L7: Lophotrochozoa: Phylum Annelida (Segmented Worms) Flashcards
Differentiate between metamerism and tagmatization Compare general anatomy of the Errantia and Sedentaria clades Compare reproductive characteristics of Errantia and Sedentaria Describe structure and function of metanephridia Describe the variation in digestive systems among different groups of annelids
What animals are in the phylum Annelida
Segmented worms
Where do annelida inhabit
Mostly marine, some freshwater and terrestrial
Describe what it means to have a metameric body
Body consisting of similar segments
Pertaining to the phylum Annelida…
Describe what paired epidermal setae are
Stiff hairs associated with the epidermis
Pertaining to the phylum Annelida…
T/F: Open circulatory system
False - closed
Describe the nervous system of annelids
Location of nerve cord and ganglia
Ventral nerve cord with dorsal suprapharyngeal ganglia
Describe the similarities and differences between protonephridia and metanephridia
Both are excretatory structures. Protonephridia are tufts of flagella that funnel fluid into the tubules. No internal openings. Metanephridia have internal openings into the coelom and flagella that beat in water from the body cavity (coelom)
Annelida are comrpised of what two principle clades?
- Errantia
- Sedentaria
Errantia are ____ mobile, live in ____ environments and are predatory
Highly;marine
Sedentaria are ____ mobile and live in ____
Less;tubes
Describe metamerism
Segmentatal organization of body parts
Describe Tagmatization
The specialization of body regions of a metameric
animal for specific functions
Pertaining to the phylum Annelida…
What is the benefit of segmenting?
- More resistant to injury - one segment injury doesn’t kill animal
- Each segment acts as a hydrostatic chamber for movement
- Allows for tagmatization
Describe some of the external anatomical features of Annelids
Parapodia: Sensory bristle like structures around mouth
Prostomium: Top part of first segment that grows out to create an overhang
How do annelids move?
Generatees waves with its muscles that pushes it along
Describe the annelid digestive system structure: Crop
Thin walled structure that holds food
Describe the annelid digestive system structure: Gizzard
Thick walled, highly muscularized grinding structure
How does annelid Siboglinid digest food with no digestive system?
Lives in symbiosis with chemoautotrophic bacteria
Describe general annelid reproduction
Monoecious/fertilization/larvae
- Dioecious
- Internal and external fertilization
- Gametes releaseed via nephridia or through body wall
- Trochophore larvae
- Often semelparous
Describe the difference between semelparity and Iteroparity
Semelparity: One reproductive event in their lives
Iteroparity: An organism that is able to have multiple reproductive events in lifetime
Describe general Clitellata reproduction
Monoecious, mutual sperm stransfer, eggs laid in cocoon, direct development
Regarding class Errantia…
Live in what kind of environment?
Mostly marine
Regarding class Errantia…
T/F Small parapodia
False - prominant lobes/setae in parapodia
Regarding class Errantia…
T/F: Mobile predators
True
