Exam 1 Class collapsed Flashcards
(34 cards)
What are some key similari7es and differences between ostracoderms and placoderms?
similarities: encased in heavy bone armor, small taill, head shield composed of large plate of fused dermal bone
differences: placoderms have jaws with teeth, paired pectoral and pelvic fins, notochord with ossified neural and hemal arches, some large, claspers for internal fertilization
Why do we think that the cartilaginous skeleton of chondrichthyans reflects a secondary loss of ossified bone?
there ancestors had a lot more bone suggesting that they lost it to be lighter in the water and perhaps more streamlined
Why is the lateral line a mechanoreceptor organ? Where does it derive from developmentally?
lateral line (neuromast cells in line) function along fish water currents going to when prey next to it with pores along whole body.
derived from latetal line and otic ectodermal placodes- respond selectively to mechanical stimuli (asymmetry of the bundle). translate mechanical information into electrical signal
detecting water currents, maintinaing balance and hearing sounds. lateral line
What is the relationship between the presence of a swim bladder and locomotion in fish?
the swim bladder help with buoyancy keeping them afloat so that they swim straight and up and do not have to exert extra energy to stay afloat so they can better swim
How are fleshy fin appendages different from ray fin appendages and how do they function in sarcopterygians?
fleshy fin appendages have one large bone and have short projecting appendages with soft muscle and internal bony elements for pivoting in shallow water and holding on to the bottom and some have lungs. they don’t have whereas the ray fin appendages derived from endoskeleton mAny long thin bones
Why is the human hand homologous to Tiktaliik’s fin?
the bone structure in the human limbs derive from the fin making it homologous and they both have the one big bone, two smaller bones and then many small bones
Is internal fertilization likely to be an adaptation for species living out of water? why or why not?
living out of water you have to worry about desiccation of the young and so for them to be better protected if they are internally fertilized and then giving a coating or grow inside the mother the animals will fair much different environmental conditions and pressure
Compare the traits of tiktaliik and acnthostega that are more like their fish ancestors, and those that are more like terrestrial vertebrates?
tiktallik had much larger fins, scales, and primitive jaw
(fish)
(vertebrates- neck, wrist, flat head and expanded ribs eyes on top of head and lungs
acnthostega- inter cranial joint, labyrondont teeth, lateral arches, lateral line system, ray finned tale, ossified renal arches
vertebrates- weight bearing girdles, limbs with digits and dermal skull bones, eyes on top of head and lungs
What do we know about the origin of lissamphibia?
they arose from temnospondyls
after lungs appeared, what happens to the relative role of skin for gas exchange in vertebrates?
for some they lost the role of lungs and just used the surface of their skin for respiration- salamanders
in others skin became a protector from losing the water form the inside and in both it still led to a change in the circulatory system to better supply blood and oxygen to the rest of the body and internal organs from the oxygen absorption surface
those with more well developed lung relied less on the skin
compare the main characteristics of the three main orders of amphibians that exist today/
rana (frog)- not solid skull long hindelegs for jumping, no tail, external fertilization, indirect development (tadpole), sound
ambystoma/caudata urodela (salamanders)-not solid skull, have tail, divergent respiration, internal fertilization, no ear drum, paedomorphs
caecilians- legless, burrowing and aquatic, internal fertilization either laying eggs or carrying young or placenta, solid skull, direct development, parental care
What is heterochrony? why is it important and what is the most common type found in salamanders? explain.
developmental changes in rate and timing of growth that lead to change in size and shape
peramorphosis- where traits grow larger faster or earlier
paedo-morphs prevalent because it protects them in this environment rate of growth of trait growing slower, staying smaller or growing later in development
Would u expect salamanders to call out to their mates like frogs do? why or why not?
no they don’t have well developed ears like frogs
if the salient and caudata have reduced skulls why is this not the case in the gymnophiona?
(frogs) and (salamanders)
they need them for burrowing
Draw an amniote phylogeny and identify 4 synapomorphies of each lineage including skull type.
Sauropsodia (reptilesand birds)- have diapsid skull and turtles have anapsid. and synapsidia (mammals)
Why are reptiles considered an artificial taxa?
because they do not include birds
Identify the main bones involved in skull fenestration in different skull types.
all four bones are in anapsid, synapsid, and diapsid
upper temporal bar- temporal arches squamosal at furthest point back in skull, and post-orbital bone bone right behind eye socket
lower temporal bar- jugal front lowest bone closest to eye and quadrtojugal bones furthest back and bottommost bone
From a temperature where sex ratio is 50:50 how would an increase of 2 degrees affect turtles and crocodiles? would sex determination in frogs be equally affected?
depending on turtle species its male or female
crocs anything up to a 32oC male after female
no its not affected by temperature but the size of chromosomes
Compare the skulls of a gharial and a crocodiles: which type of lever do they represent? which one would seem to be able to catch prey faster? which once can catch stronger prey?
both are type three levers
gavilalidae (narrow snout feed on fish can open wider cuz its longer and it is faster) and crocodylidae (largest and catch largest prey, which feeds on everything else more powerful)
What other adaptation in crocodiles allow them to feed on large prey?
crocodile once catch prey roll trying to drown them for whole behavior and efficient mechanism.
jaw bones don’t deform under great pressure
What can bone deformation studies tell us about the likely function of a structure?
red change more shape with a lot more in the gharial vs. crocodile ocnfirming how form and function acting together to act on waht they are feeding and bone not going to deform in a gharial.
crocodile bones take a lot more pressure to break meaning that a lot more muscle mass and force can be applied to it before it breaks and with that applied muscle mass it is stronger
snakes have many special adaptations, describe their main adaptations to swallow prey, and detect infrared signals and odors.
venom to break it down when they bite
back of jaw can open widely and left and right. can stretch ligament bringing lower jaws appart two lower jaws connected with bone. jaws facing backwards use jaw to jaw walk crawling on prey eat anterior and recognize salitary end of animal
pit organs of pit vipers- allow snakes to sense infrared creating visual image as snakes can see in the dark thanks to protein channels that are activated by heat from the bodies of their prey. membrane hangs in between space and heats up by infrared radiation TRPA channels opening, and peaks opening channel allowing ions to flow through membrane with receptor endings of nerve snesing that ions flowing in creating electrical signal of brain. , can form image 1 meter away
compare the changes in the general olfactory structure in main vertebrate groups.
fish- water flow comes in and out of skin in nasal sac.
choanate fish have water entering external narls into nasal sac- large and connects to mouth with water going out of mouth.
In amphibians they developed vomeronasalvernonasal organ olfactory tissue sensing pheromones form other individuals.
reptile- have same pathway with additioinal vestibules and a vomeronasal organ. estibule and in nasal chamber have terminals making it so more ability to detect odors and vestibular organ is sepeate (jacobson organ) using tongue all the time as primary sense of smell and when they retract goes right in opening of organ and tell what smells are.
mammals great reduciton in nasalpharyngeal organ and instead have a duct flow.
What are the distinguishing characteristics of Archosaurs?
split into pseudosuchia- crocs and other relatives, and ornithosuchia-dinosaurs and birds.
high narrow skull with pointed snout, diapsid skull, two fenestra lightening weight
