Questions and Answers
Which of the following are characteristics of nematodes?
Are nematode roundworms segmented or unsegmented?
Unsegmented
What do nematodes eat?
Everything
What are the two classes of nematodes?
Signup and view all the answers
Is the nematode digestive tract complete or incomplete?
Signup and view all the answers
What two characteristics are unique in nematodes?
Signup and view all the answers
What is the nematode cuticle made of?
Signup and view all the answers
Describe the nematode digestive system.
Signup and view all the answers
What helps push food along in the nematode?
Signup and view all the answers
Describe the nematode nervous system.
Signup and view all the answers
What do nematodes excrete in terms of nitrogenous waste?
Signup and view all the answers
What are the osmoregulation and excretion systems of a nematode?
Signup and view all the answers
Describe the glandular system in aquatic nematodes.
Signup and view all the answers
Describe the tubular system in parasitic nematodes.
Signup and view all the answers
Are nematodes dioecious or monoecious?
Signup and view all the answers
Where do nematodes have their gonads?
Signup and view all the answers
What is the bursa in a nematode?
Signup and view all the answers
What kind of fertilization occurs in nematodes?
Signup and view all the answers
What is ovoviviparity and what phylum may exhibit this?
Signup and view all the answers
Do nematodes have a larva?
Signup and view all the answers
How many times does a nematode larva molt?
Signup and view all the answers
What evolutionary adaptations do parasitic nematodes possess?
Signup and view all the answers
What are five important nematode parasites of humans?
Signup and view all the answers
What does Wuchereria spp (Filarial worms) cause in humans?
Signup and view all the answers
What super group do nematodes belong to?
Signup and view all the answers
Study Notes
Nematode Characteristics
- Triploblastic, bilateral, and unsegmented.
- Pseudocoelomate structure with a round cross-section.
- Elastic cuticle made of collagen that undergoes molting.
- Complete digestive tract comprised of mouth, buccal cavity, pharynx, intestine, rectum, and anus.
- Unique excretory system featuring 1-2 renette cells or collecting tubules.
- Presence of only longitudinal muscles.
Nematode Classification
- Classified into two main classes:
- Secernentea (Phasmidea)
- Adenophorea (Aphasmidia)
Feeding Habits
- Nematodes are omnivorous, feeding on a wide range of organic materials.
Digestive and Excretory Systems
- Digestive system utilizes hydrostatic pressure from pseudocoelom and a muscular pharynx to propel food.
- Nematodes excrete nitrogenous waste as ammonia and urea.
- Osmoregulation and excretion managed through a glandular system and tubular system.
Glandular and Tubular Systems
- Aquatic nematodes possess a glandular system with renettes that absorb waste and release it externally.
- Parasitic nematodes have a tubular system where renettes form a large canal leading to an excretory pore.
Reproductive Characteristics
- Most nematodes are dioecious, with gonads located freely in the pseudocoelom.
- Sperm transfer during copulation is aided by a bursa at the posterior end.
- Internal fertilization is the norm, with some species exhibiting ovoviviparity (larval birth).
- Nematodes typically undergo four larval molts during development.
Parasitic Adaptations
- Parasitic nematodes display high reproductive potential and complex life cycles enhancing host transmission.
- Adaptations include enzyme-resistant cuticles, resistant eggs, and encysted larvae for survival.
Human Parasites
- Five significant human nematode parasites include:
- Ascaris lumbricoides (Giant Intestinal Roundworm)
- Enterobius vermicularis (Human Pinworm)
- Necator americanus (New World Hookworm)
- Trichinella spiralis (Porkworm)
- Wuchereria spp. (Filarial Worms), which causes elephantiasis.
Evolutionary Background
- Nematodes belong to the supergroup Ecdysozoa, characterized by molting exoskeletons.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
Test your knowledge on Phylum Nematoda with these flashcards. Explore key characteristics, dietary habits, and structural features of nematodes. Perfect for biology students studying roundworms.