Biology Invertebrates
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- Porifera: What animals are in the phylum Porifera?
- Sponges
- Porifera: How do sponges reproduce?
- Asexually, sponges reproduce by budding. During more extreme conditions the sponges use special buds called gemmules that are more hardy. Sexually, sponges are hermaphroditic, but release sperm and eggs separately. Female sponges capture the sperm and the cycle continues from there.
- Porifera: What symmetry do sponges show?
- No specific type of symmetry
- Porifera: Briefly describe the body structure of a sponge.
- Sponges have a skeleton-like structure made of a substance called spongin. Many have spike-like particles on their outer skeleton called spicules. At the top each sponge's cylinder is a hole used for ingestion and excretion called the osculum.
- Porifera: What is the function of choanocytes (collar cells)?
- Choanocytes line the inside of a sponge and use flagella to draw in nutrients and oxygen from the water flowing through.
- Porifera: How do sponges feed?
- Using a process called filter feeding, collar cells engulf bacteria, unicellular algae, or protozoans and carry the food to special cells called amebocytes. There the food is digested and the waste released.
- Porifera: Are sponges sessile or motile?
- All sponges are sessile.
- Porifera: How do sponges defend themselves?
- Sponges can secrete chemicals and use their spicules to ward off predators.
- Cnidaria: What animals are cnidarians?
- Jellyfish and Portuguese Man-of-War are cnidarians.
- Cnidaria: How do cnidarians reproduce?
- Asexually, cnidarians reproduce by division. Sexually, cnidarians produce a cloned larva.
- Cnidaria: What symmetry do cnidarians show?
- Cnidarians show both bilateral and radial symmetry, depending on the organism.
- Cnidaria: Describe the cnidarians' digestion.
- Food is ingested into a hollow gut cavity, at which point digestive cells secrete enzymes and break down the food. Nutrients reach cells by diffusion. The digestive system is incomplete.
- Cnidaria: Give examples of and differences between both polyp and medusa cnidarians.
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Polyps: Sessile and vase-shaped. Examples are hydra and sea anenomes.
Medusa: Motile and bell-shaped. Examples are jellyfish. - Cnidaria: Describe the defense system of cnidarians.
- Cnidarians' tentacles and hollow cavities are lined with cnidocytes, or stinging cells, which shoot out poisonous barbs called nematocysts.
- Cnidaria: What is the nervous system of cnidarians?
- Cnidarians have a nerve net that controls the body movements.
- Cnidaria: How do cnidarians perform gas exchange?
- The mouth and gastrovascular cavity perform gas exchange through diffusion.
- Playthelminthes: What are some examples of platyhelminthes.
- Flatworms, tapeworms, and planaria.