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Importance of Responses to Stimuli in 1.4 Animals Stereoscopic and Monocular Visions What is the importance Study Figure 1.30 to understand of the location of eyes to stereoscopic an...

Importance of Responses to Stimuli in 1.4 Animals Stereoscopic and Monocular Visions What is the importance Study Figure 1.30 to understand of the location of eyes to stereoscopic and monocular visions. humans and animals? Table 1.3 shows the characteristics and importance of stereoscopic and LIM monocular visions in animals. t
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monocular vision. Large Small overlap overlap Field of monocular vision Field of monocular vision Field of stereoscopic vision Field of stereoscopic vision (a) Stereoscopic vision (b) Monocular vision Figure 1.30 Stereoscopic and monocular visions 36 1.4.1  Chapter 1: Stimuli and Responses Table 1.3 Differences between stereoscopic and monocular vision Stereoscopic vision Monocular vision Both eyes located in front of the head. Both eyes located at the sides of the head. A narrow field of vision. A wide field of vision. Fields of vision overlap to a great extent. Fields of vision do not overlap or overlap only Overlapping fields of vision produce vision slightly. in three dimensions. Three dimensional images formed in the Two dimensional images formed in the non- overlapping fields of vision allow the distance, overlapping fields of vision prevent the distance, size and depth of objects to be estimated size and depth of objects from being estimated accurately. accurately. The ability to estimate distance accurately helps A wide field of vision helps animals to detect their animals to hunt. enemies coming from any direction. Humans and most predators have stereoscopic Most prey have monocular vision. vision. Stereophonic Hearing What is the importance of having a Source of sound pair of ears to humans and animals? Stereophonic hearing is hearing using both ears. Stereophonic hearing allows us to determine the direction of the sound accurately. Look at Figure 1.31. The importance of stereophonic hearing to humans is to determine Figure 1.31 Stereophonic hearing the location of a source of sound. Stereophonic hearing helps predators to determine the location of their prey. Conversely, stereophonic hearing also helps prey Based on the above to determine the location of their diagram, the ear which is LIM predators and to escape nearer to the source of from them. sound (right ear) receives sound earlier and louder than the other ear. BRAIN The difference in time and loudness of the TEASER sound received by both ears is detected by the brain which then allows us to determine How does the ear function as a the direction of the source of sound which is sense of ‘sight’ for the blind? from the right. 1.4.1 37 Hearing Frequencies of Animals I CAN Different animals can hear sounds of different frequencies REMEMBER! as shown in Figure 1.32. Frequencies of sounds that can be detected by the human ear are limited to the range of 20 Hz to 20 000 Hz. Sea lion 450 – 50 000 Hz Rat Dolphin 200 – 80 000 Hz 40 – 100 000 Hz Frequencies of hearing range Bat Elephant 2 000 – 110 000 Hz 16 – 12 000 Hz Dog 67 – 45 000 Hz Figure 1.32 Frequencies of hearing range of different animals Activity 1.11 Instructions 1. Work collaboratively in groups. CPS, ISS, ICS Technology- 2. Each group will be assigned by your teacher to create a based activity multimedia presentation such as MS PowerPoint or animation on one of the following topics: (a) Stereoscopic and monocular visions in animals (b) Stereophonic hearing (c) Different hearing frequencies for different animals 38 1.4.1  Chapter 1: Stimuli and Responses Sensory Organs Ensure the Survival of MARVELS OF Animals on Earth SCIENCE Animals such as ants, snakes, Responses to stimuli ensure the survival of animals on frogs and birds are believed to Earth. The sensory organs and responses of several animals be able to predict earthquakes. are shown in Photograph 1.23. Carry out Activity 1.12 to Scientists are investigating the investigate the sensory organs and responses of several types of stimuli detected by these other animals. animals before earthquakes occur. Sensory organ: Response: Lateral line Lateral Secretion of line Websites pheromone Electric field of an electric eel http://links.andl17.com/BT_ Science_39 Response: Producing electric field Photograph 1.23 Sensory organs and responses of animals Activity 1.12 To explain the sensory organs and responses of other animals on Earth ICS Discussion Instructions activity 1. Work in groups. 2. Each group is required to gather information on how responses of animals in Photograph 1.23 are able to ensure their survival on Earth. 3. Discuss the information gathered. 4. Present the outcome of the discussion of each group in class using multimedia presentation. Formative Practice 1.4 1. State two types of vision of animals. 2. State the factor that determines the type of vision of animals. 3. What is the type of vision of a primary consumer? Give your reasons. 4. What is the importance of stereophonic hearing? 5. In the dark, Azman can determine the location of a mewing cat. Explain how Azman is able to determine the location of the cat. 1.4.2 39