Concept 1: Analyzing the
diversity of animals
(Ch 26, 32, 33, 34)
Holtz: pg. 186-197
A glimpse into…
Developmental Biology
What DEFINES an animal?
What DEFINES an animal?

Animals (Metazoa):
 Multicellular
 Heterotrophic
(consumers)
 Eukaryotes (…not prokaryotes)
 Tissues develop from embryonic layers
Cell Structure and Specialization

Unique to Animals:
 No

cells walls
Instead: separate structures (desmosomes, gap
junctions, and/or tight junctions) hold cells together
 Muscle
and nervous tissue
Reproduction and Development

Primarily sexual (but some asexual)


Sperm and egg
Zygote grows by many mitotic divisions


Called cleavage
Zygote to blastula to gastrula (usually in egg)





Gastrulation: http://www.youtube.com/watch?v=1MnwHRURKns
http://www.youtube.com/watch?v=j87y7EAj8qE
http://www.youtube.com/watch?v=8v6cXkzlEQA
Larva to adult by metamorphosis
Same gene to regulate expression (Hox gene)
Body Plans

Useful for categorization
 Symmetry
 Tissues
 Body
Cavities
 Protosome vs Deuterosome development
Symmetry

“no” symmetry


Radial Symmetry



Poriphera
All parts radiate from the centre
Cnidaria
Bilateral Symmetry


Distinct anterior (head-end), posterior (tail-end), left, right, dorsal
(top), ventral (bottom)
Some have cephilization


Sensory organs and central nervous system in the head end
Good for unidirectional movement
Larva: Bilateral
Adult: Radial
Symmetry
Porife Cnida Platy
No
R?
Rad
-ial
Classed as Bilateral animal,
BUT radial symmetry as adult
Nem
Annel Mollu Arthr
Bilateral
Echin Chor
Types of Tissue Layers

Tissue: Group of specialized cells

Diploblastic – two layers (radial animals: Cnideria … and Porifera…
kinda)

1) Ectoderm


2) Endoderm


outer body cover (and nervous)
Lines the “digestive tract” and associated organs
Triploblastic – three layers (all bilateral animals)


1) Ectoderm, 2) Endoderm
3) Mesoderm



Muscles and other organs
Development: http://www.youtube.com/watch?v=8v6cXkzlEQA
Human Development:http://www.youtube.com/watch?v=UgT5rUQ9EmQ
Types of Tissue Layers
Porife Cnida Platy
Nem
Annel Mollu Arthr
Rad
-ial
Bilateral
Diplo
blasti
Triploblastic
Echin Chor
Body Cavities

Coelom – fluid filled body cavity separating the digestive
tract from the outer body
Acoelomates – no cavity at all
 (Porifera, Cnideria,) Platyhelminthes
 Pseudocoelomates – animals with a cavity, but not all from
mesoderm
 Organs held in place loosely
 Nematoda
 Coelomates – animals with a “true” Coelom (lined with
mesoderm)
 Organs suspended in order
 Annelida, Mollusca, Arthropoda, Enchinodermata,
Chordata

Body Cavities
Porife Cnida Platy
Nem
Some Rad
rad
-ial
Echin Chor
Bilateral
Diplo
blasti
(No meso,
so acoel…)
Annel Mollu Arthr
Triploblastic
Acoel pseu
om
do
Coelomate
Protostome vs Deuterostome
Protostome vs Deuterostome
Protostomes
Cleavage
Coelom formation
Blastopore
formation
Phyla
Deuterostomes
Protostome vs Deuterostome
Cleavage
Coelom formation
Blastopore
formation
Phyla
Protostomes
Deuterostomes
spiral
Radial
Protostome vs Deuterostome
Protostomes
Deuterostomes
Cleavage
spiral
Radial
Coelom formation
schizocoelous
enterocoelous
Blastopore
formation
Phyla
Protostome vs Deuterostome
Protostomes
Deuterostomes
Cleavage
spiral
Radial
Coelom formation
schizocoelous
enterocoelous
Blastopore
formation
Becomes mouth
Becomes anus
Phyla
Protostome vs Deuterostome
Porife Cnida Platy
Nem
Some Rad
rad
-ial
Echin Chor
Bilateral
Diplo
blasti
(No meso,
so acoel…)
Annel Mollu Arthr
Triploblastic
Acoel pseu
om
do
Protostomes
Coelomate
Deuterostom
Question...

An animal with anterior, posterior, dorsal,
and ventral surfaces on its body must
exhibit
A)
B)
C)
D)
E)
Protostomic development
Coelomate development
Segmentation
Radial symmetry
Bilateral symmetry
Question...

An animal with anterior, posterior, dorsal,
and ventral surfaces on its body must
exhibit
A)
B)
C)
D)
E)
Protostomic development
Coelomate development
Segmentation
Radial symmetry
Bilateral symmetry
Reminder…

Field/Lab Notebook Project starts on
FRIDAY with
 Walk
Through the Animal Phyla
Now…

Try #2 -10, 14, 34 – 40 in Holtzclaw