Kingdom Animalia
Diversity
Microscopic → macroscopic
Basic body structure and function → complex
Sessile → motile
Characteristics
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Eukaryotic
Multicellular
Cells do not have cell walls
Heterotrophic
Capable of complex movement (most)
Interactive & Social (some)
Reproduce sexually & asexually
99% are invertebrates (without backbones) 1% are
vertebrates (have backbones)
Trends in Animal Evolution
● Simple → Complex
○ Levels of tissue organization increases
● Asymmetrical → Radial Symmetry → Bilateral Symmetry
● Cephalization - concentration of sense organs and nerve
cells at anterior (head) end
The Body Cavity
Body Cavity - space which is located between the gut
(endoderm layer) and the body wall (mesoderm layer)
3 layers of tissues in animals:
● Ectoderm - outermost layer of cells
● Mesoderm - middle layer of cells
● Endoderm - innermost layer of cells
Trends in Body Cavity
Simple
Acoelomate - have no body
cavity
Pseudocoelomate - has a fluid
filled body cavity; mesodermal
layer still quite primitive
Coelomate - has a true body
cavity; mesoderm layer is
Complex
advanced and specialized