Phylum: Mollusca - PowerPoint PPT Presentation

1 / 9
About This Presentation
Title:

Phylum: Mollusca

Description:

Reproduction usually external fertilization in the water. ... They move by jet propulsion. Many have an ink sac to distract potential predators. – PowerPoint PPT presentation

Number of Views:237
Avg rating:3.0/5.0
Slides: 10
Provided by: Lake148
Category:
Tags: mollusca | phylum | water

less

Transcript and Presenter's Notes

Title: Phylum: Mollusca


1
Phylum Mollusca
  • Gastropods, Bivalves Cephalopods

2
Mollusks
  • Mollusks are soft-bodied animals that usually
    have an internal or external shell.
  • Ex. Clams, squid, octopi, mussels, nudibranchs.
  • They have a free swimming larval stage called a
    trochophore.

3
Body Plan 4 parts
  • 1. foot used for crawling, burrowing and
    tentacles
  • 2. mantle thin layer of tissue that covers
    organs
  • 3. shell made by glands in the mantle that
    secrete calcium carbonate
  • 4. visceral mass guts. (internal organs)

4
Feeding
  • Feeding radula ribbon of teeth
  • Others are filter feeders using an incurrent and
    excurrent siphon

5
Respiration and Circulation
  • Respiration gills
  • Circulation - Open circulatory system heart
    and open sinuses. Open works for slow moving
    creatures
  • Closed circulatory system blood is contained in
    veins and arteries. Octopi and squid

6
Response/Movement/Reproduction
  • Response- Clams- simple nervous system/eyespot
  • Octopi brains, complex behavior. Octopi and
    squid can open jars for reward or to avoid
    punishment
  • Movement mucus with the foot/muscle or jet
    propulsion for the octopus.
  • Reproduction usually external fertilization in
    the water. Some tentacled mollusks do internal
    fertilization. Some can be hermaphrodites.

7
3 main groups of Mollusks
  • 1. Gastropods shell-less or single shelled
    mollusks that move by using a muscular foot.
  • Ex. Sea hares can squirt ink at
    predators
  • Nudibranches sea slugs, have chemicals in
    their bodies that taste bad. Can recycle
    nematocysts from cnidarians they eat.

8
3 main groups of Mollusks
  • 2. Bivalves two shells held together by two
    powerful muscles.
  • Ex. Clams, oysters, mussels and scallops.
    Scallops can flap their shells to move when
    threatened. Filter water over gills use mucus
    and cilia on gills to trap food particles.

9
3 Main Groups of Mollusks
  • 3. Cephalopods head-footed . Soft bodied.
    The head is attached to a single foot. The foot
    is divided into tentacles or arms.
  • Example squid, octopus, nautilus, cuttlefish.
    They move by jet propulsion. Many have an ink
    sac to distract potential predators.
  • They have a pen for a backbone.
Write a Comment
User Comments (0)
About PowerShow.com