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G11 Pre-AP Biology
Multicellular eukaryotes.
Cells lack cell walls.
Heterotrophs.
Mobile in at least one stage of life.
Sexual reproduction.
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Level of Organization
Cells, tissue, organs, organ systems. Sponges only have 2 layers of cells, no tissues. "Hydra, jelly fish, corals, sea anemones: 2 layers of cells, but have tissues like muscle and NS"
Number of Body Layers:
Do they have 3 layers (ectoderm, mesoderm, endoderm). Ectoderm: Skin and ns, shell, scales, feathers. Endoderm: Inner lining of gut, respitory system. Mesoderm: Circulatory, reproductive, excretory, muscular. "Sponges, corals, hydra, jelly fish do not have 3 body layers" !Pasted image 20261001110343.png
Symmetry and Body Plans:
Radial symmetry, bilateral symmetry, no symmetry.
Body Cavity
Fluid filled body cavity called coelom.
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Segmentation
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Embryonic Openings
Protostomes: Opening develops into mouth. Deuterostomes: Opening develops into the anus.
Movement
Sessile/stationary (attach to one place as an adult) vs ability to move.
Reproduction
Mainly sexual, internal vs external fertilization.
Presence of Backbone
Vertebrates vs invertebrates.