Chemosensory and Visual Adaptations Flashcards
(103 cards)
1
Q
What is the most universal sensory modality?
A
Chemoreception
2
Q
What two receptors make up chemoreception?
A
gustatory-taste and olfactory-smell
3
Q
Did the chemosensory systems evolve dependently or independently in many groups?
A
independently
4
Q
What is olfaction?
A
sense of smell
5
Q
What types of neurons are involved in olfaction?
A
bipolar neurons
6
Q
How many different odors can mammals discern?
A
Well over 10,000
7
Q
How are air-born molecules sensed?
A
The molecules are collected in the nasal concha and dissolved in a fluid in order to bind to receptors and produce a signal
8
Q
What does it mean that the binding to the sir born molecules for olfaction is reversal?
A
The receptor can bind to the molecule and then after sometime it is released so we do not constantly recognize the smell
9
Q
What are sencilia?
A
the combination of the words sensory and cilia; they are processes long enough to fall over and sit below the mucopolysaccharide fluid that collects the airborn molecules
10
Q
What are the sententacular cells in olfaction?
A
Non-neuronal cells that support the cells physically and also help bind molecules and pass them across to the sensory cells
11
Q
What is the primary odor hypothesis?
A
We do not have 10,000 receptors for the 10,000 different smells we can smell. Instead there are a finite number of specific receptor types and then differential activation of these types to greater or lesser degrees and the combinations of them have unique signature that the brain interprets as a specific sound.
12
Q
What are the primary odors?
A
musky floral pepperminty camphoraceous-vicks vapor rub ethereal-gas pungent putrid
13
Q
What do organisms use olfaction for?
A
- foraging feeding
- location or navigation
- reproduction and development
- protection
14
Q
How much greater do dogs have olfaction senses than humans do?
A
40 times
15
Q
What part of the brain do all the olfaction senses get interpreted by animals lower than mammals?
A
The midbrain which is the most primitive part of the brain
16
Q
For humans where is olfaction sensation interpreted and processed? Why does this make smelling different to us than other senses we have?
A
Mostly interpreted in the higher center in the cerebral cortex region a fair amount is processed in the midbrain. This is unusual bc most senses are passed up really quickly to higher brain centers. This makes olfaction different from other senses, a certain smell will often bring up memories and emotional images
17
Q
What are three examples of how organisms use chemoreception-olfaction?
A
- Parasites: every species has its own species of roundworm, when entering the intestine the worms look for chemical cues to start development, dog roundworms in humans do not receive the right chemical sensations and go looking for them to begin development and can end up in bad places such as the brain etc.
- Insects gypsy moths: male moths more showy frilly antennas and females less showy and sometimes flightless. Males use big antennas more surface area and females release pheromones. We isolate pheromones into bug zapers and control population of males.
- Cnidarians release sperm and eggs into water. Eggs release chemical that attracts the sperm
- Barnacles: They are sessile organisms but reproduce by internal fertilization so barnacles have enormously long penises and the barnacle colonies release chemicals and the larval form of barnacles which is the only motile form will swim towards chemical and attach near colony no further than one penis length away.
18
Q
How do mammals use gustatory responses?
A
We have taste buds that occur in groups (40-60)
19
Q
What type of cells are taste buds?
A
secondary epithelial sense cells
20
Q
How do vertebrates taste?
A
molecules come in dissolve in salvia and fluid in mouth settle on taste hairs and initiate action potential sent to brain
21
Q
Are taste buds hair cells?
A
yes they are modified hair cells that are no longer sensitive to sheer or torque forces but to chemical stimuli
22
Q
Why are taste buds kept below the epithelial tissue?
A
For protection. They are less likely to be damaged there. Taste buds are expensive to make and this is a way to limit their exposure to damaging substances.
23
Q
What are the four classic tastes and the 2 non-traditional tastes?
A
sour salty sweet bitter
water umami
24
Q
Can humans taste water? Can fish taste water?
A
We taste the ions in water the dissolved amino acids but we can not describe the taste of water. Fish can taste water they can tell saltwater from fresh water and lack salty taste buds
25
Where are the remnants of the system that can taste water in humans?
In the brain and help determine thirst
26
What does the taste bud umami pick up?
amino acids gultamic acid meat
27
Why do humans have a predisposition for sweet tastes?
sweet tastes often corresponds to things high in calories and less toxic and in the old days when humans scavenged for food sweet things were safe to eat
28
How are the taste buds in vertebrates distributed?
irregularly
29
In birds how good is their sense of smell and tastes?
No sense of taste decent sense of smell. For example vulture have no taste but fairly good sense of smell
30
How do salmon use magneto reception and chemoreception?
They find the coastline using magneto reception. They follow the coastline up using the sense of smell then taste to taste the freshwater of stream.
31
What is another name for the Vomoronasal organ?
Jacobson's organ
32
Gustation in reptiles and amphibians using the Jacobson's organ is a ______ sense?
Chemotaxic sense it gives them the direction to go in based on the number of molecules present
33
What is the role of the forked tongue?
for directionality to tract prey it sticks the tongue out into the air and then sticks it into the roof of the mouth and it senses if more molecules on right than left the prey went right
34
What mammals have the Jacobson's organ?
cats
35
jacobson's organ picks up senses using what but is actually a what sense?
using the tongue but is an olfactory sense
36
What sense gives more detailed information about and near and distant environment than any other sense?
Vision/photoreception
37
True or false. Vision is instantaneous?
True.
38
What types of information can vision supply?
1. intensity/contrast-distance
2. wavelength-color
3. plane of polarization-used for distance and direction like a sextant
39
WHat is dermal light sense? and what is another name for this type of sense?
It is the sense of light on the skin's surface. Occurs in nearly all animal phyla. Another name for it would be diffuse photosensitivity
40
How does the dermal light sense work?
The mechanism is not entirely clear. Photosensitive nerve endings? No
Heat sensors? NO
41
What types of information is the dermal light sense important for?
- Nocturnal animals with the ability to tell light from dark but not with eyesight
- Time certain events such as daylight or breeding times
- Out and about and the environment changes for example if your small and a shadow passes over you you may want to take cover so you are not eaten
42
What types of animals do eyespots show up in and are they image forming?
flatworms annelids and arthropods and no they are not image forming
43
What different forms can eye spots be in?
1. flat sheets- no directionality
2. concave- precursor to the vesicular lens eye that we have
3. convex- directionality, leads to the multifaceted compound eye in insects
44
Do eye spots have photoreceptors?
No they have light shades. Light bounces around so a photon that is sensed more than once is worthless
45
What are the two types of image forming eyes?
vesicular eyes and convex(multifaceted) eyes
46
What types of eyes do humans have?
vesicular or compound eye
47
How did vesicular and convex eyes evolve? And what are the two arrangements?
Independently of one another. Two arrangements:
1. Laminar stacks-flat sheets
2. Rhabdomeric tubes
48
Photons are extremely tiny. What are the ways in which the photons can be received by the sensors in the eyes?
1. the organisms can be in a very intense environment-no animal does this bc this amount of intensity is bad for biological tissues
2. adaptations in the animal structures by fold the membrane many times increasing the surface area and adding photoreceptive pigments on the surface area
49
Where do your find the photoreceptive pigments?
in the terminal tips of the photoreceptors
50
What is the photoreceptor pigment?
Rhodabson
51
How is the photon amplified? And how can the signal be amplified a second time?
As the photon passes through the light traps its hits the many rhodobson in the folded laminar stacks.
Occurs in corpuscular (active at dawn or dusk) or nocturnal animals and they have a layer in the eye that is reflective- itis called the tapadinum lucidnum and this amplifies the signal times two
52
What do image forming eyes make?
complete sharp images
53
What is the vesicular eye composed of?
cornea retina and lens
54
What four different groups have vesicular eyes evolved in? And what arrangement do they exhibit?
1. jellyfish- rhabdomeric arrangement
2. annelids-rhabdomeric arrangement
3. mollusks-rhabdomeric arrangement
4. vertebrates-laminar arrangement
55
What are the convex eyes made of?
Individual photoreceptor units known as omatidia
56
What three animal phyla are the convex eyes found in?
1. annelid
2. mollusks
3. arthropods
57
What are the three tunics (coverings) that make up the vertebrate eye? And what are the characteristics of each?
1. Sclera-outer tunic-dense connective tissue-white-give shape and rigidity
2. Choroid-middle tunic-vascular tunic-dark in color-contain melanin
3. Retina-inner tunic-sensory- sensory cells present here rods and cons
58
Why is it said that humans have a reverse eye?
The sensory cells are present in the sensory retina can have two different arrangements depending on if you are referring to humans or squid. You would expect the rods and cons sensory tips that contain the laminar folds would be lined up along sensory tunic and point outward aka ventrad toward the source of incoming light but they are not! In vertebrates they are flipped upside down and the tips are pushed into the middle vascular tunic! They point scalard
59
5/6 of the outer tunic the scalera is the white rigid material what is the last 1/6 made of?
It is the cornea which is transparent to allow light to pass through
60
What two fluids are found in the eye and what are their functions?
1. Aqueous humor is found near the cornea water like fluid
2. Vitritious humor is found in the back of the eye and is syrup like to create hydrostatic pressure so the eye does not fall in on itself and gives it shape
61
Can light pass through the two fluids easily?
Yes both are transparent and photons easily pass through them
62
What is the function of the iris?
Limits the amount of light let into the eye
63
What is an aberration? and how is it corrected?
Where the light coming into the eye hits a little above or below the retina causing blurry vision. It is corrected through lens.
64
Fovea is found on the optic plane, what is the optic plane?
The plane of vision one looks most frequently
65
What type of receptors are found here?
The ones most useful to the animal for humans the cons are found here color receptors
66
In the fovea region of the eye what has been done to the nerves?
They have been squashed down and are transparent so light has an easy path to the cons in our main plane of vision
67
How many rods compared to cons are found in the entire eye? and in the fovea region?
more rods than cons are found in the entire eye 20:1 but there is a higher number of cons in the fovea region they are more highly concentrated here
68
Why cant dogs see color?
They have more rods than cons
69
What three ways can light be focused or accommodated?
1. move retina
2. move lens
3. change lens shape
70
How much of the accommodating ability comes from the cornea? How do we know this?
80%
| Going under water opening eyes and everything is all fuzzy
71
How much of the accommodation comes from the lens?
15% gives sharp clear image
72
What modifications can be done to the lens?
1. Change shape/curvature- give sharp image
| 2. Change color
73
How does changing the color of the lens effect vision? Give an example.
Changing the color will filter out different wavelengths. Predators will have lens tinted yellow that defeat the effect of countershading of their prey and improve contrast.
74
What is counter shading?
change across the animal and allows light to strict the animals and reflect away at a shorter wavelength that destroys depth perception and contrast
75
What types of animals lack lens and what does this do?
insects and people with cataracts who have had the lens removed. People lens filter out some of the ultraviolet so people who have lens removed can see further into the ultraviolet.
76
How do you protect Rhodobsin pigments cells?
Make sure the choriod region and the outer region of sensory retina have many many pigments and take the sensory tip of the rods and cons and shove it scalard into the inner and middle tunic.
77
The outer segments of the photosensitive region on the rods and cons continue to grow why? What part of the eye is responsible for phagocytizing the tips and recycling it?
bc the tips are the furthest away from the cell body it is the oldest of the rhodobpsin pigments and it is breaking down on the tips
the choriod region
78
what are rods sensitive to?
low light not color
79
The retina can exist in what two states?
light adapted state-animals active during the day and dark adapted state-nocturnal animals
80
In light adapted retina what modifications occur?
protect the sensory cells from high light levels so the rods migrate scalerad and tips bury themselves deeper into dark pigment region of scalar-move as much as 10-20 microns. Bc rons are so sensitive to light when they are in use nerves synapse between groups of rods and wires them together and pick up dim light and when encounter bright light ties broken to protect them
81
In dark adapted retina what modifications occurs?
Exact opposite. Cons migrate to scalerad not as far. Rods migrate vitrad.
82
What is the trichromatic vision theory?
We have three different wavelength sensitive cons and they come in three different colors blue green and red
83
What is the most efficient way to sharpen the image?
Change the shape of the lens-15% accommodation
84
How do annelids change the focal length to focus light?
Move the retina closer or further away and much less efficient and takes longer than change the shape of lens
85
How do jellyfish change focal length in order to ficus light?
Move the lens. They squeeze the eyeball which in turn moves the lens closer or further away.
86
How are the lens of vertebrates on land and water different?
Land: Flex with axillary muscles and thin
Aquatic: They are in water and therefor do not need a cornea component it is completely gone or reduced. The lens takes over the entire accommodation ability and is very thick and spherical.
87
What are the photorecptor units of multifaceted/convex eye?
There is a number of visual units and each one of the units is an ommatidium
88
Does the corneal lens in the insect ommatidia have any focusing ability?
No
89
Do insects need the crystalline cone for normal vision?
No
90
What are insects called that lack a crystalline cone?
acrystalline insects
91
What are the retinula cells in the multifaceted eye?
The sensory cells.
92
What is the useful function that the eye is convex and not concave? Give an example.
The organism can see around itself. For example, the dragonfly have as many as 10,000 ommatidia in each eye and can see 360 degree field.
93
What is the flicker resolution in the dragonfly?
It is how many frames per second can the eye perceive as individual frames before it just is seen as constant motion. Helps show patterns to see where the next move will be. They have over 300 frames per second. They can track objects through space very well. They give up total resolution but can tract objects very well.
94
What is human flicker resolution?
23 frames per second
95
Each ommatidia sees a little tiny patch of a bigger image. true or false?
true
96
Why do you not need the crystalline cone for accommodation?
Each ommatidia acts as a pinhole camera. They have a fixed angle of resolution, in that certain angle the unit will give a high resolution of the image. Infinite focal distance.
97
What is another name for the pineal eye? And what organisms are they found in and best developed in?
Median eye and it is found in vertebrates and best developed in lamprey and lizards
98
What type of function does the pineal eye have?
It is a system for timing and detecting daylight and light intensity.
99
What does the pineal gland do for us?
sleep cycle and day length it is now inside the brain close interacting with optical nerve
100
What does the pinneal gland do for fish?
reproductive seasons and the pinneal gland times this
101
What is the pineal eye in the tuatara lizard and what is its function?
It sits in the middle of the head and is transparent with a disattached rudimentary retina and lens so it can be said that is was once a paired structure. It is not image forming and used for daytime and nighttime.
102
What is the behavioral response of frogs and amphibians to light being blocked?
From the pineal eye blocked light triggers an escape response.
103
What is the significance of the eyes of the eyeless shrimp Rimicaris exoculata?
Found in the vents in the mid atlantic and one of the most numerous animals found here. They are exceptionally found around the vent because of the bacteria found in the vents. The vents are called black smokers bc it is saturated with sulfur. Shrimp thrive on the bacteria. The shrimp are blind they lost their eyes. The shrimp have white patches on the back of the carapace. In the white patches Rhodopsin pigments were found here-light sensitive. Animals use the white patches with rhodobsin pigments to see infrared radiation and the black smokers sends out an infrared signature and this allows the shrimp to get as close as they can to the sulfur bc thats where the most bacteria are but not get fried.
