Animals that lack a backbone.
Animals that have a backbone.
An organism has spherical symmetry if it can be cut into two identical halves by any cut that runs through the organism's center.
An organism has radial symmetry if it can be cut into two identical halves by any longitudinal cut through its center.
An organism has bilateral symmetry if it can only be cut into two identical halves by a single longitudinal cut along its center which divides it into right and left halves.
An outer layer of cells designed to provide protection.
The jellylike substance that separates the epidermis from the inner cells in a sponge.
Flagellated cells that push water through a sponge.
Cells that move using pseudopods and perform a variety of functions in animals.
A cluster of cells encased in a hard, spicule-reinforced shell.
The sessile, tubular form of a cnidarian with a mouth and tentacles at one end and a basal disk at the other.
A free-swimming cnidarian with a bell-shaped body and tentacles.
Animal tissue consisting of one or more layers of cells that have only one free surface, because the other surface adheres to a membrane or other substance.
The jelly-like substance that separates the epithelial cells in a cnidarian.
Small capsules that contain a toxin which is injected into prey or predators.
Organs that produce sperm.
Organs that produce eggs.
The end of an animal that contains its head.
The end of an animal that contains its tail.
A system designed to transport food and other necessary substances throughout a creature's body.
A system of sensitive cells that respond to stimuli such as sound, touch, and taste.
Masses of nerve cell bodies.
Possessing both male and female reproductive organs.
The ability to regrow a missing part of the body.
A sheath of tissue that encloses the vital organs of a mollusk, secretes its shell, and performs respiration.
A tough, multilayered structure secreted by the mantle, generally used for protection, but sometimes for body support.
A hump that contains a mollusk's heart, digestive, and excretory organs.
A muscular organ that is used for locomotion and takes a variety of forms depending on the animal.
An organ covered with teeth that mollusks use to scrape food into their mouths.
An organism with a single shell.
An organism with two shells.
Do the vast majority of animals have a backbone?
Determine the symmetry of the following organisms:
A. Eagle B. Jellyfish C. Centipede D. Mushroom
A. Bilateral. B. Radial. C. Bilateral. D. Radial.
How do sponges get their prey?
Sponges get their prey by pulling water into themselves.
If a sponge is soft, does it contain spicules or spongin? What purpose do these substances serve in a sponge?
It contains spongin. These substances support the sponge.
What is the predominant mode of asexual reproduction in a sponge?
What roles do amoebocytes play in the anatomy of a sponge?
Amoebocytes help digest and transport nutrients, they help carry waste to be excreted , they bring necessary gases such as oxygen to the cells, and they form the spicules or spongin.
When does a sponge produce gemmules?
During inclement times.
What is the difference between the nematocysts of a hydra and those of a sea anemone?
Hydra nematocysts are triggered with pressure, while the sea anemone's are triggered chemically.
Why do cnidarians not need respiratory or excretory systems?
Cnidarians do not need these systems because their body walls are so thin that gases diffuse right through them.
Some biology books say that jellyfish live "dual lives." Why?
Jellyfish spend part of their lives as polyps and the other part as medusas.
If a jellyfish produces sexually, what form is it in?
It must be in medusa form.
What is another name for a large coral colony?
What benefits do earthworms give the plants in the soil they inhabit?
Earthworms bring minerals up from the lower parts of the soil and mix them with the nutrients at the top of the soil, which makes the soil fertile for plants. Their tunnels also allow oxygen to travel the roots of a plant more easily.
If you pick up two earthworms and the first feels very slimy near the clitellum and the second does not, what can you conclude about the first earthworm?
The first one must have recently mated but not yet produced a cocoon.
What similarities exist between the hydra's sexual reproduction and the earthworm's? What differences exist?
The earthworm is hermaphroditic and the hydra can be as well. However, although the hydra can sometimes mate with itself, an earthworm cannot.
What will happen to an earthworm if its cuticle gets dry?
The earthworm will suffocate.
Why don't planarians need circulatory systems?
Planarians do not need circulatory systems because the intestine is so highly-branched that all cells are near it, so they can get their food directly from the intestine.
If a flatworm has no complex nervous or digestive systems, is it most likely free-living or parasitic?
What is the main mode of asexual reproduction in a planarian?
Place each of the following organisms in one of these phyla: Porifera, Cnidaria, Annelida, Mollusca, Platyhelminthes.
A. Sea anemone. B. Clam. C. Sponge. D. Flatworm. E. Segmented worm.
A. Cnidaria. B. Mollusca. C. Porifera. D. Platyhelminthes. E. Annelida.