1. Animal Eye Adaptations
Lesson 29 - Animal Eye Adaptations
Animal Eye Adaptations
Herbivores vs. Carnivores
Evolution of the Eye

2. Animal Eye Adaptations
Different animals have evolved differently overtime. As each animal became more specialized to fulfill its role in the ecosystem, the animal that had the best adaptation for vision to serve that purpose dominated

3. Herbivores vs. Carnivores
Herbivores need to be aware of their surroundings
Plant eaters are low on the food chain so they need to be able to see all around to make sure that animals are not hunting them
Therefore, most herbivores have eyes mounted on the side of their head for a wider field of view (MONOCULAR VISION)

4. Herbivores vs. Carnivores
Carnivores need to be able to hunt and chase prey
Meat eaters don’t need to worry as much about keeping an eye out for other predators. They need better depth perception for hunting animals
Therefore, most carnivores have eyes mounted on the front of their head for accuracy (BINOCULAR VISION)

5. Monocular vs. Binocular
Monocular vision means that only one eye “sees” the field of view
Binocular vision means that two eyes “see” the field of vision

6. Monocular vs. Binocular

7. Inbetweeners
Animals that are both predator and prey usually have their eyes placed in the middle of some sort depending on how much they need to defend or hunt in their life

8. Monocular vs. Binocular
MONOCULAR PRO
Spreading the eyes out allows the animal to see a wider field of view (almost 360 degrees in some cases)
MONOCULAR CON
Only having one eye on an area decreases the depth perception and the animal only sees that area in 2-D
BINOCULAR PRO
Keeping the eyes close allows the animal to have a great depth perception and see in 3-D
BINOCULAR CON
Keeping the eyes close together decreases the field of view to usually 180 degrees or less

9. Nocturnal Animals NOCTURNAL ANIMALS
Use RODS more than cones to see at night because they are activated in low light and at night there isn’t much light
DAY ANIMALS
Use CONES more than rods because cones are activated in bright light and there is lots of available light during the day…They also can see in colour

10. Nocturnal Animals
At night, there is very little light available so pupil dilation is key for nocturnal animals because they need to open up a larger area to collect as many light rays as possible.
Some animals control there pupil size by using muscles not fixed in the center of the eye but to the outer edge which allows them to open the iris even more

11. Using Other Light
Honey Bee’s eyes are tuned into to pickup UV wavelengths of light rather than the visible spectrum wavelengths that we see… WHY?
Mosquitoes and Snakes “see” Infrared (heat) wavelengths which allows them to see their warm blooded prey even where there isn’t much light

12. Lenses & Photoreceptors
Thicker lenses allow the animal to adjust to see further i.e. the eagle and its ability to use its very fat lens and the cornea to focus light
More photoreceptors means the animal can see in greater detail (increase the resolution of the eye just like a better digital camera)

13. From Science in Action 8

14. For the Test
You will need to be able to remember the key points we covered to day
You must use what you know about vision and light to make predictions as too why animals “see” the way they do
The test is coming quickly so work on your cheat sheet