Lab 5: Phylum Nematoda Flashcards
Within the clade bilateria, what are the two other clades that diverge from it?
Protostomia and Deuterostomia
What clade within bilateria do platyhelminthes and nematoda belong to?
Protostomia
What are the two clades within the protostomia clade?
Spiralia and Ecdysozoa
From the clades diverged from the protostomia, what do platyhelminthes and nematoda come from?
Platyhelminthes belong to spiralia and nematoda belongs to Ecdysozoa
Blastocoel
the fluid-filled space in the blastula
What becomes the mouth in protostomes (nematodes)?
The blastopore
What becomes the mouth and anus in deuterostomes?
a second opening becomes the mouth and the first opening, the blastopore, becomes the anus
Are nematodes triploblastic?
Yes
What kind of symmetry do nematodes have?
bilateral symmetry
What is Spiralia?
refers to a special type of cleavage that occurs in early development in most animals clade; spiral cleavage
What process is ecdysis?
the process of shedding the cuticle that covers the outside of a nematodes body
What are acoelomates?
Animals without a body cavity. Ex. flatworm
What is a blastocoelom?
The body cavity of nematodes; the space called the blastocoel develops into the blastocoelom in an adult roundworm.
Does mesoderm fill the entire cavity in a nematode?
No, only along the inside of the body wall
T/F The organs of the roundworm are not covered in tissue derived from mesoderm
True
What kind of nervous system do nematodes have?
centralized
What is the cuticles function in ecdysozoans?
-Maintaining shape, gives roundworms their shape
-Protection from a variety of environments including digestive enzymes parasitic roundworms would be exposed to
-Movement/locomotion: serves as an atagonist to longitudinal muscles
What is the cuticle in ecdysozoans?
It covers the outside of the bodies, is multi-layered, composed primarily of collagen, and is secreted by the epidermis, and NON-LIVING
T/F Nematodes have circular and longitudinal muscles
F: only longitudinal muscles that run the length of the worm
What acts as the fluid-filled internal space of a hydrostatic skeleton in a nematode?
The blastocoelom
What do roundworms feed on?
bacteria, fungus, small animals, and dead plants and animals (also many eat roots)
What kind of digestive system does a nematode have?
Complete
What does the digestive system of a nematode consist of?
a mouth, a muscular tube called pharnyx that pumps food into the intestine, and an anus
What secretes enzymes in a nematode?
The intestine
Where does the digested nutrients move from after the intestine?
The blastocoelom
Cuticles are permeable to ___ and ___
gases and water
What serves as a simple circulatory system and distributes gases and nutrients to all parts of the worm?
The fluid-filled blastocoelom
What waste is excreted by nematodes?
Ammonia
What germ layer does muscle tissue develop from?
Mesoderm
