Seeing With Ears:The Echolocation
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This document presents information about echolocation in animals. It begins with an introduction to echolocation and mentions that bats, dolphins, and whales use this ability to navigate with sound. It then provides details on how echolocation works, such as bats emitting clicks and interpreting the echoes to locate objects. The document also discusses how animals like moths have evolved defenses against echolocating predators. Finally, it notes how technology has been inspired by echolocation abilities in nature, with examples including sonar, radar, and assistive devices for blind humans.
Seeing With Ears:The Echolocation
- 1. Presented By: Ravikash Maurya (14484sc038) Banaras Hindu University, Varanasi
- 2. This ppt was prepared for Seminar presentation purpose in M.Sc. semester IV In Department of Zoology Institute of Science Banaras Hindu University (BHU) Varanasi (India).
- 3. Ears are adopter of sound(signal) & Brain is interpreter of signal. This property is known as “Echolocation”. (Discovered by Griffin in 1938) A new trending term is “Biosonar”.
- 4. An Echo is a reflection of sound after hitting an object.
- 5. "Echolocation is a property of using echo to determine where objects are in space” In other words, with the help of echoes, the brain draw an image of the objects.
- 6. There are some animals who have developed property to Echo-locate objects without help of vision. The property of echolocation is well developed in mammals.
- 7. Bats Dolphins Whales Echolocating Animals Echolocation is Only found in Microchiropteran bats Echolocation help them for navigation & foraging in total darkness. Echolocation helps Whales to navigate where vision is extremely limited in range due to Absorption or Turbidity. Dolphin’s habitats have low visibility due to dirty water & Turbidity. Echolocation help them for foraging.
- 8. How do Animals echolocate?? The echolocating animals cry loud so that their sound become Echo after hitting the target. Animals Sound Echo Target
- 9. Principle Of Echolocation Echo locating bats emit sound Pulses(Clicks) of very high frequency and listen for returning echoes to form an auditory scene..
- 10. What a bat can detect by using echolocation o Distance(Range)- by comparing the time of emitted pulse to the time of the returning Echo. o Size- larger animals reflect more sound(high intensity) and smaller animal reflect less sound (low intensity). o Movement- by comparing amount of echo obtained on Left & Right ear. o Velocity- by taking advantage of Doppler Shift. Echo of higher frequency = Target is gaining. Echo of lower frequency = Target is outstanding.
- 11. Phases & Sequence of Echolocation Redrawn From: Simmons & Kick(1984) There are 4 steps in Prey capturing by bats- 1- Search 2- Approach 3-Track 4-Capture
- 13. You should not forget that echoes of other bats in a space create a noise. Then, how a bat recognize it’s own voice in noise? The “JAR” solves this problem. Noise of Other Bats Bat
- 14. Experimental Evidence of JAR What is JAR ? • Each bat change its sound frequency to increase the difference between the two bat's sound frequencies. • By doing this, they avoid jamming of echolocating calls. Experimental Evidence • Gillam et al had provided first experimental evidence of JAR. • They presented “Playback stimuli” (recorded echolocating sounds of six different frequencies ) to bat. Outcome • The bat exhibit a JAR by increasing frequency of clicks from the given Playback stimuli. Reference: Gillam E.H. et al. Rapid jamming avoidance in biosonar. Proc. R. Soc. B 274, 651–660 (2007)
- 15. Co-evolution of Bat & Prey With the evolution of Echolocation in bat, their Prey has also been evolved. Some important evolved escaping property of Prey are- By interfering Bat’s Sonar System (eg. Tiger Moth). By flying in irregular pattern. By becoming just quiet. By having hairy wings.
- 16. 22 Mammals Genome Including 4 newly sequenced Bat genes 805,053 Amino Acids Within 2,326 Orthologous Coding gene Sequences Convergence of 200 loci Strong Evidence for convergence in Bat & Bottleneck Dolphins Convergent Evolution Of Echolocation Reference: Parker et al. Genome-wide signatures of convergent evolution in echolocating mammals. Nature 502, 228-236(2013).
- 17. Learning From Nature Many equipment have been developed using the clue of Natural Echolocation . Examples of Some Echo-locating Inventions All these equipment produce ultrasounds for echolocation . RADAR SONAR Driverless Car Tactic Devices for Blinds
- 18. • RAdio Detection And Ranging • It is similar to bats, used for Arial echolocation. • Radar uses Radio wave or Microwave to determine the range, angle, or velocity of objects.
- 19. • Sound Navigation And Ranging • Similar to Dolphins, used for Underwater echolocation. • It uses ultrasound to navigate.
- 20. • It uses Radar for navigation. Downloaded from: Google official Blog (https://goo.gl/wYhSl2)
- 21. Tactic Devices for Blinds Downloaded from: PhysOrg.com (http://goo.gl/Pura08)
- 22. Descriptions • Name: Ben Underwood • Life : 1992-2009 (17 Years Only) • Location: California (USA) • Handicapped : Yes. His eyes were removed during operation of Retinoblastoma (a Retinal Cancer) • Special Property: Ben used to echolocate the surrounding by producing “Click” Sounds (With His Tongue). He was able to locate buildings, playing football, riding bike etc. • Death: When same cancer returned. • Tribute: His Mom wrote a book about Him-“Echoes of an Angel”. Website: www.Benunderwood.com vDownloadedFrom: Benunderwood.com
- 23. Blind men teach themselves to see with Ears Downloaded from-http://goo.gl/hOkcmk
- 24. References 1. Chiu C., Xian W., Moss C.F. Flying in silence: Echolocating bats cease vocalizing to avoid sonar jamming. PNAS 105, 13116–13121(2008). 2. Gillam E.H., Ulanovsky N., McCracken G.F. Rapid jamming avoidance in biosonar. Proc. R. Soc. B 274, 651–660 (2007) . 3. Jones G, Siemers B.M. The communicative potential of bat echolocation pulses. Journal of Comparative Physiology A 197(5), 447-457(2011). 4. Kno¨rnschild M., Jung K., Nagy M.,Metz M.,Kalko E. Bat echolocation calls facilitate social communication. Proc. R. Soc. B 279, 4827–4835(2012) . 5. Madsen P. T., Surlykke A. Functional Convergence in Bat and Toothed Whale Biosonars. Physiology 28, 276–283(2013). 6. Parker J., Tsagkogeorga G., Cotton J.A., Liu Y., Provero P., Stupka E., Rossiter S.J. Genome-wide signatures of convergent evolution in echolocating mammals. Nature 502, 228-236(2013). 7. Shnitzler H.U., Kalko E.K.V. Echolocation by insect-eating bats. BioScience 51, 557-569(2001). 8. Surlykke A, Kalko E.K.V. Echolocating Bats Cry Out Loud to Detect Their Prey. PLoS ONE 3(4), 1-10(2008). 9. Whitelow W. L. Au, Simmon J. A. Echolocation in Dolphins and Bats, Physics Today, 40-45(2007).
- 25. Thanking You..
Editor's Notes
- #2: Good afternoon. I am Ravikash Maurya, going to speak about “seeing With ears”. The entitlement is literal , but I am going to describe it scientifically.
- #4: The phenomenon of seeing with ears could be achieved by listening a sound coming from a target .Ears listen the sound and brain make an image of object.
- #5: When a sound hitts a target, it bounced off in the form of echo. For example –when you shout in an empty room, you can here copy of your voice. This copy of voice is nothing but an echo.
- #7: Property of echolocation is found in many animals but it is well developed in mammals.
- #9: And this echo is listen by animals. And The brain draw an image of the target.
- #10: How the bat know the position of a prey? It calculate total time taken by direct sound and echo.
- #13: Now I am going to show a vedio. This is a moth which will be captured by bat. The bat emitt clicks to detect and catch their prey. [play]. [stop] This is sound analysis of bat. In last, there is continuous buzz of clicks k/a feeding buzz. It is for better visual of target. {stop} now, how bat see with the help of sound. {play} Echolocation can be imagined using flash light in a dark environnet. Each newly released flash will prepare a visula snapchart of surrounding. If obstacles such as trees are far apart, you can freely moove around with your flash.If a flash detect hidden object such as apple on a tree, you can increase frequency of flashes to get better visual information of object.
- #14: One question might be glittering in your mind that there are many bats in a space who emitt echolocating calls which creates a noise. This is c/a jamming.
- #22: Scientists have also developed tactic devices for blinds. Tactic devices are those who communicate with blind people by giving pressure on the body part on which, blinds are wearing these devices. It uses ultrasound waves. As blind people come near to an object, tactic devices increases pressure on the body part.
- #24: After Ben underwood, scientists are now giving training to blind people to echolocate. Blind people produce sound with tongue or finger.