Gnathifera

Question 1

Gnathifera Taxonomy

Answer 1

Phylum Gnathostomulida
Phylum Rotifera
Phylum Acanthocephala
Phylum Micrognathozoa

Question 2

Phylum Gnathostomulida Characteristics

Answer 2

80 species
Small, intestinal, parasitic worms
Pharynx with unique jaws
Monolayered, monociliated epidermis for protection 
No circ or resp systems
Protonephridia
Hermaphroditism

Question 3

Phylum Micrognathozoa Characteristics

Answer 3

Single species
Complex body (head, thorax, abdomen)
Thorax has plates for protection
Unique adhesive pad to attach to structures
Parthenogenesis reproduction: polar bodies act like sperm to restore diploid
Found on moths in Greenland

Question 4

Gnathifera Common Name

Answer 4

Jawed Animals

Question 5

Phylum Acanthocephala Characteristics

Answer 5

1200 species
Obligate intestinal parasite
Eversible proboscis (retracts inside out) with proboscis receptacle
Syncytial body wall with lacunar canals
Ligament sac
Gonochoristic

Question 6

Acanthocephala Males

Answer 6

Cement gland: covers cloaca to stop any other mating

Question 7

Acanthocephala Females

Answer 7

Ovary balls: float freely in ligament sac fluid

Question 8

Acanthocephala Ligament Sac

Answer 8

Extends from posterior end of proboscis receptacle to near genital pore, subdividing pseudocoel
Contains ovarian balls

Question 9

Acanthor Stage: Acanthocephala

Answer 9

Following copulation and fertilization, fertilized eggs develop into acanthors to be released to exit host encased in protective shells
Develop further only when in invertebrate host = intermediate host

Question 10

Phylum Rotifera

Answer 10

Wheeled animals
Bio indicator
Triploblastic
Bilateral symmetry
No respiratory or circulatory systems
FW, marine, semi-terrestrial, few parasitic
Omnivores
Pelagic- external body moves independent of body

Question 11

Rotifera Defining Characteristics

Answer 11

Corona: feeding structure
Pseudocoelom
Glycocalyx: carb structure surrounding body for protection
Lamina Layer: thick, protective fluid filled cavity
Mastax: grinds food

Question 12

Rotifera Musculature

Answer 12

Muscles in defined muscle bands

Hydrostatic skeleton

Question 13

Rotifera Digestion/Feeding

Answer 13

Mastax: grinds food
Complete digestive system
Stomach uses enzymes to break down food
Intestine absorbs nutrients 
Omnivores
Corona: outer ring; collection of cilia to move water and catch food to bring to mouth

Question 14

Rotifera Foot and Toes

Answer 14

Annulated: ringed/body broken into rings which allows for telescoping movement
Cement glands: allow to cement in place to hold on

Question 15

Rotifera Nervous System

Answer 15

Collection of nerve cell bodies to control movement

Antenna: sensory structures for muscles

Question 16

Rotifera Excretion

Answer 16

Protonephridia:

Question 17

Rotifera Reproduction (Cl. Monogononta)

Answer 17

Parthenogenesis: diploid females produce diploid eggs by mitosis and develops into diploid female = amictic females
Mictic females: produce haploid eggs through meiosis that turn into haploid males to mate with females to introduce genetic differences; promoted by change in environment

Question 18

Rotifera: Cl. Monogononta Characteristics

Answer 18

Sessile: many have protective tube
Lorica: protective outer cuticle (hinders telescoping)
Sticky mucus: catches stuff for tube such as fecal pellets for protection
Polymorphic Development: change morphologically in response to predator

Question 19

Rotifera: Monogononta–Polymorphic Development

Answer 19

Change morphology in response to predators