Phylum Nematoda Notes

notes for phylum Nematoda

1. Phylum: Nematoda Phylum: Nematoda
“Round Worms”“Round Worms”
Mr. “I Got Worms” ChapmanMr. “I Got Worms” Chapman

2. Phylum: NematodaPhylum: Nematoda
Some of the most abundant animals on Some of the most abundant animals on
earthearth
In each acre of fertile garden there are In each acre of fertile garden there are
how many nemtaodeshow many nemtaodes
5 Billion 5 Billion
Believe to be 16,000 to 500,000 speciesBelieve to be 16,000 to 500,000 species
Most are parasiticMost are parasitic

5. NematodesNematodes
Examples:Examples:
PinwormsPinworms
Hook WormsHook Worms
Guinea wormsGuinea worms
AscarisAscaris
Soil NematodesSoil Nematodes

6. Micrograph of hookworm headMicrograph of hookworm head Cutting teeth of hookwormCutting teeth of hookworm

7. Symbiotic RelationshipsSymbiotic Relationships
Mutualism:Mutualism:
When both organisms benefit. Ex. Clownfish and When both organisms benefit. Ex. Clownfish and
anenome.anenome.
Parasitism:Parasitism:
When one benefits (parasite) and the other is When one benefits (parasite) and the other is
harmed (host).harmed (host).
Commensalisms:Commensalisms:
When one benefits and the other is not affected. When one benefits and the other is not affected.
Example: Rino’s and birdsExample: Rino’s and birds

8. Phylum: NematodaPhylum: Nematoda
Important role in Important role in
recycling nutrients in recycling nutrients in
soilsoil
Lack cilia (except for Lack cilia (except for
sensor structures)sensor structures)

9. CharacteristicsCharacteristics
Triploblastic, bilateral, unsegmented, and Triploblastic, bilateral, unsegmented, and
pseudocoelomate.pseudocoelomate.
Covered by a cuticleCovered by a cuticle
–Has to molt to growHas to molt to grow
Complete digestive tractComplete digestive tract

10. CharacteristicsCharacteristics
Body wall has only Body wall has only
longitudinal muscles longitudinal muscles
with a ganglion at with a ganglion at
anterior end.anterior end.
Has Eye spotsHas Eye spots
Tapered at both ends Tapered at both ends
(comes to point)(comes to point)

11. FeedingFeeding
CarnivoreCarnivore
HerbivoreHerbivore
OmnivoreOmnivore
SaprobesSaprobes
–Feeds on decomposing organismsFeeds on decomposing organisms
–Blood and tissue fluidsBlood and tissue fluids

12. Digestive SystemDigestive System
Have mouth with teethHave mouth with teeth
Muscular pharynxMuscular pharynx
Long tubular intestinesLong tubular intestines
–Where digestion and absorption occursWhere digestion and absorption occurs

14. ReproductionReproduction
Most are Dioecious and DimorphicMost are Dioecious and Dimorphic
DioeciousDioecious – having male and females – having male and females
sexessexes
DimorphicDimorphic – two different forms, so males – two different forms, so males
and females look differentand females look different
Males are smaller than femalesMales are smaller than females

15. ReproductionReproduction
Female – has ovaries, tubular uterus, Female – has ovaries, tubular uterus,
Male – single testis, tube that connects to Male – single testis, tube that connects to
cloaca.cloaca.
Cloaca – one opening used for Cloaca – one opening used for
reproduction and excretory. reproduction and excretory.

17. Important EvolutionImportant Evolution
High reproductive potentialHigh reproductive potential
Life cycles (different from flatworms)Life cycles (different from flatworms)
–Increases likelihood of transmission from one Increases likelihood of transmission from one
host to anotherhost to another
Enzyme-resistant cuticleEnzyme-resistant cuticle
Resistant eggResistant egg