1. A glimpse into… Developmental Biology
Concept 1: Analyzing the diversity of animals (Ch 26, 32, 33, 34) Holtz: pg
A glimpse into… Developmental Biology

2. What DEFINES an animal?

3. What DEFINES an animal? Animals (Metazoa): Multicellular
Heterotrophic (consumers)
Eukaryotes (…not prokaryotes)
Tissues develop from embryonic layers

4. 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

5. 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:
Larva to adult by metamorphosis
Same gene to regulate expression (Hox gene)

7. Body Plans Useful for categorization Symmetry Tissues Body Cavities
Protosome vs Deuterosome development

8. Symmetry “no” symmetry Radial Symmetry Bilateral 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

9. Symmetry No R? Rad -ial Bilateral Porife Cnida Platy Nem Annel Mollu
Larva: Bilateral
Adult: Radial
Classed as Bilateral animal, BUT radial symmetry as adult
Symmetry
Porife
Cnida
Platy
Nem
Annel
Mollu
Arthr
Echin
Chor
No R?
Rad -ial
Bilateral

10. Types of Tissue Layers Tissue: Group of specialized cells
Diploblastic – two layers (radial animals: Cnideria … and Porifera… kinda)
1) Ectoderm
outer body cover (and nervous)
2) Endoderm
Lines the “digestive tract” and associated organs
Triploblastic – three layers (all bilateral animals)
1) Ectoderm, 2) Endoderm
3) Mesoderm
Muscles and other organs
Development:
Human Development:

11. Types of Tissue Layers Porife Cnida Platy Nem Annel Mollu Arthr Echin
Chor
Rad -ial
Bilateral
Diploblasti
Triploblastic

12. 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

13. Body Cavities Porife Cnida Platy Nem Annel Mollu Arthr Echin Chor
Some rad
Rad -ial
Bilateral
Diploblasti
Triploblastic
(No meso, so acoel…)
Acoelom
pseudo
Coelomate

14. Protostome vs Deuterostome

16. Protostome vs Deuterostome
Protostomes
Deuterostomes
Cleavage
Coelom formation
Blastopore formation
Phyla

17. Protostome vs Deuterostome
Protostomes
Deuterostomes
Cleavage
spiral
Radial
Coelom formation
Blastopore formation
Phyla

18. Protostome vs Deuterostome
Protostomes
Deuterostomes
Cleavage
spiral
Radial
Coelom formation
schizocoelous
enterocoelous
Blastopore formation
Phyla

19. Protostome vs Deuterostome
Protostomes
Deuterostomes
Cleavage
spiral
Radial
Coelom formation
schizocoelous
enterocoelous
Blastopore formation
Becomes mouth
Becomes anus
Phyla

20. Protostome vs Deuterostome
Porife
Cnida
Platy
Nem
Annel
Mollu
Arthr
Echin
Chor
Some rad
Rad -ial
Bilateral
Diploblasti
Triploblastic
(No meso, so acoel…)
Acoelom
pseudo
Coelomate
Protostomes
Deuterostom

22. Question...
An animal with anterior, posterior, dorsal, and ventral surfaces on its body must exhibit
Protostomic development
Coelomate development
Segmentation
Radial symmetry
Bilateral symmetry

23. Question...
An animal with anterior, posterior, dorsal, and ventral surfaces on its body must exhibit
Protostomic development
Coelomate development
Segmentation
Radial symmetry
Bilateral symmetry

24. Reminder… Field/Lab Notebook Project starts on FRIDAY with
Walk Through the Animal Phyla

25. Now…
Try #2 -10, 14, 34 – 40 in Holtzclaw