ANIMALDIVERSITY

Where are We?

What makes an Animal?

• Eukaryotic• Heterotrophic• Multicellular• Diploid• Are motile at some stage

of the Life Cycle

Evolutionary History in Development

Why is embryonic development important in our understanding of evolution?

• Evolutionary Developmental Biology (“Evo-Devo”)– Comparisons of

developmental characters in different organisms can often reveal ancestral relationships

– Excellent characters for use in building phylogenies

Ernst Haeckel 1892

Development

Videos

• Development of the Blastula• Gastrulation

Blastopore

Mouth: protostomes Anus: deuterostomes

Triploblastic Development

Protostomes

(“mouth first”)

Deuterostomes

(“mouth second”)

Blastopore=mouth

Blastopore=anus

Body Plan: Symmetry

Symmetry

Radial Symmetry Bilateral Symmetry

Symmetry Practice

Tissues• Parazoa - group of organisms without true

tissues• Eumetazoa - group of animals with true

tissues

Germ Layers

• Diploblastic– Endoderm + ectoderm

• Triploblastic– Endoderm + mesoderm + ectoderm

Triploblastic Animals - Body Cavities

Red = ectoderm

Yellow = endoderm

Blue = mesoderm

Lophotrochozoa

LophotrochozoaTrochophore larvaeLophophore

• Used for filter feeding

Ecdysozoa

Today’s Lab• Work through all stations (use flowchart!)• Identify unknowns in tank• Show me your tree!

Flow ChartTrue Tissues?

Parazoa Eumetazoa

yesno

Number of Germ Layers?

two three

Diploblastic Triploblastic

Fate of blastopore?

mouth anus

Protostome Deuterostome

Which clade?

Lophotrochozoa Ecdysozoa

Trochophore larvae or lochophore(or neither) ?

Asymmetry

Radial symmetry

Bilateral symmetry

Acoelomate, Pseudocoelem, or CoelemCoelom