Lecture 10 Chordata Diversity

What are the four synapomorphies of Phylum Chordata

notochord, dorsal hollow nerve chord, muscular post-anal tail, and pharyngeal gill slits

What does the notochord do?

It is the attachment site for muscle

What does the dorsal hollow nerve chord do?

composed of nervous tissue and it becomes our brain and spinal cord

What does the pharyngeal slits do?

used for breathing or eating

What does the muscular post-anal tail do?

It is used to propel aquatic species

What occurs to the notochord when species grow?

it gets replaced with vertebrae

What occurs to the dorsal hollow nerve cord when species grow?

It turns into the central nervous system (brain and spinal cord)

What are characteristics of subphylum Urochordata?

has all 4 synapomorphies as larvae but as an adult it only maintains 1 which is the pharyngeal gill slits, larvae are mobile while adult are sessile, and some attach to become free floating

What are characteristics of subphylum Cephalochordata?

has all 4 synapomorphies, 6 cm long, burrow in sediment, and uses pharyngeal slits to suspension feed

What are the synapomorphies of subphylum Vertebrata?

has a head, vertebral elements to protect dorsal hollow nerve chord, more active than other subphylum, and has a heart with 2+ chambers, erythrocytes with hemoglobin, and kidneys to filter blood

What are the characteristics of subphylum Vertebrata class Myxini?

Has cartilage skull, no jaw but has a palp, gills, notochord, and can secrete slime from slime gland to suffocate predators

What are the characteristics of subphylum Vertebrata class Petromyzentida?

has cartilaginous skeleton, no jaw, notochord, vertebral elements to protect dorsal hollow nerve chord, and are parasites that eat blood and soft tissue of fish

What is the synapomorphies of clade Gnathostomata?

has jaws, mineralized skeleton, some have cartilage skeleton, has paired and median fins, and some tetrapods have limbs instead of fins

What is a paired fin?

It can be used to help the fish steer and has a paired fin on each side of the fish.

What is a median fin?

It is an unpaired fin that is along the midline of the fish body. They provide balance to the animal

What is the synapomorphies for clade Osteichthyes?

mineralized skeleton and has a swim bladder to maintain buoyancy

What are the characteristics of clade Osteichthyes Class Actinopterygii

ray finned fish, composed of tiny and delicate repeated bony flexible elements, muscle is found of the base of the fin, many different feeding and reproductive strategies, and variation in size

What are the synapomorphies of clade Sarcopterygii?

bones are covered in muscle, fin have pattern of bones, and larger muscular fin

What are the characteristics of clade Sarcopterygii class Actinistia?

live deep in ocean and composed of bone and covered by muscle

What are the characteristics of clade Sarcopterygii class Dipnoi?

lobe fins, lung, gills, and live in lands and ponds that dry up

What are the synapomorphies of clade tetrapods?

four feet, 4 limbs with digits, and bone for pelvic girdle use to vertebral column

What are the characteristics of clade tetrapod class Lissamphibia?

4 digits forelimbs, gland skins that secrete mucus and poison, fat bodies to store energy, and has external fertilization

What is the synapomorphies for clade amniotes?

less tied to water, amniotic eggs don’t need water, and has a broader range of where they can live

What is the characteristics of clade archosaurs?

has fenestrae in skull, teeth in socket, and ridge of femur

What is the characteristics of clade lepidosaurs?

overlapping scales shed in flakes, tail autonomy (ability to grow back tail only once), and have hemipene (intromittent organ)

What is the characteristics of clade turtles?

have shells, no skull openings, and are closely related to archosaurs

What are the synapomorphies of class Mammalia?

has hair and mammary glands

What are the characteristics of class Mammalia subclass Monotremata

lack nipples, has hair, and mammary glands

What are the characteristics of class Mammalia subclass Metatheria

live birth, uses marsupial pouch to nurse babies, and have nipples

What are the characteristics of class Mammalia subclass Eutheria?

have complex placenta, no pouch, and have nipples