1.4 | Importance of Responses to Stimuli in Animals

1.4 | Importance of Responses to Stimuli in Animals

Stereoscopic and Monocular Visions

Stereoscopic vision

  • Both eyes located in front of the head.

  • A narrow field of vision

  • Fields of vision overlap to a great extent. Overlapping fields of vision produce vision in three dimensions

  • Three dimensional images formed in the overlapping fields of vision allow the distance, size and depth of objects to be estimated accurately.

  • The ability to estimate distance accurately helps animals to hunt.

  • Humans and most predators have stereoscopic vision

Monocular vision

  • Both eyes located at the sides of the head

  • A wide field of vision

  • Fields of vision do not overlap or overlap only slightly

  • Two dimensional images formed in the non-overlapping fields of vision prevent the distance, size and depth of objects from being estimated accurately.

  • A wide fi eld of vision helps animals to detect their enemies coming from any direction.

  • Most prey have monocular vision.

Stereophonic Hearing

  • Stereophonic hearing is hearing using both ears.

  • Stereophonic hearing allows us to determine the direction of the sound accurately.

  • Human ear are limited to the range of 20 Hz to 20 000 Hz.

  • Different animals can hear sounds of different frequencies.

Dog

67 - 45000 Hz

Mouse

200 - 76000 Hz

Bat

2000 - 1110000 Hz

Dolphin

150 - 150000 Hz

Sensory Organs Ensure the Survival of Animals on Earth

Porcupine

Quills respond when being attacked. That protect them against predators.

Electric ell

Producing electric field to determine the direction & changes in the environment

Beetle

Secretion of pheromone helps in finding a partner

Fish

Lateral line detects water changes, traces of prey & assists movement.