BCLN BIOLOGY 11 – Rev July 2014
Unit 11 ~ 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.
11.1 NOTES: MOLLUSKS
General Characteristics of Mollusks
__________________________ are a very diverse group of
animals
that
___________________________________
____________________________________. They contain
members that are _________________________________
_______________________________________. However, all
have ___________________________________. These body
parts
are
the
________________________________
_________________________________________________
___________________________________________________________________.
The _________________________________________________________________
___________________ for those mollusks that have one
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BCLN BIOLOGY 11 – Rev July 2014
Phylum Mollusca is made up of over 112,000 species of soft-bodied animals. These
animals generally exhibit ____________________________________________
_________________________________ as well as the three main body parts
(visceral mass, foot and mantle) introduced above. Mollusks _____________________
_____________________________________________________________________
_______________________________. Many mollusks have ____________________
_______________________________. Nitrogenous waste is excreted through
______________________. Mollusks have an _____________________________
______________________ with a dorsal heart and vessels. The hemocoel aids fluid
return to the heart. A ___________________________________________________
____________________________________ (a flexible tongue like strip of tissue
covered with tough abrasive teeth that point backward). The radula is used to graze,
drill, or function as a poisonous dart. The nervous system has a __________________
_____________________________________________________________________
_______________________________________________ with the development of
the _____________________________________ (nearly indistinguishable from
annelids). The trochophore larvae becomes the veliger larvae for swimming.
Mollusks are true ___________________________ with a reduced main body cavity
called the hemocoel. They are also Protostomes so the mouth develops first in the
embryo.
There are four main classes of Mollusks that we will study in this unit. They are:
1. Amphineura (polyplacophora)
2. Bivalvia
3. Gastropoda
4. Cephalopoda.
The Chitons
The Chitons belong to Class _____________________
____________________.
Chitons are _____________
____________________ with a shell that is made up of
____________________________________________.They
have a muscular foot for locomotion (crawling). Chitons have a
reduced head. There are about 650 species of these organisms.
They can be found clinging to rocks in the intertidal zone and use
a tooth-like radula to scrape food off of rocks. Chitons are
herbivores. Breathing is facilitated by _________________.
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BCLN BIOLOGY 11 – Rev July 2014
Gastropods
Class __________________________________________
has adapted their foot so it is located on their ventral
surface or belly. This is the largest molluscan class and
includes ________________________________________
______________. They are characterized by a _________
______________ with the characteristic cone shape or no
shell. Gastropods _________________________________
_______________________________________________
_____________________________. The muscular foot
extends along the ventral surface of the organism.
Gastropods undergo a process called _________________
during larval development. In torsion the visceral mass
twists 180 degrees in relation to the head. This results in
the mantle cavity, gills and anus being brought to the front
of the animal. This allows the gastropod to retract its head
into its mantle cavity when threatened.
The head of gastropods contains ____________________
______________________________________. A scraping
____________________ is used to pick up food. Slugs do
not have a shell. They _____________________________
____________________________________. They usually
become active during the cool moist part of the day.
Gastropods are the only molluscan class to become
terrestrial.
Gastropods have an ______________________________________________
with a circulatory fluid called hemolymph.
Nudibranchs (Sea Slugs) are marine gastropods that lack shells.
Nudibranch means “naked gill” and refers to the fact that gas exchange
happens across the entire surface of these animals. The images below show
how these animals maximize their surface area and their vivid colours.
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Bivalves
The name ___________________________________________
___________________________________________________
__________________________________________________.
The mantle of a bivalve is responsible for excreting the shell to
surround and protect the body. Strong muscles hold the shell
closed in all members to the class. The muscular foot varies
from bivalve to bivalve. It is most prominent in the clam which
uses its large muscular foot to dig through the sand. Scallops
can move by jet propulsion and swim through the water
escaping predators such as sea stars. An oyster's shell will grow
directly on a rock to provide a permanent home.
_______________________________ but some scallops swim.
Bivalves are __________________
_______________ animals and live
in the intertidal zone. They exhibit a
large visceral hump and a muscular
foot with a reduced head covered
with a thin mantle. _____________
____________________________
____________________________
____________________________
___________________________. .
Bivalves are __________________
______________ and take water
containing food into the mantle
cavity via the incurrent siphon and
pass it over the mouth. Excess
water is forced out through the
excurrent siphon. The ____________________________________________________
___________________________. They have no radula. The general anatomy of a
clam is shown above as an example of a bivalve.
Respiration is performed by the ___________________________________________
_____________________________. This food then passes the ___________________
__________________________________, where it follows an __________________
________________________________. Food is digested in the stomach and then
passes to the __________________________ for absorption. The intestine is a long
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BCLN BIOLOGY 11 – Rev July 2014
coiled
organ
ending
in
an
_______________ where the waste
is expelled. Also found in the visceral
mass is the heart. The ___________
_____________________________
_____________________________
_____________________________
to supply it with oxygen and remove
nutrients and wastes. The diagram
below shows the circulatory system
of a clam. Recall, _______________
_____________________________
____________________________________
with
a
dorsal
heart
and
vessels.
Geoducks burrow in the sand or amongst rocks or attach to substrate by secreting
byssal threads. They many leap with a foot. They have separate sexes and external
fertilization.
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PLEASE LABEL THE CLAM ANATOMY
IN THE DIAGRAM BELOW BEFORE PROCEEDING ANY FURTHER!
Clam Part 1
Clam Part 2
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Clam Part 3
Clam Part 4
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Cephalopods
The name _______________________________________
_______________________________________________
are given this term because the ______________________
_______________________________________________
_______________________________________________
_________________________. All members of this class are
___________________. Of the invertebrates, it can be
argued that the ___________________________________
_______________________________________________.
This is because of their ____________________________
_______________________________________.
Their
ability to learn and muscular control are so advanced that
they can be trained to open jars to obtain food. They have
quite an __________________________________ that is
distinctly different from that of a human.
The cephalopods are also fast swimmers and
_________________________________
___________________. To generate this propulsion they
take water in slowly and expel it so quickly that they are
propelled forward. Other features of cephalopods include a
__________________________________________ and a
____________________ which is a toothed tongue. Many
of the animals that an octopus typically feeds on have
either a shell or an exoskeleton so the chitinous beak is
necessary for feeding. For predator diversion the
cephalopods possess an ________________________________________________
________________________________.
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BCLN BIOLOGY 11 – Rev July 2014
11.1 PRACTICE: MOLLUSKS
1. What three body parts are shared by all members of Phylum Mollusca and what
are their functions? (3 marks)
2. How does Phylum Mollusca compare to Phylum Annelida with respect to:
a. Body Symmetry (1 mark)
b. Segmentation (2 marks)
c. Body Plan (acoelomate, pseudocoelomate or coelomate)? (1 mark)
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BCLN BIOLOGY 11 – Rev July 2014
3. What is the significant difference between the circulatory systems of Phylum
Annelida and that of Phylum Mollusca? How might the Phylum Mollusca's
circulatory system serve as a selective advantage? (3 marks)
4. Chitons, of the Class ____________________________ (Polyplacophora) and
Phylum _______________________ have a unique shell made up of eight
articulating plates that help to protect them while enabling them to remain mobile.
(2 marks)
5. Class ________________________ of Phylum _______________________
includes snails, slugs and sea slugs and are the only molluscan class to include
terrestrial members. (2 marks)
6. What does torsion refer to and how does it provide gastropods with a selective
advantage? (2 marks)
7. Nudibranchs means "__________________________________" and refers to
sea slugs that lack a shell. These organisms are among some of the most
beautiful in the world coming in unique shapes that maximize their surface area
for gas _______________________________. (2 marks)
8. Class __________________________ of Phylum ________________________
includes clams, oysters, muscles and scallops. (2 marks)
9. Class ________________________ of Phylum _________________________
include octopi, squid, cuttlefish and nautiluses. This class is arguably the "most
advanced" of all invertebrate classes based on their ______________________
______________________________________________ that allows them to
learn and perform complex muscular tasks. (3 marks)
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BCLN BIOLOGY 11 – Rev July 2014
10. Cephalopods are wonderfully well adapted to survive in their environment:
a. Identify three "advances" that provide cephalopods with a selective
advantage and explain how the advances help them to survive their
environment. (6 marks)
b. Using our current understanding of Darwin's theory of evolution, explain in
general how these adaptations or advances came to be in present day
cephalopods. (3 marks)
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BCLN BIOLOGY 11 – Rev July 2014
11.2 NOTES: ECHINODERMS
General Characteristics of Echinoderms
__________________________________
__________________________________
__________________________________
________________________. This means
that the first embryonic opening becomes
the anus and the second becomes the
mouth. Because of this trait, it is thought
that echinoderms are more advanced than
some of the other animals. However,
__________________________________
__________________________________.
For example, their ___________________
____________________ would usually be
considered more primitive than bilateral
symmetry, so it is difficult to see their
relation
to
the
vertebrates.
Also,
echinoderms have ___________________
__________________________ and have
a ______________________________ for
controlling motor and sensory functions. However, when in larval form, an echinoderm
is a free swimming bilaterally symmetrical organism. It is this larval form that scientists
believe evolved into some of the prochordates that are mentioned later in this course.
Echinoderms are fairly diverse in appearance within the phylum. Typified by the
______________________________________________________________________
they vary in outer appearance but have similar internal structures. They are
___________________________________________ and can be found from the
intertidal zone to deep ocean waters. The digestive system is relatively short, and
digestive glands are located within the arms of the starfish, or on the outer body wall of
the other members. Digestion, however, is a bit different from other animals, in that,
much of it takes place outside the body of the starfish. The echinoderm will put its
stomach outside of its body and begin to digest its prey before it takes it in to finish the
process. They can be ___________________________________________________.
Sex organs are also located in the arms of the starfish, and echinoderms are capable of
both
__________________________________________________.
External
reproduction ___________________________________________________________
___________________________. The regeneration properties of starfish allow them to
regrow lost limbs as well as the limb to regrow a body. __________________________
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BCLN BIOLOGY 11 – Rev July 2014
_________________________________________________, are found throughout the
body wall providing the echinoderm with oxygen.
The method of locomotion in the starfish is truly unique. The _____________________
________________________________________ is a network of tubes ending in
______________________________. An organ called an ____________________ will
pump water into the tubes increasing the pressure in the tube foot causing it to expand
and create suction on a nearby surface. As the pressure on the tube foot decreases, the
tube contracts without decreasing the suction, and the starfish is pulled in that direction.
Class Asteroidea
Sea Stars have ___________________________________
with several arms (5 or multiple of 5) radiating from a central
body. The _______________________________________
__________________________. The anus is at the center
of
the
disc
together
with
the
water
intake
______________________________. The upper surface is
often very colorful with _____________________________
________________________________________________
_______________________________________________.
Sea stars have a __________________________________
_________________________ to allow movement. Sea
stars have _______________________________________
________________________________.
They have a
___________________________________. Reproduction
is ____________________ with most species having
separate sexes. Free swimming larva called bipinnaria are
produced. Sea stars are ____________________ and feed
on and externally digested their food. The picture below
shows a sea star feeding on a bivalve. Notice all the tube
feet at work. They also have two stomachs. Food moves
first into the ______________________________________
_______________________________.
Sea stars also exhibit the ability to ____________________
______________________________ ...flip themselves over
even with an arm missing.
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PLEASE LABEL THE SEASTAR (STARFISH)
DIAGRAMS BELOW BEFORE PROCEEDING ANY FURTHER!
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Class Crinoidea (feather stars)
Feather stars have _________________________________. The
body of a typical feather star is cup-shaped with ________________
_____________________________________________________.
Some have five arms while others may have as many as 200. The
arms, called pinnules, are coated with a sticky substance that helps
them catch food. Cirri attached to the underside of the body. The
mouth and their anus are situated on the upper side of the feather
star. Online is a video of a feather star swimming.
Class Ophiuroidea (brittle stars)
_______________________________________________________.
They have __________________________________ with a central
disc and five highly flexible arms that protrude. Unlike sea stars, there
is no replication of internal organs in each arm just one set in the
central disk.
Brittle stars have a much smaller central disc and no anus. Wastes
are eliminated through the mouth which is situated on the underside
in the center.
On the underside of the body disk there is an opening at the base
each arm on both sides. These ten openings are breathing and reproductive
outlets. They take in water to gain oxygen and shed eggs or sperm into the
sea.
Class Echinoidea (sea urchins)
Sea urchins have a _________________________________
body and an external _______________________________.
The mouth consists of a complex arrangement of muscles
and plates surrounding the circular opening. Sea urchins have
a centrally located jaw (called Aristotle's lantern) with
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horny teeth. The anus is located on the upper surface. Some
sea urchins have a spherical, bulb-like cloaca to store fecal
material. The cloaca protrudes from the anal opening and can
be withdrawn into the shell.
Sea urchins have movable spines of various sizes and forms
that are attached to the body. _________________________
________________________________________________
______________. They also have _____________________
________________________________________________
______________. Some of these pedicellaria are poisonous.
Class Holothuroidea (sea cucumbers)
__________________________________________________
________________ unlike most other Echinoderms that
display radial symmetry. Sea cucumbers have a distinct dorsal
and ventral side or back and bottom.
They are cucumber shaped with an elongated, muscular, and
flexible body. The mouth is at one end and the anus is at the
other. Around the mouth there are ______________________
_______________________________________ used in food
collecting. These tentacles are modified tube feet.
Online is a video of a sea cucumber feeding.
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11.2 PRACTICE: ECHINODERMS
1. Echinoderms can be difficult to place on an evolutionary ladder:
a. What traits suggests that echinoderms are more "evolutionarily
advanced" than the animal phyla studied thus far in Biology 11?
(2 marks)
b. What traits complicate the classification of echinoderms because
they appear more "primitive" and reminiscent of "less advanced"
animal phyla? (3 marks)
c. Which animal phyla have been studied thus far in Biology 11
including the echinoderms? (6 marks, 7 phyla)
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2. Class ______________________ of Phylum _____________________
include Sea Stars (we no longer use the term Starfish as it is misleading
as there isn't anything "fishy" about these creatures). Sea stars have
mini pincers on their surface called ___________________________
that help keep the organism algae-free. (3 marks)
3. Briefly explain how sea stars move. (3 marks)
4. Sea Stars tend to compete with the shellfish industry as they often feed
on shellfish. Fishermen used to cut up any sea stars they found while
harvesting and then throw them back in the water thinking they were
eliminating their competition. Were they? Why or why not? (2 marks)
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5. Class _______________________ of Phylum ____________________
include feather stars which can have up to 200 arms. (2 marks)
6. A sea star has its mouth and anus located on its underside whereas as
feather star has its mouth and anus located on the upside. How might
these locations prove to be a selective advantage to each organism? (2
marks)
7. Class _______________________ of Phylum ____________________
include brittle stars that, unlike sea stars, do not contain replicate
internal organs in each arm. (2 marks)
8. The brittle star has a mouth but lacks a separate anus. What other
animal phyla is this reminiscent of? (2 marks)
~ END OF BIOLOGY 11 UNIT 11 LEARNING GUIDE ~
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BCLN BIOLOGY 11 – Rev July 2014
UNIT 11 ANSWER KEY
11.1 PRACTICE: MOLLUSKS
1. What three body parts are shared by all members of Phylum Mollusca and what are their
functions? (3 marks)
-
visceral mass = contains the organs
-
foot = large muscle
-
mantle = outer covering that secretes shells in mollusks that have such
2. How does Phylum Mollusca compare to Phylum Annelida with respect to:
a. Body Symmetry (1 mark)
- both have bilateral symmetry
b. Segmentation (2 marks)
- Annelida are segmented, Mollusca are not
c. Body Plan (acoelomate, pseudocoelomate or coelomate)? (1 mark)
-
both are coelomate
3. What is the significant difference between the circulatory systems of Phylum Annelida and that of
Phylum Mollusca? How might the Phylum Mollusca's circulatory system serve as a selective
advantage? (3 marks)
- Annelida have a closed circulatory system where blood remains in vessels at all
times barring injury to said vessels
-
Mollusca have an open circulatory system where hemolymph (equivalent of blood)
circulates through heart and vessels but also bathes organs in an open cavity
-
an advantage of an open circulatory system is that it is not sensitive to pressure
changes such as may be experienced by molluscks at various ocean depths and
thus, it allows the mollusk to inhabit a more diverse range of ocean depths
4. Chitons, of the Class ____________________________ (Polyplacophora) and Phylum
_______________________ have a unique shell made up of eight articulating plates that help to
protect them while enabling them to remain mobile. (2 marks)
5. Class ________________________ of Phylum _______________________ includes snails,
slugs and sea slugs and are the only molluscan class to include terrestrial members. (2 marks)
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BCLN BIOLOGY 11 – Rev July 2014
6. What does torsion refer to and how does it provide gastropods with a selective advantage? (2
marks)
- torsion = during gastropod development when the visceral mass twists 180 ° to
align the gills and anus to the front opening of the shell
-
enables the gastropod to breath and excrete waste all through a single opening
in the shell and to also retract head into shell, this decreases the chance of a
predator removing the gastropod from its shell and thus, increases its chance of
survival
7. Nudibranchs means "__________________________________" and refers to sea slugs that lack
a shell. These organisms are among some of the most beautiful in the world coming in unique
shapes that maximize their surface area for gas _______________________________. (2
marks)
8. Class __________________________ of Phylum ________________________ includes clams,
oysters, muscles and scallops. (2 marks)
9. Class ________________________ of Phylum _________________________ include octopi,
squid, cuttlefish and nautiluses. This class is arguably the "most advanced" of all invertebrate
classes
based
on
their
______________________
______________________________________________ that allows them to learn and perform
complex muscular tasks. (3 marks)
10. Cephalopods are wonderfully well adapted to survive in their environment:
a. Identify three "advances" that provide cephalopods with a selective advantage and
explain how the advances help them to survive their environment. (6 marks)
- Move by jet propulsion = efficient, fast, easy to maneuver = better fro
catching prey and escaping predators = survival
-
Ink sac = obsucres predator view allowing for escape = survival
-
Advanced eye = can see prey and predator well to capture food yet escape
being food itself = survival
-
Chromatophore = pigmented cells for camouflage = hide from prey and
predator = helps it capture food while escaping becoming food itself =
survival
b. Using our current understanding of Darwin's theory of evolution, explain in general how
these adaptations or advances came to be in present day cephalopods. (3 marks)
According to our current understanding of Darwin's Theory of evolution
these adaptations came to be through the combined processes of random
variation (arising through mutation and genetic recombination), natural
selection (the environment 'selecting" for organisms with the traits best
suited for survival) and reproduction (necessary to pass on the traits
beneficial for survival.
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BCLN BIOLOGY 11 – Rev July 2014
11.2 PRACTICE: ECHINODERMS
1. Echinoderms can be difficult to place on an evolutionary ladder:
a. What traits suggests that echinoderms are more "evolutionarily advanced" than
the animal phyla studied thus far in Biology 11? (2 marks)
- deuterstome = blastopore becomes anus similar to vertebrates
-
bilateral symmetry in free-swimming larval form
b. What traits complicate the classification of echinoderms because they appear
more "primitive" and reminiscent of "less advanced" animal phyla? (3 marks)
- radial symmetry as opposed to bilateral in adult form
-
lack cephalization
-
limited nervous system (nerve net only)
c. Which animal phyla have been studied thus far in Biology 11 including the
echinoderms? (6 marks, 7 phyla)
- Porifera
- Cnidarian
- Platyhelminthes
- Nematoda (Aschelminthes)
- Annelida
- Mollusca
- Echinoderms
2. Class ______________________ of Phylum _____________________ include Sea
Stars (we no longer use the term Starfish as it is misleading as there isn't anything
"fishy" about these creatures). Sea stars have mini pincers on their surface called
___________________________ that help keep the organism algae-free. (3 marks)
3. Briefly explain how sea stars move. (3 marks)
- use tube feet…move water from vascular system into or out of the tube feet to
create or release suction…allows sea star to attach and detach from rocks and
to move as it stretches out its arms
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4. Sea Stars tend to compete with the shellfish industry as they often feed on shellfish.
Fishermen used to cut up any sea stars they found while harvesting and then throw
them back in the water thinking they were eliminating their competition. Were they?
Why or why not? (2 marks)
- the fisherman were not eliminating their competition but rather
enabling the population to expand as sea stars are capable of
regeneration from severed limbs…not only would the sea star grow
back a new limb but a new sea star would grow from the severed limb
5. Class _______________________ of Phylum ____________________ include feather
stars which can have up to 200 arms. (2 marks)
6. A sea star has its mouth and anus located on its underside whereas as feather star has
its mouth and anus located on the upside. How might these locations prove to be a
selective advantage to each organism? (2 marks)
-
sea stars are motile and can descend down upon prey and thus, it would be
advantageous to have mouth on its underside
-
feather stars catch food within the water current using their feather like
appendages that rise upwards into the water and thus, it would be advantages to
have a mouth facing upward to capture the food that falls down from the
feather like appendages
7. Class _______________________ of Phylum ____________________ include brittle
stars that, unlike sea stars, do not contain replicate internal organs in each arm. (2
marks)
8. The brittle star has a mouth but lacks a separate anus. What other animal phyla is this
reminiscent of? (2 marks)
- Cnidaria
-
Platyhelminthes
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