Question

name:
shape of life: mollusks

• start by watching this video: https://www.youtube.com/watch?v=xkjejifdcbq

1. what is the primary feature that all mollusks have? what does this structure do (in most cases)?
2. give two examples of a natural predators of mollusks:
3. what are some ways that mollusks have evolved ways of protecting themselves from predators:
4. what is a radula and what does it do?
5. describe some of the evolutionary changes that occurred in mollusks to take them from abalone to octopus, and what selective pressures led to those changes:

Explanation:

1. Most mollusks have a mantle, which can secrete a shell for protection and is involved in respiration and waste - removal.
2. Crabs and starfish are natural predators of mollusks. Crabs use their claws to break open shells, and starfish can evert their stomachs to digest mollusks in place.
3. Mollusks have evolved hard shells (like snails and clams) for physical protection, and some cephalopods (like octopuses) have developed camouflage abilities to avoid predators.
4. A radula is a toothed, ribbon - like structure in the mouths of many mollusks. It is used for scraping and cutting food, such as algae off rocks.
5. From abalone (a gastropod) to octopus (a cephalopod), mollusks have evolved from more sedentary, shell - bearing forms to more mobile, intelligent forms with reduced or no external shells. Selective pressures such as predation, competition for food, and the need to move in search of resources led to these changes. Octopuses developed advanced nervous systems and camouflage abilities to better survive in their environments.

Answer:

1. The primary feature is the mantle. It can secrete a shell for protection and is involved in respiration and waste - removal.
2. Crabs, Starfish
3. Hard shells for physical protection, camouflage abilities (in cephalopods like octopuses)
4. A radula is a toothed, ribbon - like structure in the mouth of many mollusks. It is used for scraping and cutting food.
5. Mollusks evolved from more sedentary, shell - bearing forms (like abalone) to more mobile, intelligent forms with reduced or no external shells (like octopuses). Selective pressures included predation, competition for food, and the need to move in search of resources.