Chapter 2 Animals-Section 1 Flashcards
What are four body structure characteristics of all mollusks?
1) invertebrates with soft unsegmented body
2) often covered by a shell
3) has a mantle
4) has a foot
What is a mantle and what does it do?
A mantle is a thin layer of tissue that covers a mollusk’s internal organs.
In many mollusks what does the mantle produce?
A hard shell
What are some different functions of the mollusk’s foot?
The foots different functions are crawling, digging, or catching prey.
What type of symmetry do mollusks have?
Bilateral symmetry
True or false
Like segmented worms, the body parts of mollusks are usually repeated.
False
The body parts of mollusks are not usually repeated
Most groups of mollusks have what type of circulatory system?
Open circulatory system. This means the blood is not always inside blood vessels.
Explain how the open circulatory system works
The heart pumps blood into a short vessel that opens into the body spaces containing the internal organs. The blood sloshes over the organs and returns eventually to the heart.
Most mollusks that live in water have what?
Gills which are organs that remove oxygen from the water
What are tiny hairlike structures on the gills called
Cilia
What is the function of the cilia?
The cilia move back-and-forth making water flow over the gills.
What is the function of the gills?
The gills remove the oxygen from the water and oxygen moves into the blood. At the same time carbon dioxide, a waste gas, moves out of the blood and into the water.
What is a radula and what does it do?
A radula is a flexible ribbon of tiny teeth used to obtain food
What are the two shells in bivalves held together by?
Hinges and strong muscles
How do you bivalves capture food?
Bivalves capture food as water flows over their gills. Food particles stick to the mucus that covers the girls. The cilia on the gills then move the food particles into the bivalves mouth.
What happens if an object such as a grain of sand gets stuck between the bivalves mantle and shell?
The bivalve’s mantle produces a smooth, pearly coat to cover the irritating object. Sometimes a pearl forms eventually around the object.
Give example of a cephalopod with an external shell, one with a small shell within the body, and one with no shell.
Nautiluses have an external shell, squids have a small shell within the body, and octopuses have no shell
A cephalopod tentacles contain what? And what do these do?
Cephalopods tentacles contain sensitive suckers. The suckers receive sensations of taste as well as touch.
How does jet propulsion work?
Current water is squeezed out of the mantle cavity and through a tube. Then like rockets they shoot off in the opposite direction.
Describe a cephalopods foot?
A Cephalopods foot is adapted to form tentacles around its mouth.
What are the largest group of mollusks?
Gastropods
What are the physical characteristics used to classify mollusks into groups?
The presence of a shell, the type of shell, the type of foot, and the type of nervous system
What are the three major groups of mollusks?
Gastropods, bivalves, and cephalopods
What is a herbivore? Carnivore? Omnivore?
Herbivore is an animal who eats plants. A carnivore is an animal who eats other animals. An omnivore is an animal that eats both plants and other animals.
