lecture 5 Flashcards
how do Deuterostomes differ from Protostomes (2)? what do they have in common (2)?
Differ:
Deuterostomes have enterocoelom and radial cleavage.
Protostomes have schizocoelom.
In common:
tissues, bilateral symmetry
what organ system is unique to echinoderms, and what is its function?
water vascular system, which operates the tube feet that are used for locomotion and/or feeding
what does Echinodermata have in common with Cnidaria (3 things but number one is most NB)? why are they in separate lineages (2 reasons)?
In common:
- adults are radially symmetrical
- tissue
- both reproduce sexually and asexually
Separated: #Cnidaria= radial symmetry and diploblastic # Echinodermata=bilateral symmetry in juvenile and triploblastic
what morphological feature is common to the hemichordates and chordates?
Both Hemichordata and Chordata contain pharyngeal gill slits.
what are the key morphological characteristics of the chordates separating the, from other deuterostomes?
- dorsal hollow nerve cord
- perforated pharynx
- notochord
- segmented body wall muscles
what 3 phyla do deuterostomes include?
- Echinodermata
- Hemichordata
- Chordata
schizocoelom vs enterocoelom
Both true coelom just form differently.
Schizocoelom: mesodermal cells separate and create cavity between them, lined by mesoderm
Enterocoelom: mesodermal cells form as outpockets from embryonic gut
what does the notochord do
supports the invertebrate/embryo from head to tail
5 groups Echinoderms
examples
- Asteroidea (sea stars)
- ophiuroidea (brittle and basket stars)
- crinoidea (sea lilies and feather stars)
- Echinoidea (sea urchins and sand dollars)
- holothuroidea (sea cucumbers)
3 characteristics unique to vertebrates
- internal skeleton
- neural crest cells
- brain
2 facts about asteroidea (sea stars)
Astero-idea
- central disk, 5 -20 radiating ‘arms’
2. NB predators
a fact about ophiuroidea (brittle and basket stars)
Op-Hi-Uro-Idea
central disk and long, slender arms that are sometimes branched
2 facts about Crinoidea (sea lilies and feather stars)
Crino-idea
- upward pointing mouth surrounded to 5 or a 100 arms
2. filter feeders
a facts about Echinoidea (sea urchins and sand dolars)
Echino-idea
- lack arms; most have moveable spines extending from solid tests
a fact about Holothuroidea (sea cucumbers)
Holo-Thuro-idea
- long, soft and fleshy body with a tough, leathery covering
common name for hemichordata
acorn worms
what structures distinguish vertebrates from invertebrate chordates? 2
- vertebrates have an internal bony skeleton, including a cranium and vertebral column in most groups,
- structures derived from neural crest cells
how does a perforated pharynx enable hemichordates to acquire food and oxygen from sea water?
water enters the pharynx of a hemichordate through its mouth, and exits the pharynx through the branchial slits. The animal extracts oxygen and particular food from the water as it passes through the pharynx
function of notochord
supports the invertebrate/embryo from head to tail
function of segmental muscles in the body wall and tail
allows each muscle block to contract independently
common name of a cephalopoda
lancelets
2 characteristics of lancelets
- long body =pointed at both ends
2. sediment dweller
common name for urochordata
tunicates (sea squirts)
tunicates undergo major modification to their chordate characters when they changes from……..
swimming larvae (possessing chordate features) to sessile adults
when tunicates become sessile adults what major modification to chordate characters do they undergo?2
- secrete gelatinous ‘tunic’
2. filter feeder via perforated pharynx
a perforated pharynx is composed of 2 things
- gill arches
2. pharyngeal slits
3 characteristics unique to vertebrates
- internal skeleton-cranium
- neural crest cells
- brain
purpose of the internal skeleton of vertebrates 2
- provide structural support for muscles.
2. enable most vertebrates to move rapidly through the environment
what is bone and which group is it lost from
a connective tissue in which living cells secrete the materialized matrix that surrounds them.
lost by chondrichthyes
the skeleton is divided into 2 parts and what does each include
- axial skeleton- cranium, vertebral columns, ribs and sternum (breast bones)
- appendicular skeleton- bones of appendages
vertebral column is made up of individual vertebrae what is the purpose of this
surrounds and protects the dorsal hollow nerve cord (and the cranium surrounds the brain)
neural crest cells are independent of
endo-ecto and mesoderm
oldest known vertebrate fossil about 550 mya has 6 characterisics
- fish shaped
- fibrous cranium and segmented body wall muscles
- no bone
- unpaired fins so a dorsal fin and ventrolateral fin
- gill openings
- mouth
