Evolution - Learning assignment 2, the evolution of the eye

Question 1

What are the stages in order of the eye’s evolution?

Answer 1

Nondirectional photoreception
Directional photo reception
Low resolution vision
High resolution vision

Question 2

What does the stage of nondirectional photoreception involve?

Answer 2

Where the eye can detect light but not where its coming from
Organisms have just a few photoreceptor cells so they can respond to light

Question 3

What does the stage of directional photo reception involve?

Answer 3

The organism can sense light and its direction
They have a screening pigment, which partly shades/covers the photo receptors so they can detect which direction light is coming from

Question 4

What does the stage of low resolution vision involve?

Answer 4

Organisms can detect their own motion and avoid objects
They can have cup shaped eyes with more receptors
Or they can have compound eyes with additional cups that can produce images of objects

Question 5

What does the high resolution vison stage involve?

Answer 5

Animals can do complex tasks, which helps with things such as selecting mates and recognising predators and prey
Organisms have now developed sensory structures like lenses, corneas and irises which help to focus light onto the photoreceptors which helps make images with higher resolution