from the environment.

• The symbiont induces morphological changes in host creating functional light organ

From Nyholm & McFall-Nagai 2004 Nature vol.2 August

Bobtail squid light organ III

From Nyholm & McFall-Ngai 2004 Nature vol 2 August

Cephalopod communication

• Body Patterns