Unit 2: Invertebrates Flashcards
(27 cards)
What type of body symmetry and germ layers do sponges (Phylum Porifera) have?
Asymmetrical; no true tissues (no germ layers).
What unique cells are found in Cnidarians and what is their function?
Cnidocytes, which contain nematocysts used for stinging and capturing prey
What body form is dominant in Scyphozoa vs. Anthozoa?
Scyphozoa = Medusa dominant; Anthozoa = Polyp only
What is the main difference between Cnidarians and Ctenophores regarding stinging structures?
Cnidarians have cnidocytes; Ctenophores do not—they have colloblasts
What is the function of flame cells in Platyhelminthes?
Excretion—part of their primitive excretory system
What major trait allows Dugesia (a planarian) to regenerate body parts?
High regenerative ability; stem cell-like tissues.
What parasitic flatworm causes Schistosomiasis?
Genus Schistosoma (Class Trematoda
What are the scolex and proglottids in Taenia used for?
Scolex attaches to host; proglottids contain reproductive organs
What body cavity type do rotifers have, and what structures help them feed?
Pseudocoelomate; corona and mastax aid feeding
What structure is unique to ribbon worms (Phylum Nemertea)?
Rhynchocoel—a fluid-filled cavity that houses a proboscis
What organ systems do mollusks possess that sponges do not?
Mollusks have complete digestive, circulatory, respiratory, and reproductive systems; sponges lack all of these
What is the function of the radula in mollusks?
A tongue-like structure used for scraping or rasping food.
What adaptation allows cephalopods to move quickly?
Jet propulsion via their siphon.
What trait distinguishes bivalves from other mollusks?
They lack a radula and are filter feeders using gills
What is segmentation and which phylum first shows it clearly?
Repetition of body structures; first seen in Phylum Annelida
What structure in earthworms aids in reproduction?
The clitellum, which secretes mucus and forms a cocoon for fertilization
What chemical in leeches prevents blood from clotting?
Hirudin
What feature gives Polychaetes their name?
Many bristles (chaetae) on parapodia.
What type of movement is characteristic of nematodes and why?
Whip-like movement due to only having longitudinal muscles
Why is C. elegans significant in biology?
It’s a model organism used in genetics and developmental biology due to its simple body and transparency
What allows tardigrades to survive extreme conditions?
Cryptobiosis—a state of suspended metabolism and water loss
What does “arthropod” mean and what is their key body plan?
“Jointed feet”; segmented body with exoskeleton and jointed limbs
What subphylum of arthropods includes insects, and how do they breathe?
Hexapoda; through spiracles and a tracheal system.
How can you tell centipedes and millipedes apart based on legs?
Centipedes: 1 pair/segment, carnivorous; Millipedes: 2 pairs/segment, herbivorous
