L6: Molluscs cont. Flashcards
Describe how the anatomical characteristics unique to molluscs have been modified in cephalopods Indicate the features of cephalopods that make them effective predators How does the structure of the cephalopod and vertebrate eyes illustrate the concept of convergent evolution Describe some attributes of cephalopods that are indicative of a very complex nervous system
What animals are in the class Cephalopoda
Octopus, squids, nautilus
What environments do Cephalopoda inhabit?
Marine
In the class Cephalopoda..
Describe the modified foot structure
Foot turned into the circle or arms/tentacles and funnel-shaped siphon
In the class Cephalopoda..
T/F: Closed circulatory system
True
In the class Cephalopoda..
Describe the structure of the mantle
Muscular, surrounds body
In the class Cephalopoda..
T/F: Species diversity has increased over time
False - has decreased
In the class Cephalopoda..
Describe the function of the papilli
To allow for buoyancy control. As gas is allowed through them, animal gets more buoyant, as gas is removed, less buoyant
Describe the shell of cephalopods
Consists of a series of chambers closed off by septa
Contains papilli that are a cord of tissues that go through the chambers
In the class Cephalopoda..
Describe the function of the mantle
Motility. Mantle squeezes in water, then lets go. As water is pushed out, animal moves
T/F: Modern cephalopods have internal, reduced shells
True
Only remaining part of the shell is in the Pen at posterior
In the class Cephalopoda..
What is the function of the branchial heart in each gill
Provides an extra bump of motile force of blood to the gills
Describe the nervous system of Cephalopoda
- Highly developed sensory systems (vision)
- Giant nerve fibre that extends from brain to bottom
- Many nerves on skin to allow to change skin pigmentation based on environment
Describe the differences between vertebrate and cephalopod eyes/vision
- Lens in cephalopods moves forwards & backwards; vertebrates adjust lens thickness
- Different optic nerve location
- No coloured vision in cephalopods
