Lecture 13 Flashcards
Non- Arthropod
What is the Ecdysozoa group, and what are its main characteristics?
It is a Bilateria group within the Protostomia; all Ecdysozoa can molt their outer cuticle layer and do not have jointed legs.
What are the defining features of non-arthropod ecdysozoans?
Non-arthropod ecdysozoans do not have jointed legs, and they include phyla like Nematoda, Nematomorpha, and Panarthropoda.
What are some characteristics of Phylum Nematoda?
Known as roundworms, with 30,000 to 1,000,000 species worldwide, abundant in various habitats, and include both ecto- and endoparasites.
Describe the cuticle and movement of Nematoda.
They have a thick cuticle made of collagen, used for defense and support, which can be molted. They move with a thrashing motion in water and more controlled movement in soil.
What is the role of the pseudocoelom in Nematoda?
The fluid-filled pseudocoelom functions as a hydrostatic skeleton, lined partially with mesoderm.
Name some common nematode parasites and their effects on humans.
Intestinal roundworm (Ascaris): Infects up to 1 billion people.
Hookworms: Infect 650 million people, feed on blood.
Pinworms: Common in developed countries, don’t need an intermediate host.
Filarial worms: Transmitted by mosquitoes.
What makes Caenorhabditis elegans significant in research?
It is a non-hazardous model organism with 959 cells, a fully mapped genome, and a known nervous system, widely used in biological studies.
Describe Phylum Nematomorpha.
Known as horsehair worms, with 320 species, they are pseudocoelomate, live in moist areas, are semi-parasitic, and parasitize arthropods.
What is unique about the reproductive cycle of Paragodius obamai in Phylum Nematomorpha?
It is parthenogenetic, producing females without the presence of males.
What are the synapomorphies of Panarthropoda?
Small coelom, Ventrolateral appendages for walking, Open circulatory system with hemolymph, combining blood and lymph to bathe tissues.
What are the characteristics of Phylum Onychophora?
Known as velvet worms or “claw to bear” worms, with a soft cuticle, 14-43 pairs of unjointed legs, and they attack predators by shooting slime.
Describe Phylum Tardigrada.
Known as water bears or moss piglets, with 8 unjointed legs, a pair of stylets and sucking pharynx, and capable of cryptobiosis in adverse environments.
What is cryptobiosis in Tardigrada?
A survival state where tardigrades suspend all biological activity in unfavorable conditions.
What types of environments can tardigrades inhabit?
Tardigrades are found in marine, freshwater, and damp terrestrial habitats and can survive extreme temperatures.
