Lecture 3
weakly electric fish (electrolocation)
-send out electrical field-receive in coming field interpret depending how it is distorted -prey, rock, alive -surrounding objects disrupts the electric field
Nose # of Receptor groups? goes to?
1 olfactory cortex
Magnetism Magnetoreception Function
1. Daily movements -hammer head sharks -seamounts (magnetic hot spots)-the shape of their head helps with triangulation 2. Migration -birds-ion crystals (site of magnetic reception), hatching- logger hear sea turtles 3. Homing -birds, mice
Electricity Detection - electroreception
1. modified neuromast cells 2. some vertebrates detect only
vomeronasal organ # of Receptor groups? Goes to?
2 mid brain
echolocation -information in sounds how does a bat vary intensity, frequency, and pattern of calls when locating prey
3 bones in middle ear of bats collapses so they can't transmit the sound as much when they make sound
What is the general relation between body and brain size? For a given body size, how do the brains of mammals and birds compare to each other and to other amniotes?
All amniotes have a relatively enlarged forebrain compared with amphibians, especially the forebrain (telencephalon). The brains of mammals and birds are larger in proportion to their body size than are reptiles. For a 1 kg animal, the avg. mammal would weight 9.9 g, bird 6.7g, and reptile 0.7g. Both birds and mammals have larger brains proportion to their body size.
How do Cetaceans (whales) transmit soundwaves to the inner ear?
An enlarged canal in the lower jaw that in modern cetaceans houses a sound-conducting fat pad. Reduction in the size of the semi circular canals for underwater navigation.
Chemicals Taste vs. olfaction Olfaction: long distance, receptors and scent discrimination; fish vs. tetrapods; dogs vs. humans
Distance, cranial nerve 1 Slight change in structure/concertation of odorant signals different receptors-concentration allows for search dogs to follow tracks 1. Different receptors with changing concentration Receptors 1. Fish - no choanae, more/different classes of receptors 2. Tetrapods - internal nares, less classes of receptors but more of a certain kind
Weakly electric fish such as the bony tongues use electricity for electrolocation. How does electrolocation work and allow the fish to differentiate between animate versus inanimate objects
Establish a three-dimensional electric field, allowing it to detect objects in its environment. A conductive object causes the lines of force to converge, whereas a nonconductive object caused them to diverge
Tetrapod animals need to amplify airborne sounds to set the hairs of the inner ear in motion. Describe how the structures of the middle ear do this (how do these structures vary between tetrapod groups?).
In sauropsids vibrations received by the tympanum (eardrum) are transmitted through the middle ear by a single bone, the stapes. In synapsids vibrations are transmitted by the ossicular chain of three bones, the malleus, incus, and stapes. All synapsids have relatively long ear canals and nearly all extant synapsids have a pinna (external ear) that helps to channel sound to the ear canal
Where are taste-bud organs located on fish
In the mouth and around the head and anterior fins
Vertebrates with reduced/no vomeronasal organs
Humans-have one but issue with nerves, birds don't have one
What was the original function of the inner ear of early vertebrates? Describe the components of the vestibular apparatus
Initially served to detect an animal's position in space and is still retained today. Semicircular canals, utricle and saccule (macula), ampullae (crista), vestibular ganglion
How does an electric eel maximize the intensity of the shock delivered
It bends its body, placing prey between its positive and negative poles and thus increasing the voltage
Emission - some fish detect & emit
Production modified muscles = electrocytes •Stacked to increase voltage •Don't contract -still have flux of ions but no physical contractions •Change in ions
Vertebrates with vomeronasal organs
Salamanders (bumps head on grounds), snakes (tongue picks up particles from air and inserts in pallet to organ), dogs
Describe differences in sound perception in air versus water.
Sound travels 4 times faster in water than in air, and in the open sea sound can travel for hundreds of kilometers
Chemicals Taste vs. olfaction Cranial nerves
Taste comes in through several cranial nerves (VII, IX, X) Olfaction, cranial nerve I
Chemicals Taste vs. olfaction Taste: short range, location of taste receptors - fish vs. terrestrial tetrapods
Taste receptors - location: mammal-10,000, catfish-100,000-175,000 (in water, effective all over body) Tasted used to tell if something is edible Several broad taste receptors Signal salty, bitter, sweet, sour
Chemicals Taste vs. olfaction Relative distance
Taste short range - contact Olfaction distance
What is the vomeronasal organ and which vertebrates possess it
Tetrapods, except birds. An additional chemosensory system
sound production and signals amphibians - air sacs
air sacs: take in air through cavity then close off to produce sound have tympanic membrane (frogs) most times its producing sound is territorial
Pheromones - definition and functions Functions
alarm, mating, territory
Pheromones - definition and functions Conspecific signals
an organism belonging to the same species as another organism.
Bird songs/calls Function
bird sing to attract mates, recognition (Males with higher repertoire are healthier. -Males can stick around all winter and sing even when there are no females because they migrate. -Why? Territorial competition between males, see better repertoire of songs will "win" competition. -Birds will go see male on their territorial boundary and wont focus on getting food so he becomes less healthy)
lateral lines function
detecting prey/predators coming near them by water movement, schooling behavior
vertebrate ears variation in how vibration translated fish
fish have swim bladder, Weberian ossicles-specialized, vibrates and transmitted to middle ear
vertebrate ears variation in how vibration translated frogs
frogs have a tympanic membrane, single bone in middle ear (columella - equivalent to stapes)
vertebrate ears basic structure kangaroo rat
large middle ear, hears low frequency (such as snakes moving on sand, wing sound of bird) Morse code with hind feet
sound production and signals mammals use what
larynx
lateral lines anatomy
neuromast cells (mostly around head) connected to nerves
Explain the statement: During homing and migration there is a hierarchy of cues depending upon local conditions and how far a bird is from home.
o A bird far from home relied on the sun and polarized light to navigate on clear days, but it can switch to magnetic direction sensing on overcast days. In both conditions, the bird can use local odors and recognition of landmarks as it approaches home
Why is an internal clock important for birds using the sun or stars to navigate
o A bird must know what time of day it is in order to use the sun to tell direction, and its timekeeping ability requires some sort of internal clock.
What are the differences in location of taste buds between fish, mammals and sauropsids
o Fish - taste receptors all over body surface o Mammals - taste receptors are distributed in the oral cavity, particularly on the tongue o Sauropsids - taste receptors are only on the tongue and palate
With respect to bird ears, what is the columella, to what is it equivalent in mammals
o Is a bone that contributes to hearing in amphibians, reptiles and birds, corresponding to the stapes in mammals.
Despite its small size, the avian auditory system is as sensitive as that of humans. What features of the avian ear enable this
o Most birds have tympanic membranes that are large in relation to head size. A large tympanic membrane enhances auditory sensitivity, and owls have the largest tympanic relative to their head size among birds.
Identify and briefly describe the cues that migrating sea turtles use
o Olfaction and magnetic orientation. They can sense both compass directions and their location on Earth's surface, and make appropriate changes in course to reach their goal
What features allow owls to be so acoustically sensitive
o Owls have large cochleae and well-developed auditory centers in the brain
What is the sensory organs of Crocodylians and where are they found
o Small bulges on the head that function as sensitive pressure receptors that help with detecting and capturing prey
vertebrate ears basic structure owl
oval shape of face directs sound to asymmetric ears, helps in triangulation of sound, critical in small head
Strong Electric Fish
protection predation 600 volts (electric eels)
vertebrate ears variation in how vibration translated salamander/frogs
salamander/frogs picks up vibrations along feet, transferred to middle ear
vertebrate ears variation in how vibration translated snakes
snakes have vertebrae transmit sound to middle ear
Pheromones - definition and functions Organic compounds (many and complex)
steroids
Pheromones - definition and functions Examples
swordtail fish: internal fertilization; live birth; female choice of mate based only on chemical cues hyena: 2 types of pheromones when patrolling territories -one pheromone is short term (used within group) and the other is long term (for territory)
sound production and signals birds syrinx and advantages
syrinx located at base of trachea advantageous because weight want to be focused by feet so not as top heavy when flying position of neck can change sounds, noises it makes
Heat Snakes: pit vipers Pit organs of snakes
•Change of 0.003oC •0.5 seconds can detect mouse 10oC and strike •s-shaped movement of head to help with triangulation •membrane: suspended in pit, sensitive to infrared vibrations
What sensory systems do sharks use in prey detection and what seems to be the ordered sequence of their use of these systems
Olfaction -alerts shark to potential prey Mechanoreception -tracks the wake of its prey Vision takes over Unfamiliar prey shark bumps/scraps surface of prey with rostrum Electroreception to track prey
The vomeronasal organ - "tastes smells"; which vertebrates have?
Only tetrapods, no fish, have vomeronasal organ "taste smell"
Briefly describe experimental evidence that has demonstrated olfaction versus the electrolocation capacity of sharks
Prey covered by agar to block olfactory cues, shark attacked prey, responding to electrical activity of prey's muscles Prey replaced by pieces of fish that emitted odor but no electrical activity, shark swam past it until it smelt it Prey covered with electrical insulation and agar to block odor, shark unable to detect it
Pit organs Why not found in bird & mammal predators ????????????
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What vertebrates have a lateral line system
Aquatic vertebrates and fishes because air is not dense enough to stimulate the neuromast organs
How do taste and smell differ with respect to innervation
Both are interlinked but different in their innervation. Smell is mediated by the somatic sensory system, sensing items at a distance, with the sensations received in the forebrain Taste is mediated by the visceral sensory system, sensing items on direct contact, with the sensations received initially in the hindbrain
Bird songs/calls Varies with context
Can send signals to give away location if predator there, other birds will come in and mob predator (bat/owl/hawk) (in forest, broader wavelength doesn't travel far by can get around objects better) In forests can have lower frequency than in open areas/grassy areas because wavelength with higher frequency have longer wavelength (high frequency can travel longer in narrow wavelength)
Describe the form and function of the Weberian apparatus.
Consists of small bones that connect gas bladder with inner ear. Using gas bladder as an amplifier and the chain of bones as conductors, greatly enhances the hearing sensitivity - broader frequency range of detection than other fishes
From what structure in fish is the Eustachian tube derived and how does it function
Derived from the spiracle, brings water through gills
How does the structure of the neuromast organs allow a fish to sense the direction of displacement
Hair cells detect water movement, and overlapping sensory fields allow the direction of a stimulus to be identified
Chemotransmission and signals Using chemicals to deter predation: amphibians (widespread), hedgehogs, bird (Pitohui of New Guinea)
Hedgehog: anoint themselves to deter predation with something gross Pitohui (bird from New Guinea): neurotoxin from beetle gets into feathers (co-evolution)
Magnetism Magnetoreception
Magnetic reception - evidence for and location of detectors Earth's fields -magnetic hot spots -seasonal migrating, daily foraging movements
What types of modified tissue are used to produce electrical discharges
Modified muscles or nerve cells
How and why do urban birds adjust vocalizations?
They adjust by timing to avoid noisy periods from other species. They also adjust frequency when they fall into the range of anthropogenic noise like traffic.
How do lizards and snakes use color and hearing to avoid predation?
They can use Eavesdropping to hear birdcalls which they will either run for cover or stop foraging in order to stop movement. They can also use color for deterrence. Some lizard have black and white marking on their underside. They will show this side to show that may be ready to flee. Some predators will leave them alone in order to find more unsuspecting prey.
How do the dart-poison frogs of Madagascar and Central America obtain the array of alkaloids that constitute their poison
They obtain them from the ant and millipedes they eat
Why is olfaction a more effective rapid-response distance sense for terrestrial than aquatic vertebrates
Volatile odor molecules generally travel faster in air than in water
vertebrate ears echolocation examples
bats, dolphins, oil birds (lives in caves and comes out at night)
sound production and signals fish - modify swim bladder, FRT's
can make sound through modified swim bladder (muscles pushing away/contracting against swim bladder) produces low 'croaking' sound herrings can produce sound through FRTs produce bubbles + sounds with gas for reproductive purposes
vertebrate ears variation in how vibration translated lizards
lizards have columella instead of stapes
vertebrate ears variation in how vibration translated mammals
mammals have cochlea
Signals - electrocommunication Function
mating -species, sex, individual specific