Lecture 9 Perception

Transcription

1 Lecture 9 Perception

2 Perception 1. Hearing 2. Smell 3. Vision 4. Lateral line 5. Electroreception 6. Touch and Taste

3 Hearing Important in mating, prey detection, and predator avoidance We will focus on hearing in bony fishes

4 Hearing teleost Otolith ear stone solid bone deposit surrounded by sensory hair cells gravity pulls down and excites sensory hair cells also vibrate due to sound dense otoliths take longer to vibrate & difference triggers excitation of auditory nerves

5 Hearing teleost Gas Bladder sound waves vibrate gas filled spaces enhances sound detection largest group of hearing specialist = Otophysans (>74% of freshwater spp.) Weberian apparatus

6 Hearing Mating calls identify sexes & conspecifics hamlets (Serranidae)

7 Geomagnetic reception? Not much known about how this is achieved Lagenal otolith is a good candidate small & very high iron content

8 Smell Organs of smell contained within olfactory chambers incurrent and excurrent nostril cilia move water across used to locate habitat, mates, prey, and to avoid predation

9 Smell Hammerhead stereochemoreception

10 sensitivity depends on what the animal uses its sense of smell for Smell

11 Smell Schreckstoff alarm and reaction -Ostariophysi

12 Vision Fishes photoreceptors correlates with habitat Photoreceptors Rods sensitive to low light Cones greater resolution several types sensitive to variable wavelengths

13 Vision Teleosts diameter of pupil is fixed deep sea fishes have wide pupils Diretmus argenteus Anableps spp.

14 Vision Elasmobranchs have a muscular iris and can control the amount of light that enters

15 Vision male panuco swordtail Xiphophorus nigrensis Species can detect UV sensitive photoreceptors UV-reflective markings on its tail that drives the ladies crazy but predators can t see it

16 Vision Sauron the deceiver aka comet fish Calloplesiops altivelis fishes use visual mimicry to deceive e.g., ocelli (false eye)

17 Vision Sensory bias results in divergent displays Reflectance H. caryi Wavelength E. lateralis

18 Lake Victoria Cichlids Vision -mechanism & maintenance Cichlids can interbreed without loss of fertility isolated by mate choice Assortative mating is strongly determined by coloration Dull coloration, few color morphs, and low species diversity are characteristic of turbid areas

19 shape discrimination among various fishes Vision

20 Lateral line neuromasts detects vibrations prey, predators, other fish, or obstacles

21 Lateral line lantern fish blind cavefish relies on lateral line system more than any other sense lake trout

22 Lateral line On some sharks, lateral line extends to head Can detect where the prey is coming from and relative speed

23 Lateral line Developing lateral line in Zebrafish (Danio rerio) stained for neuronal connections

24 lateral line placement gives clues to fishes ecology prey predators habitat Lateral line

25 Electroreception Derived from sensory hair cells found in lateral lines Two main receptor types: Ampullary receptors responsible for passive electrorecption Tuberous receptors only found in fishes that use electric organs to generate electric field

26 Electroreception Ampullary receptors widespread among fishes lampreys, chondrichthyes, lungfishes, coelacanths, sturgeons, paddlefishes, osteoglossiformes, gymnotiformes, & siluriformes particularly abundant on elasmobranchs identified as ampullae of Lorenzini who has higher density?

27 Electroreception - density can change w/ development

28 Electroreception Tuberous receptors responsible for active electrorecption detection electric field produced by fishes own electric organ only in freshwater fishes mormyrid elephantfishes & gymnotiform knifefishes

29 mormyrid elephantfishes Electroreception gymnotiform knifefishes

30 Electroreception Mormyriform elephantfishes use EODs for: orientation Electric organ discharge (EOD) territorial interactions species ID individual recognition courtship communicate social status

31 Electroreception Elephant fish Electric eel likely convergence

32 Touch and Taste Taste probably the least developed sense in fishes used primarily for food recognition in and around mouth (lips & barbels) and in some cases fins The gurnard uses both

33 Touch and Taste