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30 Cards in this Set

  • Front
  • Back
Which type of symmetry has body parts arranged around a central axis?
Radial symmetry is when parts are arranged around a central axis.
What is symmetry?
Symmetry refers to how body parts are arranged on an organism; patterns of arrangement.
What is bilateral symmetry?
Bilateral symmetry is when body parts are arranged in pairs on each side of a central axis.
Define the term coelom.
A coelom is a body cavity.
Name the 3 germ layers and what each layer gives rise to.
The ectoderm is the outer layer which gives rise to the skin, nerves, and sense organs. The
mesoderm is the middle layer that gives rise to the circulatory system, reproductive system, and
muscles. The endoderm is the inner layer which gives rise to the digestive system and respiratory
What is an acoelomate animal? Name an example of an acoelomate.
An acoelomate animal is one in which there is no body cavity (coelom), it is solid. An example
would be a flatworm.
Define the terms anterior, posterior, dorsal, and ventral.
Anterior is the front end, posterior is the back end, dorsal refers to the top or back, and ventral
refers to the underside or belly area.
In sponges, what two things form their support structure (skeleton)?
Spongin and spicules make up the support system of a sponge.
How do sponges get their food?
Sponges are filter feeders, which means they create water current and trap food particles in the
water with their collar cells (choanocytes).
What is the name of the large opening at the top of the sponge?
The osculum is the large opening at the top of the sponge through which water leaves the sponge.
Which cells line the interior of the sponge and create water currents by beating their flagella?
The collar cells (choanocytes) line the interior of the sponge and create water currents by beating
their flagella.
Which cells of a sponge move throughout the body wall of a sponge and distribute
The amebocytes move throughout the sponge carrying out different functions.
What does the term hermaphrodite mean?
Hermaphrodites have the ability to produce both eggs and sperm.
What is regeneration?
Regeneration is the regrowing of lost body parts.
How do sponges reproduce asexually?
Sponges reproduce asexually through the formation of gemmules, regeneration, and budding.
Name some examples of the Phylum Cnidaria.
Some members of the phylum Cnidaria include jellyfish, coral, hydra, and sea anemones.
Why was the phylum given the name Cnidaria?
It was given the name to refer to the stinging cells they contain (the stinging cells are called
cnidocytes). The prefix cnido- means stinging.
Name the two distinct life stages in many cnidarians.
The two distinct life stages are the polyp and medusa.
Define the term sessile.
The term sessile means firmly attached to the bottom. Sessile animals do not move.
What are anthozoans?
Anthozoans are cnidarians such as sea anemones. They have an elongated body with tentacles
around the top. The name anthozoa literally means, “flower animal”.
Which class of cnidarians contains the common jellyfish?
The jellyfish are in the class Scyphozoa.
What are nematocysts? Name 3 ways in which they work.
Nematocysts are the stinging cells characteristic of all cnidarians. They work by paralyzing,
poisoning, or entangling their prey.
What two compounds are spicules made of?
Spicules are made up of calcium carbonate or silicon dioxide.
What is a gemmule?
A gemmule is a food-filled ball of amebocytes produced by sponges to survive harsh conditions; a
form of asexual reproduction in sponges.
Which of the two phyla we have discussed in this unit contains all of the corals?
Corals are in the phylum Cnidaria
What level of organization do sponges have?
Sponges have the cellular level of organization.
What level of organization do cnidarians have?
Cnidarians have the tissue level of organization.
Where do most sponges live (what habitat)?
Most sponges live in a marine environment. Only 150 species of the 10,000 species are freshwater.
What are ostia?
Ostia are the openings in the side of the sponge through which water enters the sponge.
What is the hollow interior cavity of the sponge called?
The hollow interior of the sponge is called the spongocoel.