Marine
Invertebrates
(Sponges and Rotifers)
Sponges
1. Sponges are multi-cellular, and come in
many sizes, colors, and shapes.
2. Sponges have few specialized structures,
and are found in warmer, tropical waters.
3. Sponges are made up of 2 layers:
a) Endoderm- inner layer
b) Ectoderm- outer layer
4. Between the 2 layers is a jelly-like material
called mesenchyme.
5. Sponges belong to the phylum
Porifera, which means “pore bearing”.
6. Sponges are considered Benthic
organisms, they are bottom dwelling.
Sponge Anatomy
How do Sponges Feed?
1. Sponges are sessile- they spend
their lives attached to an object.
2. Sponges bodies contain many
holes.
3. Sponges bodies are elastic.
4. All parts of a sponge are the
same.
5. They feed by taking in the
plankton and algae found in
water through small pores called
ostia.
6. Water and wastes exit through a
large hole called the osculum.
7. Collar Cells line the inside of
the sponge and have
flagella that sweep food into
and pump water out of the
sponge.
8. Digestion takes place inside
the food vacuoles in each
individual cell.
9. Gases are also exchanged
at the cellular level.
10. Sponges have no nervous
tissue, they do not respond
to touch, and will not move.
How do
Sponges
Reproduce?
1. Sponges can be
male, female, or
both
(hermaphroditic).
2. They can also
reproduce
asexually by
regeneration.
Let’s go to the Video!
QuickTime™ and a
Sorenson Video 3 decompressor
are needed to see this picture.
Rotifers
1. Rotifer means “wheel bearer”.
2. Rotifers live in the moist sands along the
shore, as well as, in freshwater.
3. They belong to the phylum Rotifera.
4. They can change the shape of their
bodies and telescope them to make it
easier to move their cilia.
5. They are both sessile and motile.
How do Rotifers Eat?
1. They are predators…they create a
current by beating their cilia and take
food in.
2. Food passes through a one way
digestive tract.
3. Food is digested in the stomach or the
intestines.
4. Wastes are eliminated through the
anus.
How do Rotifers Reproduce?
1.
2.
3.
4.
Rotifers can be male or female.
Males produce sperm in the testes.
Females produce eggs in the ovaries.
Gametes are released into the water where
they fuse.
5. Rotifers fertilize externally.
6. They can also reproduce asexually by a
method called parthenogenesis ( a
complete egg is produced w/o fertilization
and has a complete set of chromosomes).
Rotifers
Let’s go to the Video!
QuickTime™ and a
Sorenson Video 3 decompressor
are needed to see this picture.
Blue Tube
http://www.youtube.com/watch?v=T7E1rq
7zHLc
http://www.youtube.com/watch?v=KOFF2
XNYJGO&feature=related