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