Animal Origins and Evolution of
Body Plans
By: Sara Maxon
Andrew Hollenbeck
What Characteristics distinguish the
Animals?
Animals share a set of derived traits including
similarities in their sequences of many of their
genes, structure of their cell junction and
components of their extracellular matrix.
Embryotic Development
Diploblastic- Animals with 2 embryotic layers
Triploblastic- Animals with 3 embryotic layers
Protostomes- mouth arises first and anus forms
later
Dueterostomes- anus forms first an mouth
forms later
What are features of animal body
plans?
Animal body plans can be described in terms of
symmetry, body cavity structure, segmentation,
and types of appendages
Most animals have…
Radial Symmetry- When one half of the body is
mirror to the other. Usually move slowly or not
at all.
Bilateral Symmetry- When only the right of left
half are mirror to the other. Usually moves
rapidly. Cephalization (Sensory and nervous
tissues in an anterior head)
Animals can be described as…
Acoelomates- lacks enclosed fluid filled body
Pseudocoelomates- animals have a fluid filled
space where internal organs are suspended
Coelomates- animals have a body cavity that
develops within the mesoderm
How do animals get their food?
Motile animals move to find food. While sessile
animals stay in place and get food by filter
feeding. (strains small organisms and organic
molecules from their environment)
Life cycles among animals?
Dispersal stage- when animals move so they
don’t die where they were born.
Major groups of animals?
Sponges- no true cell layer or organs
Placozans- have few cell types and actual organs
Ctenophores- have 2 cell layers and are
separated by a inert extracellular matrix called
mesoglea
The life cycle of most cnidarians has two distinct
stages; a sessile polyp stage and a motile
medusa stage. A fertilized egg develops into a
free swimming larval planula, which settles to
the bottom and develops into a polyp.
Works cited
Sadava D, Hillis D. Heller H, Berenbaum M,2011,Sinaur
Associates Inc., Life The Science of Biology 9th Edition
"Biology 130 Matheny Flashcards FINAL | StudyBlue." StudyBlue.
N.p., n.d. Web. 15 Oct. 2014.
"The Later Days of a Dandelion - DK." - Seeing Horticulture:
Tuesday Afternoon Lab, Fall 2009. N.p., n.d. Web. 15 Oct. 2014.
"Polyp and Medusa Forms of Cnidarians. - Biology Forums
Gallery." Polyp and Medusa Forms of Cnidarians. - Biology
Forums Gallery. N.p., n.d. Web. 15 Oct. 2014
"EVOLUTIONARY TAXONOMY." EVOLUTIONARY TAXONOMY. N.p.,
n.d. Web. 15 Oct. 2014.