3. Evolution of Vision Flashcards
Vertebrates have __________ eyes
___________ have camera-type eyes
Invertebrates have _________ eyes, formed by __________
___________ have compound eyes, formed by ommatidia
Describe the structure of camera-type eyes (3 points)
- Each eye has one lens
- Light is absorbed in retina
- Ciliary photoreceptors
What am I?
Describe the structure of compound eyes (3 points)
- Many lenses, one for each ommatidia
- Light is absorbed in rhabdomes
- Rhabdomeric photoreceptors
Reverse card!
___________ have camera-type eyes
Vertebrates have __________ eyes
Reverse card!
___________ have compound eyes, formed by ommatidia
Invertebrates have _________ eyes, formed by __________
Reverse card!
- Each eye has one lens
- Light is absorbed in retina
- Ciliary photoreceptors
What am I?
Describe the structure of camera-type eyes (3 points)
Reverse card!
- Many lenses, one for each ommatidia
- Light is absorbed in rhabdomes
- Rhabdomeric photoreceptors
Describe the structure of compound eyes (3 points)
What is this? Name and define.
- Rhabdomeric photoreceptor
- Microvillar
- The photoreceptor of invertebrates
What is this? Name and define.
- Ciliary photoreceptor
- Rods and cones
- The photoreceptor of vertebrates.
Rhabdomeric photoreceptors correspond with ______ in evolutionary lineage.
__________ photoreceptors correspond with protosomes in evolutionary lineage.
Protosomes and deuterosomes separated how long ago?
These two lineages of animals separated 580 million years ago.
Name three types of animal that have ciliary AND rhabdomeric photoreceptors.
- Lancelet
- Some molluscs
- Annelids
All have what?
Melanopsin
Pigment of rhabdomeric origin found in the human retina (less than 1% of ganglion cells). It tells us whether it’s night or day.
Describe a primitive form of spatial vision, e.g. the kind a starfish has.
____________ can be achieved by shielding photoreceptors from light with pigment epithelium. The eye can then detect what direction the light is coming from.
Many animals, like __________ have this kind of vision.
When did proper spatial vision and eyes appear?
____________ appeared during the Cambrian explosion, 503 million years ago.
When did vertebrate eyes evolve?
____________ evolved around 500 million years ago, before the separation of jawed and jawless vertebrates.
How do we know that the vertebrate eye evolved 500 million years ago?
The lamprey, a jawless vertebrate, has a similar retina structure to us. This means that _______________ years ago, before the seperation of jawed and jawless vertebrates.
_______ are the first animal with a photoreceptor structure similar to ours. They diverged from the ________, our evolutionary ancestors, ___________ years ago.
Tunicates (sea squits), are _______________. They diverged from the Craniates, our evolutionary ancestors, 550 million years ago.
How do we know that cones evolved before rods?
Lampreys have cones, but no rods. This tells us that ____________
The two routes of eye evolution in molluscs are _________. The only well known developed ________ eye is the ___________.
The lens route and the pinhole route are the ___________. The only well known developed pinhole eye is the Nautilus eye.
In terrestrial eyes, most refraction happens _________.
In __________ eyes, most refraction happens at the cornea.
In aquatic eyes, most refraction happens _________.
In __________ eyes, most refraction happens on the lens.
Terrestrial eyes have… (2 points)
- Curved cornea
- Oval lens
What am I?
Aquatic eyes have… (2 points)
- flatter cornea
- spherical lens
Reverse card!
__________ photoreceptors correspond with protosomes in evolutionary lineage.
Rhabdomeric photoreceptors correspond with ______ in evolutionary lineage.
Reverse card!
These two lineages of animals separated 580 million years ago.
Protosomes and deuterosomes separated how long ago?
Reverse card!
- Lancelet
- Some molluscs
- Annelids
All have what?
Name three types of animal that have ciliary AND rhabdomeric photoreceptors.
Reverse card!
Pigment of rhabdomeric origin found in the human retina (less than 1% of ganglion cells). It tells us whether it’s night or day.
Melanopsin
Reverse card!
____________ can be achieved by shielding photoreceptors from light with pigment epithelium. The eye can then detect what direction the light is coming from.
Many animals, like __________ have this kind of vision.
Describe a primitive form of spatial vision, e.g. the kind a starfish has.
Reverse card!
____________ appeared during the Cambrian explosion, 503 million years ago.
When did proper spatial vision and eyes appear?
Reverse card!
____________ evolved around 500 million years ago, before the separation of jawed and jawless vertebrates.
When did vertebrate eyes evolve?
Reverse card!
The lamprey, a jawless vertebrate, has a similar retina structure to us. This means that _______________ years ago, before the seperation of jawed and jawless vertebrates.
How do we know that the vertebrate eye evolved 500 million years ago?
Reverse card!
Tunicates (sea squits), are _______________. They diverged from the Craniates, our evolutionary ancestors, 550 million years ago.
_______ are the first animal with a photoreceptor structure similar to ours. They diverged from the ________, our evolutionary ancestors, ___________ years ago.
Reverse card!
Lampreys have cones, but no rods. This tells us that ____________
How do we know that cones evolved before rods?
Reverse card!
The lens route and the pinhole route are the ___________. The only well known developed pinhole eye is the Nautilus eye.
The two routes of eye evolution in molluscs are _________. The only well known developed ________ eye is the ___________.
Reverse card!
In __________ eyes, most refraction happens at the cornea.
In terrestrial eyes, most refraction happens _________.
Reverse card!
In __________ eyes, most refraction happens on the lens.
In aquatic eyes, most refraction happens _________.
Reverse card!
- Curved cornea
- Oval lens
What am I?
Terrestrial eyes have… (2 points)
Reverse card!
- flatter cornea
- spherical lens
Aquatic eyes have… (2 points)
Describe what is happening in this image.
In terrestrial eyes, most refraction happens at the cornea. But water has a high refractive index, so underwater, there’s more refraction - and the light isn’t focused on the retina, it’s focused behind it, so underwater, things look blurry.
Describe what is happening in this image.
In aquatic eyes, most refraction happens on the lens. Because of the high refractive index of water, aquatic creatures have a lens with a lower radius of curvature, which bends light stronger, so that its focused on the retina.
Out of water, vision would be blurry because the light would be focused in front of the retina.
How has the rock pool fish adapted to seeing in air and water?
Flat faced goggles in all directions.
What am I?
How has the diving duck adapted to seeing in air and water?
Soft lens squishes through the iris when it dives to achieve higher curvature.
What am I?
How has the four-eyed fish adapted to seeing in air and water?
It has two retinas (one that receives light from the air, and one that receives light from the water), and an oval lens that is flatter on the side above the water, and more curved on the side below the water.
What am I?
High resolution usually requires large eyes because we need:
- 2.
_____________ usually requires ___________ because we need:
- large focal distance
- large pupil (to avoid diffraction, must be much larger than wavelength of light).
How do birds of prey achieve high resolution?
_______________ by using a telescope that increases the effective focal distance.
Birds of prey have high spatial resolution in the _______. The rest of the eye has normal spatial resolution.
Birds of prey have ___________ in the fovea. The rest of the eye has ____________.
Owls have _________ eyes because __________.
This comes at the cost of periphery - they can’t move their eyes more than a few degrees, so have to rotate their head instead.
Owls have tubular shaped eyes because spherical eyes with such a focal length would not fit in the head.
This comes at the cost of ______________.
Big eyes are good for __________, but _____________.
Horse eyes are very big, but the behavioural resolution of a horse eye is 2.5 times worse than that of a human.
Big eyes are good for increasing sensitivity, but they don’t always mean good vision.
Horse eyes are very big, but the _______________ of a horse eye is ___________ than that of a human.
Why is the optical design of compound eyes inferior to the optical design of camera-type eyes?
Compound eyes have many pupils, and to achieve good resolution, each pupil would need a large diameter.
To achieve the resolution of a human eye, the compound eye would have to have 2mm ommatidia, and it would be enormously large.
This means that the _______________ is inferior to _______________.
Describe an apposition eye.
- the photoreceptors of each ommatidium receive light exclusively from that ommatidium’s lens.
- Most diurnal insects have this type of eye.
What am I?
Describe a superposition eye.
- light from many lenses is focused onto each photoreceptor, which dramatically increases light capture.
- Most nocturnal insects have this type of eye.
What am I?
What are the two types of compound eyes?
Apposition and superposition are ______________.
What type of eye does a dung beetle have?
Name an insect with superposition eyes.
Three properties of mantis shrimp vision:
I have…
- Apposition eyes
- 12 dimensional colour vision
- The ability to see linear and circular polarisation
What am I?
Reverse card!
Flat faced goggles in all directions.
What am I?
How has the rock pool fish adapted to seeing in air and water?
Reverse card!
Soft lens squishes through the iris when it dives to achieve higher curvature.
What am I?
How has the diving duck adapted to seeing in air and water?
Reverse card!
It has two retinas (one that receives light from the air, and one that receives light from the water), and an oval lens that is flatter on the side above the water, and more curved on the side below the water.
What am I?
How has the four-eyed fish adapted to seeing in air and water?
Reverse card!
_____________ usually requires ___________ because we need:
- large focal distance
- large pupil (to avoid diffraction, must be much larger than wavelength of light).
High resolution usually requires large eyes because we need:
- 2.
Reverse card!
_______________ by using a telescope that increases the effective focal distance.
How do birds of prey achieve high resolution?
Reverse card!
Birds of prey have ___________ in the fovea. The rest of the eye has ____________.
Birds of prey have high spatial resolution in the _______. The rest of the eye has normal spatial resolution.
Reverse card!
Owls have tubular shaped eyes because spherical eyes with such a focal length would not fit in the head.
This comes at the cost of ______________.
Owls have _________ eyes because __________.
This comes at the cost of periphery - they can’t move their eyes more than a few degrees, so have to rotate their head instead.
Reverse card!
Big eyes are good for increasing sensitivity, but they don’t always mean good vision.
Horse eyes are very big, but the _______________ of a horse eye is ___________ than that of a human.
Big eyes are good for __________, but _____________.
Horse eyes are very big, but the behavioural resolution of a horse eye is 2.5 times worse than that of a human.
Reverse card!
Compound eyes have many pupils, and to achieve good resolution, each pupil would need a large diameter.
To achieve the resolution of a human eye, the compound eye would have to have 2mm ommatidia, and it would be enormously large.
This means that the _______________ is inferior to _______________.
Why is the optical design of compound eyes inferior to the optical design of camera-type eyes?
Reverse card!
- the photoreceptors of each ommatidium receive light exclusively from that ommatidium’s lens.
- Most diurnal insects have this type of eye.
What am I?
Describe an apposition eye.
Reverse card!
- light from many lenses is focused onto each photoreceptor, which dramatically increases light capture.
- Most nocturnal insects have this type of eye.
What am I?
Describe a superposition eye.
Reverse card!
Apposition and superposition are ______________.
What are the two types of compound eyes?
Reverse card!
Name an insect with superposition eyes.
What type of eye does a dung beetle have?
Reverse card!
I have…
- Apposition eyes
- 12 dimensional colour vision
- The ability to see linear and circular polarisation
What am I?
Three properties of mantis shrimp vision:
Ciliary photoreceptors correspond with __________.
_________ photoreceptors correspond with deuterosomes.
Reverse card!
_________ photoreceptors correspond with deuterosomes.
Ciliary photoreceptors correspond with __________.
