Animals Flashcards
Tight junctions
Prevent fluid from moving across a layer of cells
Desmosomes
Connected to cytoskeleton
Space between: spot rivets
Gap junctions
Ions pass between cells
Development
Single cell -> blastula -> gastrula
Blastula
Hollow ball of cells
Stage of embryonic development
Blastocoel
Cavity of blastula
Gastrulation
Cells move from outside of blastula to inside
Archenteron
Gut
Protostome
“1st the mouth”
8 cell stage: top tier of cells sits in the furrow of the bottom tier (spiral and determinate)
Mesoderm splits to form coelom
Mouth develops from blastophore
Blastophore
Opening of gastrula
Deuterostome
"2nd the mouth" 8 cell stage: cells stack on top of each other Each cell is capable of forming a larva Folds of archenteron form coelom Anus develops from blastophore
Radial symmetry
Distinct top and bottom sides
No distinct left and right sides
Bilateral symmetry
Distinct top, bottom, right, and left sides
Coelom
Body cavity
Diploblast
Only ectoderm and endoderm
Ectoderm and endoderm
Outside cell layer and inside cell layer of embryo, respectively
Triploblast
Ectoderm, endoderm, and mesoderm
Coelomate
Mesoderm tissue layers line ectoderm and coelom (suspend internal organs)
Pseudocoelomate
Mesoderm lines ectoderm, but not coelom
Fluid lines coelom
Acoelomate
Mesoderm tissue fills space between digestive tract and ectoderm
Porifera
Sponges No true tissues Hermaphrodites Sessile (stuck to site) Flagellated swimming larvae
Sponge body plan
Pores
Spongocoel (central cavity)
Choanocytes (flagellated and collared cells that engulf food)
Ameobocytes (eat food, carry nutrients, manufacture skeletal fibers)
Osculum (large opening)
Cnidaria
Jellies, corals, hydras
Radial symmetry
Central gastrovascular cavity
Diploblastic
2 forms: polyp (hydra) or medusae (jelly)
Asexual (budding) and sexual reproduction
Cnidocytes
Structures on cnidaria tentacles that release sticky chemicals that bind and/or stun prey
Nematocysts: more complex cnidocytes
Hydrozoa
Cnidarians
Hydra
Scyphozoa
Cnidarians
Jellyfishes
No polyps
Cubozoa
Cnidarians Box-shaped Lens and cornea, but no brain Simple light-sensing cells Sea wasp
Anthozoa
Cnidarians
Coral and anemone
No medusae
Contain symbiotic bacteria
Lophotrochozoa
Bilateral symmetry
Triploblastic
Most are coelomates
Lophophore
Crown of feeding tentacles
Trocophore
Ciliated larval stage
Platyhelminthes
Lophotrochozoans Flatworms Acoelomate Gas exchange and waste: diffusion Gastrovascular cavity: one opening and branching Parasitic: require 2 hosts (Flukes) Regenerative abilities Eyespots (planaria)
Turbellaria
Platyhelminthes
Typical flatworms