Biology
Worms Review Key
1.
Describe the planaria’s digestive system.
The digestive system consists of a highly branched intestine, which has only one opening: the
pharynx. This means that the planaria can only eat again once it is egested the waste material from
the intestine, through the pharynx.
2.
Describe the members of the phylum platyhelminthes.
Platyhelminthes are dorsoventrally flattened (top to bottom) acoelomate (pronounced AY-SEE-LOMATE) worms. They are solid, with only one opening into the body (the pharynx). Pme c;ass
(Turbellaria) is free-living. The trematodes (flukes) and cestodes (tapeworms) are dangerous parasites
3.
How would you avoid getting each of the following:
Trichinosis
Cook meat thoroughly
Blood Fluke
stay out of infested waters
Hookwarm
Wear shoes in infested areas
Elephantiasis
wear insect repellent, protective clothing or
netting
Tapeworm
Cook meant thoroughly
Roundworms
don’t kiss your dog on the lips; deworm pets as
recommended by your vet; wash hands after
handling potential hosts or dirt in infested
areas
4.
Describe a parasitic segmented worm.
The leech is a parasitic segmented worm in the Phylum Annelida. It is aquatic and has suckers to
attach to a host. It sucks blood from the host until it is full and falls off, or is removed. The species
Hirudo medicinalis is used in medicine after certain delicate surgical procedures.
5.
Which phylum studied are acoelomates? Pseudocoelomates?
The phylum Platyhelminthes are the acoelomates. The phylum Nematoda are the pseudocoelomates
6.
By which process do flatworms reproduce asexually?
Only the turbellarians reproduce asexually. They do this by using their mucus to stick to a rock or
other solid surface, and swimming away, leaving the posterior end behind. Both parts usually the
regenerate the missing portion.
7.
Why don’t flatworms need a circulatory or respiratory system?
Their bodies are very thin and necessary things, like oxygen and nutrients, move by diffusion, which is
why the free-living ones are so small. The parasitic ones get everything they need from the host, so
there is no limit as to how big they can grow
8.
How do tapeworms obtain their nutrition?
Predigested from the host
9.
Name 3 parasitic roundworms (common and scientific names).
Ascaris lumbricoides (large round worm)
Necator americanus (hookworm)
Trichinella spiralis (trichina worm)
10.
What is the common name for segmented worms?
Earthworms (some), annelids (all classes)
11.
What is an example of segmentation in humans?
Ribs, vertebrae
12.
What 2 structures allows for coordinated movement in annelids?
Circular muscles & longitudinal muscles + nerve cords (transverse and lateral)
13.
How do earthworms obtain oxygen?
Diffusion across the body surface (why they must stay moist)
14.
What major digestive structure do earthworms lack?
A stomach
15.
What is the advantage of a closed circulatory system over an open circulatory system?
Efficiency is improved because the blood is forced to flow past each cell
16.
What is the function of the clitellum?
Reproduction—it makes a mucus cocoon for the developing eggs
17.
How are earthworms beneficial to the environment?
They aerate the soil by moving through is, and return nutrients which are beneficial to plants by
leaving behind waste that has been broken down in the digestive system
18.
The basic body plan of an annelid can be described as a __tube_____ within a ____tube_____.