Lesson 14 - Brachiopods and Bivalves

4 Pages

Earth and Ocean Sciences
Course Code
EOSC 326
Louise Longridge

This preview shows page 1. Sign up to view the full 4 pages of the document.
Lesson 14 Learning Objectives 1 Compare and contrast the morphology of the brachiopods and bivalves2 Compare and contrast brachiopod and bivalve shell mechanics and feeding efficiency3 Distinguish inarticulate from articulate brachiopods4 List and describe the 4 main modes of life seen in the brachiopods and the 6 main modes of life seen in the bivalves5 Interpret the contrasting biological histories of the bivalves and brachiopods The modes of life for the majority of bivalves and brachiopods are independent of reef systemsBivalves and brachiopods look similar on the outside but they are very different internally and are not closely relatedBrachiopodsMarine filter feeders majority of the 30000 species are now extinct only about 300 species remainHabitat Ranges from intertidal zone to depths of 6000 meters and range from the tropics to the Polar RegionsSymmetry Contains two shellsvalves brachiopods are equilateral but inequivalved This means each valve is symmetric but the two valves are not mirror images of one anotherMorphologyo Respiration and feeding occurs using an organ called lophophore it takes up 23 of the body cavityo The rest of the body cavity contains organs responsible for digestion reproduction excretion nervoussensory and circulationo The pedicle is a fleshy stalk that protrudes from the animal used to attach the animal to surfaces Also have adjustor muscles to reorient itself with respect to the pedicle o The size of the animal is limited by the size of the lophophore complex structures called brachidia help support larger lophophores they are attached to the shell and are shaped like a loop or spiralClassification There are two classes of brachiopods the Articulata and Inarticulata The difference between the two is in the system used for opening and closing the valves o Articulata Uses a hinge and muscle system along with teeth and sockets to keep the valves closed The adductor muscle is responsible for closing the valves and the diductor muscle is responsible for opening the valves up to 10The cardinal process is a projection at the posterior edgeof the dorsal valve where the diductor muscle is attached
More Less
Unlock Document

Only page 1 are available for preview. Some parts have been intentionally blurred.

Unlock Document
You're Reading a Preview

Unlock to view full version

Unlock Document

Log In


Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.