introduction to invertebrates Flashcards
Kingdom Animalia
Multicellular body formed of eukaryotic cells
- lack of cell walls and plastids
Heterotrophic nutrition
Movement by shortening of contractile fibers (muscle fibers)
Invertebrates lack a true body cavity (coelom)
Classification criteria
Symmetry:
- bilateral, radial, none
Level of organization:
- cellular tissue, tissue, organ, organ system
Embryonic tissues (germ layers)
- ectoderm, endoderm, and mesoderm
Body plan
- tube within a tube, saclike
Fate of Blastopore
- mouth, anus (Porifera and Cnidaria have none)
Segmentation:
- yes, no
Phylum Porifera
Sponges
Primitive, multicellular
Filter feed using collar cells
Spicules
- help classify
- helps form sponge skeleton
Symmetry: Asymmetrical or Radial
LoO: Cellular Tissue
Germ: None
Coelom: N/A
Body Plan: N/A
Phylum Cnidaria
Jellyfish
Unsegmented
Polyp
- asexual reproductive generation; mouth at top
Medusa
- sexual reproductive generation; mouth at bottom
No centralized nervous system
Stinging Cells
Symmetry: Radial
LoO: Tissue
Germ: Ectoderm and Endoderm
Coelom: N/A
Body Plan: Saclike
Phylum Platyhelminthes
Flatworms
Unsegmented
Free living and parasitic
- Planarians
- Tapeworms
- Taenia
Hermaphroditic (have male and female sex organs)
Symmetry: Bilateral
LoO: Organ
Germ: Meso-, Ecto-, Endoderm
Coelom: Acoelomate
Body Plan: Saclike
Phylum Nematoda
Round worms
Unsegmented
Free living and parasitic
- Ascaris
- Trichinella
- Filarial worm
Complete digestive tract (mouth and anus)
Symmetry: Bilateral
LoO: Organ system
Germ: Ecto-, Endo-, Mesoderm
Coelom: Pseudocoelomate
Body Plan: Tube within a tube
Phylum Rotifera
Rotifers (freshwater animal)
Pseudocoelom
Complete digestive tract
Corona: crown of cilia around the mouth
Cephalization
concentration of sense organs and nervous control located at the anterior end
“head” and brain formation implies cephalization
