Symbiosis
What is symbiosis?
Symbiosis is when 2 or more organisms have a relationship with one another.
What does "arthro" mean in the word "Arthropod"?
"Arthro" means jointed.
Are cnidarians vertebrates or invertebrates?
Cnidarians are invertebrates.
Are mollusks vertebrates or invertebrates?
Mollusks are invertebrates.
T/F: Mollusks have soft bodies but may contain hard structures inside or outside their bodies.
True
What are examples of symbiosis?
1) Mutualism
2) Commensalism
3) Parasitism
What is the main function of an arthropod’s exoskeleton, and what is it made of?
The exoskeleton protects the arthropod and is made of chitin, a strong protein.
What are nematocysts and where are they found on cnidarians?
Nematocysts are stinging cells found on the tentacles of cnidarians.
What is the function of the radula in mollusks?
The radula is a tongue-like structure with tiny teeth, used for scraping food.
T/F: The term "cephalopod" means "head-foot."
True
What is mutualism?
Mutualism is a relationship between two or more organisms where both organisms are affected in a good way.
What are the three main body parts of a crustacean, and which one may be combined?
The three main body parts are the cephalo (head), thorax, and abdomen. The cephalo and thorax may be combined into a cephalothorax.
What is the main difference between the polyp and medusa body forms in cnidarians?
Polyps are tubular and sessile (stationary), while medusas are bell-shaped and free-swimming.
What are the main differences between the three mollusk classes: cephalopods, bivalves, and gastropods?
Cephalopods: Head and foot merged
Bivalves: Have two shells
Gastropods: One or no shell
T/F: Gastropods include animals like clams and mussels that have two shells.
False
Clams and mussels are bivalves, not gastropods.
What is commensalism?
Commensalism is a relationship between two organisms one organism has benefits and the other has no benefit but is not harmed either.
How do the appendages of crustaceans serve different functions based on where they are located on the body?
Antennae (head) are used for sensing, mandibles (head) for biting and holding food, walking legs (thorax) for walking and feeding, swimmerets (abdomen) for swimming and helping gills, and the telson (tail) for steering and swimming.
Explain the symbiotic relationship between coral and zooxanthellae.
Zooxanthellae provide oxygen and nutrients to the coral, while the coral provides carbon dioxide to the algae. Both organisms benefit from the relationship.
Explain how a squid uses its siphon and ink sac for defense.
The squid releases ink from the ink sac through the siphon. The siphon also helps the squid propel away quickly by blowing out water.
T/F: The beak of a squid is located outside its body for easier feeding.
False
The beak is inside the body, and it’s used to crush food before it enters the mouth.
What is parasitism?
Parasitism is when one organism (usually a parasite)gets benefits but the other organism is harmed.
Compare and contrast the marine chelicerates and crustaceans based on body structure and sensory appendages.
Chelicerates have two body parts (cephalothorax and abdomen), no antennae, and use claw-like chelicerae for feeding. Crustaceans have three parts (head, thorax, abdomen—sometimes with a cephalothorax), have antennae for sensing, and possess compound eyes for detecting movement.
Compare and contrast the four cnidarian classes in terms of body forms and characteristics.
Anthozoa: Only polyp form; includes coral, sea anemones, sea pens; corals build calcium shells and live in colonies.
Scyphozoa: True sea jellies; alternate between polyp and medusa phases but are mostly medusas; swim by muscle contraction.
Cubozoa: Box jellies; cube-shaped with four tentacle clusters; mostly medusas.
Hydrozoa: Most diverse; includes fire coral and Portuguese man-of-war; mostly polyps, some medusas; form large colonies.
Describe how the external structures of a squid each play a specific role in its survival.
Arms, tentacles, suction cups and chromatophores
Arms (there are 8of them): Grab food and pass it to the mouth; covered in suction cups.
Tentacles (there are 2 of them): Reach out to catch food; suction cups only at the ends.
Suction Cups: Help grip prey on both arms and tentacles.
Chromatophores: Change size/color for camouflage and communication.
T/F: The squid’s pen is a modern structure used for writing behavior patterns in sand.
False
The pen is a remnant of a hard shell from the squid’s ancestors, not used for writing.