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.