BCLN BIOLOGY 11 – Rev July 2014
Unit 10 ~ Learning Guide
Name: _______________
INSTRUCTIONS
Complete the following notes and questions as you work through the related lessons.
You are required to have this package completed BEFORE you write your unit test. Do
your best and ask questions about anything that you don't understand BEFORE you
write the unit test.
10.1 NOTES: FLATWORMS
Characteristics of Flatworms
Flatworms (phylum _____________________________) are a step “up” the ladder of
evolution being _______________________________________________________
_________________________.
Flatworms have a _________________
____________. This body plan means
they have_________________________
__________________________________
________________________. However,
__________________________________
__________________________________
__________________________________
__________________________________
__________________________________
__________________________________
______________________________________________________________________
These specialized systems are exemplified by the Planaria which is a heterotrophic
free-living flatworm.
There are three Classes of flatworms:
1. Class Turbellaria (ex. Planaria) - free living, incomplete gut, no suckers or
hooks.
2. Class Trematoda (ex. Flukes) - parasitic, incomplete gut, ______________
_____________________________
3. Class Cestodae (ex. Tapeworms) - parasitic, no gut, _________________
________________________________________________________________
Page 1 of 42
BCLN BIOLOGY 11 – Rev July 2014
Body Plan Summary






Both primitive and advance characteristics
__________________________________________
__________________________________________
________________________ = concentration of
sensory organ and nervous tissue at anterior end of
body
___________________________________________ (germ layers).
o Ectoderm – forms outer epidermis.
o Mesoderm - forms muscle tissue and reproductive, and excretory organs.
o Endoderm – forms inner gut.
_____________________________________________________________
Movement
Some larval stages move using cilia while adults move using muscle contractions.
A Closer Look at Flatworm Classes
1. Class Turbellaria
Planaria ______________________________
_____________________________________
______________. The __________________
_____________________________________
on the end of a muscular ________________
_____________________________________
_____________________________________
_____________________________________
____________________________________.
The _____________________________________________________________
___________________________ to the body. Indigestible wastes leave the
same way they came in through mouth.
There are approximately 4,500 species that live in the _______________. Some
live in __________________________________.
Page 2 of 42
BCLN BIOLOGY 11 – Rev July 2014
Planaria Digestive System
The digestive system in Planaria is similar to that of the cnidarians. It consists of
a
________________________________________________________________
________________________________. A pharynx extends from the underside
of the flatworm and sucks up food through the mouth. The food is then
__________________________________________________________.
Wastes are expelled through the same opening. Nutrients can be carried through
the organism efficiently by ______________ because the flatworm is so thin.
PLEASE LABEL THE PLANARIA DIGESTIVE SYSTEM
IN THE DIAGRAM BELOW BEFORE PROCEEDING ANY FURTHER!
Page 3 of 42
BCLN BIOLOGY 11 – Rev July 2014
Planaria Reproductive System
Planarians are __________________________, meaning
they are ______________________________________
but they _______________________________________
_______________________
between
organisms.
Adjacent flatworms will align themselves so that they will
simultaneously fertilize each other. Planaria also have
amazing ______________________________________.
Planaria is cut lengthwise, it will grow into two separate
animals. And, if a planarian is cut down the center, but not
completely, it will develop two heads.
PLEASE LABEL THE PLANARIA REPRODUCTIVE SYSTEM
IN THE DIAGRAM BELOW BEFORE PROCEEDING ANY FURTHER!
Page 4 of 42
BCLN BIOLOGY 11 – Rev July 2014
Planaria Excretory System
Excretion is the expulsion of excess water and wastes. These wastes differ from
those expelled from the gastrovascular cavity in that wastes excreted by the
excretory system were first digested and entered the body of the flatworm.
Planarians have specialized cells called ________________________________
________________________________________________________________
________________________________________________________________
________________________________________________________________
________________________________________________________________
________________________________________________________________.
PLEASE LABEL THE PLANARIA EXCRETORY SYSTEM
IN THE DIAGRAM BELOW BEFORE PROCEEDING ANY FURTHER!
Page 5 of 42
BCLN BIOLOGY 11 – Rev July 2014
Planaria Nervous System
The nervous system of the planarian consists of _________________________
________________________________________________________________
_____________________________________. This type of nervous system is
referred to as a _____________________________________________. The
cephalization consists of a brain, chemosensitive organs, and two eyespots. The
chemosensitive organs guide the flatworm toward food and the eyespots are
sensitive to light. Planaria will move away from light probably to avoid predation.
The nervous system also controls muscles used for movement.
PLEASE LABEL THE PLANARIA EXCRETORY SYSTEM
IN THE DIAGRAM BELOW BEFORE PROCEEDING ANY FURTHER!
Page 6 of 42
BCLN BIOLOGY 11 – Rev July 2014
Other Systems in Planaria
CIRCULATORY and RESPIRATORY SYSTEMS
 not true systems
 part of the gastrovascular cavity
 ___________________________________________________________
___________________________________________________________
MUSCULAR SYSTEM
 a true system
 controlled by longitudinal, circular, and oblique layers of muscle
sometimes assisted by secreting a layer of mucus
SKELETAL SYSTEM
 NONE
2. Class Trematoda
There are an estimated 9000 species of Trematoda. Many of
these are _______________________ (liver, lung, heart,
intestine).
Flukes
are
____________________________________.
Flukes have _______________________________________
_________________________________________________
_________________________________________________
_____________________. They absorb nutrients through the
gastrovascular cavity. They have ______________________
__________________ for excretion. Nerve cords and anterior ganglia make up
the nervous system. They are ___________________________________.
Flukes have a _________________________________________________ with
numerous larval stages that infect a number of hosts.
The entire external surface of a fluke is covered by a continuous sheet of fused
cells
called
the
_______________________________________.
The
Page 7 of 42
BCLN BIOLOGY 11 – Rev July 2014
________________________________ consists of a layer of protein and
carbohydrates that ________________________________________________
_______________________________________________________________.
Liver Fluke Life Cycle
PLEASE WATCH THE TERMATODA LIFE CYCLE
VIDEO BEFORE PROCEEDING ANY FURTHER!
3. Class Cestodae
There are an estimated 5000 species of
Cestodae. An example is tapeworms.
Tapeworms are ___________________
animals and are specialized for living
within a host. Most body systems have
been lost as they are not required as the
host provides nutrients. There are _____
_________________________________
_________________________________.
Tapeworms _______________________
________________________ through their skin. The ____________________
Page 8 of 42
BCLN BIOLOGY 11 – Rev July 2014
______________________________________
________________________________.
The
adult tapeworm to the right has a
______________________________________
______________________________________
______________________________________
______________________________________
________. While the tapeworm grows in the
host's
intestine,
_____________________
______________________________________
______________________________________
_____________. This species occurs most
often in rabbits, cats and rodents, but sometimes
humans, causing diarrhea, weight loss and
abdominal discomfort. Adult tapeworms may grow 5-10 meters in length.
Tapeworms have a Scolex with hooks and suckers used to attach to the
inside wall of the host intestine
Proglottids are body segments specialized for reproduction
Page 9 of 42
BCLN BIOLOGY 11 – Rev July 2014
Tapeworm Life Cycle/Reproduction Summary
 Carried out by _______________________________________________
________________________________.
 Tapeworms are ___________________________________ - contain
both ovaries and testes and _________________________________
__________________________________
 Zygotes are passed out of host’s body with feces.
 Larvae hatch in water and in grass.
 Larvae are eaten by a herbivore (____________________________) and
the larvae then burrows through the wall of the intestine and into the blood
stream. Intermediate hosts contain tapeworm cysts __________________
that _______________________________________________________
___________________________________________________________
___________________________________________________________
MMmmm Tapeworms
As part of a University of Salford experiment to develop a diagnostic test for beef
tapeworm, biologist Mike Leahy volunteered to grow this gruesome parasite
inside his own gut. Mike swallowed the immature tapeworm cyst with a glass of
red wine and the worm started to grow at an initial rate of four centimetres a
week. Twelve weeks later he had to call a halt to the unusual experiment
because he was getting married! After a dose of anti-worm pill Mike passed out
an intact tapeworm three metres long.
Page 10 of 42
BCLN BIOLOGY 11 – Rev July 2014
Parasitic Flatworms and Humans
Flatworms that are parasitic on humans fall into two categories, ___________________
______________________________. Due to the fact that they live in the gut of a host
animal these flatworms have an anatomy ___________________________________.
Generally, _____________________________________________________________
_____________________________________________________________________.
Parasitic flatworms will usually have hooks on the scolex (anterior region) to attach it to
the wall of the gut and they have an _________________________________________
_____________________________________________. When a flatworm reproduces,
the eggs are passed out with the feces. When consumed by another host the life cycle
continues.
Flukes and tapeworms can infect many different animal hosts. ____________________
______________________________________. One host when sexually mature called
the primary host and a secondary host in which the eggs mature to larvae.
10.1 PRACTICE: FLATWORMS
1. Members of the Phylum Platyhelminthes are "more affectionately" termed
______________________________. (1 mark)
2. How is the body plan of the Planarians of Phylum Platyhelminthes comparable to
that of the Phylum Cnidaria? (2 marks)
Page 11 of 42
BCLN BIOLOGY 11 – Rev July 2014
3. How does the symmetry of the Planarians of Phylum Platyhelminthes compare to
that of the Phylums Cnidaria and Porifera? Draw a diagram showing the
differences. (3 marks)
4. Germ layers give rise to all the other tissues that will develop over an organisms'
life time.
a. How do the germ layer of Phylum Platyhelminthes compare to that of the
Phylums Cnidaria and Porifera? (1 mark)
b. In what ways do the germ layers of Phylum Platyhelminthes allow for
greater specialization? (4 marks)
Page 12 of 42
BCLN BIOLOGY 11 – Rev July 2014
5. Planaria belong to the Class _________________________ of the Phylum
______________________________ and are free-living. (2 marks)
6. Free-living species do not require a ______________ to survive whereas
__________________________ species require a host to survive. Free-living
species tend to have more ___________________ systems as they must
provide for themselves. (3 marks)
7. A planaria obtains food via its mouth, which is attached to an extendable tube
called the _______________________. The food is then digested in the
________________________________________. The resulting nutrients are
then absorbed and ___________________ throughout the thin tissues of the
body. (3 marks)
8. Planaria are ______________________________ meaning they are both male
and female, capable of producing both sperm and eggs. (1 mark)
9. Planaria excrete waste via their ____________________ which have cilia that
beat to move fluid along the excretory canals and out the ___________________
__________________. (3 marks)
10. Lateral is a term frequently used in biology. Please define. (1 mark)
11. Planaria are truly cephalized whereas tapeworms only "appear to" be cephalized.
Define cephalization and explain why the term is does not truly apply to
tapeworms. (2 marks)
Page 13 of 42
BCLN BIOLOGY 11 – Rev July 2014
12. If a scientist were to study a free-living worm and a parasitic worm out of context
(not knowing their life cycles) and were to only compare their body systems,
which type of worm, is the scientist most likely to conclude, evolved first? Why
would the scientist conclude this? Is the scientist likely to be correct? Why or
why not? (4 marks)
13. Tapeworms are somewhat unusual hermaphrodites in that a single individual's
sperm can actually fertilize _________________________ eggs. (1 mark)
14. Compare and contrast the terms primary host and secondary host. (3 marks)
Page 14 of 42
BCLN BIOLOGY 11 – Rev July 2014
10.2 NOTES: ROUNDWORMS
General Characteristics Roundworms
Roundworms
belong
to
the
Phylum
___________________ (also called _________________
______________________________________________)
Nematodes are the most speciose (meaning rich in
numbers of species) phylum after the arthropods. They
occur in nearly every habitat including ________________
_____________________________________________
__________________________________ (they don't like
dry places however). One species is known that can live in
old vinegar (Turbatrix aceti) and another that has only been
found in German beer mats. Though only about 80 000
species have been described some scientists estimate
there may be as many as a million species all told. They
can occur in very dense numbers in the soil and rotting
vegetation, as many as 90 000 have been found in a single rotting apple, while millions
occur in the top 3cm (1 inch) of a square metre of good quality soil.
While there are a huge number of ______________________________ Nematodes
there are also a large number of ____________________________________, many of
which cause diseases to man and other animals as well as to plants, nearly every living
organism has been found to be parasitized by one species of nematode or another.
Most nematodes are reasonably small, they range in size from 100 micrometres in
length (1/10th of a mm or 1/250th of an inch) to the female Giant Nematode
Dioctophyme renale which may be up to 1 metre, or 3 ft long.
Page 15 of 42
BCLN BIOLOGY 11 – Rev July 2014
Body Systems in Roundworms
Roundworms (phylum ______________)
have a __________________________
________________________________
_______________. This body plan is
more advanced than the Platyhelminthes
and Cnidarians which, you should recall
from previous units, have a single
opening functioning as a mouth and anus
called a sac plan. Nematodes ________
_________________________________
__________________. This design allows for _________________________________
____________________. At the anterior (head) end there is a mouth which has 3 lips
behind which predatory species possess a few teeth, this leads to a
______________________. The pharynx of Nematodes is an efficient pump and forces
food into the intestines as it can be used to suck liquid food into the mouth.
______________________________________________________________________
_________________________________________.
Digestive System
Roundworms have a ___________________________________________. It is a long
tube shaped digestive tract with ____________________________________________
______________________________________________________________________
______________________. As food is pushed through digestive tract it is digested and
_____________________________________________ into the cells of the body.
Undigested remains continue on through tract and are ________________________
_________________________.
Free living round worms are often __________________________________________
______________________________________________________________________
______________________________________________________________________
______________________________________________________________________
______________________________________________________________________
They excrete metabolic waste through their body walls by _____________________.
Page 16 of 42
BCLN BIOLOGY 11 – Rev July 2014
Circulatory and Respiratory Systems
Roundworms have _____________________
________________________________. They
breathe and excrete waste through their body
walls. They do not have an internal transport
(circulatory)
system
and
rely
on
_____________________.
The ___________________________ is filled
with fluid and it distributes digested foods and
dissolved oxygen to the body. It also acts as a
________________________________.
Excretory System
In roundworms, _________________________________________________________
______________________________________________________________________
______________________________________________________________________
Nervous System
Nematodes, especially free living forms generally have a reasonably well developed
nervous system. This is comprised of a circum-pharyngeal nerve ring and longitudinal
nerves that extend down through the body to the various parts of the gut and the
reproductive organs. _____________________________________________________
____________________________________. They have simple sense organs.
Reproduction
Nematodes are copiously reproductive and most of their body cavity, which is a
_________________________________, is filled with paired sets of reproductive
organs, either ovaries or testes. ____________________________________________
______________________________________________. The female has long coiled
ovaries that produce thousands of eggs every day. Eggs are stored in a uterus. The
vagina leads to an external opening. ______________________________________
___________________________________________. Sperm cells pass through the
Page 17 of 42
BCLN BIOLOGY 11 – Rev July 2014
sperm duct though an opening at the posterior end of the worm. During copulation
sperm is released into the vagina resulting in internal fertilization. After fertilization,
______________________________________________________________________
___________. The females lay eggs over a prolonged time period, thus a female
Ascaris lumbricoides may lay her eggs at the rate of 200,000 per day and have had a
total 27 million eggs within her at the start of her reproductive career.
Summary of Round Worms
1. Primitive Characteristics:
 _________________________________
 no circulatory system
 no skeletal system
 _____________________________________________________
2. Advanced Characteristics:
 _____________________________________________
 cylindrical shape (round worms)
 _____________________________________________
i. Ectoderm – produces tough cuticle.
ii. Mesoderm – muscle and various organs.
iii. Endoderm – digestive tract
 ____________________________________________ – mouth to anus!
 _____________________________ - between the mesoderm and the gut
is a fluid filled space.
Ascaris
Ascaris is usually diagrammed to typify roundworm anatomy. Ascaris is a roundworm
that is ___________________________________________. The entire life cycle can
take place in the human body and the eggs can be passed out with feces. Eggs in food
or water are _____________________________________, the eggs hatch in the
small intestine, larvae enter the blood vessels and are carried to the lungs, larvae then
travel to the throat and are swallowed. Adult ascaris worms live in the small intestine
with eggs leaving the host in the feces.
With a longitudinal cross section the tube within a tube design can be observed. It can
also be observed that the digestive system is not very well developed as the length of
the gut after the pharynx is unchanged and reproductive organs are quite large in
Page 18 of 42
BCLN BIOLOGY 11 – Rev July 2014
comparison to the body. This is a characteristic of an internal parasite to have a simple
digestive system and well developed sex organs.
Ascariasis is the human disease caused by __________________________ with as
many as ____________________________________________________________
________________________________. It is common in tropical regions, regions with
poor sanitation, poor personal hygiene, and places where human feces are used as
fertilizer. Intake of food or drink contaminated with Ascaris eggs causes the infection.
The symptoms of Ascariasis are:
 passing worms in stool
 vomiting up worms
 worms exiting through the nose or mouth
 low-grade fever.
 cough.
 bloody sputum.
 wheezing
 shortness of breath
 skin rash.
 vomiting
 stomach pain.
 Note: There may be no symptoms.
PLEASE LABEL THE ASCARIS
DIAGRAM BELOW BEFORE PROCEEDING ANY FURTHER!
Page 19 of 42
BCLN BIOLOGY 11 – Rev July 2014
Other Parasitic Roundworms
Even though _____________________________________
________________________________________________
_____________ are typically enough to ward off roundworm
infection many roundworm diseases are common worldwide
including some in North America. ______________________
___________________________________ are common in
North America, while more serious infections such as
________________________________________________
are common in Africa and are rarely seen here.
Trichina worm causes Trichinosis when the host eats
_________________________________________________
_______________________________________. Trichinosis
forms cysts in the muscles of its victims and causes
symptoms such as pain, blisters, muscular weakness, and
anemia. The images below show a trichina worm and a cyst
formed in muscle around a worm.
Pinworms are tiny pin-shaped nematodes known as
Enterobius vermicularis to the medical and zoology
communities. Also called seatworms or threadworms these
small, whitish roundworms are responsible for contagious
intestinal _________________________________________
_________________________________________________
_________________________________________________
________________________________________________.
Although adult pinworms inhabit the large intestine, the eggs
are laid outside of the anus during the night creating a severe
itching sensation. Other symptoms include disturbed sleep,
decreased appetite and weight loss. Spread from person to
person usually occurs with ____________________________
_________________________________________________
___________________________________. The eggs can also drift through the air
where they are inhaled or swallowed. Once they enter the new host the eggs hatch in
the small intestine and travel down to the large intestine for maturation.
Page 20 of 42
BCLN BIOLOGY 11 – Rev July 2014
Other Parasitic Roundworms
Hookworm ________________
__________________________
__________________________
__________________________
__________________________
__________________________
__________________________
__________________________
__________________________
__________________________
__________________________
__________________________
__________________________
Filaria worms _______________
__________________________
__________________________
__________________________
Called _____________________
Elephantiasis is transferred by
mosquitoes and blocks lymph
vessels as the worms increase in
size. Lymph vessels return fluid
to the bloodstream from the
tissues so when the vessels are
blocked the limbs increase
greatly in size.
Page 21 of 42
Loiasis, called eye worm or loa
loa, is endemic to the rainforests
of central and western Africa
where mango flies of the
Chrysops species serve as both
intermediate host and the
parasite vector. About 13 million
people are currently infected.
BCLN BIOLOGY 11 – Rev July 2014
Guinea worms, also known as the
stick worm, form ulcerating blisters in
human skin. People get infected
when they drink standing water
containing a tiny water flea that is
infected with the even tinier larvae of
the Guinea worm. Over the course of
a year in the human body, the
immature worms pierce the intestinal
wall, grow to adulthood, and mate.
The males die, and the females
make their way through the body,
maturing to a length of as much as 3
feet, and ending up near the surface
of the skin, usually in the lower limbs.
The worms cause _______________
_____________________________.
To soothe the burning, sufferers tend
to go into the water, where the
blisters burst, allowing the ____________________
_______________________________________________
_____________________________________.
In
the
water, the larvae are swallowed by small water fleas, and
the cycle begins again. These parasites can cause longterm suffering and sometimes crippling after-effects. The
worms are slowly removed from the body by winding them slowly around a stick to pull
them out.
Page 22 of 42
BCLN BIOLOGY 11 – Rev July 2014
10.2 PRACTICE: ROUNDWORMS
1. Roundworms belong to the Phylum ______________________________ which
is also known as the ________________________________, (2 marks)
2. Phylum Nemotoda include many diverse species including those which are
____________________________ in that they require a host and those which
are ____________________________________. (2 marks)
3. Compare and contrast the body of Phylum Nematoda to that of Phylum Cnidaria.
(3 marks)
4. The digestive systems of free-living members of Phylum Nematoda are seen to
be "evolutionarily advanced" compared to those of members of the Phylum
Cnidaria:
a. What is the "advancement" and what is this type of digestive system
referred to as? (2 marks)
Page 23 of 42
BCLN BIOLOGY 11 – Rev July 2014
b. How might this "evolutionary advance" provide a selective advantage to
Phylum Nematoda? (2 marks)
5. Fluid in the psuedocoelom of Nematoda allow digested food and oxygen to
_________________________ throughout the body and also acts as a
____________________________________________ helping to provide the
organism with support and movement. (2 marks)
6. Most species of Phylum Nematoda have separate sexes, male and female, and
thus, they are termed ________________________________. (1 mark)
7. Identify at least three "primitive" and three "advanced" characteristics of Phylum
Nematoda. (6 marks)
Page 24 of 42
BCLN BIOLOGY 11 – Rev July 2014
8. Choose one parasitic member of Phylum Nematoda that uses humans as part of
its life cycle and:
a. Briefly describe its life cycle. (3 marks)
b. Identify the symptoms and/or impacts it has on its human host. (2 marks)
Page 25 of 42
BCLN BIOLOGY 11 – Rev July 2014
10.3 NOTES: SEGMENTED WORMS
General Characteristics of Annelids
The annelids or ___________________________________________________
___________________________________________________________. The general
characteristics of an Annelid are similar to those of a roundworm. They are __________
______________________________________________________________________
_________________________________. However, an Annelid also has a
_______________________________________________________. Both the coelom
and segmentation allow for greater specification of body parts. ____________________
___________________________________________________ and allow structural
support by creating a hydroelastic skeleton. ___________________________________
____________________________________________ which will be discussed in the
anatomy of the earthworm later in this lesson. The _____________________________
____________________________________________________ (filtering organ) in
each segment. The Annelid moves by alternating contractions of circular and
longitudinal muscles. The circular muscles encompass the body wall and therefore
contractions cause the body to become long and thin. The longitudinal muscles run the
length of the body and cause the body to shorten and fatten.
The Phylum name Annelida means ¨Ringed in Form¨. ___________________________
______________________________________ within the animal for different purposes.
The coelom is divided into separate compartments (septa) by partitions. These septa
enable different compartments to contract or expand independently. Duplication of
some of the organ systems in each segment provides insurance against injury.
There are three Classes of Annelids that we will discuss:
1. Class Polychaeta meaning ___________________________________
2. Class Oligochaeta which ____________________________________
3. Class Hirudinea which _________________________________
Page 26 of 42
BCLN BIOLOGY 11 – Rev July 2014
Marine Worms
Class Polychaeta are so named because they have many
_________________ on their segments. These
_____________________________________________
_____________________________________________
________________________________.
In
some
marine worms they are arranged like a paddle and are
called ____________________. __________________
____________________________________________
because Annelids breathe through their body wall by
_____________________ and parapodia expand the
surface area of the animal. Some marine worms such as
Nereis have a more noticeable cephalization. Nereis has
an invertible pharynx that exposes chitinous (made of
chitin - a strong complex carbohydrate common to fungi cell walls and some animals)
jaws, eyes, and other sense organs. Some marine worms have bristles to aid in
defense. Nereis seen to the right is an example of a free living predatory marine worm.
Predatory worms also have _______________________________________________
___________________________________________. Other marine worms live in
tubes that may be made of calcium, silica (sand) or protein. These tube worms are filter
feeders.
Here's
what
these
worms
look
like
when
retracted.
Page 27 of 42
BCLN BIOLOGY 11 – Rev July 2014
Earthworms
Segmented worms of the class ________________________
(maximum 20 setae per segment) and are exemplified by the
common ________________________, Lumbricus terrestris.
Earthworms do not have cephalization as advanced as
marine worms such as Nereis, but they do _______________
_________________________________________________
______________________________. They do not have eyes, but are capable of
detecting and avoiding water without actually coming in contact with it. Earthworms live
in soil and freshwater while some types are found in the ocean. Earthworms act as
_________________________________, maintain the fertility of soil, release nutrients
into the soil, loosen and _________________________________________. Some
segmented worms such as the Tubifex (sludgeworm) seen in the third picture can
survive in polluted sediments and areas with little oxygen.
Earthworm Digestion
The digestive system of the earthworm and other annelids is quite advanced. In the
earthworm, _______________________________________________ as they burrow
____________________________________________. From the pharynx food moves
through the ____________________________________________________________.
It ____________________________________________________________________
______________________________________________________________________
______________. The intestines have a typhlosole, which is a fold that increases
surface area for absorption. _______________________________________ (castings
that are good for the garden) _______________________________________.
Here's an image showing Oligochaeta digestive system.
Earthworm Circulation
Page 28 of 42
BCLN BIOLOGY 11 – Rev July 2014
The circulatory system of an Earthworm consists of a ___________________________
__________________________________________________________________ that
connect the two vessels together behind the head region. The branches ____________
______________________________________________________________________
______________________________________________________________________
__________________________________________. Due to the pulsating action of the
branches, which is similar to the action of hearts, they are termed ¨hearts¨ or
pseudohearts.
The purpose of this ___________________________________________________ is to
transport oxygen, carbon dioxide, nutrients and wastes throughout the body of the earthworm.
Earthworms have _____________________________________________________________
________________________________ and into small blood vessels when the skin is moist.
Earthworm Excretion
As stated in the general characteristics,
_________________________________
_________________________________
_____________________. In earthworms,
_________________________________
_________________________________
_________________________________.
The cellular wastes and excess water are
eliminated through these nephridia. Each
segment of the earthworm except the first
three and last one have nephridia.
Earthworm Nervous System
Page 29 of 42
BCLN BIOLOGY 11 – Rev July 2014
The nervous system of an Earthworm is
_________________________________
_________________________________
______________. Most body segments
have a single ganglion. These worms also
have an __________________________
______________________________ and
can respond to light, touch, chemicals,
moisture, temperature, and vibrations.
Movement in these worms is made
possible by segmentation. ____________
_________________________________
_________________________________.
To move, ________________________
_________________________________
______________________________ and
contracts circular muscles in front of these segments. Hydrostatic fluid in the coelom
increases pressure and elongates the worm. Then longitudinal muscles pull posterior
segments forward as they contract and shorten.
Page 30 of 42
BCLN BIOLOGY 11 – Rev July 2014
Earthworm Reproduction
Earthworms are ________________________
______________________________________
______________________________________
______________________________________
______________________. The clitellum is the
relatively large band around the earth worm.
________________________________
__________________________ (an individual
worm cannot fertilize its own eggs) by aligning
head regions with clitellums. Two earthworms press their ventral surfaces together with
the anterior ends pointing in opposite directions. _______________________________
___________________________________________________ as it transfers. Each
earthworm injects sperm into the mucus which moves into a pouch-like seminal
receptacle of each worm. After several days each worm secretes a tube of mucus and
chitin (thick carbohydrate) which picks up the worms eggs and stored sperm. The sperm
and egg are then expelled through a slime tube and fertilization takes place. The tube
closes up to form a protective case for 2-3 weeks until the young worms hatch.
PLEASE LABEL THE EARTHWORM
DIAGRAMS BELOW BEFORE PROCEEDING ANY FURTHER!
Page 31 of 42
BCLN BIOLOGY 11 – Rev July 2014
Page 32 of 42
BCLN BIOLOGY 11 – Rev July 2014
Leeches
Class
__________________________________________
_____________________________ with approximately 300
species. Although ____________________________________
________________________________, many leeches are
annelids which are ____________________________________
______________________. They ________________________
___________________________________________________
___________________________________________________.
They also ___________________________________________
___________________________________________________
_______________. If undisturbed, a leech can ingest 10 times
its own weight in blood. A leech will drop off once finished eating
and will not need to eat again for up to a year.
Leeches are used in medicine ________________________________________ in amputated
digits (fingers or toes) that have been surgically reattached.
Body Plan Comparison in Worms
This lesson compares the body plan of the three classes of worms discussed in this
unit. The diagrams below are keyed as follows:
 Ectoderm = blue
 Mesoderm = red
 Endoderm = yellow
_____________________
_____________________
_____________________
_____________________
Body filled with mesoderm.
Body cavity partially lined Body cavity entirely lined
with mesoderm.
with mesoderm.
Page 33 of 42
_____________________
_____________________
BCLN BIOLOGY 11 – Rev July 2014
Page 34 of 42
BCLN BIOLOGY 11 – Rev July 2014
10.3 PRACTICE: SEGMENTED WORMS
1. The phylum name Annelida means _________________________________
______________________________ and reflects the fact that Annelids are
____________________________. (2 marks)
2. Compare and contrast the following between Phylum Nematoda and Phylum
Annelida:
a. Symmetry (1 mark)
b. Germ Layers (1 mark)
c. Body Plan (3 marks)
3. Class _____________________ of Phylum _______________________
include marine worms that have many bristle-like setae on their segments.
These setae can be used for _______________________ and to increase
surface area to assist in __________________________. (4 marks)
4. Class ________________________ of Phylum _________________________
include earthworms. (2 marks)
Page 35 of 42
BCLN BIOLOGY 11 – Rev July 2014
5. Earthworms have a brain and sense organs at their anterior end and thus, are
considered to be ________________________________. (1 mark)
6. Earthworms have a ___________________ digestive system, running from
mouth to anus, which includes a ______________________ for storing food, a
_________________ for grinding food, and a __________________________
(special fold) in the intestine to increase surface area such that nutrient
absorption is maximized. (4 marks)
7. Earthworms have a dorsal and ventral blood vessel and five
______________________________ that circulate blood throughout the worm.
(1 mark)
8. In earthworms, waste is filtered from the blood via ______________________,
the waste is then excreted out via the ________________________________.
(2 marks)
9. Earthworms are _______________________________ as each individual has
both male and female reproductive organs.
During reproduction the
_________________________ secretes a mucus layer that enables sperm to
move from one worm to the other. (2 marks)
10. Class ________________________ of Phylum _________________________
include leeches which are parasitic. (2 marks)
11. Identify two evolutionary advances that enable a leech to feed of its host and
explain how these advances may have provided the leeches with a selective
advantage. (4 marks)
~ END OF BIOLOGY 11 UNIT 10 LEARNING GUIDE ~
Page 36 of 42
BCLN BIOLOGY 11 – Rev July 2014
UNTI 10 ANSWER KEY
10.1 PRACTICE: FLATWORMS
1. Members
of
the
Phylum
Platyhelminthes
______________________________. (1 mark)
are
"more
affectionately"
termed
2. How is the body plan of the Planarians of Phylum Platyhelminthes comparable to that of the
Phylum Cnidaria? (2 marks)
- both Cnidarian and Platyhelminthes have a comparable body plan in that they
have a single opening that functions as both the mouth for ingestion of food and
anus for excretion of waste
3. How does the symmetry of the Planarians of Phylum Platyhelminthes compare to that of the
Phylums Cnidaria and Porifera? Draw a diagram showing the differences. (3 marks)
-
Porifera
are
asymmetrical,
Cnidarians
are
radially
symmetrical
and
Platyhelminthes are bilaterally symmetrical
Porifera
(sponges)
Asymmetrical
Cnidaria
(jelly fish and sea anemones)
radially symmetrical
Platyhelminthes
(flatworms)
bilaterally symmetrical
4. Germ layers give rise to all the other tissues that will develop over an organisms' life time.
a. How do the germ layer of Phylum Platyhelminthes compare to that of the Phylums
Cnidaria and Porifera? (1 mark)
Porifera and Cnidaria are recognized to have two germ layers, the endoderm and
the ectoderm whereas Platyhelminthes have all three germ layers, the
ectoderm, the endoderm and the mesoderm.
Page 37 of 42
BCLN BIOLOGY 11 – Rev July 2014
b. In what ways do the germ layers of Phylum Platyhelminthes allow for greater
specialization? (4 marks)
Existence of all three germ layers allows for the creation of a variety of
specialized tissues including those that give rise to the digestive system,
excretory system, reproductive system, nervous system and musculature
system.
5. Planaria
belong
to
the
Class
_________________________
______________________________ and are free-living. (2 marks)
of
the
Phylum
6. Free-living species do
not require
a ______________ to survive
whereas
__________________________ species require a host to survive. Free-living species tend to
have more ___________________ systems as they must provide for themselves. (3 marks)
7. A planaria obtains food via its mouth, which is attached to an extendable tube called the
_______________________.
The
food
is
then
digested
in
the
________________________________________. The resulting nutrients are then absorbed
and ___________________ throughout the thin tissues of the body. (3 marks)
8. Planaria are ______________________________ meaning they are both male and female,
capable of producing both sperm and eggs. (1 mark)
9. Planaria excrete waste via their ____________________ which have cilia that beat to move fluid
along the excretory canals and out the ___________________ __________________. (3 marks)
10. Lateral is a term frequently used in biology. Please define. (1 mark)
Lateral = to or from the side
11. Planaria are truly cephalized whereas tapeworms only "appear to" be cephalized. Define
cephalization and explain why the term is does not truly apply to tapeworms. (2 marks)
- cephalization = to have a sensory structures concentrated at the anterior end (=
head)
-
the hooks and scolex of a tapeworm appear "head-like" but the lack the sensory
organs necessary to truly define an anterior regions as a head.
12. If a scientist were to study a free-living worm and a parasitic worm out of context (not knowing
their life cycles) and were to only compare their body systems, which type of worm, is the
scientist most likely to conclude, evolved first? Why would the scientist conclude this? Is the
scientist likely to be correct? Why or why not? (4 marks)
Parasitic worms tend to be less complex that free-living worms and less complex
organisms are typically thought to have evolved first. Thus, scientists may conclude
that the parasitic worm evolved before the free-living worm. However, this is likely
an incorrect conclusion as upon closer inspection it appears that the free-living
worms may have evolved first, then found a host and then, through random mutation,
Page 38 of 42
BCLN BIOLOGY 11 – Rev July 2014
lost some its more complex structures but was able to survive and even thrive in
natural selection as the host provided for it despite its lack of structures and its
overall efficiency increased as it was not putting energy towards maintaining
unnecessary/redundant organ systems.
13. Tapeworms are somewhat unusual hermaphrodites in that a single individual's sperm can
actually fertilize _________________________ eggs. (1 mark)
14. Compare and contrast the terms primary host and secondary host. (3 marks)
-
In general, host refers to an organism that a parasite infects and that is
necessary for a parasite's survival and continued life cycle
-
a primary host (also known as a definitive host) is the host in which the sexually
mature parasite exists
-
a secondary host (also known as an intermediate host) is a host in which an
immature form of the parasite exists
10.2 PRACTICE: ROUNDWORMS
1. Roundworms belong to the Phylum ______________________________ which is also known as
the ________________________________, (2 marks)
2. Phylum Nemotoda include many diverse species including those which are
____________________________ in that they require a host and those which are
____________________________________. (2 marks)
3. Compare and contrast the body of Phylum Nematoda to that of Phylum Cnidaria. (3 marks)
4. The digestive systems of free-living members of Phylum Nematoda are seen to be "evolutionarily
advanced" compared to those of members of the Phylum Cnidaria:
a. What is the "advancement" and what is this type of digestive system referred to as? (2
marks)
The body plan of Phylum Cnidaria has a digestive system that has only a single
opening that serves as both a mouth and an anus whereas the body plan of
Nemotoda has a digestive system that includes two openings (mouth and anus),
unidirectional food flow (from mouth to anus) and further specialization for
digestion, absorption and excretion as food moves along the digestive system.
Page 39 of 42
BCLN BIOLOGY 11 – Rev July 2014
b. How might this "evolutionary advance" provide a selective advantage to Phylum
Nematoda? (2 marks)
- allows for more efficient digestion as food and waste do not mix, rather
food is broken down into nutrients, absorbed and wastes are concentrated
as the food progresses throughout the system where the early region of the
system specializes in food breakdown, the mid-part of the system
specializes in absorption and the final portion of the system specializes in
excretion
5. Fluid in the pseudocoelom of Nematoda allow digested food and oxygen to
_________________________
throughout
the
body
and
also
acts
as
a
____________________________________________ helping to provide the organism with
support and movement. (2 marks)
6. Most species of Phylum Nematoda have separate sexes, male and female, and thus, they are
termed ________________________________. (1 mark)
7. Identify at least three "primitive" and three "advanced" characteristics of Phylum Nematoda. (6
marks)
-
primitive characteristics = not segmented, no circulatory system (diffusion via
pseudocoelomic fluid), no skeletal system, lack a true brain
-
advanced characteristics = bilateral symmetry, has all three gemr layers
(endoderm, mesoderm, ectoderm), has a complete digestive tract (mouth to
anus)
8. Choose one parasitic member of Phylum Nematoda that uses humans as part of its life cycle and:
a. Briefly describe its life cycle. (3 marks)
-
Answers may vary but may include:
o
Ascaris:

Egg ingested in food or water by human (primary and only host)

Larvae enter blood vessels and travel to long

Larvae coughed up from lung and then swallowed

Adult Ascaris grows in intestine

Adult Ascaris produces eggs which are shed into feces that
contaminate water and food supply, thus perpetuating the
Ascaris life cycle
o
Guinea Worm

Larvae infects water flea (intermediate host)

Human (primary host) drinks contaminated water
Page 40 of 42
BCLN BIOLOGY 11 – Rev July 2014

Larvae matures into adult worm in human and about a year later
moves through the lower body until it exits via a painful blister

Painful blisters drive human host into water for relief but upon
exposure to water the exiting worm releases larvae into water

Water fleas ingest the larvae thus perpetuating the Guinea worm
life cycle
b. Identify the symptoms and/or impacts it has on its human host. (2 marks)
o
o
Ascaris:

Worms in stool

Stomach pain and vomiting up worms

Worms exiting mouth, nose, anus

Fever

Cough, wheezing, shortness of breath and bloody sputum

Skin rash

Possible to lack any symtoms
Guinea Worm

painful blisters with exiting worm
10.3 PRACTICE: SEGMENTED WORMS
1. The
phylum
name
Annelida
means
_________________________________
______________________________
and
reflects
the
fact
that
Annelids
are
____________________________. (2 marks)
2. Compare and contrast the following between Phylum Nematoda and Phylum Annelida:
a. Symmetry (1 mark)
- both have bilateral symmetry
b. Germ Layers (1 mark)
- both have all three germ layers
c. Body Plan (3 marks)
- both Nematoda and Annelida have a coelomic body cavity however,
-
Nematoda = psuedocoelomates containing a coelomic cavity that is
surrounded by endoderm on one side and mesoderm whereas
-
Annelida – coelomates containing a coelomic cavity entirely surrounded by
mesoderm
Page 41 of 42
BCLN BIOLOGY 11 – Rev July 2014
3. Class _____________________ of Phylum _______________________ include marine worms
that have many bristle-like setae on their segments. These setae can be used for
_______________________
and
to
increase
surface
area
to
assist
in
__________________________. (4 marks)
4. Class ________________________
earthworms. (2 marks)
of
Phylum
_________________________
include
5. Earthworms have a brain and sense organs at their anterior end and thus, are considered to be
________________________________. (1 mark)
6. Earthworms have a ___________________ digestive system, running from mouth to anus,
which includes a ______________________ for storing food, a _________________ for
grinding food, and a __________________________ (special fold) in the intestine to increase
surface area such that nutrient absorption is maximized. (4 marks)
7. Earthworms
have
a
dorsal
and
ventral
blood
vessel
and
______________________________ that circulate blood throughout the worm. (1 mark)
five
8. In earthworms, waste is filtered from the blood via ______________________, the waste is
then excreted out via the ________________________________. (2 marks)
9. Earthworms are _______________________________ as each individual has both male and
female reproductive organs. During reproduction the _________________________ secretes
a mucus layer that enables sperm to move from one worm to the other. (2 m arks)
10. Class ________________________ of Phylum _________________________ include leeches
which are parasitic. (2 marks)
11. Identify two evolutionary advances that enable a leech to feed of its host and explain how these
advances may have provided the leeches with a selective advantage. (4 marks)
- produces an anesthetic that numbs its host so that the host is unaware that
the leech is feeding upon it and thus, it does not disturb the leech
-
produces an anticoagulant that prevents the host's blood from clotting such
that the leech can feed faster and more extensively
Page 42 of 42