Emily's Final Review Flashcards
What are 3 things that mammals special?
Lactation, endothermy, food processing.
Why can mammals breathe and run at the same time?
The mode of locomotion is more up and down, which forces air out of the lungs when the animal lands and then the diaphragm brings air in when the animal takes off from the ground.
What are the major differences between early synapsids and derived synapsids?
Fewer ribs (evolved diaphragm), tail reduced (no side-to-side motion), legs are parasagittal (not sprawled), shoulder girdle is less attached to vertebral column (shock absorption).
Which systemic artery is lost in mammals and which is lost in birds?
Mammals: Right is lost; Birds: Left is lost.
What term describes the ankle structures of birds and dinosaurs?
Mesotarsal.
What term describes the ankle structure of mammals?
Crurotarsal.
What term describes how fish remove nitrogenous waste and what does it mean?
Amonnotelic - secrete ammonia.
What term describes how mammals remove nitrogenous waste and what does it mean?
Ureotelic - Secrete urea.
What term describes how sauropsids remove nitrogenous waste and what does it mean?
Uricotelic - Secrete uric acid.
How does ADH control urine concentration in a mammalian kidney?
When water needs to be conserved, more ADH will be released, causing aquaporin channels to be inserted into the membrane of the collecting duct and water will flow out of the urine and back into cells. Opposite is true when excess water needs to be removed.
What features evolved in mammalia?
Dentary-squamosal jaw articulation, diphyodont dentition, prismatic enamel, double-rooted molars, dorsoventral flexion of the backbone.
Which bone became the Incus?
The Quadrate.
Which bone became the Malleus?
The Articular.
Why is the Coracoid and clavicles reduced in mammals?
Light shoulder girdle, better for limb extension, more shock absorption.
What are 7 synapomorphies of mammals?
Hair, milk, single bone in lower jaw (dentary), double-rooted cheek teeth, three ear ossicles, prismatic tooth enamel, crurotarsal ankle, calcaneal heel.
What is NOT a synapomorphy in mammals?
Vivipary.
What is hair a derivative of?
Epidermal scales and they are made of keratin.
What is the dentary bone derived from?
Dermal ossification.
What is the purpose of prismatic tooth enamel?
Improves durability and pressure distribution for chewing.
What does the calcaneus attach to and what is its purpose?
Attaches to the Achilles tendon and is used for greater force when pushing off.
What type of teeth do all mammals have?
Diphyodont teeth.
List 6 characteristics of modern mammals.
Endothermic and homeothermic, mammary glands, dentary-squamosal jaw joint, secondary palate present, three middle ear ossicles, lumbar ribs absent.
What is the purpose of the talonid structure on the molar?
To pulp food - better for eating vegetation.
What is a key innovation seen in mammals?
The development of specialized herbivory.
Why did diphyodont teeth evolve?
Lactation and diphyodont teeth coevolved, teeth erupt when the face becomes big enough, changes in maternal investment.
What features change as mammals get larger?
Spine becomes more rigid, less limb bending (support weight), scapula becomes part of limb rotation.
What are the 3 living lineages of mammals?
Monotremes, marsupials, placentals.
What is the structure of the male Monotreme reproductive system?
Penis is inside cloaca and can be everted; testes are inside the body wall.
What is the structure of the male Marsupial reproductive system?
Testes are in front of the penis outside of the body wall.
What is the structure of the male Placental reproductive system?
Testes are behind the penis and outside of the body wall; testes descend and loop vas deferens around ureters.
What is the structure of the female Monotreme reproductive system?
One ovary; cloacal opening.
What is the structure of the female Marsupial reproductive system?
Ureter splits the vagina into two; two uteri; pseudovaginal canal runs in between lateral vaginas.
What is the structure of the female Placental reproductive system?
One vagina; ureters run lateral to the uterus.
What mode of reproduction is seen in Monotremes, Marsupials and Placentals?
Monotremes: Oviparous. Marsupials: Viviparous. Placentals: Viviparous.
What is the length of the gestation period in Monotremes, Marsupials and Placentals?
Monotremes: None. Marsupials: Short. Placentals: Long.
How long is the lactation period in Monotremes, Marsupials and Placentals?
Monotremes: Long. Marsupials: Really long. Placentals: Shorter.
Is gestation or lactation cheaper?
Gestation is cheaper.
What occurred that separated Australidelphia from Ameridelphia?
Both were present in Gondwana and then the continent split, causing the two groups to undergo different evolutionary events.
What are 4 synapomorphies of Placentals?
Dental formula of 3/3, 1/1, 4/4, 3/3. All teeth except the molars are replaced. Has a corpus callosum. Testes are caudal to the penis.
Which premolar is replaced in Marsupials?
3rd premolar.
What is the most diverse clade of mammals?
Glires - Rodentia.
What group is Cetacea within?
Artiodactyla.
Which group of Ungulata has an even number of digits?
Artiodactyla.
Which group of Ungulata has an odd number of digits? What else do they have on their femur?
Perissodactyla. 3rd trochanter on femur for tendon attachment.
Why are marine mammals large?
To reduce their SA:V ratio, as being smaller would lead to too much heat loss in the water. Also helps in reducing drag.
What type of teeth do marine mammals most commonly have?
Homodont dentition.
What is the standard metabolic rate?
The minimum rate of O2 consumption for life -> temperature sensitive
What is the resting metabolic rate enhanced by?
- Feeding
- Digestion
- Skeletal muscle activity
- Shivering
- Non-shivering thermogenesis
What does the hypothalamus do in thermoregulation?
Controls behavioural responses
What feature do some mammals have that allow them to control the temperature of the blood going to their brain?
Countercurrent heat exchanger in the turbinates of the nose
What is the best option for endotherms to maintain a stable body temperature in cold environments?
Increasing the conservation of heat rather than the production of it.
What strategy is best for marine mammals to retain heat and what is the best for terrestrial mammals?
Marine: Subcutaneous fat
Terrestrial: Fur
How does a countercurrent heat exchanger work?
Veins with cooler blood surround arteries in limbs and the arteries transfer heat to the veins. This allows more heat to be conserved in the extremities that can be returned to the core of the animal.
What are some strategies for reducing heat loss?
- Avoidance
- Burrows, dens, seeking warmer climates
- Social thermoregulation
- Facultative hypothermia (less than 100g)
- Seasonal hypothermia
Why can’t large animals enter torpor?
The cost to arouse is too much and it would take too long. Not efficient.
What is the difference between daily torpor and deep torpor?
Daily torpor is used by small mammals who can enter torpor and arouse within the same day. Deep torpor is used by larger mammals to enter a more prolonged state of hibernation, but has a much higher cost.
What are some risks involved with torpor?
- Being eaten by predators
- Nitrogenous waste removal
Why do Baleen whales migrate from Mexico to Alaska?
Baleen whales migrate to Alaska for large patches of zooplankton and then return to Mexico during their calving season. This is because the neonates are born without blubber and would freeze if they were in cold waters.
When is endothermy the most effective?
When the body temperature is greater than the ambient temperature
What are some strategies for living in very warm climates?
- Being nocturnal
- Going to water or mud
- Relaxing homeostasis and letting the body temperature go up
- Changing posture to reduce SA
What are some strategies used for water conservation?
- Elongating the loops of Henle and allowing for more concentrated urine to be produced
- Avoiding using evaporative cooling
- Being active at night
How does endothermy relate to lactation and complex teeth?
More energy is needed from food for endothermy. This leads to more complex teeth for the breakdown of cell walls and lactation for neonates so they can acquire adult nutrients.
What is a Diapsid?
Two temporal fenestra
What occurs in the skull of a turtle?
Temporal fenestra is secondarily closed
What occurs in the skull of a lizard?
The lower temporal bar is lost
What occurs in the skull of a snake?
The upper and lower temporal bars are lost
What is a Sphenodon and what does its skull look like?
A Tuatara and it has an upper and lower temporal bar
Is Squamata a monophyletic or a paraphyletic group?
Monophyletic
Are lizards monophyletic or paraphyletic?
Paraphyletic
Are Serpentes monophyletic or paraphyletic?
Monophyletic
What feature allows the quadrate to swing open for a wider gape?
Loss of the lower temporal bar
What feature allows snakes to ‘walk’ their jaws over their prey?
Loss of the upper temporal bar
What group are the Pygopodidae within?
Gekkota
What is the vomeronasal system used for in Squamates?
Used for prey detection. In mammals it is used for pheromone detection.
What is gustation?
Taste buds on the lingual and oral surfaces
What is the function of pit organs and what type of predators are they found in?
Pit organs detect infrared signals from prey. Used in sit-and-wait predators
What is caudal autotomy and how does it work?
The ability to lose the tail when attacked by a predator in order to escape. Fracture planes and muscle bundles separate autotomy planes and contraction breaks the muscle and blocks the blood vessels. The tail falls off and twitches to confuse the predator and will grow back as fatty tissue.
What are the functions of crypsis?
- Avoid detection from predators
- Send signals to others
- Hiding as a sit-and-wait predator to ambush prey
What is deterrance?
An anti-predator mechanism that is used to threaten predators. Can be warning colouration, spines on body/tail, poison, etc.
Which glands secrete pheromones in lizards?
Femoral glands
What are some ways in which lizards can communicate?
- Crypsis/colour change
- Vocalizations
- Pheromones
- Coloured structures (dewlap)
What is the most common form of reproduction in snakes and lizards?
Oviparity
Why did some species of Squamates evolve ovovivipary?
Allows the female to transmit more heat to the embryo
What is parthenogenesis?
Asexual reproduction where the eggs can develop without fertilization
How is body temperature regulated in Squamates?
Behavioural (ex. basking, burrowing)
When do Squamates usually seek heat and why?
After feeding because it helps in digestion and assimilation
Where would a small lizard most likely be found?
In cleared areas with little shade. Their small SA:V ratio causes them to lose heat more rapidly and therefore they must spend more time in sunlight
What are ecomorphs? What group of lizards is this seen in?
Species of different phyletic origin with similar morphological adaptations to similar niches. Seen in Anolis.
How can you tell the difference between a legless lizard and a snake?
- Lizards have long tails and short trunks
- Snakes have short tails and long trunks
- Lizards have smaller heads and eat smaller prey
- Snakes have a single lung
What adaptations do sea snakes have?
- Laterally compressed body
- Nasal valves to prevent water from entering
- No ventral scales
What are the 4 types of locomotion seen in snakes?
- Lateral undulation
- Concertina locomotion (inchworm; burrowing snakes)
- Rectilinear locomotion
- Side winding
Which bones in the snake skull are mobile?
- Maxilla
- Dentary
- Pterygoid
- Articular
- Quadrate
- Supratemporal
Why do snakes have teeth that are hooked backwards?
So that they can hold onto their prey
How can snakes walk their jaws over prey? List the steps
- Mandibular and Pterygoid teeth of left side anchored
- Head rotated to the left to advance right jaw. Mandible protracted
- Right jaw advances
- Mandibular and Pterygoid teeth of right side anchored. Left teeth released. Head begins to rotate right.
What are the two predation styles of snakes?
- Constriction
- Venom
List some characteristics of snakes that use constriction.
- Short trunk and short vertebrae for strength
- Sit and wait predators - can’t locomote fast
- Hunt mammalian prey since they need O2 more readily
List some characteristics of snakes that use venom.
- Fast moving
- Live in grasslands
- Evolved Duvernoy’s gland for venom
- Evolved more sophisticated olfaction
- Have plicidentine - venom channel
What nerve is inside the pit organ that detects heat?
Trigeminal nerve
What kind of components are usually in snake venom?
- Proteinases
- Anticoagulants
- Neurotoxins (sometimes)
- Phospholipases
- Phosphatases
What are 5 synapomorphies of Testudines?
- Elements of axial skeleton fused to dermal plates dorsally to form the carapace
- Carapace fused to bony ventral plates of plastron
- Carapace and plastron covered in keratinous plates (scutes) whose boundaries are not the same as the osteoderms
- Limb girdles internal to rib cage
- Loss of teeth, have a keratinous beak
Why don’t the boundaries of the dermal bone line up with the boundaries of the scutes in turtle shells?
Prevents points of weakness that would allow the shell to break easily
What are the ribs fused to in turtles?
The costal plates
During development, what occurs that causes the ribs to grow out straight over the scapula in turtles?
Shh signals in the Carapacial ridge cause the ribs to grow past the limb girdles and the muscles then fold over
What is the difference seen in Cryptodira and Pleurodira?
- Cryptodira vertically folds the neck into the shell
- Pleurodira horizontally folds the neck into the shell
Are Pleurodira aquatic or terrestrial? Where are they found?
Aquatic. Only found in Gondwanan continents
How does locomotion differ in terrestrial turtles vs in aquatic turtles?
Terrestrial turtles have a sprawled posture and have synchronous movement of diagonal limb pairs. Aquatic turtles use alternating hind limb thrusts and can alter foot area depending on stage of thrust.
What do sea turtles use their forelimbs and hindlimbs for?
Forelimbs - propulsion in a figure 8
Hindlimbs - steering
How do turtles inhale?
-Contract abdominal oblique and serratus
-Abdominals pull down and back on the posterior limiting membrane
-Expands abdominal cavity to create a negative pressure and draw air in
How do turtles exhale?
-Pectoralis pulls shoulder girdle back
-Viscera bulges and pushes on lungs
-Abdominal oblique and serratus relax, moving the posterior limiting membrane forward
-All pushes on cavity and air gets forced out of lungs
What is the lung attached to in turtles?
The viscera and the shell
What factors affect the sex ratio in turtles?
-Temperature
-Humidity
-[CO2] and [O2}
What kind of reproduction do turtles have?
Oviparity
Why do turtles use intracardiac shunting?
They can bypass the lungs when diving so that air bubbles don’t build up which would cause the Bends. It is also used in thermoregulation to shunt blood to the periphery to deposit heat there instead of the lungs where it would be lost.
How can turtles shunt?
The musculature in the pulmonary vein constricts and reduces or stops blood from moving to the lungs and all the blood goes to the rest of the body.
Why is nest emergence synchronized in turtles?
To avoid predation as it’s harder to get all of the hatchlings as opposed to just one at a time
What is Type 1A sex determination?
Females are at high temperatures; males at low temperatures
Which side of the femur is the 4th trochanter located and what does it do?
Located on the medial side and helps to retract the femur
What is Type 2 sex determination?
Females at high and low temperatures; males at intermediate temperatures
What is Type 1B sex determination?
Females at low temperatures; males at high temperatures
How do turtles navigate?
Use magnetic fields and currents
What are 5 synapomorphies of Archosauria?
-Antorbital fenestra
-Mandibular fenestra
-Thecodont teeth (tooth root in jaw)
-Double row of osteoderms along vertebral column
-Fourth trochanter on femur (muscle attachment to tail)
What are the limbs used for in swimming?
Steering - no propulsion
What are the 3 clades within Crocodylia?
-Crocodylidae
-Alligatoridae
-Gavialidae
What kind of ankle do crocodiles have?
Crurotarsal
What allows crocodylians to breathe with their nostrils and eyes above the water?
A secondary palate
What kind of respiration do crocodilians use?
Cuirassal breathing
Explain cuirassal breathing.
-Diaphragmatic contracts and pulls the liver back
-Liver pulls lungs back and creates a negative pressure
-Air is drawn in
-Stiff ventral plate
-Allows for easier breathing while locomoting
What is the structure that allows crocodiles to shunt?
Foramen of Panizza - connects right and left systemic arteries
When do crocodiles use shunting and how do they do it?
-Use it when they are holding their breath underwater
-The cogwheel valve in the pulmonary artery contracts and prevents blood from moving through
-Blood is then redirected through the Foramen of Panizza where it goes through both systemic arteries and flows to body
How does crocodilian sex determination work? What type is it?
Temperature dependent sex determination where males are at high temperatures and females are at low temperatures. This is Type 1B.
How do crocodiles communicate?
Through audible vocalizations and subsonic vibrations
Why do crocodiles send deoxygenated blood to their gut?
It aids in digestion. The low [O2] and high [CO2} causes the blood to be more acidic, which helps break down tissues
What are 4 synapomorphies of Aves? What is NOT a synapomorphy?
-Laterally oriented glenoid fossa on the scapula
-Feathers modified for flight
-A short tail (23 or fewer caudal vertebrae)
-A reversed hallux
-Feathers are NOT a synapomorphy
What is the most diverse group of tetrapods?
Aves
What 2 groups is Aves divided into?
-Palaeognathae (old jaws)
-Neognathae (new jaws)
What are feathers?
A keratin outgrowth that is likely a highly derived form of a scale
What are the 4 basic properties of an airfoil?
-Thrust
-Weight
-Lift
-Drag
How do feathers connect?
The proximal barbules hook onto the distal barbules of the next feather
How does increasing the angle of the wing generate lift?
Air will move faster over top, which generates a pressure difference and creates lift. Low pressure air will be on top of the wing and high pressure air will be underneath. It also minimizes the effect of drag
Which part of the wing generates lift and which part generates thrust and direction?
-Inner wing (secondary feathers) generate lift
-Outer wing (primary feathers) generate thrust and direction
How can birds overcome turbulence?
By slotting the alula, which forces air in between and reduces the effect of turbulence
What happens when the alula is moved out?
It creates vortices that stabilize airflow at low speeds
What is the purpose of slits between the feathers?
Reduces turbulence
What is wing loading?
The ratio of a birds weight to its wing area
Do smaller birds have small or large wing loading? How does this affect flying?
Small birds usually have smaller wing loading. This results in slower flight, lower stalling speed, and easy take-off and landings
What type of wings have a low aspect ratio?
-Elliptical
-Passive soaring
What is the aspect ratio?
It is the square of the wingspan divided by the wing area.
What type of wings have high aspect ratios?
-Active soaring
-High speed
-Hovering
Wings that are long and narrow
What are the 2 requirements for soaring?
-Low wing loading
-Large size
What are the 2 types of soaring?
-Static (passive) soaring - vertically moving air
-Dynamic (active) soaring - horizontally moving air
How does flapping flight work in small birds?
-Lift and thrust are generated on the downstroke
-Upstroke is only for recovery and feathers are separated so wing is not a foil
What 2 currents are used in passive soaring?
-Obstruction currents (cliffs)
-Thermal currents (warm spots)
How is dynamic soaring used?
-Air at the surface of water is slowed down due to friction
-The bird can climb up the gradient of air speed and glide back down
What is the most energetically expensive form of flight?
True hovering (hummingbirds)
How does flapping flight work in large birds?
-Downstroke is the same and generates lift and thrust
-During upstroke, the humerus is rotated and the wing moves in a figure 8 pattern
-This generates lift and thrust on the upstroke as well
What are feathers homologous with in reptiles and mammals?
Reptiles: Scales
Mammals: Hair
Are feathers continuously growing?
No, they are dead when fully grown and cannot repair themselves
What is the structure called that runs down the center of a contour feather?
Rachis
Where does the blood vessel enter in a contour feather?
Through the lower umbilicus and runs through the calamus
What are the 5 types of feathers?
-Filoplume
-Down feather
-Semiplume
-Bristle
-Contour (vaned)
How do feathers develop?
-Feather papillae from the dermis grow out and form a cone which protects the feather as is develops inside. The cone then disintegrates and the feather becomes exposed
Why do peacocks have so many caudal feathers?
Sexual selection
What is molting?
When all feathers are shed at the same time so that they grow back evenly and organized. Papillae are activated and push feathers out
Why does molting occur?
-Replace worn/damaged feathers
-Change insulation properties
-Change colouration for breeding
How is blue colouration produced?
Particular air bubble arrangement within the keratin complex that scatters all wavelengths except for blue. Known as Tyndall scattering.
How is most green colouration produced?
Blue structure with yellow pigment on top
How is iridescence produced?
-Melanin is arranged in rows
-Some light is absorbed by the melanin and the rest bounces out
-Colour that is perceived depends on the angle being viewed
What type of colour vision do birds have?
Tetrachromatic (can see UV spectrum and RGB)
What are 3 ways birds can change colour?
-Molting
-Fading and bleaching of feathers
-Wear and abrasion (preening)
What is preening?
The process of cleaning and maintaining feathers
Which gland secretes oil that can be spread over feathers during preening?
Uropygial gland
What is anting?
Allowing ants to crawl into plumage. Formic acid from ants may help inhibit bacterial and fungal infections. Can be active or passive.
What type of sex determination do birds have and which are males and which are females? Which is the default?
Chromosomal sex determination
-ZZ -> Male (default)
-ZW -> Female
How does food processing work in birds?
-Esophagus has an out-pocketing called the crop that stores food
-The proventriculus has digestive enzymes that break the food down
-The gizzard is muscular and further breaks down the food
-Absorption occurs in the small intestine and the large intestine
What allows birds to have kinetic skulls?
The quadrate joint
Why are all birds oviparous?
Because bird body temperature ranges from 40-42 degrees and optimal temperature for eggs is 37 degrees. Staying in the mothers body would be too warm
What is the eggshell made of?
Calcium carbonate
How is the shell formed?
Mammillary bodies attached to the outer shell membrane secrete calcium carbonate that crystallizes and moves around and up
Why do some brooding birds lose feathers on their ventral side?
Develops more blood vessels and exposes them so that more heat can be transferred to the eggs.
Do large birds or small birds typically have longer periods of parental care?
Large birds
