Terms To Know Lab 6

Question 1

Radula

Answer 1

A toothed, rasping, tongue like organ in the mouth of molluscs that is used as a scraper to remove food particles for ingestion.
- every mollusca organism except bivalves has it

Question 2

Torsion

Answer 2

• present only in gastropoda
• this is a major derived feature of this group
• this is a rotation of the visceral mass and its overlying mantle and shell by as much as 180 degrees wjth respected to the head and foot
• the mantle cavity and anus are moved from a posterior to more of an anterior position, somewhat above and behind the head. The gut is twisted into a U shape, with the nerve cords twisted into a figure-eight
• opisthobranchs have undergone de-torsion

Question 3

Mantle

Answer 3

The outer, dorsal body wall of molluscs.
-Specialized epidermal cells of the mantle functions as shell glands, which produce the calcacerous shells characteristic of molluscs

Question 4

Visceral mass

Answer 4

The large differentiated central tissue within which major organs develop (major organs being heart&; circulatory system, kidneys, stomach, intestine, digestive gland, and gonads)

Question 5

Muscular foot

Answer 5

It often has a flattened creeping sole

Question 6

Siphuncle

Answer 6

A cord or tbe that extends from the visceral mass into the shell chambers , functioning as a conduit for gas secretion for flotation.

Question 7

Siphon

Answer 7

Is used for propulsion, reproduction, and ink release

- characterstic that unites all cephalapods

Question 8

Operculum

Answer 8

Corneous or calcacerous anatomical structure like a trap door which exists in many) (but not all) groups of sea snails and freshwater snails, and also in a frw groups of land snails

Question 9

Chromatophores

Answer 9

Pigment- containing and light reflecting cells

-found in a variety of animals ie frogs, amphibians, etc)

Question 10

Feeding strategies of the different species we looked for

Answer 10

Radula is present in every family except for bivalves)

Bivalves filter food from the water using cilia and music on their games

Question 11

Why are nudibranches brightly colored?

Answer 11

To serve as an example of warning coloration

Question 12

What function is the function of the ink sac?

Answer 12

Functions as a “smoke-screen” to confuse potential predators

-deeived feature for cephalods too

Question 13

What structure do cephalopods use for feeding?

Answer 13

Horn as well (beak-like structure to grasp onto them) (and tentacles around mouth)

Question 14

Homology

Answer 14

Similarity resulting from common ancestry, STRUCTURE

Question 15

Convergence

Answer 15

Independent evolution of a similar feature jntel or more lineages, FUNCTION

Question 16

What is the benefit of the mantle cavity behind the head after torsion?

Answer 16

It allows clean water from in front or the snail to enter the mantle cavity rather than water contaminated with silt stirred up by the snails crawling. The twist in the mantles sensory organs also makes the snail more sensitive to stimuli comjng from the direction it flows.

Question 17

How are the chitons well suited for their habitat in the intertidal?

Answer 17

The seperate shell plates allow the chiton to curve around and tightly adhere to a substrate.