Multicellular, heterotrophic eukaryotes.
Lack cell walls (which fungi have).
Cells linked with collagen and have intercellular junctions.
Specialized tissues for movement and impulse conduction.
One hypothesis for the origin of animals is from a flagellated protist
determinate development, usually spiral cleveage
Lophophorates (Bryozoa, Brachiopodia)
Trochozoans (Annelida, Mollusca)
Ecdysozoans (Nematoda, Arthropoda)
indeterminate development, radial cleavage
Hemi, Uro and Cephlochorates
Parazoa vs. eumetazoans.
Diploblastic vs. triploblastic tissues.
Protostomes vs. deuterostomes.
Acoelomate, pseudocoelomate, and coelomate organization
Two cell (tissue) layers: ectoderm and endoderm
Three cell layers: ectoderm, mesoderm, and endoderm
unique type of junctions between their cells
extracellular matrix containing collagen and proteoglycans
division of a zygote
cells divide in a even pattern
cells divide in a permutation of radial cleavage
3 types of cells in triploblastic
concentration of sensory organs and nervous tissue in a head at the anterior end of the animal
infolding of the embryo to make the blastophore
Lack a fluid-filled body cavity.
Space between gut and body wall is filled with mesenchyme
Movement is by cilia
cells in acoelomate animals
Body cavity is a a fluid-filled space in which organs are suspended
But not lined with mesoderm (thus a pseudocoel).
Muscles are only on the outside wall of the animal
True coelom that develops from mesoderm
Coelom lined with a layer of mesodermal muscle tissue called peritoneum
Peritoneum covers the organs
specialized mesoderm tissue that lines body cavity in coelomate
Cushions internal organs.
Can provide a hydrostatic skeleton.
Allows external layer of muscles to move independently of organs and gut.
Provides space to store reproductive cells (eggs) and wastes.
functions of body cavity
solid masses of mesoderm split to form coelom. in protostome
folds of endoderm make coelom. in deuterostomes
Traditional view: annelids with arthropods because of segmentation.
Alternative view: annelids with mollusks because of trochophore larva.
Molecular data: supports annelids with mollusks.
Annelid-arthropods or annelid-mollusks?
is a horseshoe-shaped crown of ciliated tentacles.
Considered plants until 1765.
Habitat: mostly marine and sessile.
Body plan: Pores and central cavity; cellular organization and no true tissues or organs (epidermis, mesohyl, spicules).
Feeding: filter feeders with intracellular digestion.
Osmoregulation / Excretion: by vacuoles.
Reproduction: hermaphrodites; asexual budding.
Structures: osculum, pores, atrium, spicules.
Cells: choanocytes, amoebocytes.
Water flow via Bernoulli effect.
The two cell layers are separated by a thick, gelatinous mesoglea.
Ctenes are comb-like rows of fused cilia; they move through the water by beating the cilia
The feeding tentacles are covered with cells that discharge adhesive material when they contact prey.
Simple life cycles with external fertilization and with the zygotes developing directly into small ctenophores.
In enclosed bays, populations can explode and damage local ecosystems.
The two cell layers in a ctenophore are separated by a thick, gelatinous _____
are comb-like rows of fused cilia; they move through the water by beating the cilia
Habitat: mostly marine, some freshwater.
Body plan: radial symmetry; tentacles in 4 or 6 multiples; two tissue layers with some connective tissue (mesoglea); specialized cells (nerve cells, muscle fibers, etc).
Feeding: carnivores; extracellular protelytic enzymes.
No specialized organs for osmoregulation, excretion, respiration or circulation.
Reproduction: polyps and medusa, hermaphroditic.
cell of cnidarians used to sting. organelle it uses is nematocyst
(Sea anemones, sea pens, and corals)
Polyp stage dominates the life cycle
Sea anemones are all solitary
Sea pens and corals are colonial
Corals and anemones have photosynthetic endosymbionts in their tissues that provide some of their nutrition
(Jellyfish; all marine)
Medusa stage dominates the life cycle
(Hydra, Portuguese man-of-war, fire corals)
In some species, polyps dominate in some species while others have only medusae
Most are colonial; the polyps are connected and share a single gastrovascular cavity.
Some polyps are specialized for feeding, others produce medusae.
Polyps of most species secrete a matrix of organic molecules on which they deposit calcium carbonate, which forms a skeleton.
Living polyps form a layer on top of a growing mass of skeletal remains. Forms coral reefs and islands.
______ grow in nutrient-poor tropical waters.
Photosynthetic dinoflagellates live endosymbiotically in their cells.
The _____ receive nutrition from the dinoflagellates
Dinoflagellates receive nitrogen and a place to live.
Warming can lead to loss of the endosymbionts (coral bleaching).
Reef-forming _____ are restricted to clear surface waters, where light levels are high enough to support photosynthesis.