Invertebrates Jeopardy Animal Kingdom SpongesCnidariansFlatwormsRoundworms

What is an animal? An animal is a multicellular, eukaryotic heterotroph whose cells lack cell walls.

Describe the 7 essential functions performed by all animals Feeding, respiration, circulation, excretion, response, movement, and reproduction.

In what ways are complex animals different from simple animals? Complex animals tend to have high levels of cell specialization and internal organization, bilateral symmetry, cephalisation, and a body cavity.

How are body symmetry and cephalization related? Animals with bilateral symmetry usually exhibit cephalisation. There is usually an anterior end – the end leading in movement – in which most of the sense organs and nerve tissue are concentrated.

How might having specialized cells increase efficiency in multicellular animals? Each specialized cell type performs different tasks for the organism. Multicellular animals with specialized cells can carry out different functions using only those cells specialized for each task.

What features do sponges share with all other animals? Sponges are heterotrophic, have no cell walls, and contain specialized cells.

How do sponges use water to carry out essential functions? The movement of water through a sponge carries needed materials, such as food and oxygen, and carries wastes away. Water also carries sperm to eggs.

Describe the different types of sponge skeletons The skeleton of many sponges is made of spiny spicules. Softer sponges have a skeleton made of flexible spongin.

Why are symbiotic relationships critical to the ecology of sponges? Bacteria, cyanobacteria, and plantlike protests provide food and oxygen to many sponges, while the sponges provide a protected area where these organisms can thrive.

Why would sponges be unable to live on land? Sponges depend on the movement of water for most functions, including feeding, respiration, circulation, excretion, and reproduction.

Describe three characteristics that all cnidarians share. All cnidarians are soft-bodied, carnivorous, and have stinging tentacles arranged in circles around their mouths.

How do the two body plans of cnidarians differ? A polyp has a cylindrical body with armlike tentacles; the mouth points upward. A medusa has a bell-shaped body with the mouth pointing downward.

Describe the three groups of cnidarians and give an example from each. Hydrozoans, such as hydras, spend most of their lives as polyps. Scyphozoans, such as jellyfishes, live their lives primarily as medusas. Anthozoans, such as corals, have only the polyp stage in their life cycle.

Describe how the digestion and absorption of food take place in cnidarians. Extracellular digestion takes place in the gastrovascular cavity. Cells in the gastroderm absorb partially digested materials. Digestion is completed intracellularly.

How does the lifestyle of a medusa differ from that of most polyps? A polyp is sessile and, thus, does not move around. A medusa is motile, and thus, needs a more complex nervous system to detect stimuli in different environments.

What is a flatworm? A flatworm is a soft, flattened worm with tissues, organ systems, three germ layers, bilateral symmetry, and cephalisation.

List the three groups of flatworms and give an example of each. Turbellaria: planarian; Trematoda: fluke; Cestoda: tapeworm.

How do the feeding methods of parasitic and free-living flatworms relate to their specific environments? Many parasitic flatworms obtain nutrients directly from their host’s body; they lack digestive systems. Free-living flatworms actively capture and digest food; they have feeding organs and a digestive system.

Describe the life cycle of the blood fluke, Schistosoma mansoni S. mansoni matures and reproduces sexually in the blood vessels of human intestines. Embryos are released and passed out with feces. Embryos hatch into swimming larvae that infect an intermediate host (a snail), where they reproduce asexually. Larvae released from the intermediate host into water can infect humans by boring through the skin.

Explain why you should cook meat and fish thoroughly, especially in areas that have parasitic worms. High temperatures destroy worm cysts, which can cause disease in humans.

What is a roundworm? A roundworm is an unsegmented worm that has a pseudocoelom and a digestive system with two openings – a mouth and an anus.

What are the parasitic roundworms? Parasitic roundworms include trichinosis- causing worms, filarial worms, ascarid worms, and hookworms.

Describe how humans become infected with the parasitic roundworm Ascaris. A human becomes infected by ingesting food or water containing Ascaris eggs.

How do hookworms enter the human body? Hookworms enter the human body by burrowing into the skin of a foot.

How might the spread of elephantiasis be reduced? The spread of elephantiasis could be reduced by reducing numbers of biting insects and by encouraging people to wear protective clothing and use insect repellent.