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