Exam 1 Class collapsed

Question 1

What are some key similari7es and differences between ostracoderms and placoderms?

Answer 1

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

Question 2

Why do we think that the cartilaginous skeleton of chondrichthyans reflects a secondary loss of ossified bone?

Answer 2

there ancestors had a lot more bone suggesting that they lost it to be lighter in the water and perhaps more streamlined

Question 3

Why is the lateral line a mechanoreceptor organ? Where does it derive from developmentally?

Answer 3

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

Question 4

What is the relationship between the presence of a swim bladder and locomotion in fish?

Answer 4

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

Question 5

How are fleshy fin appendages different from ray fin appendages and how do they function in sarcopterygians?

Answer 5

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

Question 6

Why is the human hand homologous to Tiktaliik’s fin?

Answer 6

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

Question 7

Is internal fertilization likely to be an adaptation for species living out of water? why or why not?

Answer 7

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

Question 8

Compare the traits of tiktaliik and acnthostega that are more like their fish ancestors, and those that are more like terrestrial vertebrates?

Answer 8

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

Question 9

What do we know about the origin of lissamphibia?

Answer 9

they arose from temnospondyls

Question 10

after lungs appeared, what happens to the relative role of skin for gas exchange in vertebrates?

Answer 10

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

Question 11

compare the main characteristics of the three main orders of amphibians that exist today/

Answer 11

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

Question 12

What is heterochrony? why is it important and what is the most common type found in salamanders? explain.

Answer 12

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

Question 13

Would u expect salamanders to call out to their mates like frogs do? why or why not?

Answer 13

no they don’t have well developed ears like frogs

Question 14

if the salient and caudata have reduced skulls why is this not the case in the gymnophiona?

Answer 14

(frogs) and (salamanders)

they need them for burrowing

Question 15

Draw an amniote phylogeny and identify 4 synapomorphies of each lineage including skull type.

Answer 15

Sauropsodia (reptilesand birds)- have diapsid skull and turtles have anapsid. and synapsidia (mammals)

Question 16

Why are reptiles considered an artificial taxa?

Answer 16

because they do not include birds

Question 17

Identify the main bones involved in skull fenestration in different skull types.

Answer 17

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

Question 18

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?

Answer 18

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

Question 19

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?

Answer 19

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)

Question 20

What other adaptation in crocodiles allow them to feed on large prey?

Answer 20

crocodile once catch prey roll trying to drown them for whole behavior and efficient mechanism.
jaw bones don’t deform under great pressure

Question 21

What can bone deformation studies tell us about the likely function of a structure?

Answer 21

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

Question 22

snakes have many special adaptations, describe their main adaptations to swallow prey, and detect infrared signals and odors.

Answer 22

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

Question 23

compare the changes in the general olfactory structure in main vertebrate groups.

Answer 23

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.

Question 24

What are the distinguishing characteristics of Archosaurs?

Answer 24

split into pseudosuchia- crocs and other relatives, and ornithosuchia-dinosaurs and birds.

high narrow skull with pointed snout, diapsid skull, two fenestra lightening weight

Question 25

Explain how the difference between the crurotarsal and metatarsal joint results in different gaits (make sure you know the bones involved and who has them)

Answer 25

crurotarsal- crocodiles have ankle rotation, an erect walk and sprawling with belly run and gallop and the joint is S-shaped peg in astragalus fits in calcaneum bone

metatarsal: dinosaurs nd birds limbs move parallel to vertebral column walking erectly and a straight ling in from of astragalus and calcaneum.

bones Back left tibia, back right fibula
front left astragalus, and front right calcaneum

Question 26

Explain which dinosaur lineage birds evolved from (give one distinguishing trait in each step), and when do we think feather may have appeared.

Answer 26

Birds began from saurischian dinosaurs seen in hip and wrist with different radiating bones opening in different posiitons with a mix of diet.

therapods-

coelarhceria- wishbone and few sternum and some evolved feathers

ornithiscian dinosaurs- bones parallel to eachother, third digit is longest. feathers were found in these as well.

Tetanurae divides into two groups: tyrannosuridae and maniraptora. inferred first appearance of flight in arcaeopteryx, reduced fused tail called a pygostyle (reduced tail).

Question 27

What are the current hypotheses about evolution of flights n birds?

Answer 27

aboreal hypothesis- dinosaurs able to climb up in trees and spending time up there and started using gliding and jumping from branches to down and feature that allowed them to parchaute, glide, and flight.
cursorial insect-net- where birds were able to run a littler fast picking up more speed and feathers to catch insect and leap after insect with appendage helping to get that lift gliding, and then leads to flight
curorial climbing- animal on ground run and use feathery appendages for climbing pushing in towards surface of tree to go up then leading to gliding and flight

Question 28

Discuss the evidence to suggest that dinosaurs may have been endothermic.

Answer 28

Evidence for endotherms: feathers may have evolved for warmth (insulation), size!! (would be hard to use environment to regulate temp of something so big), movement: activity (would be hard to sustain this behavior if ectotherm), some dinos were found in temperate climate (would have no place big enough for them to go to hibernate if it got too cold-like ectoderms do), bone rings (typically found in reptiles (ectoderms) but most species of dinos didn’t have them (some did)-may also be evidence for ectoderm. Bone rings change based on seasonal changes in environment, because of changes in metabolism), composition of ecosystem (would need lots of prey items around. Looking at fossils, always find more prey than top predators), birds are endotherms.

Question 29

What would you expect to see in the muscles of a flightless bird when compared to a bird that migrates long distances?

Answer 29

more streamlined, and thinner muscle meant for long=term flight. they also have a keel, ridge on sternum which is main attachment sight for flight muscles not founds on those who are flightless

birds who were flightless would have much thicker thicker muscles for things like swimming like quick speed

Question 30

Why do we describe bird flight as a pulley system?

Answer 30

with pectoral muscle providing downstroke and one over shoulder raising wing by pulling back over the shoulder so its being a pulley over the edge of the shoulder joint with tendon moving back and forth on shoulder moving wing.

Question 31

What adaptations enable bird flight?

Answer 31

lighter bones that are hollow and fused, modified muscles, very large and efficient four chambered heart, different kinds of feathers that create power and lift, barbs on feathers to keep them as one unit, smaller and less pronounced reproductive system lack penis , respiration that doesn’t involve huge organs such as diaphragm with air sacs acting like bellows

Question 32

What is oviparous?

Answer 32

-fertilized egg is laid,

Question 33

What is ovoviparous?

Answer 33

eggs develop within female and living young are born no placenta or placental structures,

Question 34

What is viviparous?

Answer 34

embryos develop within female and living young are born some placenta-like sturctures of maternal origin