A glimpse into… Developmental Biology 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 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

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

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: 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 Echin Chor Rad -ial Bilateral Diploblasti Triploblastic

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 Annel Mollu Arthr Echin Chor Some rad Rad -ial Bilateral Diploblasti Triploblastic (No meso, so acoel…) Acoelom pseudo Coelomate

Protostome vs Deuterostome

Protostome vs Deuterostome Protostomes Deuterostomes Cleavage Coelom formation Blastopore formation Phyla

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

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 Annel Mollu Arthr Echin Chor Some rad Rad -ial Bilateral Diploblasti Triploblastic (No meso, so acoel…) Acoelom pseudo Coelomate Protostomes Deuterostom

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

Question... An animal with anterior, posterior, dorsal, and ventral surfaces on its body must exhibit 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