Lecture 14 Flashcards by Rebecca Young

what are the classes of hemichordata

enteropneusta and pterobranchia

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where do hemichordates live

marine bottom dwellers and live in sediments

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what kind of feeders are hemichordates

deposit feeders or filter feeders

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what is the superphylum containing echinoderms and hemichordates called

ambulcraria

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what phylums are in the superphylum ambulacraria

echinodermata and hemichordata

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what are enteropneusta

acorn worms
free living
slow moving

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what are pterobranchia

colonial worm like animals

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what kind of feeders are enteropneusta

deposit feeders
organic material in sediment

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where do enteropneusta live

in burrows or on the sea floor

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the body of enteropneusta is covered in what

mucous

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what are the parts of the body of enteropneusta

proboscis
collar
trunk

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what is the proboscis of enteropneusta

a muscular tongue like projection

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what is the collar of enteropneusta

ring of connective tissue with mouth at anterior ridge

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what is the trunk of enteropneusta

longest body region with gill slits

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what does enteropneusta do to open its mouth

the proboscis move outward

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how do pterobranchia live

in colonies on the ocean floor in a cluster of tubes

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what kind of feeders are pterobranchia

filter feeders

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how does the body of a pterobranchia differ from an enteropneusta

proboscis is flattened into cephalic shield
collar has many branching arms with tentacles

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what are the subphylums of chrodata

urochordata
cephalochordata
vertabrata

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urochordata: lifestyle

mostly sessile as adults

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urochodata: cranium?

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urochordata: notochord?

in juveniles

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cephalochordata: lifestyle?

free living

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cephalochordata: cranium?

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cephalochordata: notochord?

present throughout lifetime

vertebrata: lifestyle?

free living and highly active

vertebrata: cranium?

yes

vertebrata: notochord

replaced by centrum of vertebrae

what are the hallmark characteristics of chordates?

1. notochord 2. dorsal hollow nerve 3. pharyngeal pouches or slits 4. endostyle or thyroid gland 5. postanal tail

what is a notochord

flexible rod of cells wrapped in fibrous and elastic sheaths

what is the first part of the endoskeleton to form during development of chordates

notochord

in chordates, the nerve chord is always in what location relative to the gastrointestinal tract

always dorsal

what is cephalization

in most chordates what portion of the nerve cord forms a brain

anterior portion

in most chordates the anterior portion of the nerve cord forms what

brain

in vertebrates, the nerve cord passes through what

neural arches of vertebrae

what is the pharyngeal cavity in chordates

what are pharyngeal slits

openings in the pharyngeal cavity that lead to the external environment

how are phaygenal slits formed

the invagination of the ectoderm and evagination of the endoderm of the pharynx

in aquatic chordates, the pharygeal slits create what

a complete opening from the pharynx to the outside

in amniotes, what are pharygeal slits replaced with

just grooves called pharygeal pouches

what gland is found in all chordates and no other animals

endostyle or thyroid gland

what is an endostyle

a recognized precursor of the thyroid gland that secretes a mucous that traps food particles

the thyroid gland is found in members of what subphylum and is a component of the endocrine system

vertebrata

what structure do all chordates have

a postanal tail

what is a postanal tail

a tail that extends posterior to the anus

what structure is the remnant of a tail in humans

the coccyx

what are urochordates

marine animals that are sessile in their adult form

what is the tunic of urochordates

a tough outer layer which acts as an exoskeleton for support and protection

what kind of feeders are urochordates

filter feeders

what key features of chordates are urochordates missing in adulthood

- notochord - dorsal hollow nerve cord - post anal tail

describe the feeding of urochordates

1. water is drawn into the incurrent siphon by ciliary action 2. water drawn through pharygeal slits (stigmata in urochordates) in a basket like structure 3. endostyle on one side of the stigmata secretes mucous that traps food as water paassed through 4. mucous containing food passes into esophagus and through intestine 5. water and feces exit the atrium through the excurrect siphon

what are cephalochordates

lancelots - kind of look like a mix between worms and fish

how many of the hallmark chordate characteristics do cephalochordates possess

all five

describe the musculature of cephalochordates

segmented trunk w myomeres arranged in a chevron pattern

what structure do cephalochordates have that resemble a vertebrate pancreas

hepatic cecum

how do cephalochordates feed

filter feeders - water in mouth - goes through pharyngeal slits - exits atrial pore

what are vertebrates

all that have a vertebral column

vertebrata aka ________ because ...

craniata because they all have a cranium

how many of the chordate characteristics do vertebrates possess

all five

what kind of endoskeleton do vertebrates have

hardened

what did structural stability in vertebrates enable

almost unlimited body size

is most vertebrate, the notochord is replaced by what

centrum of the vertebra

in vertebrates, what are neural spines

provide more area for muscle attachment

what organ systems are modified in vertebrates

- respiratory - digestive - circulatory - nervous

what respiratory adaptations do vertebrates have

- pharynx has muscles to pump water - highly vascularized gills for gas exchange in pharynx

what digestive adaptations do vertebrates have

- food moved by muscles in gut not cilia - accessory organs (liver/pancreas)

what circulatory adaptations do vertebrates have

- ventral chambered heart and erythrocytes

what brain and sensory adaptations do vertebrates have

- tripartite brain - brain encased in cranium - additional sensory organs

what additional sensory systems do vertebrates have

- eyes with lenses - olfactory organs - pressure and vibration receptors - inner ear for equilibrium - electroreceptors for prey detection

the subphylum vertebrata is made up of what superclasses

agnatha and gnathostomata

what is in the superclass agnatha

- jawless fish - hangfish and lampreys

what is in the superclass gnathostomata

- jawed fishes and tetrapods

all jawed vertebrates are called

gnathostomes

how did jaws evolve in gnathostomes

modification of cartilaginous gil arches

what are fishes

all aquatic vertebrates except tetrapods

Lecture 14 Flashcards

(76 cards)