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Wednesday, March 13, 2019
Phylum Mollusca I Slides
https://docs.google.com/presentation/d/1k1vW4DeWw3oW_mVrhMeb_H6l8RworaMrbj8UGYRbZdo/edit?usp=sharing
Thursday, March 7, 2019
Annelid Diversity Information (from stations in class)
Sabellidae (Feather Duster Worms)
Feather duster worms live in tubes made of a protein material secreted by the worm and the tubes are attached to solid substrates. They can often be seen attached to the submerged sides of floating docks. The head appendages of sabellids are called radioles. The crown of ciliated radioles, each with 2 rows of short side-branches (making them look like two-edged combs), is held into the water and used to capture suspended phytoplankton. Sabellids are suspension feeders. They also use their radioles as gills (for breathing) and they have little eyes all over them so they can “keep an eye out” for trouble.
Terebellidae (Spaghetti Worms)
Many terebellids live in tubes made of sand grains cemented together by secretions from the collar area of the worm. The common name of ‘spaghetti worm’ comes from the many long, spaghetti-like tentacles that arise from the head. Each tentacle has a ciliated groove running down its length. Individual sand grains and small living organisms are picked-up by cilia and mucus within the tentacle groove and are carried to the mouth by beating of the cilia or by muscular contraction of the tentacle. Some particles are used for tube construction, whereas others are eaten. Terebellids are selective deposit feeders. A second type of tentacle-like appendage arising from the anterior end of terebellids function as gills. These are shorter than the feeding tentacles and are typically coiled and red in colour.
Nereididae (Ragworms)
Nereids are free-swimming and burrowing worms. Nereids have a pair of parapodia arising from most segments of the body that act like a paddles during locomotion. The parapodia also function as gills. Ragworms have a pharynx that can shoot out of their head like a sock being pulled inside out. The pharynx is armed with jaws, which are used to capture animal prey or to grasp and shred kelp. Many species of ragworms have sensory structures associated with the head such as eyes, tentacles, and/or palps (function like a blind persons walking stick). These sensory structures allow the worm to monitor its environment while it actively forages for food and avoids potential threats.
Siboglinidae (Hot Vent Worms)
Siboglinids such as the giant hot vent worms are benthic, tube dwelling marine worms. Instead of a digestive tract, they have a non-structured mass of cells called a trophosome. The cells in the trophosome are filled with bacteria that are able to turn the toxic gas that the hot vents spew out into food! The red plume that sticks out of the tube are gills and are red because like our blood, the fluid inside their gills has hemoglobin.
Clitellata (Earthworms & Leeches)
The Clitellata are a class of annelid worms, characterized by having a clitellum - the 'collar' that forms a reproductive cocoon during part of their life cycles. Clitellates live on land, in freshwater or in the ocean. Earthworms mostly live on land, burrowing in damp soil and leeches are mostly aquatic, a few living in the sea but mostly inhabiting freshwater locations, particularly the sediments on the bottom of lakes, ponds and sluggish streams. Earthworms are deposit feeders, meaning they digest organic material in sediment (they eat dirt). Leeches are either ectoparasites or predators. Although the predatory species typically ingest prey whole, the ectoparasites pierce the skin of their prey and suck-in body fluids and sometimes tissue of their victim. Leeches have an anesthetic in their saliva, which numbs the area where they are feeding so that their host does not notice them.
WHAT IS GOING TO BE ON QUIZ #2?? Read this!
The quiz will be 10 multiple choice questions that cover Intro to Bilateria, Phylum Platyhelminthes and Phylum Annelida. The quiz will NOT have any questions on the parasitic roundworms.
There will be one short answer question that asks you to compare and contrast annelids and flatworms.
There will be one drawing question where you will have the choice of drawing one of two options (just like the first quiz).
There will be one short answer question that asks you to compare and contrast annelids and flatworms.
There will be one drawing question where you will have the choice of drawing one of two options (just like the first quiz).
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