BIOLOGY EXAM #4 ERIK EKDALE SDSU TEST QUESTIONS AND ANSWERS 2024.

secondary palate anatomical structure that divides the nasal cavity from the oral cavity in vertebrates located posteriorly; allows for breathing while eating furcula fused clavicle of birds and some dinosaurs; stabilizes shoulder (wish bone) Brainpower Read More Previous Play Next Rewind 10 seconds Move forward 10 seconds Unmute 0:02 / 0:15 Full screen From which specific reptilian lineage did modern birds descend? Archosauria List the two major living clades of Archosauria (lead lizard) Pseudosuchia (crocodiles and their relatives) Orinthosuchia (dinosaurs, pterosaurs and birds) List the major synapomorphies shared by all archosaurs 4 chambered heart (key in endothermy) nest building and parental care secondary bony palate (2nd roof of mouth) What group do birds belong to? Are birds Sauropods or Theropoda? Saurischia; (lizard hipped), a lineage of herbivore dinosaurs that eventually led to birds; Theropoda Discuss the evidence that non-avian dinosaurs were ectothermic they lack respiratory structures found in birds and mammals that warm and moisten air ectothermic an animal that is dependent on external sources of body heat Are the furcula, hollow bones and feathers adaptations for flight? How do you know? No; these features were exaptation for flight because they were present before birds were able to fly What was Archaeopteryx? It was the earliest bird found in Germany that possessed Therapod-like features (long bony tail and teeth) and was bird-like with asymmetrical flight features Briefly describe the "Ground Up" hypothesis for the origin of flight -hinds limbs improved speed -forelimbs lengthened to grab prey; the way that they grasp for prey is similar to flight stroke -those with feathers made it easier for lift How does respiration in birds differ from mammals ? -Inhalation (mammals): fresh air brought into lungs -Exhalation (mammals): stale air pushed out of lungs through windpipe [trachea] -Inhalation (birds): fresh air brought into posterior sacs, stale air from lungs drawn into anterior sacs -Exhalation (birds): fresh air pushed into lungs from posterior sacs, stale air pushed out of trachea from anterior lungs Identify four potential causes for the extinction of non - avian dinosaurs Asteroid impact Volcanoes Sea Level Fall Climate Change What aspects of bird wings provide lift during flight -air moves faster over wing, lowering air pressure -wing slots direct faster moving air over wing surface and prevent stalling at low speeds -feathers endothermic temperature regulators in birds; energetically expensive; requires lots of oxygen How do the limbs of dinosaurs differ from other archosaurs? the legs are under the body Discuss the evidence for either ectothermy or endothermy in non-bird dinosaurs evidence for ectothermy: dinosaurs lack respiratory structures found in birds and mammals that warm and moisten air; other non-avian archosaurs are ectothermic evidence for endothermy: dinosaur fossils discovered in polar regions, living descendants are endothermic, limbs under body indicate vigorous locomotion, bird-like respiratory system in saurischins (hollow bones have air sacs connected to lungs) What are the potential causes of dinosaur extinction -asteroid impact (Mexico) -volcanoes (India) -sea level fall (loss of coastal habitats) -climate change If forelimbs of birds are modified for flying, how do they catch food? beaks are modified, accustomed to each bird, that allows for feeding and catching food (no teeth) Discuss wing mechanics (How do they work?) lift (from feathers) maintained by cross-sectional area and constant angle of attack adjustment; air moves faster over wing, lowering air pressure, air flowing past wing is deflected downward, displacing the wing upward, birds do not flap wings up and down Discuss the origin of flight "ground up" hypothesis -hind limbs are developed for speed, forelimbs strengthened for grasping prey -feathers on forelimb provide lift Which features of birds are adaptations for flight? -keeled sternum (powered flight) Which features of birds are exaptations for flight? -furcular ("wishbone") [present in dinosaurs that couldn't fly] -hollow bones -feathers -endothermy Describe the unique method of respiration employed by birds hollow bones; part of the respiratory system; air is unidirectional through lungs, gas exchange occurs in lungs, posterior and anterior air sacs act as bellows (no gas exchange) inhalation: fresh air brought into posterior sacs, stale air from lungs drawn into anterior sacs exhalation: fresh air pushed into lungs from posterior sacs, stale air pushed out of trachea from anterior lungs Major synapomorphies of mammalia -mammary glands (produce milk)(modified sweat glands) -hair -single bone in lower jaw (dentary) -middle ear with three bones (ossicles) Synapsid Skull mammals possess this skull; has one window (members of amniota can be distinguished based on temporal openings) Other features of mammalia -secondary bony palate (shared with archosaurs) -4 chambered heart (shared with most reptiles) -endothermy -muscular diaphragm -differentiated teeth Homodont/Heterodont Heterodont : different teeth for different jobs that allows specilization in diet (i.e. different tooth morphology like molars) Homodont: set of teeth that possess the same tooth morphology Hair original use likely evolved for tactile sensation first and later for insulation aposematic coloration defensive warning signal; example is the spotted skunk spines/quills defensive structure composed of hair; often seen on porcupine polyphyodont vs diphyodont polyphodont: replacement of teeth from time to time several times in lifetime so jaws are never without teeth diphyodont: milk teeth are replaced by larger permanent teeth that fit the jaw bone How can the teeth of a mammal inform us about diet? Flat teeth indicate that the mammal is a herbivore while sharp teeth indicates that the mammal is carnivorous What was the lifestyle of early mammals like? -were small and nocturnal -enlarged brain, fully modern mammal ear, good sense of smell Diphyodont animal with two successive sets of teeth; deciduous and permanent set Monophyodont having one set of teeth; does not get replaced at a later stage of growth Homodont having all the same type of teeth; example : armadillo Heterodont having different teeth; each set with specialized functions, example: sloth Vibrissae whiskers; utilized as organs of touch, generally located around the face Cloaca cavity at the end of the digestive track for the release of excretory and genital products; found in birds, reptiles, amphibians, most fish and monotremes Marsupium pouch that protects eggs, offsprings, or reproductive structures; most marsupials possess this quality (exception of numbat); generated from yolk sac, embryo absorbs nutrients from uterine wall