unit 11 ~ learning guide name: - bc learning...

BCLN BIOLOGY 11 – Rev July 2014

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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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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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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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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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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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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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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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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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_________________________________________________, 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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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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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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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

unit 11 ~ learning guide name: - bc learning...

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