Animal Senses 9/2/16

Transcription

1 Animal Senses 9/2/16

2 Animal Senses 9/4/15

3 Fly Hair Cells

4 Animal hearing Elephants can hear lower frequencies than humans 10 Hz (humans 20 Hz) But not as high 12,000 Hz (humans 20,000 Hz)

5 Elephant Ears Ears are bigger & tougher Ear canal, ossicles, ear drum and cochlea Why might this be? A. Longer objects have lower natural frequencies B. Shorter objects have lower natural frequencies C. Does not affect how the ear works.

6 Animal Hearing Bats can hear higher frequencies than humans 114,000 Hz (humans 20,000 Hz) Ultrasound (defined by human ears) But not as low - 10,300 Hz (humans 20Hz)

7 Sound bounces off of solid objects

8 Listen for echoes Echolocators listen for the sounds bouncing back Have you heard of active SONAR? A. Yes, I know what it is B. Yes, I think I have some idea C. Yes, I have no idea what it is D. No, never heard of it

9 SONAR (SOund Navigation and Ranging) Uses the idea of sound bouncing back. Use speed of sound in (salt) water and delay to calculate distance. Echolocation is Nature s SONAR

10 Listen for echoes Most produce their own sounds (such as clicks) and listen for them to come back. They are active echolocators Active SONAR sends out beeps Passive SONAR listens for sounds but does not produce beeps, have to listen to what s already out there.

11 Human Echolocation All Humans do this subconsciously Does that make them active or passive echo locators? (not the folks on the videos, average humans like you and me) A. Active B. Passive C. Both

12 Listen for the delay The delay tells the brain how far away an object is. This is how dolphins and bats know how far away their prey is!

13 Speed of Sound 4.8 seconds to travel a mile in air 1.1 seconds to travel through water 0.25 or ¼ of a second to travel through solids!

14 What did you hear? How was the sound in the railing different from the sound you heard through the air? A. In the railing sound was a high pitched tink B. In the railing sound was like a gong or church bells C. In the railing sound was the same

15 Ear Buds If you listen to an ear bud 1 inch from your ear, it sounds lame. If you put it in your ear, you get full range beautiful sound. How does this work??

16 Ear Buds Vibrations go directly from speaker to your solid flesh and bone so low frequencies not lost. Uses your skull to amplify the sound via sympathetic vibration

17 Locating sounds

18 Elephants Very good at localizing sounds. Large space between ears Bigger time delay between right and left ear Bigger difference in loudness/intensity between right and left ear Extend ears perpendicularly to better localize One young Asian elephant who was tested could localize to 1 degree. Online Humans and Dolphins can also do this.

19 7 year old Indian Elephant Independence, KS Zoo 2.2 m tall 1.1 m between ears 50 L per test

20 Bat, Dolphin and Whale Communication Was it easier to see or hear the whales? A. See them B. Hear them

21 Bat, Dolphin and Whale Communication Sound travels well through the water but as you get deeper or further apart, it s hard to depend on the eyes.

22 Sound vs. Sight What detector do you think dolphins and whales use to hunt? A. Ears only B. Eyes only C. Ears and eyes primarily ears D. Ears and eyes primarily eyes

23 Echolocation vs. Sight Whales and dolphins have good vision. Whales and dolphins see better than bats, but both use echolocation as their primary tool.

24 Sound vs. Sight What detector do you think dolphins and whales use to hunt? A. Ears only B. Eyes only C. Ears and eyes primarily ears D. Ears and eyes primarily eyes

25 Light Eyes similar to ears in many ways Light energy/waves, enter eyes (instead of air vibrations) Cornea and lens focuses the light on the back of the eye (instead of vibrations traveling along bones into cochlea). Energy is sensed by cone and rod cells (instead of hair cells)

26 The Human Eye

27 Light Light energy/waves, enter eyes Cornea and lens focuses the light on the back of the eye Energy is sensed by cone and rod cells.

28 Rod Cells (green) Cone Cells (blue) False color image

29 Color Vision In dim light, are cones or rods more sensitive? A. Cones B. Rods C. Equal

30 Cones 3 types in humans 1. Sensitive to red 2. Sensitive to green 3. Sensitive to Blue

31 Color Sensitivity

32 Color Blindness I. Most People II. Red-blind III. Green-blind IV. Violet blind V. Totally color blind

33 Animal Color Vision

34 25 Electromagnetic Induction and Electromagnetic Waves

35 Electromagnetic waves Here s another representation of Electromagnetic waves. This one shows you examples of the size of the different waves and at what temperature an object must be to emit these waves.

36 How was all this discovered? One tiny bit at a time! Galileo, an Italian astronomer and physicist, was the greatest contributor to our understanding of sound. He demonstrated that the frequency of sound waves determined the pitch. This was done by scraping a chisel across a brass plate producing a screech. Galileo then related the spacing of the grooves induced by the chisel to the pitch of the screech.

37 How was all this discovered? One tiny bit at a time! Leonardo DaVinci - (1500) discovered that sound travels in waves Marin Mersenne - (1640) first measured the speed of sound in air. Robert Boyle - (1660) discovered that sound waves must travel in a medium Sir Isaac Newton - (late 1660's) relationship between the speed of sound and the density and compressibility of the medium. Daniel Bernoulli - (mid 1700's) explained that a string could vibrate at more than one frequency.

38 Acousticians Architectural acousticians Instrument makers Concert hall designers Speech scientist Hearing specialist Medical acoustics Animal bioacousticians Underwater acousticians

39 Career Profiles Read a career profile Each person in the group describes their scientist to the rest of the group.