Highest_priority_cards_13_-_all_duplicates

Question 1

Q: Name some features of a skull that can tell us something about the animal

Answer 1

(details on separate cards)
Eye placement
Eye size
Presence/size of sagittal crest
Width/length of jaw
Presence of different kinds of teeth
Shape of teeth
Length of snout
Size of nasal cavity
Size/surface area of turbinates
Auditory bullae size

Question 2

Q: What can we learn by looking at skull features? (just a general list, details on separate cards)

Answer 2

Physical and behavioral adaptations.
Diet (type/number of teeth, positioning of jaw muscle attachment sites, eye positioning).
Forward placement of the eyes in the skull indicates depth perception.
Size of the eye orbits in relation to the size of the skull may indicate when an animal is active.
Length and position of the nose indicates the importance of the sense of smell.
The position of foramen magnum indicates posture.
The size of auditory bullae indicates level of hearing.
Social patterns.

Question 3

Q: What can we learn about an animal by observing the eye sockets on the skull?

Answer 3

-Eyes that face forward allow for binocular and stereoscopic vision, aiding depth perception
–Suggest it’s a predator
–For calculating distance to prey
–For swinging/leaping through arboreal habitat (monkeys have forward facing eyes)
-Eyes on sides allow for greater peripheral vision, wide range of view; can provide nearly 360-degree field of view at all times to watch for predators approaching
–Suggests it’s a prey animal
–“Eyes in the front, the animal hunts. Eyes on the side, the animal hides.”
–Note: Within a herd, there can be 360 degree vigilance since individuals face different directions.
-Eye sockets that are large relative to skull size may suggest nocturnal activity
–Larger eye lets animal see better in dim light
–E.g., cats, owls.
–Many nocturnal animals have a reflective layer behind the retina (tapetum lucidum, Latin for “shining layer”) that reflects the light back through the retina, aiding night vision. E.g., cats, lemurs.
–California sea lion has large eyes; minimal light in the ocean at depth.

Question 4

Q: Depth perception

Answer 4

Visual ability to perceive the world in three dimensions and the distance of an object.

Question 5

Q: Stereoscopic vision

Answer 5

The single perception of a slightly different image from each eye, resulting in depth perception.

Question 6

Q: What can we learn about an animal by observing the nasal cavity in the skull?

Answer 6

-Relative size of nasal passage (larger indicates good sense of smell)
-Size/surface area of turbinate bones
–The thin, bony structures inside the nasal passage (turbinate bones), provide framework for membranes which sense odor in vertebrates
—Grizzly bear has an extremely acute sense of smell, and well developed turbinates; can detect animal carcasses ~20 miles.
–Turbinates also filtrate, heat, and humidify inhaled air, and capture >75% of water vapor exhaled, helping protect from dehydration.
—Snow leopard’s enlarged nasal cavity helps them warm the cold air they breathe while retaining water.
-Length of snout
–Elongated nose might suggest animal hunts by following scents, or that it uses nose to probe the ground or vegetation.
—Deer’s long nose and higher eye placement allows him to scan for predators while grazing.
—Wolves, bears hunt by scent using long noses that contain millions of scent receptors.
—Cats have acute sense of smell, but doesn’t measure up to dog’s, which has longer nose.
—Humans have poor sense of smell compared to most animals. Also short snout and small turbinates.

Question 7

Q: Turbinate bone

Answer 7

Delicate bones in the nasal cavity that direct the flow of air through the nasal passages and provide framework with lots of surface area for membranes which sense odor in vertebrates.
Covered with mucous membranes, which warm and moisten the incoming air.

Question 8

Q: What is a Jacobson’s Organ?

Answer 8

-Some animals have auxiliary olfactory sense organ (the VMO or Jacobson’s Organ) at the roof of the animal’s mouth
-Used to detect chemical stimuli.
-Snakes and lizards, cats, wolves, ungulates, and lemurs.
-In some mammals (i.e. cats and hooved animals), organ is involved in the flehmen response (lifting upper lip, grimace), and is used to detect pheromones, chemical messengers carrying info between individuals of same species.

Question 9

Q: What can we learn about an animal by observing the auditory bullae on the skull?

Answer 9

(singular bulla)
Auditory bulla: Bony structure on the ventral, posterior portion of the skull that encloses parts of the middle and inner ear.
In general, large protrusions indicate an excellent sense of hearing.
Cats: large auditory regions and very acute hearing. Deer and antelope: poorer sense of hearing. Birds: these auditory regions are relatively prominent.

Question 10

Q: How are herbivore skulls adapted to consuming plants?

Answer 10

Well-developed premolars and (broad) molars, often with sharp ridges on the tops for grinding.
Incisors are clipper-like to snip off foliage from branches.
Canines reduced or absent.
Long diastema (toothless portion from the premolars to the incisors) provides room to reposition plant material during grinding.
Narrower mouths in relation to head size very muscular tongues to move food around.

Question 11

Q: What is a dental pad? Who has one?

Answer 11

Some ruminating species (e.g., deer, cows, and giraffes) have only lower, flat shaped incisors that meet the upper toothless gum, called a dental pad.
Plate of bone under the skin to grind against.
Zebras and other horse-like species have both large upper and lower incisors.

Question 12

Q: Compare jaw shape of carnivores vs. herbivores. (general)

Answer 12

Carnivorous animals tend to have wide mouths in relation to their head size and highly developed jaw muscles, whereas the herbivore’s mouth is narrower.

Question 13

Q: Describe carnivore teeth

Answer 13

Have full set (canines, incisors, molars, premolars)
Their canines are long and used to slash, rip and tear meat. Grip prey. Used on throat in a choke hold.
Sharp premolars and molars, used to shred/tear/cut meat.
Many have carnassial teeth (details in feline section).

Question 14

Q: General shape of insectivore teeth

Answer 14

Fine, needle-like teeth. (e.g., many lizards, frogs, bats, and spiders)

Question 15

Q: Which types of teeth do omnivores have?

Answer 15

Omnivores have a full set (canines, incisors, molars, and premolars)

Question 16

Q: Describe omnivore teeth

Answer 16

Omnivore’s teeth are less specialized than those of carnivores and herbivores.
Molars in between carnivores and herbivores, with more “peaks and valleys” due to the varied diet; cheek teeth are wide with low bumpy surfaces.
Incisors are wide, narrow at the tips, and somewhat chisel-shaped, useful for biting off chunks of meat or plant material.

Question 17

Q: Describe some specific aspects of a skull that reveal information about animal jaw function, distinguishing predator/prey

Answer 17

[card duplicated in mammal section]
Skulls provide attachment sites for muscles that enable biting and chewing.
Animals that need stronger biting muscles will develop larger bony attachment ridges for these muscles, such as the sagittal crest along the top of the skull and the zygomatic arches (cheek bones) on the sides.
Predators that tackle large prey often develop a sagittal crest, since it provides attachment space for muscle, which is used to snap the jaws shut (e.g., dog/wolf).
Sagittal crests are often larger in males than in females, because they are associated with larger body size.
Herbivorous animals that do a lot of chewing to help break down the cellulose, have a larger muscle attachment sight on the lower jawbone (e.g., cow, giraffe, antelope). If this attachment area is small, chewing is not a necessity such as in a cat or dog.

Question 18

Q: Sagittal crest

Answer 18

Ridge of bone running lengthwise along the midline of the top of the skull.

Question 19

Q: Specifically, what is indicated by a larger attachment area for muscles on the side of the skull vs. on the lower jaw?

Answer 19

Larger attachment area on side of skull indicates a strong bite force for clenching onto prey
Larger attachment area on lower jaw bone indicates muscles are used for chewing and gnawing

Question 20

Q: Name a function of the zygomatic arch besides being a muscle attachment site.

Answer 20

Protects against strong blows to the face.

Question 21

Q: Why does an adult male gorilla have such a large sagittal crest?

Answer 21

Exceptionally strong jaw muscles used for fibrous vegetation.
Males and female gorillas have similar diets, but female sagittal crest is less prominent
-may form in response to sexual selection and play a role in social signaling
-male is also larger

Question 22

Q: Key difference between carnivore and herbivore (mammal) jaws. What about omnivores?

Answer 22

Mammal jaws attach directly to skull.
Carnivores have muscle attachment sites on the lower jaw that allow only open and shut movements. Joint is tight and cupped or C shaped.
Herbivores have muscle attachment sites on the lower jaw that allow for side to side movement. Joint attachment is more open and shallow and the articulation between the lower jaw and skull is well above the plane of the teeth.
Omnivores have minimal side to side motion of their jaw, but a shearing action like the carnivores.

Question 23

Q: How are jaws attached in mammals and non-mammal vertebrates?

Answer 23

Mammals are only vertebrates with lower jaws articulated directly to skull. (at the zygomatic arch)
Non-mammal jaws comprised of different bones and attach to skull through the quadrate bone.
Note: In mammals, this quadrate bone migrated to the inner ear and became one of the three middle ear bones.

Question 24

Q: How are skulls attached to spinal column in the different classes of vertebrates?

Answer 24

Skull attaches at two points in amphibians and mammals
At a single point in reptiles and birds

Question 25

Q: Mandible, Fossa, Condyle

Answer 25

Mandible: Jaw bone.
Fossa: An indentation in a bone; the socket part of a ball-and-socket type joint.
Condyle: The convex part of the joint; the ball part in a ball-and-socket joint.

Question 26

Q: Zygomatic arch

Answer 26

Band of bone that branches out from the eye socket.
Allows muscles to pass through that move the jaw.

Question 27

Q: Skull identification, reptile vs mammal

Answer 27

Reptiles are homodonts; all teeth are similar. Usually long, conical. (Turtles lack teeth.)
Reptiles have proportionately smaller brains than mammals.
Reptiles have two nasal openings in their skull. Mammals have one.
Reptiles have a single point of attachment between skull and spinal column. Mammals have two.
Lower jaw of reptile is comprised of several different bones and is hinged to the upper jaw and skull through the quadrate bone. Mammal lower jaw connects directly to skull.
The tuatara and most lizards also have a small hole at the top skull due to the parietal eye.

Question 28

Q: Summarize rodent dentition

Answer 28

Long, recurving (bending backward) continuously growing incisors (must be continually worn down).
Single pair of incisors on both upper and lower jaw.
Orange enamel on the front surface of their incisors.
No canines.
Diastema for moving food around to their molars; helps with briefly storing food in cheeks.
Flat, grinding molars.

Question 29

Q: How does rodent dentition give them access to a particular niche?

Answer 29

Specialized incisors let them chew through husks, shells and wood. This allows them to access well-protected or difficult-to-access foods, such as nuts.

Question 30

Q: One general difference between primate teeth and those of other mammals?

Answer 30

Primates also have a reduced number of teeth as compared to other mammals.

Question 31

Q: Prosimian skulls, particularly lemurs

Answer 31

-Long snouts. Lemurs rely on their sense of smell more than other primates.
-Gap between the upper incisors allows more efficient transfer of pheromones from moist nose to the Jacobson organ.
-Large eyes not fully forward giving them some depth perception. Also reflect nocturnal behavior of their ancestors. Have a tapetum lucidum.
-Lemurs have bony ring around their eyes (not a complete cup, open posteriorly). Protects eyes from mechanical stress from biting and chewing.
-Lemurs have large canines like most primates.
-Lower incisors form a dental comb used in grooming and maintaining social bonds. Also scraping resin/gum from tree bark.
-Lower jaw is in two pieces (it is unfused) and held together by a ligament.
-Foramen magnum (opening in the bottom of the skull through which the spinal cord passes) is directed backward indicating a quadrupedal stance.

Question 32

Q: Monkey skulls

Answer 32

-Reduced nose suggesting monkeys rely less on their sense of smell. Allows eyes to migrate forward. Also prevents nose from blocking visual field.
-Forward eyes provide for full depth perception with stereoscopic vision. (Aids in jumping through trees.)
-Eyes are fully enclosed in a bony circle (complete cup, like apes, unlike lemurs). Insulates eyes from chewing muscles.
-Large canines in most monkeys
-Monkey’s exhibit the primate evolutionary trend towards progressive enlargement of the brain case.
-Foramen magnum varies, but more downward/forward than lemurs, indicating progression toward upright walking.

Question 33

Q: Progression/trends from prosimians to monkeys observed in skulls

Answer 33

-Moving towards an increase in vision and the reduced reliance on the sense of smell.
-Snout decreasing. Monkeys have less fox-like snouts, larger brains, and increasingly more forward facing eyes.
-These and other anatomical features suggest that the early monkeys were becoming mostly diurnal, fruit and seed eating, forest tree-dwellers.
-Foramen magnum more downward/forward than lemurs, indicating progression toward upright walking.
-Brain size increasing.

Question 34

Q: Difference in skulls of old world vs new world monkeys?

Answer 34

In Old World Monkeys, skulls of males and females may differ in size (sexual dimorphism); the skull of the male may be twice as heavy as the skull of the female and have larger canines, which they use for defense and competing for females. Mandrill is good example.
New World Monkeys do not exhibit this sexual dimorphism, with the exception of the howler monkeys.

Question 35

Q: Ape skulls

Answer 35

-Evolved the largest brains of the primates largely due to foraging for fruit and complex social interactions. Largest brain to body size ratio of any animals.
-Forward facing eyes contained in complete bony sockets; separated from jaw muscle. Rely much more on vision than smell.
-Flattened faces.
-Bony ridge above their eyes to reduce stress on the eyes while chewing. Permits apes to consume a tough, fibrous diet.
-Position of spinal cord hole lower and more forward than monkey’s, allowing eyes to face forward when animal is upright. But posture is not fully upright like humans.
-Large canines like most primates. Same dental formula as old world monkeys.

Question 36

Q: Differences between antlers and horns

Answer 36

Antlers are bony extensions of the skull that are shed and regrown each year.
Antlers are shed annually at the end of mating season; regrown in spring. Exception: female caribou and reindeer have antlers but retain them longer than the males to help protect their young.
Antlers typically fork.
Horns have an inner bony core and an outer sheath of keratin. Exception: rhino horn is solid keratin fibers
Horns are permanent, ever-growing, and do not regenerate if injured.
In most species, only males grow antlers. In many species horns grow on both male and female (but not always).
Horns don’t fork. Exception: the pronghorn.