BIO 220 final

What are the characteristics of paleognathids (aka ratites)? How do they differ from neognathids?

"Paleognathae" - the "ratites" Grade of primitive birds, usually flightless, characterized by ancestral condition in roof of mouth - solid fusion of many sutures and a rigid structure; limits size of food items. Likely evolved from the flying birds. e.g. ostrich Egg size is constrained due to SA:V Virtually all extant forms are confined to S. Hemisphere Neognathae - the "modern birds"; primary palate is extensively modified -Real diversification/number of species in birds occurs in this group. {{Raties: palate at top of mouth is modified. More fused, maybe less flexible?}}

Crocodiles :)

(Sub)Order CROCODYLIA Alligators, caimans, crocodiles, & gavials Species diversity - 3 extant families, 7 genera, 22/23 species; size: 1.2 m to ~ 7 m in length Distribution - pan-tropical, but the genus Alligator extends in to temperate regions of North America & China (can't deal with ice) -Diapsid skull structure -Brain = tiny; big teeth and jaws with lots of muscle attachment. Synapomorphies (*= with birds): -*thecodont dentition - dermal plates beneath epidermal scales - elongate massive skull, quadrate bone fixed - diaphragmaticus muscle - originates on pelvis & inserts on liver; retracts liver which then acts as a mammalian diaphragm to create negative air pressure in thoracic cavity, and pulls air into lungs - *secondary palate in the skull - complete/nearly complete division of the ventricle (4-chambered heart) - anterior of stomach modified into muscular *gizzard - *no urinary bladder (NH4 secreted as uric acid) - *♂♂ establish territories, vocalize, & engage in complex courtship behavior - all species that have been studied have TSD development - genus Alligator can tolerate mild freezing; also a keystone species in places like the Everglades ecosystem Locomotion/swimming: swim with tail, run with legs Snout width is often a diet indicator; very narrow = fish eater, broader snouts = generalist feeders Ambush predators - have advantage in water, wait for prey to get close to edge

What is the "angle of attack" and what happens when it is too steep? (exam)

*angle attack is slight angle in wings to generate lift* -If the angle of attack is too great, the wing will produce a lot of drag. -If the angle is too small, the wing won't produce enough lift.

What was the great American interchange? What event made it possible?

- linking of the American continents via formation of the Isthmus of Panama; ~ 3 - 6 X 106 yrs ago; armadillos & opossums colonized N. America, and placentals moving south eliminated medium to large-sized marsupials in South America Lots moved from north to south. Marsupials LOST to the Eutherians. {{Opossums are the only successful marsupials to invade north America. But lots of placental mammals were able to invade the south}}

What are the trends in evolution of the dinosaurs and why are dinosaurs still of interest to us today?

--helps us understand diversity today... where alligators and birds came from today-- Permian Period - radiation of clade Synapsida (beginning 280 MYA) Mesozoic Era - "Age of Dinosaurs" (245 - 65 MYA); within this era, 3 important events: Triassic Period - origin of mammals (from theraspids) Jurassic Period - origin of birds Cretaceous Period - large radiations of 2 clades of "dinosaurs" (Ornithischia, Saurischia), as well as clade Pterosauria (REAL age of the dinosaurs) Snakes and lizards get going AFTER dinosaurs die out. Subclass DIAPSIDA - 2 temporal fenestrae Superorder: ARCHOSAURIA1 - "ruling lizards" (DINOSAURS); dominated the Mesozoic Era ("age of dinosaurs") 1synapomorphy - antorbital fenestra Order: Thecodonta† = earliest Order: Saurischia†* = theropods/sauropods *(Sub)Order: Aves = birds *(Sub)Order: Crocodylia = crocodilians Order: Ornithischia† = ankylosaurs/stegosaurs -Clade: Dinosauria -Didn't give rise to anything Order: Pterosauria† = pterosaurs -Good diapsid reptiles. Lots of diversity. True powered flight; Invertebrates= insects, Vertebrates= birds, bats, pterosaurs Superorder: LEPIDOSAURIA - "scaly lizards"; lizards, snakes, & relatives (amphisbaenians, tuataras) {{Two groups. Saurischian and Ornithodiran, bird vs lizard hipped dinos. Dinos diverse in Mesozoic. Most extinct at end of cretaceous. Birds essentially are dinosaurs so they are interesting to us for that reason. Birds are descended from dinosaurs. Included the largest land animals that ever existed, so we can study how they were able to do that.}}

Is there variation in the number of neck vertebrae in mammals? (exam)

-7 cervical vertebrae: secondarily lost in some (manatees & sloths) Differentiated from other vertebrae. (giraffes and humans and rats have same number... 7! neck length doesn't really matter...)

When a bird takes flight, how does it keep the upward stroke of its wings from causing the bird to fall? (exam)

-A bird's wing produces lift and thrust during the downstroke. -The air is deflected downwards and also to the rear. -The bird reduces its angle of attack and partially folds its wings on the upward stroke so that it passes through the air with the least possible resistance.

In what ways has flight constrained bird morphology? **(FINAL QUESTION) (POSSIBLE ER)**

-Light, lone bones (pneumatic) -Need feathers for flight/warmth -Keel of Sternum: large bone surface area for muscle attachment -Need air sacs for max oxygen (must have feathers for warmth/surface area, must have 4 chamber heart for bloodflow to keep up with activity, tons of muscle) (can't be big because they would need HUGE muscles for flight)(can't be small bc too small would be hard to keep warm)

What are advantages of homeothermy? What are disadvantages of homeothermy?

-Small homeotherms can't get too small (not smaller than Bumblebee Bat) ...ectotherms can be super duper small) -Why mammals have a good cooling system Advantages include: greater endurance in physical activity, exploit broader range of thermal environment (esp. lower temps.) Disadvantages include: high metabolic cost esp. for small homeotherms, must eat often to obtain energy

Bird wings are airfoils. Describe how they create lift. (exam)

-The airfoil is shaped such that the air provides a net upward force on the wing, while the movement of air is directed downward -The streamlining of bird's body and wings reduces these forces.

Why is drag problematic for birds, and how do they overcome it? (exam)

-drag opposes flight direction -their body shape helps reduce drag (teardrop shape limits pressure drag) -their feathers are an interesting texture that helps reduce friction drag.

What adaptations do birds use to navigate on their long migrations? Why is it advantageous for many bird species to expend lots of energy migrating long distances? (EXAM QUESTION FO SHO)

-probably brain adaptations -well developed optic lobes and cerebellum which is coordination and equilibrium -adaptation= greater cerebellum size, able to be super-efficient when flying because they have super good respiratory systems -better food -weather -mating -overall more hospitable conditions (winter makes insects less abundant) (they wouldn't stay in Mexico where it is warm year round because there would be more competition and potentially more predators)

Are hummingbird flight muscles white or red? Explain why this is important. (exam)

100% red muscle (pigeon = 86% red:14% white; chicken = 11% r: 22% intermediate: 67% w) -greatest dexterity in hovering, lateral, & backwards flight -need constant blood flow for constant oxygen that red muscle provide

D&C 59:18-20

18 Yea, all things which come of the earth, in the season thereof, are made for the benefit and the use of man, both to please the eye and to gladden the heart; 19 Yea, for food and for raiment, for taste and for smell, to strengthen the body and to enliven the soul. 20 And it pleaseth God that he hath given all these things unto man; for unto this end were they made to be used, with judgment, not to excess, neither by extortion.

How many occipital condyles do mammals have and what is their purpose?

2 occipital condyles** - skull articulates to spine (birds and reptiles have one) A protrusion on the occipital bone of the skull that forms a joint with the first cervical vertebra, enabling the head to move relative to the neck. The occipital condyle is the structure on the back of the skull that allows it to articulate with the first neck vertebra.

What is the origin of middle ear bones in mammals? Name the bones and also give the names of what they were called before. (exam maybe?)

3 middle ear ossicles - malleus, incus, & stapes (bony connection) (only mammals have inner ear bones) Transport sound better. Increases jaw articulation as well. Middle ear bones - with reduction of all lower jaw bones other than the dentary, which increases in size, mammals incorporated former reptilian jaw elements into the middle ear; these include: angular --> tympanic bone in mammals articular --> malleus in mammals quadrate --> incus in mammals stapes = stapes (columella; homologous) The bones WERE jaw bones in the reptile jaw, but became inner ear bones in mammals.

What is the importance of skull kinesis in lizards and snakes?

Can't chew... must swallow prey whole. Loss of 2nd skull arch; extreme cranial kinesis associated with specialized prey capture/swallowing (VERY mobile). Remember snakes can't chew, must eat prey whole. Elements of the jaw are independent of each other (ie left and right side of jaw can move separately- use alternating sides of mouth to pull food into mouth) Feeding: body elongation in limb-reduced/ limbless squamates redistributes body mass into the shape of a small-diameter tube with a small mouth; this decreases the maximum prey size that can be ingested - there are 3 solutions: 1- bite small pieces out of large prey (amphisbaenians) 2- specialize on large numbers of small prey (many legless lizards, worm snakes, blind snakes) 3- morphological specializations that permit swallowing large prey (most other snakes)... EXTREME CRANIAL KINESIS

Someone asks you if a turtle is an "anapsid". You answer "yes and no". Explain.

ANAPSIDA - earliest group, skull with solid dermal plates, & no temporal fenestrae Ancestors of turtles were diapsid, but now show an (highly modified) anapsid condition. True/basal anapsids are all extinct. Turtles secondarily converted to be anapsids. notes: (turtles are not originally anapsides, derived from synapsid but they are highly modified with two extra holes in skulls so some consider it not.... Maybe not on exam... weren't originally anapsid but are highly modified and now are!)

How do birds stay aloft without flapping constantly? (exam)

Air from high-pressure areas beneath the wings tends to flow over the wingtips into the low-pressure areas above the wings.

What are the functions of air sacs in birds?

Air sacs make a more efficient respiratory system possible. Human lungs can't totally deflate, so we always have a reservoir of "dead" (deoxygenated) air left inside of them. 2 Breath Cycle (humans= 1 breath cycle): 1st inhalation - 75% of air by-passes lungs to reach posterior air sacs (= reservoirs of fresh air); 1st expiration - this air passes back into lungs; (air becomes deoxygenated at the lung) (one way flow over lungs = EFFICIENT, humans have two way flow) 2nd inhalation - air in lungs passed back to anterior air sacs; 2nd expiration - air in anterior sacs passed to the outside; 2 respiratory cycles are needed to get one breath through the system. (air can only pass one way through the trachea) At 1st inhalation, 75% of air by-passes lungs to reach posterior air sacs; these are reservoirs of fresh air. At 1st expiration, this air passes back thru lungs; 2nd inhalation - air passed to anterior air sacs, & 2nd exhalation - air is exhaled 2nd function - cooling body during flight; 27X more heat produced in flight, relative to resting metabolism

Marsupial young are altricial. What does this mean? (exam? idk?)

Altricial young - born in embryonic state of development; must crawl to pouch & attach to nipple (n = 1 - 13 pr), where prolonged lactation & extensive parental care are required

Describe the 4 different skull structures in amniotes and match amniote groups with their skull structure. (probable exam question)

Amniote skull types - all differ with regard to the number of temporal fenestrae, & placement of these with respect to the post-orbital - squamosal suture Anapsid (0): turtles, early 'reptiles' Synapsid (1): mammals, therapsids Diapsid (2): crocodiles, dinosaurs, birds/snakes, lizards Euryapsid (1 on top): placodonts, marine reptiles (all extinct) (snakes= modified diapsid) By late Carboniferous/Permian time, ~ 300 MYA, amniotes had separated into 3-4 groups: (tell apart by holes in skull) ANAPSIDA - earliest group, skull with solid dermal plates, & no temporal fenestrae (common ancestor) SYNAPSIDA - 1st large radiation, Permian (280 - 210 MYA); single temporal fenestra (below po-sq suture) includes ancestors of mammals (ancient reptiles, abundant and diverse early on) DIAPSIDA - large Mesozoic radiation ("Age of Dinosaurs"); 2 temporal fenestrae; ancestors of all extant (reptiles + birds) EURYAPSIDA† - single temporal fenestra (high up on skull); several extinct marine groups (ichthyosaurs, plesiosaurs) (totatlly extinct; marine reptiles) "Holes" increase surface area for muscle attachment. Can't have a strong head (jaw) AND big brain. Can't have a big head AND move fast. SEE PIC ON PHONE {{Ancestral condition = anapsid, no holes. Euryapsid has single hole in DIFFERENT place than sinapsid. Large aqua dinos. Mammals evolved from synapsids. Snakes are modified diapsids, lost arches. Turtles are secondary anapsids.}}

Why must birds keep their feathers clean and what adaptations do birds have to accomplish this?

Birds must preen feathers - with oil from gland at base of tail (preen gland); this water-proofs/ cleans feathers;, & provides some resistence to ectoparasites. Especially water birds. Oil displaces the bird's "special oil" and then they won't be waterproof anymore. -Moisturizing feathers with preen oil so they are flexible and strong, instead of brittle and easily breakable. This helps feathers better withstand the stress of flight. -Aligning feathers for optimum waterproofing and insulation to protect against adverse conditions, such as soaking or extreme hot or cold temperatures. -Aligning feathers into the most aerodynamic shape for easier, more efficient flight. This helps birds use less energy in flight and make more acrobatic moves. -Removing feather parasites and body lice that can destroy feathers or carry disease. This keeps birds healthier and protects the entire flock or nest from an outbreak.

Turtles :)

Ancestors were diapsid, but show an anapsid condition. True/basal anapsids are all extinct. Turtles secondarily converted to be anapsids. Order: TESTUDINES - turtles, terrapins, tortoises; 2 suborders: Cryptodira - "hidden necks"; majority of extant taxa (11 families) Pleurodira - "side necks"; 2 families, extant taxa restricted to "Gondwana" land masses Diversity: 313 species; 13 families, species diversity highest in SE Asia & SE US; size ranges from ~ 7 cm - 2.2 m in length -LOW DIVERSITY: means they're a highly specialized group -Prehistorically there was a larger size distribution Distribution: cosmopolitan - marine, freshwater, & terrestrial habitats on all habitable continents, except at high elevations & high latitudes -GOOD REPTILES: all terrestrial forms, but some go back to water... still breathe air and must reproduce on land. Ice causes problems for turtles. Good fossil record -Because they are so bony Longevity - 70+ yrs in nature, for common & alligator snapping turtles Long-distance migration - the oceanic voyages of marine turtles Synapomorphies for TESTUDINES: 1) 2-part shell; carapace - dorsal half, dermal bony plates solidly fused to most of the vertebrae & all ribs; plastron - ventral component, dermal plates fused to clavicles, interclavicles, & gastralia (abdominal ribs) 2) Shells are usually covered with epidermal scutes (figure at right) 3) girdle placement - organization of ribs fused to dermal plates requires that pectoral & pelvic girdles be shifted inside of the rib cage (this occurs during embryogenesis) 4) no teeth (in extant species) - jaws covered with keratinized beak-like structure; tomium

Describe the evolutionary process of the development of a turtles shell. What are the advantages and disadvantages of a turtles shell? *** FINAL EXAM ***

Armoring protects them from being eaten. -> turtles invert to put scapula on inside and "ribs" on outside which is their shell -> temperature-dependent sex determination Shell morphology reflects ecology Flat = aquatic High domed = more likely terrestrial Cryptodira - the "hidden-necked" turtles; common freshwater turtles, land tortoises, & sea turtles -Ribs compose the shell and fit into the backbone. Vertebra fused to a part of the shell. First vertebra of shell acts as a hinge and allows a 180 degree turn to pull head inside. SEE PIC Pleurodira - the side- and snake-necked turtles; South America, Australia, & Africa - Madagascar -Turn nexk to the side and lays along the side of the shell. Girdle placement - organization of ribs fused to dermal plates requires that pectoral & pelvic girdles be shifted inside of the rib cage (this occurs during embryogenesis) -Shoulder blades are INSIDE the shell (different from humans and alligators- the shoulder blade sits outside the thoracic cavity). -Shell covers the pelvic and pectoral girdle. ADVANTAGES: -Protection from predators. -Although the shells restrict their movements, they offer stronger protection than the shells of sea turtles. (Heavier for land turtles) -Shallower, more streamlined shells to help them swim faster through the water. DISADVANTAGES: -Mobility: turtles are never very fast. Not much room for lungs and shells can weigh them down. -Digestion: Turtles can't eat too much because their stomach cannot expand. -Reproduction: female is "stuffed" full of eggs. Must lay eggs ASAP because she can't eat while yoked up eggs are inside her. {{Ribs started to develop into a shell. Shoulder blade normally outside of shell/ribs, but they evolved to have hips (pelvic girdle) and shoulders inside the rib cage.}}

Describe the diversity and function of venom in the snakes.

At least 4 clades characterized by salivary enzymes modified for extreme digestive efficiency and/or toxicity; with dentition highly modified for envenomation TEETH: -harmless snakes (no fangs) -Fixed fangs -Rotating bones attached to top fang Snakes can regulate how much venom they inject. Can bite without venom as well. Can run out of venom. Babies have more toxic venom. Snake venoms - complex mix of proteins (enzymes & specific toxins), & the composition of these varies by species 2 classes of systemic effects: -hemorrhagic - causes massive local tissue destruction (= necrosis); vipers (causes blood clotting) -neurotoxic - very little necrosis, but acts on nervous system, leads to neuromuscular paralysis; cobras, coral snakes, sea snakes (blood and circulatory system spreads poison and acts on the nervous system) Classes of venom proteins: -Enzymes= digestion; destruction of local tissue -Non-toxic proteins= vasodialation, blood coagulation, etc. -Toxic proteins= disruption of nerve-impulse transmission Source of venom: synthesized in modified salivary gland Primary function - immobilize/kill prey Secondary function - digestion (for hemorrhagic venoms) Ecological significance?? ~ 5,000+ bites/yr in the US (some proportion of these are "dry bites"); This total results in ~ 5 deaths

What sensory system is typically most highly developed in birds? Why is it often more highly developed than other sensory systems?

Birds = vision is dominant Sensory (not super great sense of smell) Humans are similar. Large part of the brain is taken up by color vision. -Birds have 4 types of cones (humans have only 3 types of cones) so they see more colors. -cerebellum extremely well developed; coordination center for muscle-position sense, equilibrium, & visual cues -optic lobes well developed -eye/vision extremely well-developed in most species; visual acuity of hawk/eagle ~ 8X better than human; for owls, ~ 10X better in dim light -good for avoiding predators, catching prey, spotting small insects

Describe the uses and advantages of hair.

Body hair - reduced in some, but always present (derived from scales, like bird's feathers) Hair: minimizes cost of endothermy Outer layer - longer, more bristle-like; often H2O repellent (useful in maintaining endothermy) (only things humans have left) Under coat - soft & densly packed; insulates (against sun, wind, rain); may trap air to retain heat (depends on hair erection muscles); water-proofed by sebum (from sebaceous gland in each follicle) (how they stay warm e.g. sea otters -- no fat/blubber. Most densely packed hair of any animal on earth)

Describe the first day in the life of a marsupial.

Born in embryonic state of development; must crawl to pouch & attach to nipple (n = 1 - 13 pr), where prolonged lactation & extensive parental care are required

What are the synapomorphies of amniotes and how do they facilitate a terrestrial lifestyle?

COMPLETE TRANSITION ON TO LAND, VIA 'TERRESTRIAL EGG' & 'TERRESTRIAL SKIN' big idea = no need of water for reproduction exam info below (3): 1) amnion (amniotic sac) 2) allantois (gas exchange/ waste) 3) chorion (becomes placenta in mammals) CRENS GOV Amniote synapomorphies: 1 - ♂♂ of most with true copulatory organ 2 - rib-ventilated aspiration (negative pressure, augmented in some by cloacal or pharyngeal gas exchange) (create vacuum by increasing surface area and air is sucked in) 3 - amniote egg - characterized by 3 "extra-embryonic" membranes (perform function that normal pond water would do): -amnion - amniotic sac in livebearers -allantois - gas exchange, waste (large surface area) -chorion - becomes placenta in mammals (membrane on boiled egg) -Fertilization is always internal, & there is never a larval stage of any kind -If the egg gets too big, the surface area of the shell won't support baby. Also gas exchange would be too limited. Why dinosaur eggs are so small (football sized). 4 - 12 pairs of cranial nerves (increases head sensory capabilities) 5 - skin covered by keratinized "water-proof" structures of epidermal origin - scales, hair, feathers, etc., epidermis itself more keratinized, & has a high [lipid] to further slow water loss; (doesn't lose water. doesn't need a humid environment. heavily keratinized and allows water to be retained in the body) 6 - complete absence of gills at all life stages (paired pharyngeal pouches present in embryos) 7 - skeleton well ossified, ribs with sternum (Gravity. Ribs come all the way around. Forms a "basket." Supports muscle mass and allows animal to move fast.) 8 - ventricle partially or completely divided (separate flow of blood; double loop system) carry the pond with you

Describe the process of molting and how birds have adapted to accomplish it.

Can molt them all at once (stay in the middle of lake for 2-3 weeks until feathers grow back) OR molt in symmetrical pattern (ie same feather molted on each side) Plumage - general pattern of adult feathers (color texture, etc.); dead at maturity, so there is a seasonal loss, or molting, of some/all feathers: -flight & tail feathers lost in exact pairs; replacements emerge before next pair is lost (which maintains balance; most birds can continue to fly) Most species molt at least once/yr, usually in late summer after nesting Bright coloration --> off-season coloration {{If the bird can be protected for a while without being able to fly (waterfowl) then it will molt all feathers at once. Birds that still need to fly will lose symmetrical pairs.}}

How do snakes and lizards use their vomeronasal organ? What is its purpose?

Chemoreception: 1) Tongue - deeply forked, tines spread apart to maximize directionality of detection of non-volatile cues from substrate (pick up molecules on tip of the tongue. Split so they can smell on both sides and know direction of scent) 2) Vomeronasal organ - paired "blind sacs" in roof of mouth that receive cues from the tongue; signal brain as to what substance is transferred into mouth (May be because they don't want dirt to get in large nasal cavities while smelling, so they have small cavities for breathing (ish) and use their tongue to smell) Tongue touches vomeronasal organ and molecules are sensed.

Describe "Amphisbaenia".

Clade AMPHISBAENIA - "double - walk"; the so-called "ring lizards" or "worm lizards"; 21 genera, ~ 168 species; mostly tropical/ subtropical distributions (Africa, South America; 1 in US); entire clade is fossorial (burrowing), with many synapomorphies evident as adaptations for this life history. Synapomorphies: - fused eyelids - skull heavily reinforced (used as a wedge for digging) - body elongate & of ~ equal diameter throughout - most completely limbless - body encircled w rings of scales, all ~ equal in size - left lung only is functional; right lung = vestigial Snakes, in contrast, are thinner on the ends. Re-evolution of form similar to caecilians (amphibians)

Birds :)

Class AVES - birds, ~ 9,850 extant species, size range - Bee Hummingbird of Cuba (~ 2 gm) to the African Ostrich (100,000 gm); ecologically birds live almost everywhere on earth (Arctic, Antarctic, open ocean, etc.) - despite the range of body sizes, their overall morphological diversity is relatively conservative due to constraints on muscle, skeletal, etc. systems associated with flight. (Birds are modified enough to no longer be considered reptiles... Birds are endotherms that fly. (Feathers could be considered scales.)) Characteristics: -beak - toothless (in all extant birds) mandibles covered by thick keratinized sheath -integument - very thin, few glands -feathers* - modified epidermal scales; function in thermoregulation & flight (* shared with some advanced theropod dinosaurs) (hair is dead, feathers are dead; their wings are "cold") -forelimbs - extensively modified as wings (not always for flight) -no urinary bladder* - derived trait shared with the Crocodylia (ditto 4-chambered heart) (can't afford to carry water) -furcula* - clavicles fused to form a "wishbone" ; sternum with huge keel -lunate wristbones* - swivel motion associated with flight -uncinate processes - interlock entire rib cage -pygostyle - fused caudal vertebrae -synsachrum - pelvic girdle fused to lumbar vertebrae, lumbar & thoracic vertebrae fused & immobile (When a bird flies, its backbone is completely rigid. Allows all the energy of the bird to go into flapping/flying) -manus - reduced to 3 digits -long flexible neck* - disproportionately long for balance -tri-dactyl foot* - hallux projects backward; digitigrade walk -pneumatic bones* - 'hollow' & light (strong with little weight; rather than be solid, they have fused struts inside) (long thin legs) -red muscle fibers with extraordinary capacity for sustained activity; high [Hb] - rapid O2 uptake (good for ENDURANCE. Allows long flight time/distances) birds cant be big because their muscles for flight would have to be HUGE

What are the synapomorphies of mammals?

Class SYNAPSIDA - 1 pr temporal fenestrae, below post-orbital/squamosal suture Clade MAMMALIA - mammals; ~ 5,500 extant species, size range = Bumblee Bat (1.5 gm) to the Blue Whale (200 tons); ecologically mammals live almost everywhere on earth (Arctic, Antarctic, open ocean, deserts, highest elevations, tropical rainforests, etc.). Synapomorphies: 1-Body hair (key synap.): reduced in some, but always present (derives from scales, like feathers for birds) 2-Mammary glands (key synap): for nursing young with milk (functional in ♀♀ only) (key adaptation in mammals. Explains their success more than any other trait) 3-Greatest diversity of glands in integument: (sweat, scent, sebaceous, etc.) 4-Fused pelvic bones: ilieu, ischium, & pubis form a single element 5-3 middle ear ossicles: malleus, incus, & stapes 6-Dentary: squamosal jaw articulation 7-Neocortex: most highly developed part of the brain Additional Characteristics :) (* = convergent conditions also found in some clades of Reptilia; ** = ancestral tetrapods) -4-chambered heart*: ventricle completely divided -2 occipital condyles**: skull articulates to spine -Homeothermy*: very well developed -Secondary palate*: very well developed -7 cervical vertebrae: secondarily lost in some (manatees & sloths) -Dentary bone: only component of lower jaw -Thoracic diaphragm: chief means of inspiration of lungs -Heterodont dentition: incisors, canines, pre- molars, & molars (unless secondarily lost in some) -Diphyodont dentition: in some (deciduous & permanent teeth)

What are hemipenes, and why are they paired?

Copulatory organ in male sqamates (snakes, lizards, etc) = paired hemipenes (s. = hemipenis) (internal fertilization required) Because each testis is dedicated to a single hemipenis, an alternating pattern of hemipenis use would allow a male a second chance to transfer a fresh batch of sperm if he has just mated recently

What is the function of the "diaphragmaticus" muscle in crocodylians?

Diaphragmaticus muscle - originates on pelvis & inserts on liver; retracts liver which then acts as a mammalian diaphragm to create negative air pressure in thoracic cavity, and pulls air into lungs.

What is diphyodont dentition?

Diphyodont dentition - in some (deciduous & permanent teeth) Lose some teeth. Example: baby teeth vs adult teeth Some MAMMALS have this

Eutheria :)

EUTHERIA - true placental mammals; includes ~ 95% of all extant species; phylogenetically these are clustered into about 21 clades (usually called orders), and include several with extremely well-developed neocortex regions and sophisticated social organizations (including the clades Carnivora, Cetacea [whales, dolphins], Primates, & Proboscidea [elephants]; among others); the largest clades - those with the most species - include Rodentia (rodents, ~ 2,300+ species) & Chiroptera (bats, ~ 1,100 sp); LARGE size permitted due to large brain with well developed neocortex Good set of traits allows them to diversify... Synapomorphies: (several skeletal features) -Chorio-allantoic placenta - nutrients provided to embryo from maternal blood stream via villa of placenta

How do snakes swallow prey larger than their head?

Extreme cranial kinesis. (highly modified diapsid skull)

Describe similarities and differences of mammalian horns and antlers.

Horns/antlers: organs of display/combat (Fight off competitors. Impress females) True horn - bony core w keratin sheath; unbranched, not shed, present in both sexes (true antelope, goats) (outgrowths of bone) (can have keratin (hair) based covering) (PERMANENT. Exception: North American prong horned antelope sheds horns) Antler - only bone, shed annually, branched, almost always grown on males only (grow out from skull with velvet covering- fastest growing tissue in the vertebrate world) (grow over period of 2-3 months) (lose and regrow every year) (Blood vessels nourish the bone until it's done growing. Then the antler (bone) is dead. Broken off doesn't hurt or bleed.)

Snakes are often highly specialized in their feeding. Describe their adaptations for prey capture and ingestion.

Feeding: body elongation in limb-reduced/ limbless squamates redistributes body mass into the shape of a small-diameter tube with a small mouth; this decreases the maximum prey size that can be ingested - there are 3 solutions: 1- bite small pieces out of large prey (amphisbaenians) 2- specialize on large numbers of small prey (many legless lizards, worm snakes, blind snakes) 3- morphological specializations that permit swallowing large prey (most other snakes)... EXTREME CRANIAL KINESIS loss of 2nd skull arch; extreme cranial kinesis associated with specialized prey capture/swallowing (VERY mobile). Remember snakes can't chew, must eat prey whole. Elements of the jaw are independent of each other (ie left and right side of jaw can move separately) 2 Ways to subdue dangerous prey: 1) Constriction: wrap around body and constrict thoracic/abdominal cavity (makes it hard for prey to fight back) 2) Modification of Salivation Enzymes: toxic venom, usually bite and release. -at least 4 clades characterized by salivary enzymes modified for extreme digestive efficiency and/or toxicity; with dentition highly modified for envenomation Skin stretches because leathery/scaly skin. Normally the scales overlap, but they can be pulled apart. Capture: - extreme specializations of tongue/ vomeronasal organs for chemoreception (smell: chemoreception through tongue) - some groups with specialized loreal (pit vipers) or labial (boas, pythons) facial pits capable of infrared heat detection (snakes have EXTRA sensory system; Infrared heat detection) highly modified diapsid skull

What does the current distribution of marsupials tell you about their evolutionary past?

From a "Sunburned Country" Great American Interchange - linking of the American continents via formation of the Isthmus of Panama; ~ 3 - 6 X 106 yrs ago; armadillos & opossums colonized N. America, and placentals moving south eliminated medium to large-sized marsupials in South America {{Gandwanan distribution. South America, Africa, Australia, Antarctica (used to all be one land mass). Only recently invaded northern hemisphere (north America now connected to south America via the isthmus in panama).}}

Describe the differences in locomotion between reptiles and mammals. How does the movement of their spines differ?

Fused pelvic bones - ilieu, ischium, & pubis form a single element (RUNNING) (Bird's bones are fused for flying) *humans move forward and some reptiles can move side to side?* *humans have legs UNDER them for more efficient walking and running* Important to speed. Why mammals can outrun other animals: -Lizards: limbs are at 45 degree angles out of the body. Spine moves side to side on a horizontal plane. -Crocodiles: walk like lizards with arms at 45 degree angle. -Mammals: limbs are shifted all the way under. Wrist is off the ground, walking on toes (makes them faster). Vertebral column moved up and down. (Some dinosaurs also had limbs underneath them rather than splayed to the sides. "Rearrangement": Spinal column/limbs/girdles - show shift in advanced synapsids (therapsids) towards rotation of limbs to ventral position beneath body, and 'running' skeleton in which spinal column flexes in a vertical plane BIPEDAL: Running= loose vertebra at the base of back -HUMANS: no ribs at base of spine (ribs provide stabilization) so we can "twist" (other primates have more ribs and cannot twist) Bipedal must deal with rotational inertia: -Dinosaurs= big tails -Ostrich= long neck -Humans= Twist torso opposite of legs.

How long is gestation in marsupials compared to similar-sized placentals? How long is lactation in marsupials compared to similar-sized placentals?

Gestation: Short = Marsupials (all with short gestation periods (8 - 43 days)) (gestation - intrauterine period of development - very short, & young of all species are born as "premies" - embryos that must complete most of their development in the mother's pouch) Long = Eutherians Lactation: Short = Eutherians Long = Marsupials (prolonged lactation & extensive parental care are required)

Lizards :)

Grade "SAURIA" - lizards; > 5,350 species; cosmopolitan distribution; large diversity of body sizes (Soina - Varanus); general biology/life histories are characterized by: - moveable eyelids, external ear opening - 2 pr limbs (but many transitions to limb reduction/loss) - most diurnal, visually oriented, pronounced sexual dimorphism in many - tail autotomy widespread in many families (break at fracture plane passing thru centra [s. = centrum] of caudal vertebrae); some regeneration possible

What is the purpose of the many glands that mammals have? (exam)

Greatest diversity of glands in integument - (sweat, scent, sebaceous, etc.) Lots of glands to keep skin moist. Homeotherms must maintain body temperature. Birds= air sacs or an "air-cooled engine". We have "water-cooled engines". Mammals can afford to sweat, birds can't because water is heavy. We have a high concentration of sweat glands around the body. -Dogs pant to cool off because some don't have sweat glands (cool by water evaporating from mouth) -Birds pant as a last ditch effot to maintain temperature and stay cool. {{Sweat = thermal regulation. Gland waterproof the fur? Mammary gland}}

What is heterodont dentition?

Heterodont dentition - incisors, canines, pre- molars, & molars (unless secondarily lost in some) Have different types of teeth in mouth. Examples: Humans (omnivores) and cate (carnivores) MAMMALS have this

Define and describe "Saurischia" and "Ornithischia". From which group did the birds evolve? What is the irony here?

IRONY: Saurischians (lizard hipped dinosaurs) gave rise to birds. Ornithischians (bird hipped dinosaurs) gave rise to nothing. Ornithischians have a reversed pubis. Birds are apparently descended from saurischian dinosaurs, but have a reversed pubis like ornithischians. Cretaceous Period - large radiations of 2 clades of "dinosaurs" (Ornithischia, Saurischia), as well as clade Pterosauria (REAL age of the dinosaurs) Subclass DIAPSIDA - 2 temporal fenestrae Order: Saurischia†* = theropods/sauropods *(Sub)Order: Aves = birds *(Sub)Order: Crocodylia = crocodilians Order: Ornithischia† = ankylosaurs/stegosaurs -Clade: Dinosauria -Didn't give rise to anything {{Pelvic girdle. Ornithischians, ischium and pelvis arranged like modern birds. Saurischians, "lizard-hip" separated. Irony= birds came from lizard hipped.}}

What is the secondary palate?

In addition to providing a passage for air, makes the skull much stronger in terms of the forces generated by a powerful bite. Separates smell from the mouth. An anatomical structure that divides the nasal cavity from the oral cavity in many vertebrates. VERY well developed in mammals

Why do birds lay eggs instead of giving live birth?

Incubation/hatching eggs (all species are strictly oviparous) In order for birds to fly they had to lose density and weight. Otherwise, there is no way that they could be light enough to be supported by the winds. One of the prime reasons that birds can fly is that they are so lightweight, much lighter than a mammal of the same size. If birds were viviparous, it would not be too long before the combined weight of the mother and fetus resulted in the mother being too heavy to fly. This would prevent her from being able to escape predators, to hunt for many foods, and so on. If, however, the fetus can be allowed to grow outside the body, in an egg, the problem is resolved. {{Can't gestate. Constrained by flight. Bird clutch size is typically 5-7 eggs. Would be too heavy to fly.}}

Why is mammalian milk "biological white gold"? ***FINAL***

It's a blend of antibiotics and highly digestible nutrients that fuel and protect the young. 1) Antibiotics (experienced immune system) 2) General Nutrition (proteins, vitamins, etc) -Mother gives experienced immune system to the baby via the milk (why babies don't eat broccoli or peanuts, but baby birds/reptiles DO. they have to eat the "poisonous food" -Energy and protein doled out in mutually beneficial, often flexible schedule -Compact energy, so growth rates of mammals are rapid. -Allows mother to gather nutrients before the baby is born. Stored as fat. Provide lots of energy over short period of time. {{Highly digestible. Can be on flexible time schedule. Typically constantly available. Mother is able to transform available things (lots of options, even things normally toxic to baby) and convert them into milk. Transmit antibodies to babies. Highly nutritive. High energy allows rapid growth. Mother can gather nutrients before the baby is born. Doesn't have to leave baby to go find food.}}

How does saltation work in kangaroos? What are advantages and disadvantages?

Kangaroo 'jumping' - a type of locomotion known as saltation The hopping gate of kangaroos & wallabies is based on large hind limbs that do not move independently of each other when bearing the animal's weight (they can't walk on land); The "heel tendon" is very large and extremely elastic, so that it is stretched almost to full capacity on each "down stroke" of the jump, and then recoils under its own tension to produce the upward spring, with virtually no muscle energy; This "pogo stick" hop is much more energetically efficient than any other mammal of the same body mass running at the same speed

Describe the shift from a quadrate-articular jaw joint to a squamosal-dentary jaw joint. (exam maybe?)

MAMMALS: Dentary: squamosal jaw articulation (Entire lower jaw made up of dentary. Bone in crocodile for jaw joint moved to mammal inner ear) (became maleous, incus, stapes maybe??) Lower jaw bones - strong trend towards increase in size of dentary (white bone in figure at right) at the expense of all other elements; eventual the transition is complete from the reptilian quadrate - articular jaw joint (upper right figure) to the mammalian squamosal-dentary jaw joint SEE PIC The ancestral synapsid (mammal-like reptile) jaw has four elements, with the articulation formed between the Articular and Quadrate bones, which is therefore referred to as a Quadro-Articular jaw. In therapsids (the ancestors of mammals), the joint has been simplified to an articulation between the Dentary and Squamosal bones, which is called a Dentary-Squamosal jaw. The Articular and Quadrate bones have moved into the middle ear as the Malleus and Incus, respectively.

What traits make monotremes seem odd to us?

MONOTREMATA - "monotremes"; egg-laying mammals; 5 extant species in 3 genera representing 2 families; restricted to the Australia-New Guinea plate *NOT A TRANSITIONAL SPECIES* Half-way mammals (between reptiles and mammals); lay eggs; don't need placenta; have milk Synapomorphies: -mammary glands (but no nipples) -several skull/dentition features unique to this clade The strange biology of these mammals is defined more by symplesiomorphic characteristics that they share with reptiles: - oviparious; all lay shelled eggs - malleus & incus present, but very large - endothermy poorly developed - digestive/urogenital tracts open into a cloaca Platypus: -Ducklike bill= electro-sensing capabilities (like sharks) Sense aquatic insects -Soft fur -Thought to be ovoviviparous (eggs hatch inside mother and born via live birth), but are oviparous (hatch from external eggs) -poisonous spurs

What traits do monotremes share with reptiles that make them different from other mammals?

MONOTREMATA - "monotremes"; egg-laying mammals; 5 extant species in 3 genera representing 2 families; restricted to the Australia-New Guinea plate The strange biology of these mammals is defined more by symplesiomorphic characteristics that they share with reptiles: - oviparious; all lay shelled eggs - malleus & incus present, but very large - endothermy poorly developed - digestive/urogenital tracts open into a cloaca

What is the purpose of the marsupium?

Marsupium - pouch supported internally by paired epipubic bones (part of pelvis) Specialized pouch for protecting, carrying, and nourishing newborn marsupial young.

What does mammalian milk consist of? How does the mother produce it? ***FINAL***

Milk (produced only in mammary glands of ♀♀): contents vary in proportions of the following: water - 40-50% proteins - 11-12% fats - 40% carbohydrates - 1-2% salts & vitamins - 1% Litter size in placentals ~ 50% number of nipples (not the case in marsupials) Modified sweat glands = derivation of mammary glands. (evolved from sweat glands) Milk comes from highly modified blood.

Describe the flight musculature of birds and how it differs from other vertebrates.

Muscle system: Pectoralis - depresses wing, main power stroke (downstroke) Supracoracoideus - raises wing (but originates on sternum, with pectoralis); these 2 muscles may comprise almost 20% of body mass in some birds (upstroke) Can pull down and up via a "pulley system" rather than placing muscle on back (like humans) SEE PIC

Marsupial baby grow quite attached to their mothers. Explain why?

Nurses for a very long period of lactation. Also requires extensive parental care in order for them the grow and develop.

What is aspect ratio?

One significant factor determining flight efficiency & type is wing shape; quantified by the ASPECT RATIO = wing length ÷ average wing width. The aspect ratio for an "average" bird would be 7 - 8, but this can vary from as low as 4 (elliptical wings, as "A" below) to a high of 18-20 (as for the albatross, panel "C" below) SEE PIC and a few others

What is parthenogenesis?

Only clade of vertebrates in which true parthenogenesis is known (1 snake; lizards from 7 families) Males don't exist at all. Doesn't require a male. Females produce embryos without eggs being fertilized.

Scaly Lizards/Snakes :)

Order SQUAMATA - "scaly"; lizards, snakes, & amphisbaenians; a large clade comprised of > 8,600 species; global distribution. Synapomorphies: - loss of quadratojugal arch in skull; frees quadrate bone to permit skull kinesis (highly mobile skull/jaw) SEE PIC - copulatory organ in males = paired hemipenes (s. = hemipenis) (internal fertilization required) General Features of Biology: -many independent transitions from oviparity to viviparity (~ 90 - 100 times in the clade) - only clade of vertebrates in which true parthenogenesis is known (1 snake; lizards from 7 families) - also many independent evolutionary transitions in the direction of body elongation - limb reduction or loss (both in lizards and snakes) Lizards have tympanum and eyelids (snakes do not). CAN have legless lizards

Describe the significance of Archaeopteryx in bird evolution?

Origin/early evolution of birds; 1st unambiguous fossil: (one of the first "missing link" fossils) 1861 - Archaeopteryx lithographica from a slate quarry in Bavarian region of Germany; skeleton shows a combination of avian features: -feathers -furcula -lunate wrist bones & theropod dinosaur features: -teeth set in sockets (thecodont) -long bony tail -unfused digits in manus -abdominal ribs Note - this was the 1st unambiguous transitional fossil from the vertebrate record; discovered just 2 yrs after publication of "The Origin" (1859) Could likely fly, but not for long distances. Halfway wings, not for flight. Maybe for heat conservation or walking around.

Mammalia :)

PROTOTHERIA: MONOTREMATA THERIA: METATHERIA - MARSUPIALIA (Transitional organism. lots of overlap between reptiles and mammals) EUTHERIA - the vast majority of living mammals; characterized by a 'true' placenta; about 19 extant orders are recognized (good placentals) ------------------------------------------------------ MONOTREMATA - "monotremes"; egg-laying mammals; 5 extant species in 3 genera representing 2 families; restricted to the Australia-New Guinea plate -poisonous spurs** -electrosensitive bills**

Why can many birds sleep on a branch and you can't?

Perching activates a unique toe-lock mechanism; bird won't fall even if asleep. (they have perching tendons in lower leg)

Describe how primary feathers differ from secondary feathers in both shape and function. (exam)

Primary feathers: (bigger) -largest of the flight feathers -They are the farthest away from the body -attached to the skin of the wing on the 'hand' of the bird. -propel the bird through the air (forward thrust) Secondary feathers: (smaller) -run along the 'arm' of the wing -sustain the bird in the air -giving it lift. (lift)

Describe similarities and differences of the mammalian jaws and reptilian jaws. (exam)

Reptilian Jaw: Additional bones in jaw (angular, articular, quadrate, stapes) Mammalian Jaw: The three reptilian jaw bones leave the jaw and become inner ear bones. (tympanic bone, malleus, incus, stapes) SEE PIC Why mammal jaw is bigger, better, faster, stronger: -lower jaw (dentary) is stronger. And only one joint for the jaw. - More bones in jaw = more loose - Can't open jaw super wide (like snakes) One closely tied joint (between squamosal (upper jaw) and dentary), therefore mammals can chew with precision. The ancestral synapsid (mammal-like reptile) jaw has four elements, with the articulation formed between the Articular and Quadrate bones, which is therefore referred to as a Quadro-Articular jaw. In therapsids (the ancestors of mammals), the joint has been simplified to an articulation between the Dentary and Squamosal bones, which is called a Dentary-Squamosal jaw. The Articular and Quadrate bones have moved into the middle ear as the Malleus and Incus, respectively.

Describe the respiratory system in birds and how it facilitates a very active lifestyle.

Respiratory system in birds - bronchi branch into parabronchi, through which air flows continuously; complemented by a unique system of air sacs throughout body (these extend into long bones). ** Birds live in the fast lane. -Homeotherms -Don't live for a long time (like some reptiles) -Reproduce fast, fly fast, etc. Soooo.. they need LOTS of OXYGEN. Air sacs make a more efficient respiratory system possible. Also work for cooling.

What adaptations to bird skeletons have occurred to facilitate flight?

Review Sesh: -> feathers: water proof, low maintenance, more surface area, insulation ->Pectorlis supracoricdies attached to big sternum for strong flight, good respiratory system, hollowish bones for lighter skeleton, fused bones and swivel bones for easy movement with flight, synsacrum, Skeleton - strong but light; example - Frigate Bird - 7' wingspan, but skeleton weighs 4 oz. Sternum of big bird = heaviest bone Flying birds = large keel for increased surface area flight muscle attachment. Bird skeletons are COMPACT Bones hollow but reinforced by 'struts' that brace the interior (= pneumatized) (almost hollow with lots of air pockets) Long and thin leg (and everything) bones

Describe the difference between white and red muscle. What can you tell about the flying style of a bird by knowing which type of muscle dominates its flight muscles? (exam)

Review sesh: -> red meat more hemoglobin more blood more oxygen sustained use (sustained) -> white muscle is fast-twitch for short bursts distance (not much oxygen to sustain use, fatigue quick)(not sustained) Flight muscle: -red - high [Hb] & [mitochondria]; fibers very narrow (= high surface: volume ratio, short diffusion distance), contractile power based on aerobic metabolism (long sustained use) -white - low [Hb] & [mitochondria]; anaerobic; capable of short bursts, but fatigues quickly (short anaerobic use)

Name and describe the 4 different types of bird wings. Which style of flight are each of the wing types good for?

SEE PIC A) Good for rapid take offs e.g. turkeys, song birds B) Fly really fast e.g. falcons C) Over open ocean, use layer of air over ocean surface, fly in loops, Ride cushion of wave D) Soaring wings over land A) Elliptical wings, Short, rounded wings with an elliptical shape; best for rapid bursts of speed & quick turns, high maneuverability, etc.; almost all 'perching birds' (songbirds) have this wing type, as do most game birds (quail, pheasant, etc.), some water birds (coots, grebes, etc.), B) High aspect ratio wings, but with tapered, 'swept back' wing tips, limited slotting; maximizes speed in a "stoop". Frigate birds, swallows, swifts, & falcons C) Dynamic Soaring Wings, Highest aspect ratio wings = built for dynamic soaring; sea gulls, gannets, & especially albatrosses D) High lift Wings, Broad, slotted "high lift" wings are most suited for 'slow soaring' on unpredictable wind currents; most typical of many hawks, vultures, eagles, & condors

Describe the difference between precocial and altricial young?

SEE PIC Precocial species are those in which the young are relatively mature and mobile from the moment of birth or hatching. The opposite developmental strategy is called "altricial," where the young are born or hatched helpless. These categories form a continuum, without distinct gaps between them. {{Altricial: young is a long way from taking care of itself. Naked, blind, helpless. Humans! Antelope, etc have babies born precocial. Have full fur, can walk within an hour or two of birth.}}

Describe the origin of feathers.

Scales in reptiles modified

What was a Euryapsid?

Single temporal fenestra (high up on skull); several extinct marine groups (ichthyosaurs, plesiosaurs) -Sea Monsters all extinct

*** What limits the lower or upper size of mammals or birds? :)

Smallest Bird = Bee Hummingbird Average Size = Robin Largest Bird = African Ostrich Largest Flying Bird = Andean Condors or Albatross SA:V Food/Energy: Thermal Temperature: Larger= easier to stay warm. a mouse eats about one quarter its own weight of food every day, which is mainly used in keeping it warm.

Snakes :)

Snakes represent an adaptive radiation. As opposed to a remnant group (only a couple species). This is what makes snakes so successful. Highly specialized, but diverse. Lots of species of snakes, but very constricted in their form. Clade SERPENTES (OPHIDIA) - snakes; large cosmopolitan clade, > 3,310 species - with highest species diversity in tropical/subtropical distributions; entire clade is carnivorous (insectivorous, etc.), completely limbless, & shows a large range of body sizes (Leptotyphlops - Eunectes/Python - next slide), morphologies, & life histories. Many synapomorphies associated with locomotion/feeding specializations: - no external ear, fused eyelids form a clear shield (in most) (shed with skin) - no tympanum; quadrate bone can transmit low frequency sound (100 - 700 Hz; human range = 50 - 2,000 Hz), and detect vibrations from ground - no pectoral girdle; pelvic girdle reduced/absent - 160 - 400 vertebrae present (dramatic increase), but without regional differentiation (a major difference between snakes & limbless lizards; DO have differentiation) - no sternum, free ends of ribs connect via muscles/ligaments to enlarged belly scales, gastrosteges; unique forms of locomotion (can climb trees because of scales attached to ribs. Can move scales to climb tree) - paired internal organs (lungs, gonads, kidneys) asymmetrical - extreme specializations of tongue/ vomeronasal organs for chemoreception (smell: chemoreception through tongue) - some groups with specialized loreal (pit vipers) or labial (boas, pythons) facial pits capable of infrared heat detection (snakes have EXTRA sensory system; Infrared heat detection) - loss of 2nd skull arch; extreme cranial kinesis associated with specialized prey capture/swallowing (VERY mobile). Remember snakes can't chew, must eat prey whole. Elements of the jaw are independent of each other (ie left and right side of jaw can move separately) -at least 4 clades characterized by salivary enzymes modified for extreme digestive efficiency and/or toxicity; with dentition highly modified for envenomation

What are the loreal and labial pits of some snakes used for?

Some groups with specialized loreal (pit vipers) or labial (boas, pythons) facial pits capable of infrared heat detection (snakes have EXTRA sensory system; Infrared heat detection) Infrared heat detection - paired "pit organs" on heads/faces of some snakes: -loreal pits - Crotalidae; the "pit vipers" (single pit) -labial pits - boas, pythons (pits along mouth) In both, capsules lined with sensory epithelial membranes, with high [nerves] - branches of the trigeminal Snake receptors scan an area and record an average thermal 'background', and then can detect a thermal difference in the average background as small as 3/1000 of a degree This permits resolution of a thermal "image" much as night vision goggles might produce (binocular vision to detect heat signatures) Snake can estimate size of object and distance from head

How does the flight of hummingbirds differ from other birds? What muscular differences facilitate this difference? (exam)

Very large supracoracoideus (50% size of pectoralis; average = 10% in other birds) -wings operate like helicopter blades - stiff but with high flexibility at shoulder; normal flight requires ~ 55 wing-beats/second (get lift from both directions of stroke. Power stroke is up AND down) -100% red muscle (pigeon = 86% red:14% white; chicken = 11% r: 22% intermediate: 67% w) -greatest dexterity in hovering, lateral, & backwards flight (can fly backward, forward @ slow and fast speeds, can hover)

Describe the structure and function of feathers.

Structural & functional adaptations for flight: -Contour feathers: majority on body; each consists of a: -quill (calamus) - grows out of skin follicle -shaft (rachis) - extend length & supports finer structures -barb - lateral extensions from both sides of shaft, arranged in parallel to form a flat surface, the vane -barbules - these are extensions from each barb that interlink with those from adjacent barbs by tiny hooks, in a herringbone pattern (what makes the feathers hold together to create a surface area The three main types of feathers are the filoplumes (sensory feathers), the contour feathers, and the down feathers (insulation). Purposes of Feathers: 1) Also function for thermal radiation. Lots of insulation in small area. 2) Flight 3) Display Bird feathers are dead and wear out and must be replaced (like human hair) Plumage - general pattern of adult feathers (color texture, etc.); dead at maturity, so there is a seasonal loss, or molting, of some/all feathers Most species molt at least once/yr, usually in late summer after nesting Birds must preen feathers - with oil from gland at base of tail (preen gland); this water-proofs/ cleans feathers;, & provides some resistence to ectoparasites Flight & tail feathers lost in exact pairs; replacements emerge before next pair is lost (which maintains balance; most birds can continue to fly) Most species molt at least once/yr, usually in late summer after nesting Birds must preen feathers - with oil from gland at base of tail (preen gland); this water-proofs/ cleans feathers;, & provides some resistence to ectoparasites

Dinos VS Reptiles-ish :)

Subclass DIAPSIDA - 2 temporal fenestrae Superorder: ARCHOSAURIA1 - "ruling lizards"; dominated the Mesozoic Era ("age of dinosaurs") 1 synapomorphy - antorbital fenestra Order: Thecodonta† = earliest Order: Saurischia†* = theropods/sauropods *(Sub)Order: Aves = birds *(Sub)Order: Crocodylia = crocodilians Order: Ornithischia† =ankylosaurs/stegosaurs Order: Pterosauria† = pterosaurs Superorder: LEPIDOSAURIA - "scaly lizards"; lizards, snakes, & relatives (amphisbaenians, tuataras) -Modified diapsids. Radiated AFTER the demise of the dinosaurs. -Ectotherms: can have rapid bursts of speed (not maintained over period of time) if it's warm. Synapomorphies: - many modifications of the skull - transverse cloacal vent - shed skin (= ecdysis) in one piece

What is a tuatara and why are they important for understanding the evolution of reptiles?

Superorder: LEPIDOSAURIA - "scaly lizards"; lizards, snakes, & relatives (amphisbaenians, tuataras) Tuatara: common recent ancestor between dinosaurs and reptiles. Order: SPHENODONTA - "wedge tooth"; tuataras; 2 species confined (now) to some offshore islands of New Zealand; "living fossils" - only survivors of an early Mesozoic clade; symplesiomorphic traits - (1) unmodified diapsid skull; (2) parietal 'eye' (= 3rd eye) ^^Remnant group. Represent basal reptiles before archosaurs (dinosaurs) diverged from lepidosaurs (lizards, snakes, etc.) -Living fossils because of skull (looks like ancient lizards) 3rd eye senses light and dark (affects circadian rhythm) Synapomorphies: -derived dentition Google: -Not a lizard nor a dinosaur, tuatara is the sole survivor of a once-widespread reptile group -As the only living member of Rhychocephalia, and only living cousin to Squamata (lizards and snakes), the tuatara has an important role to play in understanding the evolution of all animals with backbones. {{Tuatara is a sister clade to what we call reptiles (squamates, turtles, crocodiles, birds). Different morphologies.}}

Describe the role of therapsid reptiles in the evolution of mammals.

Synapsid reptiles - originated in the Carboniferous Period (300 MYA) Therapsid reptiles (= "mammal-like") provide a good fossil transition (because mammals have lots of heavy bones, they fossilize well) showing major evolutionary shifts in the origin of early mammals, including changes seen in the following features: Secondary palate - begins to develop in earliest synapsid reptiles (pelycosaurs) Dentition - begins to shift from homodont to heterodont in early synapsids Spinal column/limbs/girdles - show shift in advanced synapsids (therapsids) towards rotation of limbs to ventral position beneath body, and 'running' skeleton in which spinal column flexes in a vertical plane Lower jaw bones - strong trend towards increase in size of dentary (white bone in figure at right) at the expense of all other elements; eventual the transition is complete from the reptilian quadrate - articular jaw joint (upper right figure) to the mammalian squamosal-dentary jaw joint THEN, endothermy, mammalian milk, and hair are when mammals really began to diversify. SEE PIC. Amphibian Ancestor --> Pelycosaurs --> Therapsids --> Mammalia Pelycosaurs have a mammal like skull. We have an inner Pelycosaur (not a dinosaur) because it's in our direct lineage.

When did mammals first arise as a group and when did they really start to flourish?

Synapsid reptiles - originated in the Carboniferous Period (300 X 106 YA) 1ST unambiguous mammals - early to mid- Triassic, 220 - 195 MYA (they pre-date the 1st birds); these were small, & for the first 2/3 of mammal history (rest of the Mesozoic Era), none were larger than house cats. Once the dinosaurs go away, there was a huge expansion in form of mammals (increased diversity) Beginning in mid-cretaceous period THEN, endothermy, mammalian milk, and hair are when mammals really began to diversify. {{Early to mid Triassic they arose as a group. Didn't really radiate until at the end of the cretaceous when dinos went extinct.}}

Compare and contrast the chorio-vitelline placenta with the chorio-allantoic placenta. Which kind of placenta belongs to which group? ***FINAL***

THERIA - differences in marsupial vs placental reproduction: METATHERIA: -Marsupial pattern: short gestation, most reproductive investment is devoted to prolonged lactation & parental care -The chorio-vitelline placenta is also called the yolk sac placenta - marsupial embryos are encapsulated by shell membranes, & they float free in uterine fluid; they 'hatch' from these membranes , & 'erode' shallow depressions in uterine wall, and settle in these to absorb nutrients (from mother) thru the vascularized yolk sac; (membrane is yolk sac membrane) (Surface is slightly wavy. SA becomes limiting soon. In other words they run our too soon. Why they're born so early/small. Placenta runs out due to SA constraints) EUTHERIA: Placental pattern - long gestation, short lactation, with most reproductive investment devoted gestation & in some parental care -The chorio-allantoic placenta - in uterus, dividing blastocyst proliferates trophoblast cells at 6 days, which secrete enzymes to digest epithelial lining of endometrium (lining of uterine wall); blastocyst implants, and by 11-12 days is embedded within endometrium. -The chorio-allantoic placenta: trophoblast (feeding part of embryo) thickens & grows 1000s of chorionic villi, which extend into endometrium, and continue to proliferate with growing embryo; the embryonic placenta forms via fusion of the chorion & allantois (both highly vascularized) -The chorio-allantoic placenta - capillaries of fetal placenta & mother's uterus are close enough to allow diffusion of nutrients, wastes, respiratory gases, to pass between embryonic & maternal circulation; the absorp-tive area is huge; at term a human placenta = 7 in across, but total absorptive area = 13 m2 (50X surface area of newborn infant!) (Long extensions that go all the way into mother and placenta. These mix. This increases SA dramatically. Now, can keep up with growing baby's needs for nutrients and oxygen. So babies can be large and well developed when they're born. Can get up and be on their own.)

Marsupials :)

THERIA: METATHERIA ("halfway mammals") -MARSUPIALIA - marsupials; the pouched mammals; a modest radiation of ~ 250 extant species in 12 families; all with short gestation periods (8 - 43 days); greatest species & ecological diversity is on the Australia-New Guinea plate, with a modest radiation of opossums in South America (remnant of a formerly large radiation) (probably more diverse prehistorically) Synapomorphies: - chorio-vitelline placenta - marsupium - pouch supported internally by paired epipubic bones (part of pelvis) - altricial young - born in embryonic state of development; must crawl to pouch & attach to nipple (n = 1 - 13 pr), where prolonged lactation & extensive parental care are required

What traits are present in the clade theria that differentiate it from prototheria?

THERIA: synapomorphies; -many braincase modifications -vertical tympanic membrane -all are viviparous -mammary glands always w nipples (Prototheria = egg-laying mammal-like platypus) (theria give birth to live young)

Describe and contrast the mating and sex-determination systems in the various groups of reptiles. (exam)

TURTLES: Sex determination; GSD (Genetically based Sex-Determination) vs TSD (Temperature based Sex-Determination) Most turtles are TSD. 50-100 eggs deposited in nest. Evolved behavior: varying the depth and positioning to change the temperature. < 28.5 degrees Celsius = 100% males ~ 28-29 degrees Celsius = mix > 29.5 degrees Celsius m= 100% females Climate change / global warming means lots of females... problems! Males will mate with any female they can. Females prepare a nest. TUATARAS: Sex of a tuatara is determined by the temperature that their eggs experience - rising temperatures will skew populations towards males. CROCODILES: All species that have been studied have TSD development. Mating is similar to bird, they have a dance and vocalization. They also lay eggs. SCALY LIZARDS/SNAKES (SQUAMATA): Many independent transitions from oviparity to viviparity (~ 90 - 100 times in the clade) Went from egg bearers to live births and it evolved many times. Many groups exhibit GSD!!!!!!!! Males have hemipenes. Only clade of vertebrates in which true parthenogenesis is known (1 snake; lizards from 7 families) Males don't exist at all. Doesn't require a male. Females produce eggs without them being fertilized. (TSD: birds? no Snakes? no)

How and why do lizards lose their tails?

Tail autotomy widespread in many families (break at fracture plane passing thru centra [s. = centrum] of caudal vertebrae); some regeneration possible. -Can regrow 2-3x. Comes back as cartilaginous rod ("fake tail") -Tail breaks in the middle of single vertebra (has pre-built fractures). Blood vessels contract so it doesn't bleed much. DEFENSE/ESCAPE/DISTRACTION Why regrow tail? -Can escape again *** Tails helps with balance

What is the purpose of the thoracic diaphragm?

Thoracic diaphragm - chief means of inspiration of lungs Between abdomen and thoracic cavity (which contains heart and lungs) mammals have a diaphragm, helps breathe in and out. Allows respiration rate to be increased through exercise. Why mammals can run for long periods of time.

Compare and contrast childbearing and parental care in marsupials and true placental mammals.

True Placental Mammals: Placental pattern - long gestation, short lactation, with most reproductive investment devoted gestation & in some parental care Marsupials: Short gestation, most reproductive investment is devoted to prolonged lactation & extensive parental care

Describe similarities and differences of echidnas and platypus.

Two genera of echidnas ("spiny anteaters"); Zaglossus (New Guinea) & Tachyglossus (Australia); small insectivores (toothless) that lay single eggs; egg is pushed into a small 'pouch', hatches in 10 days into a 'puggle' which nurses from 'milk patches'; after spines develop (~ 50 days), ♀ leaves puggle in the burrow but returns every 5 days or so to nurse, until young is weaned (~ 7 months) One species of platypus (Ornithorhynchus) native to eastern Australia; one of a very few venomous mammals (spur on ♂ hind foot, venom produced in crural glands. -Officially described in 1799, earlier studies concluded that specimens brought to Europe from Australia were hoaxes -The bill is an extremely sensitive electroreceptor of impulses produced by invertebrates hiding in substrates of freshwater streams/rivers. -Nests discovered with eggs in 1884 by British naturalist, w assistance of 150 aborigines!! ♀♀ lay 1-3 leathery shelled eggs (reptilian) in a burrow; eggs incubated until hatching (10 days) & mother nurses young by releasing milk from pores; milk pools in 'patches' & is lapped up by young, which are weaned @ 4 months

What are the two types of drag birds experience and how do they differ? (exam)

lift-induced drag: (low speed) -inherent cost of the wing producing lift (this energy ends up primarily in the wingtip vortices) parasitic drag: (high speed) -including skin friction drag from the friction of air and body surfaces and form drag from the bird's frontal area

What is meant by "a bird is a bird is a bird"? **(POSSIBLE EXAM ER)**

review sesh: ->you can tell it is a bird because of the way it is -> birds do not have a ton of diversity with their bodies like mammals! -> you can just look at a bird and know it is a bird ->(turtles also aren't diverse, mostly all look the same) Birds are defined by flight. It constrains the morphological diversity of birds; they have similar radiation to snakes (constrained by being limbless) Birds are modified enough to no longer be considered reptiles... Birds are endotherms that fly. (Feathers could be considered scales.) All about being light and strong.

Why might body elongation and limb loss occur several different times in the history of squamates?

review sesh: -> filling a niche that nobody else has filled -> can moved around with relative ease on most terrain -> {swim? Look up!} -> limbs are not necessary for them to succeed in their specific niches... burrowing with reinforced heads for some maybe -One hypothesis suggests that because many species of the burrowing morph have relatively small body size,reducing the size of the tail may allow them to increase the size of the body cavity, making more room for developing eggs in gravid females -Repeated evolution of the same morphology in similar habitats or (in this case) microhabitats is an important line of evidence supporting the role of natural selection in the evolution of that morphology. - Limb-reduced species are likely able to use microhabitats not regularly used by lizards with a normal (fully limbed) body plan. Limbs would probably only impede locomotion while burrowing or moving through narrow tunnels underground. Reduced limbs and an elongate body may facilitate movement through dense vegetation {{Lots of lizards have evolved to become longer. Amphisbaenian also evolved to be really long and most are limbless. Also snakes. Seems to be versatile for different things. Example, can climb trees, most through grass super-fast (maybe faster than things with feet). Amphisbaena evolved it because they burrow. Elongate, limbless body seems to be good for several different things. Can also move through burrows easily.}}

Why are all amniotes constrained to have internal fertilization?

review sesh: -> if you have an egg with a protective shell, you have to have a way to fertilize the egg INSIDE the body so you can create the shell after and then lay the egg -> if not a hard protective shell, then there is some kind of protection even in human Because amniotes are no longer required to live in an aquatic environment, however, sperm still require an aquatic environment to fertilize the eggs. In the case of animals that lay eggs, the shell is too thick (on order to simulate an internal aquatic environment) for the sperm to penetrate once outside of the female. For viviparous amniotes, the embryo develops inside the female (again, simulating an aquatic environment) and external fertilization would not permit this) {{Amniotic sac is mostly impermeable (except gas exchange). Constrained to internal fertilization because must occur before amniotic sac completely forms. As embryo is developing, the amniotic sac finishes being made.}}

What adaptations allow locomotion in snakes?

review sesh: -> repeating body plan of repeating ribs -> they do not have a sternum so they are more flexible for locomotion -> gastronemes: belly scales allow to propel themselves against the ground - no external ear, fused eyelids form a clear shield (in most) (shed with skin) - no tympanum; quadrate bone can transmit low frequency sound (100 - 700 Hz; human range = 50 - 2,000 Hz), and detect vibrations from ground - no pectoral girdle; pelvic girdle reduced/absent - 160 - 400 vertebrae present (dramatic increase), but without regional differentiation (a major difference between snakes & limbless lizards; DO have differentiation) - no sternum, free ends of ribs connect via muscles/ligaments to enlarged belly scales, gastrosteges; unique forms of locomotion (can climb trees because of scales attached to ribs. Can move scales to climb tree) - paired internal organs (lungs, gonads, kidneys) asymmetrical

Describe the mammalian heart and contrast it with the reptilian heart. (exam)

review sesh: -> reptiles heart partially divided chambers -> mammals chambers completely divided -> mammals have more efficient blood flow because of this ^^ 4-chambered heart* - ventricle completely divided (* = convergent conditions also found in some clades of Reptilia) Double loop system; don't mix oxygenated and deoxygenated blood. Share this characteristic with crocodiles and birds. EFFICIENT in getting fully oxygenated blood into the tissue. Good for running and flying. Most reptiles also have a three-chambered heart similar to the amphibian heart that directs blood to the pulmonary and systemic circuits. The ventricle is divided more effectively by a partial septum, which results in less mixing of oxygenated and deoxygenated blood.

Other than size, why is a lizard not a good model, for a dinosaur?

review sesh: ->not from the same lineage as dinosaurs so not a good model like birds are, birds have way more in common Lizards are not a good representation of dinosaurs. Lizards have tympanum and eyelids (snakes do not) {{Body forms different. Dinos = mammalian way of legs. Underneath them rather than to the side. Dinos were larger. Share common ancestor, but probs different from both lizards and dinosaurs. People THINK that dinos were homeotherms. Lizard and dinosaur skull different. Dinos have antorbital fenestra= hole between eye and nostril (both diapsids)}}

What synapomorphies do crocodiles and birds share? How are crocodilians like birds?

review session: -> gizzards -> 4 chambered heart -> vocalization -> parental care/ nesting -> no bladder bc they just extrete urine out with feces -*thecodont dentition ( base of the tooth is completely enclosed in a deep socket of bone) - *secondary palate in the skull - complete/nearly complete division of the ventricle (4-chambered heart) - anterior of stomach modified into muscular *gizzard - *no urinary bladder (NH4 secreted as uric acid) - *♂♂ establish territories, vocalize, & engage in complex courtship behavior