Lab 4: Annelids/Nematoda Flashcards
Gastrulation (Broad definition)
Turning from a ball of cells into an organism with multiple layers
Invagination
When the cells fold in on themselves, creating an inner layer and outer layer.
What is the cell called during invagination?
Blastula
Coelom (Broad definition)
Internal body cavity within mesoderm
True coelom
a coelom that is entirely lined with mesodermic tissue
Subcategory relationship between: Bilateria, Lophotrochozoa, Protostomia, Ecdysozoa and Deuterostomia
Bilateria->(Proto/Deutero)
Proto->(Lophotrochozoa/Ecdysozoa)
Lophotrochozoa: (lophophore/trochophore)
Ciliated feeding structure, larval stage
Ecdysozoa: (Ecdysis)
Molting, producing non living cuticle
Cuticle
Shell from Ecdysis
Metameric Segmentation
serial repition of similar parts along the length of an animal
Functions of Coelom (4)
Space: organ development and gametes
Hydrostatic Skeleton
Fluid can distribute nutrients
Digestive Muscles can be separate from movement.
Chaetae:
Bristles that anchor segment of annelid during movement
Parapodia
fleshy appendages that contain bristles, and are used for locomotion, respiration, defense
Annelid Class: Polychaetes
have many fleshy parapodia
Annelid Class: Oligochaeta
earthworms, only a few “oligo” ventral bristles
Annelid Class: Hirudinea
Leeches, reduced coelom, suckers for locomotion and attaching to hosts
Annelid Feeding Strategies
predators, deposit feeder, suspension (U tube feeders) ALL SCAVENGERS
Organs for Annelid digestion
pharynx->esophagus->crop(storage)->gizzard(grinding food)->intestine (chemical breakdown and absorption)
Annelids: Excretion
Two metanephridia (little kidneys)
Annelids: Osmoregulation
Filtration due to coelomic fluid drawn through a funnel by cilia
Annelids: Reproduction
some sexual, some hemaphroditic, some asexual
Nematoda:
roundworms, ecdysozoans
Nematoda: Support
Hydrostatic skeleton, but only with longitudinal muscles. Opposition by cuticle
Nematoda: Nervous system
ring brain, chemical and touch receptors
Nematoda: Feeding Strategies
predators, herbivores, deposit feeders, parasites, full gut/digestion system
Nematoda: Gas and circulation
direct diffusion. Also pseudocoelom used for nutrient distribution
Nematoda: Excretion
anus or diffusion
Nematoda: Reproduction
sexual or hermaphroditic