Week 2 - Vision and Colour Pt 2

Question 1

Counter-shading function and what it is

Answer 1

dorsal (top) is dark (melanophores)
ventral (belly) is light
difficult to see from top

Question 2

Mirror siding function and what it is

Answer 2

scales made of iridiophores reflect light, difficult to see from sides (Mirror)

Question 3

If a fish has both counter-shading and mirror-siding, what side can be seen?

Answer 3

Can see bottom from below

Question 4

Where is dorso-ventrally compressed hard to see from?

Answer 4

bottom, casts big shadow

Question 5

What does laterally compressed hide from?

Answer 5

look straight on and bottom up

Question 6

Counter illumination function and what it is

Answer 6

produces own light from photophores to hide dark bottom

Question 7

How is counter illumination done?

Answer 7

Photophores

Question 8

Why may sensitivity of female change and when?

Answer 8

May change to bright colours during breeding season or humming etc.

Question 9

What may UV light be useful for other than foraging?

Answer 9

Mating

Question 10

What enzyme causes bioluminescence?

Answer 10

Luciferase changes the conformation of luciferin releasing photos

Question 11

What wavelength is most common photons fish produce in bioluminescence?

Answer 11

Short wavelengths

Question 12

Why are rods more important in deeper water than cones?

Answer 12

Dark waters require more rods that are sensitive to light

Question 13

2 ways to produce light

Answer 13

1. bacteria-fish symbiosis

2. Make own light

Question 14

Symbiosis in bacteria-fish symbiosis

Answer 14

fish gets light, bacteria gets safe environment and resources

Question 15

How can fish control photophores of bacteria-fish symbiosis?

Answer 15

flipping the photophore or covering it to hide illumination

Question 16

What is the function of having a different shifted bioluminescence light?

Answer 16

communication and detection of fish that can detect specific light

Question 17

Eutrophication definition

Answer 17

body of water enriched in nutrients and decreases light transmission, disrupts light travelling through water

Question 18

What are some human caused sedimentation?

Answer 18

erosion, logging and land changes can increase merkiness

Question 19

Mating issues from increased turbidity

Answer 19

Cichlids have been seen to increase the number of hybrids in higher turbitidity waters due to limited visibilities

Question 20

Foraging issues from increased turbidity

Answer 20

Limited visibilities causes difficulty in finding prey

Question 21

How can sedimentation increase affect habitats

Answer 21

Can cause habitats to shift

Question 22

How can sedimentation increase affect surfacing times

Answer 22

Less oxygen in water causing fish to surface more and more vulnerable to being eaten by birds

Question 23

Light pollution by humans can increase what

Answer 23

Predation risk and stress levels (cortisol levels)

Question 24

How can light pollution affect reproduction

Answer 24

decrease sex hormones and no signals for eggs to hatch

Question 25

Fungicides effect on reproduction

Answer 25

affects colour of fish which decreases males chance to mate

Question 26

Steroids effect on reproduction

Answer 26

sneaking mating increases and less selective reproduction, forced mating which decreases mating with quality males