eye evolution (guest lecture ) - claremont collegesfaculty.jsd.claremont.edu/dmcfarlane... ·...
TRANSCRIPT
10/25/2012
1
Eye evolution (guest lecture )
Lars Schmitz 10/25/2012
Why don’t plants have eyes?
10/25/2012
2
Questions…
• How many times did eyes evolve?
• How long did it take to evolve an
eye?
• What makes a good eye?
• How does ecology influence the
evolution of eyes?
• Were some dinosaurs nocturnal?
• Why do giant squid and ichthyosaurs
have giant eyes?
• What fish have reduced eyes?
Questions…
• How many times did eyes evolve?
• How long did it take to evolve an
eye?
• What makes a good eye?
• How does ecology influence the
evolution of eyes?
• Were some dinosaurs nocturnal?
• Why do giant squid and ichthyosaurs
have giant eyes?
• What fish have reduced eyes?
10/25/2012
3
… about a third have light-sensitive
cells.
… about a third have proper eyes.
… about a third have no visual
specializations whatsoever.
Of the ~30 animal phyla …
“proper” eye: an organ able to compare light
intensities in different directions [spatial vision]
Turbellarian Flatworm
10/25/2012
4
Chambered Eyes
Scallop
10/25/2012
5
Vertebrate eyes
10/25/2012
6
Amniote Eye
California Condor
cornea
lens
iris
pupil
Retina
10/25/2012
7
Chambered Eyes
everse (octopus)
vs.
inverse (cod)
Cephalopod eyes
10/25/2012
8
Compound Eyes
10/25/2012
9
schizochroal
holochroal
abathochroal
10/25/2012
10
Questions…
• How many times did eyes evolve?
• How long did it take to evolve an
eye?
• What makes a good eye?
• How does ecology influence the
evolution of eyes?
• Were some dinosaurs nocturnal?
• Why do giant squid and ichthyosaurs
have giant eyes?
• What fish have reduced eyes?
To suppose that the eye, with all its inimitable contrivances for adjusting the focus to different distances, for admitting different amounts of light, and for the correction of spherical and chromatic aberration, could have been formed by natural selection, seems, I freely confess, absurd in the highest possible degree. (Darwin 1872)
Darwin on eye evolution
10/25/2012
11
Yet reason tells me, that if numerous gradations from a perfect and complex eye to one very imperfect and simple, each grade being useful to its possessor, can be shown to exist; if further, the eye does vary ever so slightly, and the variations be inherited, which is certainly the case; and if any variation or modification in the organ be ever useful to an animal under changing conditions of life, then the difficulty of believing that a perfect and complex eye could be formed by natural selection, though insuperable by our imagination, can hardly be considered real. (Darwin 1872, 143-144)
Darwin on eye evolution (next paragraph)
Time required to evolve an eye
10/25/2012
12
Questions…
• How many times did eyes evolve?
• How long did it take to evolve an
eye?
• What makes a good eye?
• How does ecology influence the
evolution of eyes?
• Were some dinosaurs nocturnal?
• Why do giant squid and ichthyosaurs
have giant eyes?
• What fish have reduced eyes?
Refractive
System
Receptors Neural Processing
(Retina + Brain)
Behavioral
Anatomical
Optical
10/25/2012
13
Visual
Capacity Resolution
Field of View
Sensitivity
Light PND
S
Quantifiable as
Spatial Sampling Frequency (SF)
PND: Posterior nodal
distance
S: Separation of
receptor centers
(min. ~2 µm)
SF = ____ PND
2·s
Land (1981)
Resolution
10/25/2012
14
Land and
Nilsson 2002 Spatial Sampling Frequency
Octopus
Aeschna
Nautilus
Aquila audax
Falco berigora
resolving power
behavioral: 132-143 c/deg
anatomical: 140 c/deg
resolving power
behavioral: 69-76 c/deg
anatomical: 76 c/deg
Reymond 1985,1987
(Wedge-tailed Eagle)
(Brown Falcon)
10/25/2012
15
Accommodation
Visual
Capacity Resolution
Field of View
Sensitivity
10/25/2012
16
Sensitivity to Point Light Sources
klr eer
EAN 1
16 2
2Sensitivity ~
monochromatic light
E: # of photons originating at source l: length of receptors
A: aperture k: peak absorption coefficient r: distance to light source α: combined attenuation coefficient
for given receptors, light distance and intensity
A2
Warrant (1999)
kl
klA
PND
d3.2
2
2
2
Sensitivity=
PND
A2
d: diameter of receptors
l: length of receptors
k: peak absorption coefficient
A: aperture
PND: posterior nodal distance
(for given receptor dimensions)
Land (1981)
Sensitivity to Extended Sources
10/25/2012
17
f-number
PND
A2
Sensitivity ~
f-number = PND
A
the lower the better
PND PND
A S
TRADE OFF
Resolution Sensitivity
SF = ____
2·s
PND F =
____ PND
A
for given eyeball size,
receptors, neural processing
10/25/2012
18
Visual
Capacity Resolution
Field of View
Sensitivity
Visual Fields
Martin et al. 2007
Apteryx sp.
(Kiwi)
10/25/2012
19
Steatornis caripensis
(Oilbird)
38°
Visual
Capacity Resolution
Field of View
Sensitivity
Contrast sensitivity
improved by 40% Visual threshold
improved by 40%
Trade Off
10/25/2012
20
Questions…
• How many times did eyes evolve?
• How long did it take to evolve an
eye?
• What makes a good eye?
• How does ecology influence the
evolution of eyes?
• Were some dinosaurs nocturnal?
• Why do giant squid and ichthyosaurs
have giant eyes?
• What fish have reduced eyes?
Bio-mechanics
Bio-optics
EVOLUTION
Physical constraints
10/25/2012
21
Light Levels Luminance [photons m-2 sr-1 s-1]
8 lo
g u
nit
s
water depth [m]
terrestrial marine 1
4 lo
g u
nit
s
Po
int
Lig
ht
So
urc
es
4
Starlight
Moonlight
Bright
Sunlight
6
10
8
12
14
16
18
20
1000
800
600
400
200
0
Epipelagic
Mesopelagic
Bathypelagic
Oil Bird
Scopelarchus guentheri
Martin et al. 2004
Warrant 2004
Retinal adaptations
Tapetum Lucidum IRS
10/25/2012
22
Tapetum Lucidum
Retinal adaptations
Apteryx mantelli
kiwifoundation.org.nz
inside
outside
10/25/2012
23
Retina
10/25/2012
24
Muraenidae
perco-
morphs
holo-
centrids elopo-
morphs
Holocentridae
perco-
morphs
holo-
centrids elopo-
morphs
10/25/2012
25
Apogonidae
perco-
morphs
holo-
centrids elopo-
morphs
Priacanthidae
perco-
morphs
holo-
centrids elopo-
morphs
10/25/2012
26
Sciaenidae
perco-
morphs
holo-
centrids elopo-
morphs
Pempheridae
perco-
morphs
holo-
centrids elopo-
morphs
10/25/2012
27
Haemulidae perco-
morphs
holo-
centrids elopo-
morphs
diurnal nocturnal
10/25/2012
28
Schmitz and Wainwright 2011 (BMC Evol. Biol.)
A
D x f
2
small large
A: Aperture
D: retinal area
f: focal length
aquatic
10/25/2012
29
Schmitz and Wainwright, 2011 (BMC Evol. Biol.)
Eye morphospace of reef fish
round, large
pupil;
large lens
large, elliptical
pupil;
small lens
small, elliptical
pupil
10/25/2012
30
Light sensitivity
large, elliptical
pupil;
small lens
round, large
pupil;
large lens
small, elliptical
pupil
Diurnal
IRS
IRS
IRS
Collared Lizard
Chipmunk
King Parrot
Flame Robin
Eastern Robin
10/25/2012
31
Leopard Gecko
Nocturnal
Crested Owl
ADW
IRS
Oilbird stanford.edu/~cagan/southamerica.htm
Brown Rat ADW
Cathemeral Crepuscular
Asian Elephant
BNAO
Common Nighthawk
BNAO
Giraffe giraffe.org
10/25/2012
32
A
D x f
2
small large
A: Aperture
D: retinal area
f: focal length
terrestrial
Eye morphospace
Discriminant Axis 1
Dis
cri
min
an
t Axis
2
95% confidence ellipses
mammals, n=35
birds, n=15
squamates, n=8
Variables: eyeball diameter,
axial length,
lens diameter
Schmitz and Motani 2010, Vision Res.
misclassified
proportion (pFDA):
13.4%
10/25/2012
33
Questions…
• How many times did eyes evolve?
• How long did it take to evolve an
eye?
• What makes a good eye?
• How does ecology influence the
evolution of eyes?
• Were some dinosaurs nocturnal?
• Why do giant squid and ichthyosaurs
have giant eyes?
• What fish have reduced eyes?
Weishampel et al. 2004
-mixed time periods-
10/25/2012
34
Weishampel et al. 2004
-mixed time periods-
Scleral Rings
Bubo
Osteology
and optics?
10/25/2012
35
Mammal Bird
Scleral ring
Scaphognathus
10/25/2012
36
Lens diameter
External scleral ring
Internal scleral ring
Axial length
Eyeball diameter Orbit length
Hard-tissue Soft-tissue
Orbit length External + internal
scleral ring
diameter
Schmitz 2009 (J. Morphol.)
diurnal
nocturnal
Schmitz and Motani 2011 (Science)
10/25/2012
37
Dinosauria
Archosauria
33 Mesozoic archosaur species
10/25/2012
38
Weishampel et al. 2004
-mixed time periods-
cathemeral/
crepuscular
equivocal (either
nocturnal or cathemeral/
crepuscular)
diurnal
nocturnal
8
14
9
2
Questions…
• How many times did eyes evolve?
• How long did it take to evolve an
eye?
• What makes a good eye?
• How does ecology influence the
evolution of eyes?
• Were some dinosaurs nocturnal?
• Why do giant squid and ichthyosaurs
have giant eyes?
• What fish have reduced eyes?
10/25/2012
39
10/25/2012
40
10/25/2012
41
10/25/2012
42
10/25/2012
43
10/25/2012
44
Point light sources
Extended luminous sources (form illumination)
10/25/2012
45
Extended non-luminous sources
10/25/2012
46
10/25/2012
47
Questions…
• How many times did eyes evolve?
• How long did it take to evolve an
eye?
• What makes a good eye?
• How does ecology influence the
evolution of eyes?
• Were some dinosaurs nocturnal?
• Why do giant squid and ichthyosaurs
have giant eyes?
• What fish have reduced eyes?
10/25/2012
48
Scytalina
Forbesichthys
10/25/2012
49
Ditropichthys
Melanocetus
Oneirodes
Bufoceratias