Turtles

Question 1

Behavior of turtles

Answer 1

Swim to open sea, journey back to same beach! Use environmental cues to know which direction, direction not innate (east coast transplant)

Question 2

Sea finding in hatchlings

Answer 2

Use low bright horizon, go away from high dark silhouettes

Question 3

Swimming further into sea

Answer 3

swim into approaching waves, orient randomly without waves, use wave as orienting cues, circular orbital pattern

Question 4

Experiment to see if use magnetic cues

Answer 4

swim in simulated earth/reversed field
swam in the right/reversed direction based on field!

Question 5

Two ways to establish magnetic directional preference

Answer 5

Use light from when first exposed to ACQUIRE A MAGENTIC PREFERENCE, east/west, swim towards light
NOT INNATE MAGNETIC PREFERENCE
ALSO ACQUIRE MAG. PREF. BASED ON WAVE CUES
important to stay in gyre/stay alive

Question 6

Features of a magnetic field

Answer 6

Inclination angle, angle intersects earth, 0 at equator, 90 at poles (latitudes) (isoclinics)
Intensity, strongest at poles (isolines)

Question 7

How find where born

Answer 7

Use inclination angle lines to understand map, see where born based on inclination angle and intensity
create GPS sense of earth. isoclinic areas unique around the globe, use angle to sense where need to correct course
Imprint inclination/intensity of field at birthplace during crit period (isoclinic/isoline)

Question 8

Electromagnetic induction

Answer 8

body is conductive, magnetic field induces current for electroreceptors, turtles DONT HAVE THESE

Question 9

Magnetite

Answer 9

Clusters of crystals attract/repel based on field and open mechanoreceptor ion channels,
transduce magnetic info into neural info
maybe in turtles

Question 10

Chemical Magnetoreception

Answer 10

Magnetic field influences spin of electron during reactions, maybe in photoreceptors, theoretical