Transcript Chapter 32 - 33 invertebrate intro.

Ch. 32 - 33 – Sponges,
Cnidarians, & Ctenophores
 What
is an invertebrate?
An animal without a backbone.
 What are some examples?
 Animals are classified by their shape or
symmetry.
 What is symmetry?
Arrangement of body parts around a
central axis.
Types of Symmetry
Asymmetrical – an organism without a
definite shape.
Ex. Sponge
 2. Radial symmetry – an organism that
can be divided into similar halves by any
plane that passes through its longitudinal
axis.
Ex. hydra
 1.
Bilateral symmetry – is an
organism that can be divided
into similar halves by only one
specific plane passing through
its longitudinal axis.
Ex. Humans, spiders, fish
3.
Parts of an organisms’ surface
Posterior – lower end of the organism
Ex. Feet of humans
 2. Anterior – upper end of the organism.
Ex. Head of a human
 3. Dorsal – top surface of an organism.
Ex. Back on a human
 4. Ventral – bottom surface.
Ex. Belly of a human
 1.
Organisms Development
Organism develop from a zygote
Then into an embryo
Next is a blastula – a hollow ball
of cells
Final the blastula caves in and
forms a depression called a
blastopore. Once the blastula
forms a blastopore it is now
called a gastrula.
3 Germ Layers
1. Ectoderm – outside layer of
cells
Ex. Skin
2. Endoderm inside layer of cells
Ex. Organs
3. Mesoderm – middle layer of
cells
Ex. Muscles
Porifera (phylum)
Sponges
No
gastrula stage
No true organs
Sessile – don’t move
Very colorful
Features of a sponge
– top opening of a sponge
A sponge is hollow in the middle
The sponge’s hollow cavity is lined
with collar cells, which have
flagella.
The collar cells are used to filter out
food. Water and food enter the
sponge through its pores then pass
back out its osculum. Sponges are
filter feeders.
Osculum
Amebocytes
transport the food
from the collar cells to the rest of
sponge.
Sponges have the ability to
reproduce sexually or asexually;
sponges carry both egg and
sperm cells.
Sponges reproduce asexually by
producing buds called
gemmules.
Sponges
have the ability to
regrow missing parts. What is
this called?
Regeneration
Most sponges have both sperm
and egg cells, some have
separate sexes.
Hermaphrodite is an organism
with both egg and sperm cells.
Video Clip
Cnidaria (phylum)
Example: jellyfish, hydra, coral
Have endoderm & ectoderm
layers
All live in water (mainly marine)
Have stinging cells called
nematocyst
Have a hollow gut
Have tentacles
2 body shapes of Cnidarians
1. Polyp
Sessile and vase-like shape
2. Medusa
Swimming and bell shape
All cnidarians use their tentacles
to capture and paralyze their
prey with a coiled stinger called a
nematocyst.
3
Classes of Cnidarians
1. Hydrozoa – Hydra
Both polyps and medusa
shapes
2. Scyphozoa – jellyfish
Mostly medusa
3. Anthozoa – corals
Only as polyps
Hydrozoa (class)
 Hydra
use their nematocyst to capture
prey and engulf the whole prey into their
gastro vascular cavity. They only have
one opening (mouth and anus).
 Asexual reproduction of small buds
occurs during warm weather.
 Sexual reproduction occurs mainly in the
fall.
 Hydra are hermaphrodites.
 Video Clip
Scyphozoa (class)
Mostly medusa
Jellyfish have poisonous
tentacles with nematocyst, also.
Several humans been seriously
injured and even killed from
jellyfish off the coast of Australia.
Video Clip
Anthozoa (class)
Only
polyp
Sea anemones are polyps along
rocks.
Clown fish swim around in their
tentacles. The clown fish is
protected from the tentacles by a
chemical in their skin that doesn’t
allow the nematocyst to fire.
Video
Clip
3 main body cavities of organisms
Acoelomate – without a body cavity.
Ex. Hydra, planaria
 2. Pseudocoelomate – false body cavity.
No true digestive system. The gut is
suspended in fluid, not muscle.
Ex. Roundworm
 3. Coelomate – a true body cavity.
Ex. Earthworm, insects, humans, ect.
 1.
Rotifera (phylum)
Rotifers
Free-swimming
Marine
and freshwater
Cilia along its mouth, which is used
to sweep food into its mouth.
Looks like a spinning wheel as it
moves.
Video
Clip