Question

List five characteristics, in order from ancestral to derived that occurred during the eye development.

From early chordates' light sensitive pits to the current spherical evolved eye, in sharks for example.

Answer 1

Answer:

In order to from ancestral to derived, characteristics of eye development:

• Acuity: Visual acuity. Visual acuity (VA) is acuteness or clearness of vision, especially form vision, which is dependent on the sharpness of the retinal focus within the eye, the sensitivity of the nervous elements, and the interpretative faculty of the brain.
• Faces: When comparing facial features across species, it was found that infants of six months were better at distinguishing facial information of both humans and monkeys than older infants and adults. They found that both nine-month-olds and adults could discriminate between pictures of human faces; however, neither infants nor adults had the same capabilities when it came to pictures of monkeys. On the other hand, six-month-old infants were able to discriminate both facial features on human faces and on monkey faces. This suggests that there is a narrowing in face processing, as a result of neural network changes in early cognition.
• Depth perception: Depth perception is the visual ability to perceive the world in three dimensions (3D) and the distance of an object
• Color sensitivity: Color sensitivity improves steadily over the first year of life for humans due to strengthening of the cones of the eyes. Like adults, infants have chromatic discrimination using three photoreceptor types: long-, mid- and short-wavelength cones. These cones recombine in the precortical visual processing to form a luminance channel and two chromatic channels that help an infant to see color and brightness. The particular pathway used for color discrimination is the parvocellular pathway
• Light sensitivity: The threshold for light sensitivity is much higher in infants compared to adults. From birth, the pupils of an infant remain constricted to limit the amount of entering light. In regards to pupil dimensions, newborn's pupil grow from approximately 2.2 mm to an adult length of 3.3 mm.[2] A one-month-old infant can detect light thresholds only when it is approximately 50 times greater than that of an adult. By two months, the threshold decreases measurably to about ten times greater than that of an adult. The increase in sensitivity is the result of lengthening of the photoreceptors and further development of the retina. Therefore, postnatal maturation of the retinal structures has led to strong light adaptations for infants.