Download Sponges

Today…
• Bellringer: Are animals autotrophs or
heterotrophs? Explain your answer.
• Review Section 1 – What is an animal?
• Notes on Sponges and Cnidarians
Science 6
Today’s Goal…
• I can describe the characteristics of sponges
and cnidarians.
Sponges
• Plant or animal?
• Adult sponges are sessile – remain attached
to one place
• Sponges can’t make their own food
• About 15,000 species of sponges identified
Sponges
• Most live in oceans, some in freshwater
• Bodies made up of two layers of cells
• Filter feeders
– Filter food out of the water that flows through
their body
Sponges
• Not many animals eat sponges
• Their soft bodies are supported by sharp,
glass-like structures called spicules
• Other sponges have a material called
spongin which is similar to foam rubber and
makes them soft and flexible
• Some have both
Sponges
• Reproduction
– Asexually and sexually
– Asexual through budding
• A bud on the side of a parent sponge develops into a
small sponge or a new sponge grows from pieces of
a broken sponge
– One sponge can produce both egg and sperm
for sexual reproduction
– Figure 5 on page 502
Sponges
• Let’s see more about sponges!
Cnidarians
• Jellyfish, sea anemones, hydra, and corals
• Have tentacles surrounding their mouth
– Tentacles shoot out stinging cells called
nematocysts to capture prey
• Radial symmetry allows them to locate food
in any direction
Cnidarians
• Hollow bodied animals with cells that are
organized into tissues
• Two different body forms
–
–
–
–
Polyp – vase shaped body (sea anemone and hydra)
Medusa – free-swimming, bell-shaped body (jellyfish)
Some have both these forms
Page 503
Cnidarians
• Produce sexually and asexually
– Polyps reproduce asexually by budding
– Some polyps reproduce sexually by releasing
egg or sperm into water
– Medusa reproduce sexually to produce polyps,
then polyps reproduce asexually to form
medusa
• Figure 6
Cnidarians
• Learn more about Cnidarians!
Real Pics
• Sponges
Real Pics
• Cnidarians