animal senses.ppt

8/19/2019 Animal Senses.ppt

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Animal Senses

• How do animals sense

stimuli?

• Sensory organs

perceive stimuli (light,sounds, etc.) with a

receptor cell. The

receptor cell sends

signals to the brainwhere they are

processed and

integrated.


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Animal Senses

• ach type o! animal is e"uipped with its

own sensory receptors ∴ each animal

perceives its environment di!!erently.


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Animal Senses

• Animal senses are more varied and

sharper than human senses.

•Most sensory receptors are !ound on thehead o! an animal#in most cases, the

$head% is the !irst part o! an animal to enter

a new environment


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&our 'asic odalities

• hotoreception * response to light


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echanoreception

• +esponse to movement.

• This includes hearing, vibration, touch,

balance, etc.


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Thermoreception

• +esponse to heat


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-nsect Senses /ision

• 0ompound eyes made up o! 1223s *12223s

o! lenses

• ach individual $eye% is not as accurate as a

vertebrate eye, but the compound eyes

ta4en together are better at detecting

motion.

• +espond to minute changes in color andmotion#the brain produces 1 detailed

image.


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0hemoreception

• +esponse to chemical energy, including

smell and taste


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-nsect * 0hemical +eceptors

• &or taste and smell

• &ound on mouthparts, antennae and legs.

• A !ly3s !oot can tell whether a li"uidcontains sugar or salt.


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Sensory Hairs

• &ound mostly on head and legs

• 0an detect movement in surrounding air

or water, and can detect certain

chemicals.


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Sensory Hairs detect

heremones• These are odor producing molecules that

act as chemical messages.

• They are synthesi5ed by an individual,

released into the environment and change

the behavior o! another individual.


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Sensory Hairs detect

heremones• 1222 di!!erent insect pheremones 4nown

• ost are produced by !emales and are

airborne.

• Species speci!ic se6 attractants7.


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Animal Senses

• Speci!ic e6amples8

• A homing pigeon senses changes in

altitude as minute as !our millimeters.

igeons also see ultraviolet light and hear

e6tremely low!re"uency sound.


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Animals detect magnetic !ields

• 9sed !or navigation by pigeons and other birds,

honeybees, sea turtles, etc.


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:hat happens when an animal

that navigates using magnetic!ields has a magnet glued to its

head?


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it /ipers * ;etect Heat

• its are located on head o! pit viper

• its contain receptor cells that can detect

in!rared radiation (heat)

• A pit viper is able to $see% a !u55y image o!

a warm ob


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;esign an e6periment to test i! a

$pit% is actually sensing heat.• Is it possible the snake’s pit is simply

sensing the smell of another animal?

• Hint: Use a light bulb in your experimental

set-up!


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lephants ;etect -n!rasounds

• -n!rasound = sound too low to be heard by

the human ear

• lephants call to each other with

in!rasound and stamp their !eet which

create sound waves that travel through

earth.

• -n!rasound can travel e6ceptionally long

distances.


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lephants ;etect -n!rasounds

• -t is hypothesi5ed that this allows

elephants to coordinate movement when

they are miles apart.

• >arge elephant ears and !eet (vibrations in

ground) are the sense organs7


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Animals ;etect 9ltrasounds

• 9ltrasounds = sounds too high to be heard

by humans

• 'ats, dolphins, etc.7


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;esign an e6periment to test i!

bats actually use ultrasounds !ornavigation

• Hint: 9se cottonballs as part o! your

e6perimental setup.


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A"uatic redators detect

lectric &ields• Shar4s (and others) can detect electrical

activity in the muscles o! passing prey.


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Shar4s and A"uarium

• :hat problem might a

shar4 have in a large

tan4 in an a"uarium?


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Animals detect movement

• An animal3s ear detects sound by the

movement o! sound waves through the air

or water.

• ammals have bones in their middle ear

that transmit the in!ormation carried in the

sound waves to the brain.


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Animals detect movement

• This includes stimulus detected by the

lateral line system in !ish and other

a"uatic vertebrates.

• This system detects movements and

pressure changes in the surrounding

water.


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Animals and vision

• Some animals can sense parts o! the

electromagnetic spectrum that are

invisible to the human eye.

7


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Human (and most vertebrate)

Senses• /ertebrate eyes are camera eyes (vs.

compound eyes o! insects). &ocuses

incoming light onto a layer o! photo

receptor cells on bac4 o! retina.


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/ertebrate yes

• -ris8 The colored diaphragm in the anterior

chamber o! the eyeball which contracts and

e6pands to adens8 The transparent, dualconve6 body which

!ocuses light rays onto the retina. -t is normallycapable o! changing shape to allow the eye to

!ocus on both near and distant images.


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/ertebrate ye

• +etina * &ound on the bac4 o! the eye.

Sensory cells contain light absorbing

pigment (a molecule that absorbs only

certain wavelengths o! visible light andre!lects or transmits other wavelengths)

* cones = color vision

* rods = light vision


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/ertebrate ye

• The optic nerve attaches to retina and

there are no photoreceptor cells at that

location creating a blind spot.

• Adaptations, such as the eye, (a

characteristic that ma4es one individual

more !it than another) do not have to be

per!ect.

6periment with @9+ blind spot


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0at3s yes

• A re!lective layer behind the cats retina

called the tapetum re!lects incoming light

and bounces it bac4 o!! the cones, ma4ing

more use o! the e6isting light.

• The tapetum ma4es a cats eyes loo4 li4e

shiny green orbs at night.


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/ertebrates and Taste

• Taste is a chemical sense perceived by

speciali5ed receptor cells that ma4e up taste

buds.

• &lavor is a !unction o! both taste and smell.


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/ertebrates and Smell

• -nside the nose is a big area called the

$nasal cavity.%

• @n the roo! o! the nasal cavity are special

sensory smell cells called $ol!actory

receptor cells.%


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/ertebrates and Smell

• Smells are in the !orm o! a gas that is

breathed in when animals inhale

• The scent molecules in the gas pass by the

ol!actory receptor cells on the roo! o! thenasal cavity.

• The smell cells send the signal up a nerve

!iber to the brain.• This allows vertebrates to react "uic4ly to

smells.


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@ther Senses

• Bociceptors * Sense pain

• Thermoreceptors * ;etect changes intemperature

animal senses.ppt

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