Lecture 7

Question 1

What is the primitive character of all vertebrates?

Answer 1

a vertebral column

Question 2

What is the precursor to a vertebral column? How is it similar to a vertebral column?

Answer 2

a notochord (is a fluid fuel structure that runs through the body), had similar functions as a vertebral column like structure and support

Question 3

What is subphylum vertebrata?

Answer 3

has animals with a jointed vertebral column

Question 3

What is the difference between a cephalochordata and a chordate? Give an exmaple of a cephalochordate?

Answer 3

cephalochordates have heads as well notochords- ex pikaia (small 5 cm, discovered in the burgess shale and 505 ma, is one of oldest known ancestor of all cephalochordates)
chordates- have notochords but no head

Question 4

What was the first animal to develop a vertebral column?

Answer 4

The jawless fish

Question 5

What are some examples of jawless fish?

Answer 5

Modern hagfish and lampreys

Question 6

What are lampreys?

Answer 6

are jawless fish that are parasitic- they attach to other fish and get food from them and travel on them, have blocks of cartilage as a vertebral column

Question 7

The first vertebrates possessed what?

Answer 7

A head and a vertebral column

Question 8

Jaws likely evolved from what?

Answer 8

pre-existing support structures in the gills

Question 9

What are gnathostomes? What about the primitive forms?

Answer 9

are animals with jaws and vertebral column, some primitive forms have a skeleton made of cartilage

Question 10

What happens to the diversity of jawless animals when gnathostomes evolve?

Answer 10

decrease due to competition

Question 11

What are osteichthyes?

Answer 11

are fish with bony skeletons

Question 12

Osteichythyes can be split into what two big groups?

Answer 12

the ray finned fishes and the lobe finned fishes

Question 13

What are sarcoptergyii?

Answer 13

Are the lobed finned fishes, have fleshy and limb like fins along with vertebral column, jaws, and mineralized skeleton

Question 14

What is tiktaalik?

Answer 14

is a transitional taxon- was an extinct lob-finned fish that had weight bearing elbows, simple wrist bones, and simple fingers- called a fishapod - fish with feet, also had gills and lungs

Question 15

What are tetrapods?

Answer 15

Are vertebrates with four true limbs

Question 16

Modern tetrapods have lost what? What have they retained?

Answer 16

Have lost tehir gills, but have retained their lungs

Question 17

How are primtive amphibians (frogs, newts, toads, and salamnders) bound to water?

Answer 17

they need it to reproduce

Question 18

What are ichthyostega?

Answer 18

are the first tetrapoda (vertebrate to live on land)

Question 19

Do lobed finned fishes and primitive tetrapods share homologous structures?

Answer 19

Yes, the shoulder girdle, humerus, and radius and ulna are all present and similarly arranged in both

Question 20

What are amniota?

Answer 20

Are animals that developed a membrane called the amnion in eggs which allowed them to becoe fully terrestrial as the eggs was protected from drying out. Amniota do not include amphibians.

Question 21

What evolved with amniota?

Answer 21

a calcified/leathery shell, yolf for nutrition, and waste management system

Question 22

Are humans and other mammals also amniotes?

Answer 22

yes but the eggs is retained internally

Question 23

The amniotes are split into what two groups?

Answer 23

The diapsids and the synapsids, diapsids have a single pair of temporal fenstera, dipasids have two pairs

Question 24

What do the temporal fenestra accomodate?

Answer 24

A bulging jaw

Question 25

synapsids include what?

Answer 25

mammals and their ancestors

Question 26

Diapsida include what?

Answer 26

dinosaurs

Question 27

How is a clade a monophyletic group?

Answer 27

it is a group of organisms that includes a common ancestor and all descendants

Question 28

Are dimetrodon and wooly mammoths dinos?

Answer 28

No are synapsids- had one temporal fenestra

Question 29

What is dimetrodon referred to as? When did it live?

Answer 29

mammal like reptiles- wrong as they don’t have characteristics of mammals or reptiles- are synapsids
lived beyond the time of the dinos

Question 30

dinosaurs have two temporal openings and are therefore…

Answer 30

diapsids

Question 31

What includes diapsids?

Answer 31

birds, pterosaurs, crocodiles, lizards, snakes

Question 32

The diapsids are split into what two groups?

Answer 32

split based on differences in skeleton, are split into lepidosauromorphs (have short, non-overlapping vertebrae in the neck) and archosauromorphs (have longer vertebrae in the neck which overlap to provide support for longer necks)

Question 33

Are pterosaurs dinos?

Answer 33

no they’re flying reptiles

Question 34

What are the archosauria?

Answer 34

they are a subset of archosauromorphs so they have two pairs of openning behind the eyes, have long overlapping vertebrae in neck but they also have a addtional oppening in front of the eye called the antorbital fenestra

Question 35

what are the two groups of archosauria?

Answer 35

Ornithodira and Crurotarsi

Question 36

What differentiates the ornithodira and crurotarsi?

Answer 36

-Diffences in stance due to ankle structure (crocs sprawl- pterosaurs, bords, and dinos are upright), motion is limited to front to back

Question 37

How are pterosauria and dinosauria and birds flight an example of convergent evolution?

Answer 37

pterosauria adapted to fly by elongating digit IV, birds formed a seperated adaptation to fly

Question 38

What is a digitgrade posture?

Answer 38

Is something dinosauroorphs exhibit, is due to the hinge like ankle joints which cause them to stand on the balls of their feet- allowing for a longer stride, move effeciently and continuously

Question 39

What are the characteristics of dinosauromorpha?

Answer 39

were small (~ 1 m or
less including the tail), lightly built, insectivorous or carnivorous, and many walked
on all fours but ran bipedally.

Question 40

What indicates that primtive dinos were bipedal, and quadropedal stance came after?

Answer 40

The group of dinosauromorphs most closely related to dinosaurs were apparently
bipedal