Animal body plans AND phylogeny Flashcards
how do zoologists categorize animals?
by body plan
body plan
set of morphological and development traits
what is wrong with this statement
all body plans have remained the same
- some have been conserved
- some have undergone multiple changes over the course of evolution
two types of symmetry of body plans
- radial
- bilateral
radial symmetry
no front and back OR left and right
What symmetry is this
bilateral symmetry
What symmetry is this
radial
bilateral symmetry
two-sided symmetry
what do bilaterally symmetrical animals have
- dorsal side
- ventral side
- posterior side
- anterior side
how can animal body plans vary
- symmetry
- tissues
- body cavities
what does bilateral symmetry go hand in hand with
cephalization
do bilateral animals ALWAYS show high levels of cephalization
NO - think of how simple earthworms are
tissues
collections of specialized cells isolated from other tissues by membranous layers
how many germ layers give rise to tissues and organs of animal embryos
3
3 germ layers
- ectoderm
- endoderm
- mesoderm
ectoderm
germ layer covering the embryo’s surface
endoderm
innermost germ layer and lines the digestive tube (archenteron)
what does the endoderm line
the digestive tube (archenteron)
all true tissued animals have
endoderm and ectoderm
diploblastic animals
only have 2 or 3 germ layers - LACK mesoderm
true or false
diploblastic animals are differentiated based on coelom type
NO - they lack coelom
diploblastic animals have ____ symmetry
radial
animals with 3 germ layers have to be further organized (true or false)
true
what are further organizations of triploblastic animals
- what type of coelom do they have
- are they protostomes or deuterostome
three types of coeloms
- true coelom
- pseudocoelom
- acoelomate (no coelom)
what germ layer differentiates the coelom
mesoderm
why don’t diploblastic animals have a coelom
they have NO mesoderm
examples of diploblastic animals
- cnidarians
examples of triploblastic animals
- ALL bilaterians
- flatworms
- arthropods
- vertebrates
what do MOST triploblastic animals posses
body cavity
what is a TRUE body cavity called
coelom
coelomates
animals that posses a true coelom
what is a true coelom
a coelom surrounded COMPLETELY by mesoderm tissue
pseudocoelom
body cavity derived from mesoderm AND endoderm
triploblastic animals with pseudocoelom AKA
pseudocoelomates
what identifies a pseudocoelom
a coelom NOT completely lined with mesoderm
triploblastic animals WITHOUT a coelom
acoelomates
how to identify an acoelomate
there is NO body cavity/internal cavity
pseudocoelomate
acoelomate
coelomate
two types of animal development
- protostome development
- deuterostome development
protostome development
- cleavage is spiral and determinate
- splitting of solid masses of mesoderm forms the coelom
- mouth develops from first hole (the blastophore)
Deuterostomes development
- anus develops from the first hole (blastophore) and the mouth from the SECOND one
- mesoderm buds from the wall of the ARCHENTERON to form the coelom
- cleavage is radial and indeterminate
protostome vs deuterostome development
cleavage is spiral and derterminate
protostome
protostome vs deuterostome development
cleavage is radial and indeterminate
deuterostome development
protostome vs deuterostome development
the fate of the cell is determined much later
deuterostome development
protostome vs deuterostome development
the fate of the cell is determined very early in development
protostome
what makes possible identical twins and embryonic stem cells
indeterminate cleavage
indeterminate or determinate cleavage
each cell in the early stages of cleavage retains the capacity to develop into a complete embryo
indeterminate
blastophore forms during
gastrulation
blastophore connects ____ to the ______
archenteron to exterior of the gastrula
protostome vs deuterostome development
blastophore becomes the mouth
protostome
protostome vs deuterostome development
blastophore becomes the anus
deuterostome development
protostome vs deuterostome development
means first mouth
protostome
protostome vs deuterostome development
means second mouth
deuterostome development
5 important points about the relationships among LIVING animals that are reflected in phylogeny
- all animals share CA
- sponges are basal animals
- Eumetazoa (true animals) is a clade of animals with true tissues
- most animal phyla are bilaterians
- 3 major clades of bilaterian animals
the 3 major clades of bilaterians are all _____ except for one which is _____
invertebrates and vertebrates
what clade of bilaterians is classified as vertebrates
Chordata
how do we know sponges are basal animals
- lack of hox genes
- lack of true tissues
- lack collagen
the animal phylogeny is ______
monophyletic
What node represents the CA of ALL Animalia
Node 1 (Meterozoan)
is Bilateria a clade
yes
what is represented by A
True tissue
what do the Cnidarians and Ctenophora have in common and are they monophyletic
- share radial symmetry
- NO- they share a CA with bilateria (Paraphyletic)
what are the 3 clades within Bilateria?
- Deuterostomia
- Lophotrochozoa
- Ecdysozoans
what is represented by B
bilateral symmetry
of the three clades in bilaterian, what is sister to what?
Lophotrochozoa and Ecdysozoan are sister to Deutersotomia
what is the best way to describe clade Lophotrochozoa
as a very large polytomy