PHYLUM CHORDATA

By the end of the __ period - 540 mya, all modern phyla appear in __ __. 

One of these types of animals gave rise to __. 

What are the three subphyla of this phylum?

Cambrian, fossil records.

vertebrates

3 subphyla: urochordata, cephalochordata, craniata

DERIVED CHARACTERS OF CHORDATES

All chordates share a set of derived characters.

Although some species possess some of these traits only during __ __. 

What are some of these traits?

embryonic development

notochord, dorsal and hollow nerve cord, pharyngeol slits or clefts, and muscular, post-anal tail.

What is the notochord?

What does it provide?

Do all vertebrates have this? What happens to the notochord if a vertebrate does not have it?

notochord - a longitudinal, flexible rod located between the digestive tube and the nerve cord.

This provides skeletal support throughout most of the length of a chordate.

- not all vertebrates have this: in most vertebrates, a more complex, jointed skeleton develops and the adult retains only remnants of the embryonic notochord.

Dorsal, hollow nerve cord

How does the nerve cord develop? 

Develops into the __ __ system: the __ and the __ __.

the nerve cord develops from a plate of ectoderm that rolls into a tube dorsal to the notochord. 

central nervous, brain, spinal cord.

Pharyngeal slits or clefts

-function as __-__ structures in many __ chordates.

-are modified for __ __ in __ vertebrates.

-Develop into parts of the __, __, and __ in __ vertebrates.

suspension-feeding, invertebrate

gas exchange, aquatic

ear, head, and neck in terrestrial

chordates have this __, __-__ __ extending posterior to the anus. 

-although in many species it is __ during __ __. 

The chordate tail contains __ elements and __. 

-and it provides much of a __ force in many __ species.

muscular, post-anal tail.

lost, embryonic development

skeletal, muscle

propelling, aquatic

UROCHORDATA

more or less, most __. 

what animal?

these belong to the __-__ lineage of chordates. they are __, __ feeders commonly called __ __. 

primitive

tunicates

deepest-branching

marine, suspension, sea squirts.

UROCHORDATA continued

tunicates most resemble chordates during their __ __.

as an adult, a tunicate draws in water through an incurrent __, filtering __ __. 

larval stage

siphon, food particles

CEPHELOCHORDATA

what animals? 

these are __, __ feeders.

they are not __, but they do bury themselves into the sand. (in the ocean)

lancelets

marine, suspension

sessile

CRANIATA 

craniates are chordates that have a __. 

this opened up a completely new way of feeding for chordates: __ __.

What are some common characteristics?

head

active predation

a skull, brain, eyes, and other sensory organs

CRANIATA continued

What is the neutral crest? 

neutral crest cells give rise to a variety of structures, including some of the __ and __ of the __.

when did craniates evolve?

neutral crest - a collection of cells that appears near the dorsal margins of the closing neural tube in an embryo.

bones and cartilage, skull.

evolved at least 530 mya, during the cambrian explosion

CLASS MYXINI

what animals? 

these animals are __, but not __. 

these animals are __ marine craniates that have a cartilaginous __ and __ __ of cartilage derived from the __. 

lack __.

they are __.

hagfish

craniate, vertebrates

jawless, skull and axial rod, notochord

vertebrae

scavengers.

SUB-PHYLUM VERTEBRATA 

these are craniates that have a __. 

likely arose during __ period. 

by the start of the __ fossil, evidence is abundant.

Vertebrates have: vertebrae enclosing a __ __.

an elaborate __

__ __, in aquatic forms.

backbone

cambrian

ordovician

spinal cord, skull, fin rays

ANCESTRAL VERTEBRATES

__ - small (40mm) vertebrates from cambrian.

jaw parts mostly made of __. 

__ are jawless fish whose __ are made for respiration.

conodonts, dentine

ostracoderms, gills

CLASS CHEPHALASPIDOMORPHI

what animals? 

represent the __ living lineage of vertebrates. they have __ __ surronding the notochord and arching partly over the nerve cord. 

these animals are __ vertebrates inhabiting various __ and __ habitats

lampreys

oldest. cartilaginous segments.

jawless, marine and freshwater

the origins of bone and teeth.

__ - appears to have originated with vertebrate mouthparts.

the vertebrate __ became fully __ much later.

mineralization

endoskeleton, mineralized.

GNATHOSTOMES

these are vertebrates that have __.

these in vertebrates are __.

the ancestral form is __. 

jaws

derived

jawless

DERIVED CHARACTERS

other characters common to gnathostomes include:

enhanced __ systems, including the __ __ system.

an extensively __ __. 

paired __. 

sensory, lateral line

mineralized endoskeleton

appendages

FOSSIL GNATHOSTOMES

the earliest gnathostomes are an __ lineage of armored vertebrates called __. 

ACANTHODIANS

radiated during the __ period

share common ancestor with __. 

CHONDRICHTHYES

what animals does this clade include? 

what is their skeleton primarily composed of? 

this skeleton evolved secondarily from an ancestral __ skeleton. 

what are the two distinct lineages of chondrichthyes?

sharks, rays, and relatives

cartilage

mineralized

sharks and rays

CONDRICHTHYES continued

a second subclass is composed of a few dozen species of __. 

most sharks:

have a __ body and are __ swimmers

have acute __

have __ of __. what does this enable them to do?

ratfishes

streamlined, swift

senses

ampullae of lorenzini - can sense electrical currents.

REPRODUCTION of CHONDRICHTHYES

have __ reproduction

all have __ fertilization

what are the three ways to "give birth?" 

diverse, internal.

oviparous - lay eggs

ovoviviparous - eggs remain internal

viviparous - young receive nutrition from mother. 

RAY-FINNED FISHES AND LOBE-FINS

-The vast majority of vertebrates belong to a clade of gnathostomes called __. 

if you break the greek wording of this clade down, what does it exactly mean? 

- also these vertebrates have a __ __. 

osteichthyes 

ostei: bony, -chthyes: fish

bony endoskeleton

OSTEICHTHYES continued

- fishes breathe by drawing water over four or give pairs of __.

these have a __ bony flap called the __ allows passive water __. 

What other adapdation does the this do?

what is the swim bladder?

gills

protective, operculum

allows bony fish to breathe while sitting still.

swim bladder - air bubble, gas levels can be controlled. 

RAY-FINNED FISHES 

class __. includes nearly all the familiar __ __. 

-the fins, supported mainly by long, flexible __. these are modified for __, __, and other functions. 

actinopterygii. aquatic oseichthyes.

rays, maneuvering, defense

Class Sarcopterygii - __-__

these have __ and __ __. 

include __, __, and __. 

lobe-fins

muscular, pectoral fins

coelacanths, lungfishes, and tetrapods

TETRAPODS

gnathostomes that have __ and __. 

Lobe fins modified to allow movement on __. 

What are some specific adaptations of tetrapods? 

what is the origin of tetrapods? 

limbs and feet 

land

tetrapods have four limbs and feet with digits and ears for detecting airborne sounds

their origin is in one lineage of lobe-fins. the fins became progressively made more limb-like while the rest of the body retained adaptations for aquatic life. 

CLASS AMPHIBIA 

Have __ __ that often complements the __ in __ __. 

most are dependent on __ __ for __.

What are the three orders that branch from amphibia? 

moist skin, lungs, gas exchange

standing water, reproduction

urodela, anura, apoda

ORDER URODELA 

what animals does this include? 

describe some characteristics of these.

salamanders and newts. 

salamanders are terrestrial while newts spend most of their time in the water. 

newts are essentially salamanders that live in water. 

have a tail. 

ORDER ANURA 

what animals does this order include? 

what specific characteristics? 

frogs and toads. 

most frogs have an out eardrum that is visible on top of head.

toads have thicker skin that allows them to retain water inside. 

ORDER APODA

what animal?

describe.

Amphibian means "__ __" - a reference to the __ of an __ __ into a __ __. 

caecilians

they are legless and resemble worms/snakes. 

two lives, metamorphosis, aquatic larva, terrestrial adult.

AMNIOTES

amniotes are a group of __ that are adapted to __ __. Whose living members are __, including __ and __.

amniotes lay __ __. they can lay these __. 

tetrapods, terrestrial life.

reptiles, birds and mammals.

amniotic eggs, anywhere.

TERRESTIRAL ADAPTATIONS OF AMNIOTES?

they have relatively __ __ and the ability to use the __ __ to ventilate the __. 

REPTILES 

the reptile clade includes what type of animals?

have __ that create a __ __. 

lay shelled eggs on __.

tuatara, lizards, snakes, turtles, crocodilians, birds, and the extinct dinosaurs.

scales, waterproof barrier. 

land. (usually)

REPTILES continued 

most reptiles are __. which means? 

birds are __. which means?

describe the origin of reptiles 

reptiles - ectothermic: absorbs external heat for their body heat. 

birds - endothermic: capable of keeping the body warm through metabolism

the oldest reptilian fossibles - 300 mya

parareptiles - first major group (large, stocky herbivores)

TURTLES

Turtles occur in many __. which?

all turtles have a __. which is __. 

this is made of the __ (__) and __(__) shields that are fused to the __. 

which of these parts developed first? 

turtles are unique than other reptiles mainly bc they __ __. 

habitats. mostly terrestrial some aquatic and marine.

shell, odd. 

upper carapace, lower plastron. 

lower plastron developed first. 

breathe air. 

As parareptiles were dwindling the __ were diversifying.

the diapsides are composed of what two main lineages?

diapsids

lepidosaurs and archosaurs

LEPIDOSAURS

what are the two lineages of lepidosaurs?

describe these.

snakes are __ __.

tuatara - lizard-like reptiles (3 eyes)

squamata - most umberous and diverse reptiles, apart from birds

legless lepidosaurs.

ARCHOSAURS 

these are the __. diversidfied into a vast range of __ and __. 

traditionally, these were considered __, __ creatures. also thought to be __. 

paleontologists have also discovered signs of __ __ among dinosaurs. 

more __ than __

dinosaurs, shapes and sizes

slow, sluggish, lizards

parental care

endothermic, exothermic.

CRCODILIA 

crocodialians belong to an __ lingeage that dates back to the late __ 

BIRDS 

birds are __. but almost every feature of their reptilian anatomy has undergone modification in their adaptation to __. 

 what are the derived characters? 

what are the most obvious adaptations for flight?

archosaurs, flight.

characters that facilitate flight: hollow bones, breast muscle, clavicle, sac lungs. 

wings and feathers.

ORIGIN OF BIRDS? 

birds probably descended from __: a group of small, __ __. 

by __ mya, true birds appear in __ __. 

archaeopteryx, many transitionals with feathers, etc. 

theropods, carnivorous dinosaurs.

150, fossil record.

LIVING BIRDS, ORDER STRUTHIONIFORMES

the __. are all __. 

The rest of modern birds are grouped into __. : body size and form is __ by __.

ratites, flightless. 

neognathae

restricted by flight.