Invertebrates 4 Flashcards
(24 cards)
What group includes the annelids, rotifers, mollusks and flatworms
Lophotrocozoa
What is special about the lophotrocozoa?
-Trocophore larvae
-Lophophore feeding structure(ring of tentacles around the mouth)
What is an annelid?
-Ringed worm
-Segmented body
-True coelom
- Hydrostatic skeleton
What is segmentation?
-The division of an organisms body plan into repetitive segments.
-Most segments have similar organizations and organs
-Segments are not always identical to accommodate specialization of organs
-Segments close together are very similar
Advantages of Segmentation? (4)
- Provides multiple copies of important organs and structures
- Efficient nervous control( One ganglion and nerve in each segment means that the nervous response in each segment is very rapid/efficient and leads to efficient localized movement)
- Increases body size by unit repetition
- Regeneration(annelids can regrow segments that break off)
Is segmentation unique to annelids? If not, name an example of segmentation in a different species?
No it is not. Segmentation also developed in vertebrates as our spring and rib cage
Explain the annelid nervous system?
- Brain and ganglia (the more motile the annelid the more complex the brain/ganglia)
-Brain connected to the ventral nerve cord
-Each segment contains a ganglia
Explain the annelid respiration system?
-Respiration occurs through the skin/gills
Excretory system of the annelid?
-Annelids have tubular nephridia(equivalent to kidneys in humans) that get rid of waste
Digestive system in annelids?
-Complete digestive system (one way tract with a mouth and anus)
-Distinct regions(oesophagus, intestines, crop(stores food in esophagus))
Circulatory system in annelids?
-Closed system(blood is always contained within vessels)
-Blood is pumped throughout the organism through aortic arches(similar to hearts)
Advantages of a closed circulatory system?
- Faster transport of gasses and nutrients
-Better gas exchange between deep tissues and O2/CO2
-Organism body can be thicker as they don’t need to undergo diffusion to exchange gasses
What are the heart structures in annelids?
Aortic arches
Trocophore larvae
Free-living and swimming larvae
What is parapodia? What type of annelid does not have parapodia?
Parapodia: the locomotory organ of a segmented annelid.
Oligochaete do not have a parapodia
What is a Polychaete?
-Detritivores(feed on dead/decomposing matter)
-Filter-feeder strain organic matter from water
-Separate sexes with external fertilization(trochophore larvae)
3 Characteristics of mollusks?
-Triploblastic
-Bilaterally symmetrical
- Trocophore Larvae
3 regions of the mollusk body plan?
Foot: large muscle used for movement
Visceral Mass: Contains main organs(heart, nephridia, stomach)
Mantle: Outgrow of the body wall that encloses the visceral mass
Define Nephridia
An invertebrate organ which occurs in pairs and removes wastes similar to kidneys.
Do mollusks have closed or open circulatory systems?
Open
4 types of mollusks
- Polyplacophora
- Bivalvia
3.Gastropoda - Cephalopod
Hermaphrodite vs Dioecius
Hermaphrodite: Organisms can have both male and female organs
Dioecius: Organisms can only have female or male organs
Do mollusks produce sexually or asexually?
BOTH
