-collection of similarly produced cells
-like apical meristem
Sponges germ layer
-no germ layer
-Identical cell collection since birth
- function based on location
diploblastic
-two germ layers
-endoderm and ectoderm (tube within a tube)
-nideria, jellyfish, anemone
endoderm vs ectoderm
-creates lining of inside of digestive tract
-creates outer skin and nervous tissue
triploblastic
-endoderm and ectoderm
-mesoderm creates between, bones organism, systems
asymmetrical
no plane
sponges
radial symmetry
can pass multiple planes through angles and get halves
starfish
no lead end of movement (no accumulation of sense organs)
,bilateral
only one plane
humans
filter feeding
most primitive way of gaining food
move medium past you and take organic pieces out
sponges
sponges feeding
cells grow choanocytes that line inside, move flagella to more water through and food sticks to them
choanocyte (collar cells)
ancestors to all animals, so we all have some form
triploblastic body cavity
-between digestive tract and outer body wall
-chest, leg muscles
-red ectoderm, yellow endoderm, filled in with purple mesoderm
acoelacoelomate
-no body cavity
pseudocoelomate
-digestive tube in middle, tube ooo outside, gaps in between
-true body cavity
-organs aren't covered in mesodermal lining, exposed to body fluids and each other
risks and advantages of pseudocoelomates
-organs can bump and damage with movement
-organs are bathes in fluid, nutrients, gasses, efficient
eucoelomate
-mesodermal lining protects organs in body cavity (surrounds heart and kidney and keeps organs
attached to wall)
-need vascular (arteries and veins) system to penetrate lining and bring fluids, nutrients and gasses to
organs
triploblastic body cavity evolution
acoelomates first, then other two around same time
blastosphere
, -fertilized cell keeps dividing to form "ball of creation
-endodermal germ layer infolds to create tube, digestive system
-tube through body, not really in body
protostomes
-blastopore creating tube becomes mouth
-Insects
deuterostomes
-blastopore becomes anus
-humans
no germ layers (protostome phyla)
-phylum porifera
-evolutionary dead end, collar cell ancestor though
-sponges
disassemble and reassemble (totipotency)
-take silica from environment to build spicules (small fibrous crystal that keeps them fluffy and able to
grow into shapes)
-filter feed
diploblastic (protostome phyla)
-two germ layers
-phylum cnidaria
-jellyfish, coral polyps
-blind end gut digestive lining and outer covering
-jellyfish tentacles are offshoots of ectodermal layer
-radially symmetrical
cynidocyte cell
cell in tentacles (harpoon, nematocyst, flagellated collar cell with coiled protein) that can pull things in
makes toxins for jellyfish and anemones
lophotrochozoans (protostome phyla)
-get larger by adding in body segments
-bilaterally symmetrical
-phylum Platyhelminthes (flatworms) and annelida (leeches, earthworms)
-phylum Mollusca (snails, clams, squid)
Phylum- platyhelminthes (flatworms)
acoelomates- high surface area to body ratio, flat, gasses exchanged through tissues of body
Phylum- annelida (leeches, earthworms)
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