How do most sessile and burrowing mollusks obtain food

Biology Paper Help Needed

Marine Life: Life on the Benthos III

Evolutionary cladogram of the major marine taxa. The organisms are more complex and/or derived as you move from sponges to chordates.

Phylum Mollusca - the shelled (mostly) invertebrates There are about 200,000 spp. and only the Phylum Arthropoda (later) has more representatives. This is very abundant and diverse group which includes the following: the primitive chiton, Class Polyplacophora; snails, Class Gastropoda; slugs and nudibranchs, also Gastropoda; clams, Class Bivalvia; and, squid, octopi, and nautili, Class Cephalopoda These organisms all exhibit BILATERAL SYMMETRY (the Cnidarians have RADIAL Symmetry in comparison). They have a complete gut, with a true coelom. Most representatives have a brain and a complex nervous system. If a shell is present it is secreted by the specialized tissues of the mantle. Reproduction in this group is sexual, and a few are hermaphroditic (both male and female). Many have a planktonic larval stage that looks very different than the adult (and usually) benthic stage. Most representatives have a radula for feeding, either by scraping algae off rocks or feeding on other animals. There are a number of important subgroups, which will be covered below.

Examples of typical Mollusks: a) chiton, Class Polyplacophora; b) clam, Class Bivalvia; c) snail, Class Gastropoda; d) tusk shell, Class Scaphopoda; and, e) octopus, Class Cephalopoda.

The mollusks in the Class Monoplacophora were thought to be extinct, but were rediscovered in the 1952 during a deep sea sampling trip off the coast of Costa Rica. - Neopolina sp. Looks similar to limpets, but that is where the similarities end. Neopolina is the only genus that remains from a once prominent group. This organisms is neither a chiton or one of the limpets, but one of the ancestral types to these forms. Neopolina is considered a LIVING FOSSIL. Living Fossils are organisms that have remained largely unchanged from the ancestral or fossil types. There are about 5 species in this genus that have been described. All Neopolina have been collected in all major ocean basins from 2000 to 6000 meters (6,000 to over 18,000 feet). Neopolina doesn’t appear to exhibit torsion (twisting of the visceral mass), one of the key characteristics for gastropods. These organisms are considered rare, but this may have more to do with where they live. This is the primary reason why these

organisms are also rare in marine biology labs.

Neopolina spp., a specimen collected from Costa Rican waters in the 1970's (left) and an artist illustration (right). Used with permission.

Class Polyplacophora - these are the chitons Polyplacophora means “many plates”. This is one of the key characteristics for this group. Like the monoplacophorans, the chitons are a primitive group. They do not exhibit torsion, but they do have a muscular foot like the snails. Unlike the snails, they do not have a well defined head region. Chitons are found primarily in the intertidal and subtidal zones, and feed on algae by scraping the plants off the rocks with their radula. Chitons rely on crypsis (blending coloration) and clamping tightly to rocks for protection. Chitons can be difficult to find because they blend well with the environment.

A typical chiton, Tonicella lineata from the rocky intertidal.

A tidepool sculpin, Oligocottus maculosus, will feed on chitons in the intertidal zone.

Even though it may seem that chitons are relatively safe from predation, there are some organisms will regularly prey on chitons. The tidepool sculpin has modified jaws to remove chitons from rocks. Seastars (from this day forward, they are SEASTARS and NOT starfish!) also will prey on chitons.

Intertidal seastars like these ochre sea stars, Pisaster ochraceus, feeds on bivalves, snails, chitons, and barnacles, to list a few. Image used with permission.

Reproduction is sexual in this group and the larvae are planktonic. The largest chiton, the giant Pacific chiton (or gumboot chiton), Cryptochiton stelleri, may grow to 13 inches and about 2.5 pounds. Elephant seals will consume these on occasion.

An impressive gumboot chiton from the Washington intertidal zone. It is the only chiton that does not clamp tightly to rocks.

Class Bivalvia (meaning two halves)- the clams One of the key characteristics of this group is two symmetrical shells, connected at a hinge (usually). Many of these are important filter or SUSPENSION feeders. Some mussels can pump over 20 L of seawater across their gills a day. So in addition to filtering the water food plankton and dissolved gases, they help to remove contaminants from the environment. It is one of the reasons that mussels ans some clams are unsafe to consume certain times of the year. They will concentrate toxins and contaminants in their tissues by a process called bio-accumulation. This occurs when a critter like a mussel ingests a toxin or pollutant without negative affects. The problem occurs when another animal consumes the concentrated material in the mussel (more about this later).

Part of a mussel (Mytilus californianus) bed from the Palos Verdes region of southern California.

The gills are used for gas exchange and for feeding. There is great diversity in this group, with more than 15,000 species described thus far. Many clams have a muscular food for burrowing soft sediments. Others live permanently attached to the substrate, like mussels, oysters, and rock scallops.

Bivalves vary in size, shape and habitat. The largest clam is the giant clam (Tridacna spp., left) may reach weights to 450 pounds and a width of 4 ft. This one is releasing sperm into the water column. Oysters

(Crassostrea spp.) are highly prized as food by many and are now cultured in oyster farms (above right). Scallops are also commercially valuable, with many species highly sought after. Some scallops (Argopecten spp.) are mobile and can swim by snapping their shells together (bottom right) while others are sessile and

live permanently attached to the bottom.

Bivalves feed on planktonic organisms and may concentrate toxins from organisms like dinoflagellates.

Typical gastropod snail with shell. Some gastropods lack shells, like slugs and nudibranchs.

Class Gastropoda - snails, slugs and nudibranchs (the last two lack shells). These familiar organism are found in terrestrial and aquatic environments. The name gastropod means ‘stomach-foot’. Because they exhibit a muscular head-food arrangement. Most shell bearing gastropods demonstrate TORSION, which is the twisting of the visceral mass and is unique to the gastropods. Some snails are herbivorous and will scrape algae off rocks with their radula (see illustration above). While others are carnivorous and may use a structure similar to the ribbon worm to capture prey, and they may produce a strong toxin.

Conus californicus, the most venomous gastropod off the California coast. Live speciemens should not be handled! Image courtesy www.pt-lobos.com.

Some gastropods are carnivorous and may use a structure similar to the ribbon worm to capture prey, and they may produce a strong toxin, an example would be the cone shell (Conus californicus is our local example). They are amazingly fast and can capture and subdue small fish and crustaceans with its venom. While the venom isn’t lethal to humans (unless you happen to be allegic to bee stings), but the injury is painful.

Many gastropods and bivalves are HERMAPHRODITIC. Hermaphrodites may produce both sperm and eggs during their life time (these would be serial hermaphrodites). Some do this at the same time, functioning as male and female (synchronous hermaphrodites). Some gastropods from aggregations and will segregate according to gender with males at one level in the pile and females at another.

http://www.pt-lobos.com.
A stack of reproductive slipper shells (Credula spp.), with the larger females on the bottom and the males on top. Occasionally immature juvenile are at the very top, but do not contribute gametes until they mature

(and you thought I was making this stuff up).

Many gastropods and nudibranchs (marine slugs) lay benthic eggs, but produce planktonic larvae. This is important for dispersal. Gastropods produce larval called VELIGER LARVAE. These larval snails and slugs have wing like structures to move through the water. The trochopohore larval stage is similar among annelids, mollusks, and arthropods, which strongly suggests a common ancestor. Gastropods may spend weeks as part of the planktonic community (they are meroplanktonic). Gastropods are mostly benthic, but there are a few pelagic/planktonic types.

Egg case of Lewis’ Moon (Euspira lewisii) snail around the shell. We regularly get these in our otter trawl collections in the nearshore environment.

Veliger larva of a snail. Note the thin shell and modified foot for swimming in the water column. This life history strategy allows many organisms to exploit multiple habitats during their lives.

Not all gastropods are benthic. There are some that spend their entire life cycle in the plankton. Pteropods are one type of planktonic snail. These are holoplanktonic.

The pteropod (Clio pyramidata, left) and the heteropod (Atlanta peronii, right) are occasionally common in the open oceanic waters at depths to 500 meters (mesopelagic zone).

Heteropods are another type of planktonic snail, which is also holoplanktonic. Both groups (subclasses) have adaptation for life in the water column, including wing-like projections, and modified feeding structures. We will see more about this later, but both groups also exhibit NEOTENY. Neoteny refers to the retention of the larval form in the adult stage. This adaptation is important in many marine organisms allowing them to survive in the plankton, and may be a key factor in the evolution of vertebrates . Some gastropods are commercially valuable like abalone. There populations are endangered due to habitat destruction, overfishing, and a disease called ‘withering foot syndrome’. The abalone are taken for their meat and shells, but there are strict rules that must be observed

Some gastropods have either an internal shell or no shell at all. This is the sea hare, and is one of the largest nudibranch. Nudibranch refers to “naked gills”. Without the shell, these organisms rely on camouflage and “inking” for protection. A large one can weigh 6 pounds (now that’s a big slug!).

The largest local marine slug, the sea hare, Aplysia californica, is a gentle giant that feeds on algae.

More common marine gastropods. A) giant keyhole limpet (Megathura crenulata); B) red abalone (Haliotis refuscens), one of seven species that can be found in California waters. How is it possible to tell the difference

between species?; C) Cone shell (Conus geographus), note the color of the foot; and, D) the nudibranch (Phidiana crassicornis). Gastropods come in all shapes, sizes, colors, and can be found in a variety of

habitats.

Many of the nudibranchs exhibit aposematic coloration instead of crypsis. Aposematic or poster coloration advertizes that the critter may be toxic, venomous or both. It does not take long for predators to avoid organisms that appear to have no defenses.

This is a nudibranch called the Spanish shawl (Flabellina iodinea, left). This critter feeds on hydroids and small anemones, but doesn’t digest the nematocysts. Instead they are passed, unfired into the bright orange tentacles. When a predator tries to eat this gastropod, it gets a nasty surprise. How they move the nematocysts from the digestive system to the fleshy structures is still a mystery.

There are three major subgroups or subclasses in the class Gastropoda. The subclass Prosobranchia (torted snails which include the Orders Archeogastropoda, Mesogastropoda, and Neogastropoda). Torsion is apparent in the adult stages of the more derived groups, but is uncommon in ancestral forms. Opistobranchia would include the skugs and nudibranchs. Both of these subclass groupings are outdated because of the evolutionary relationships in these groups (there is more than one evolutionary ancestor for these groups making them polyphyletic).

Class Cephalopoda -these include the squid, cuttlefishes, and octopi These mollusks may have external, internal or no shells at all. Most cephalopods exhibit marked differences from their counterparts in the rest of the phylum. They have large brains, and very well developed nervous systems. Their visual system rival human visual systems, and in some ways, surpass it. One group of cephalopods has an external shell (Order Nautilodea; nautilus). The cuttlefish as a prominent internal shell (Order Sepioidea). The Order Teuthoidea includes all the squids which have a reduced internal shell (called a ‘pen’). And the Order Octopoda includes the octopi.

Chambered nautilus (Nautilus pompilus), the most primitive cephalopod (Order Nautilodea) Prehistoric ammonites resembled these present day organisms, but were several times larger.

The cuttlefish (Sepia officinalis, Order Sepioidea) have the ability to change color via melanophores and chromatophores. They can match a variety of backgrounds and are capable of communication.

Both cuttlefishes and octopi can rapidly change their color and texture of their skin to match almost any background. This protective coloration, called crypsis, allows organisms to avoud detection.

Cephalopods reproduce sexually, and the female will lay eggs. This reproductive process is called OVIPARITY. The squid aggregate in shallow water and the males and females attempt to pair.

Once mating is complete, the squid may search for another partner. The female will look for a suitable site to lay her eggs. She will lay 400-500 eggs per egg case, and these cases will be attached to the bottom (image above right). Market squid (and most cephalopods)are said to be terminal spawners or that they exhibit SEMALPARITY. SEMALPARITY - refers to organisms with only one reproductive event, then they die.

The market squid is important to the ecology of southern California, as well as throughout its range. They are important predators in midwater environments where they feed on shrimps and fishes. They are a highly sought after prey organism by a variety of marine organisms. Once the squid die after spawning, the bodies are eaten by a fishes and other scavengers, but the eggs are left alone. The shell of the squid is called a “pen” and is internal. It provides support so that the squid can swim quickly.

The cuttlebones from cuttlefish. These provide rigid internal support, and is one reason why cuttlefish move efficiently through the environment.

The cuttlefish is a relative to the squid and has a much larger pen called a “cuttlebone”. The octopus, cuttlefish and squid can quickly change color and texture to avoid detection. Many deep sea squid and octopi have PHOTOPHORES. Photophores are light producing organs which contain a symbiotic bacteria. The bacteria are bioluminescent. The squid use these photophores to enhance their camouflage in the mesopelagic zone. They are also used for communication, and to attract potential prey organisms.

Squid taxonomy is based largely on the corneal covering of the eye. The suborder Myopsida include the nearsore squids with the corneal covering. The suborder Oegopsida include the squids that lack corneal coverings. This group of squids is very diverse!

Some of the diversity of oegopsid squid. All have light

producing structures called photophores.

Squid may be found in a variety of sizes. Giant squid (Architeuthis spp.) may be up to 60 feet long and over 1,000 pounds.

Most squid are small, but there are some larger ones, including the largest invertebrate on earth. The giant squid is known mostly from specimens that have washed up on beaches, from the beaks (mouth parts or radula) found in the stomachs of sperm whales, and more recently video tape from Japanese researchers. These squid may be up to 30 meters (including tentacles),and way several hundred pounds.

Unusual Mollusks: Next page...

Class Scaphopoda: The Tusk Shells

Diagram of a scaphopod (left) and an elephant tusk shell (Antalis spp., right). Scaphopod means ‘shovel-foot’. Most are deposit feeders, taking nutrients from the substrate they burrow through.

This another of the burrowing mollusks. These unusual mollusks have slender shells, and they have adaptations for burrowing in soft sediments. Their anatomy is complex. They feed on mostly interstitial organisms. There shells have been popular in markets for many years

Order Nautiloidea : the chambered nautilus (image above)

These midwater cephalopods are similar to the ancestral ammonites which where one of the prevalent marine groups. The ammonites disappeared in one of the early mass extinctions, and the nautilus and its relatives remained. The nautilus feeds on midwater fishes, crustaceans, and squids. It isn’t exactly clear what organisms feed on these. The shells of this mollusks occasionally washes up on beaches, while live ones are occasionally taken in deepwater trawls.

Important minor marine groups. There are a few, but here are two examples...

Phylum Ecotprocta - These organisms are also called the cup animals.

Bryozoans are complex, colonial animals that used to be classified with the cnidarians. Bryozoans may be found growing on variety of structures and organisms. Image is magnified 400X.

Ectoprocts or bryozoans have a complete digestive system, a true cavity, and well developed nervous system. They live in large aggregations called colonies. Bryozoans are some of the more common ectoprocts of southern California.

Phylum Priapula - the cactus worms

Typical cactus worm. Another one of the important worm groups from the marine environment. Unlike the nematodes or annelids, priapulids are more derived worms, with more complex structures.

Most of these are very small organisms are important in the habitats where they occur. They are INTERSTITIAL, meaning they live between the sediment grains. These are important predators in this zone. Priapulids have a complete digestive system, a true body cavity, and a central nervous system. This is an interesting group, and part of complex of transitional types to higher invertebrates. These transitional groups have characteristics in common with lower and higher invertebrates.

There are no organs for gaseous exchange and no circulatory system, although in some species, such as Priapulus, the fluid which bathes the internal organs contains corpuscles which carry a respiratory pigment called Haemerythrin. Metabolic excretion is by means of protonephridia.

The sexes are separate and there is normally only one ovary or testis. Eggs and sperm are released into the sea and fertilization occurs in the sea. The larva has a set of plates (made of cuticle) that surround it, it is possible that it lives in the mud like the adult, it is known to go through a number of molts before it takes on the adult form.

Phylum Arthropoda - Jointed limbed animals

This is the largest, most diverse of all of the phyla. There are about 1 million described species in this phylum. There are estimates that there may be 1 million more unknown species. These are the jointed limbed animals. The arthropod body is segmented and most exhibit bilateral symmetry.

Probably the most primitive of the arthropods, the horseshoe crab (Limulus polyphemus) has remained relatively unchanged frm its ancestors. It is unique in a number of ways including having hemocyanin in the blood, which makes it blue, and moving onto the beach to reproduce and lay eggs (the original version of ‘sex

on the beach’?).

Arthropods also have a chitinous external skeleton. They must molt or shed the exoskeleton to grow. This process is called ECDYSIS. This is regulated by a gland in the cephalothorax of the organism. This places an upper size limit on most arthropods. Once they molt, the arthropod is in the “soft-shelled” stage, and is especially vulnerable. Lost appendages are replaced when the old skin is discarded. The exoskeleton provides protection from predators, and allows for rapid movement. The exoskeleton is more efficient than the hydrostatic skeleton of the worms. Most arthropods have paired appendages used for swimming, feeding, or locomotion.

Sea spiders, Class Pycnogonida, are small arthropods found in the rocky intertidal zone. They are a very diverse group.

Arthropods also have a complete digestive system, a well developed nervous system, and a complex circulatory system. Most arthropods have an open circulatory system. Blood vessels empty into a cavity called the HEMOCOEL. The gills are located near this cavity, and the gases are exchanged.

External anatomy of the American lobster (Homarus americanus).

Arthropod reproduction is sexual only with some that are are hermaphrodites. Many arthropods have a planktonic larval stage. A few representatives are holoplanktonic, a few are benthic, and there are some bathypelagic species.

Some arthropods support important commercial fisheries, and a few have impacted or endangered populations. There are management regulation to protect local stocks, like the lobster, and rock

crabs. There are several important subgroups:

Subphylum/Class Crustacea All of the members of this group are adapted to live in water. They all have 2 antennae, gills, and a calcified external skeleton. There may be as many as 35,000 spp. of described crustaceans, and most of these are marine.

Copepods are abundant in marine environments. They are important links in in the transfer of energy in environments. Calaniod copepod (left) and a cyclopoid copepod (right). Note the brood sac with eggs carried

by the female.

These crustaceans are extremely abundant, and ecologically critical. As herbivores, they feed on the planktonic primary producers, and make that sunlight energy available to all life (that consume them). Most copepods are free living and planktonic, but some are benthic or infaunal, and a few others are interesting internal parasites. There is one local parasitic copepod that targets only the eyes sanddabs (an common benthic flatfish in nearshore waters).

Amphipods (left) are laterally compressed crustaceans that are very diverse and may rival copepods in terms of abundance at mesopelagic depths. Isopods (right) are dorso-ventrally flattened crustaceans that include

the familiar ‘rolly-polly’. Most isopods are benthic, but there are a few planktonic types.

This is another of the important group of crustaceans. These may replace copepods in certain marine environments. There are about 5,000 spp. of amphipods on earth. There are a few amphipods that are terrestrial, and several examples that are ectoparasites. Along with the other arthropod characteristics, amphipods are laterally compressed. This may help them avoid detection in the water column. They too are a critical link (in terms of energy transfer) in the marine environment.

Isopods These are found in some of the same environments exploited by amphipods. Unlike amphipods, isopods are dorsal-ventrally flattened. There are free living species, but there are several parasitic types. The pill bug (or rolly-pollies) are good examples of terrestrial isopods. Fish lice and gill isopods are great examples of ectoparasites. The gill isopod looks like a roly-poly with claw-like appendages.

Gill isopods feed on the body fluids of fishes (and a few invertebrates). Some grow very large, but all will leave

the host should it die. The isopods do not seem to impact gas exchange in the gills.

Cirripedia-Barnacles

Barnacles are also included in this group. All barnacles are SESSILE, meaning they live permanently to hard substrate. Because they lived attached to the substrate, they have a planktonic larval stage. The barnacle nauplius is carried by nearshore currents to distance habitats. Barnacles are part of the fouling community and can do damage to docks, piers, and boats. Most sessile barnacles have heavy calcareous plates. They extend their modified legs and trap planktonic organisms for feeding. Like all arthropods, they have complete digestive systems. Some barnacles are parasitic, and lack the heavy calcareous plates.

Barnacles are hermaphrodites and the sessile adult life history stage presents problems for reproduction. They have the longest intromittent organ (male) in the animal kingdom for its size. Space is a limiting

resource for adult barnacles as well.

Barnacles, which are cemented to the

substrate on their heads, use their

modified legs (cirri- hence the name) to trap

and eat plankton.

Mysid shrimp (left) and euphausiids (right) are two other important groups in the marine environment in terms of energy transfer. Both groups are prolific reproducers and many species utilize these organisms for food. They may be found in the shallows or in deep sea habitats. And they are found in oceans around the

world.

Mysidacea- opossum shrimp and Euphuasiacea- Krill

Mysids and Euphausiids or krill are another of the important planktonic crustaceans. The head is fused with a few of the body segments, making this organisms distinct from the other shrimp like crustaceans (the end of the carapace is free for the mysids). The mysids are suspension feeders, while krill use their legs which have been modified into a “feeding basket”. This allows them to strain the water for phytoplankton and zooplankton. Baleen whales, some penguins and fishes feed almost exclusively on these organisms. Krill are the most common marine organism in polar waters. There is a commercial fishery for these organisms, especially around Antarctica. This fishery may directly impact the ecosystem in this area and we compete with baleen whales (like fin, and humpback) for this resource. Both of these are active, fast swimmers. As a consequence they are an important part of the MICRO-NEKTON. Smaller organisms that can move independent of major currents, but for short distances. Many of these species are part of a larger group of organisms that make the daily migration from the depths toward the surface. This is called VERTICAL MIGRATION (more later).

Nantant decapods and their relatives-Shrimps, crabs and lobsters

Shrimp, lobsters and crabs are part of the decapod crustacean group. There are over 10,000 species of decapod crustaceans, making this the largest group of arthropods. Shrimps and lobsters have adaptations for swimming. Hermit crabs (which are not true crabs) hide their long, soft abdomens in the empty shells of snails. - Rock crabs and their relatives have a reduced abdomen and is tucked under the broad cephalothorax. The sexes are separate in this group. Gender identification is easy for the crabs. The abdomen is V-shaped in males and U-shaped in females. This shape allows females to carry eggs. For most decapod crustaceans, the gametes are rarely released into the water column. There is a considerable fishery for decapod crustaceans. There are several regulations to protect stocks, but some crustaceans have been over-harvested

Panulirus interruptus, or the spiny lobster is a highly sought after sport and commercial species in southern California waters. Unlike the lobster in along the Atlantic seaboard, these lobsters lack the chelate claws

(and the meat), but they are not defenseless. They are called spiny lobster for a reason!

Other Marine Arthropods

Sand or mole crabs are another neat group, and one that most of us who has spent any time on beach are familiar with. They have adaptations to quickly burrow into soft sediments. Sand crabs are important organisms in the nearshore environment. Sand crabs are filter feeders. The long antennae have been modified for feeding. They use the movement of waves washing on the shore to strain the water for food, and as an aid to move along the beach. Females will brood the eggs, and the larvae are planktonic. After metamorphosis, the juveniles seek out soft sediments for the next stage of life. As with many of the other crustaceans, a variety of organisms prey on these critters.

Mole or sand crabs (Emerita spp.) Have adaptations to burrow into soft sediments. Females brood eggs (far right) like other crustaceans.

Diversity of crabs. Note the difference between male (bottom right) and female (top right) crabs. Though most crabs are found in and near aquatic environments, they most lay their eggs in the water (the early life

history stages are planktonic).

Mantis shrimp are another unusual crustacean group. These are not true shrimp, but appear to be a cross between a shrimp and a lobster. They have either spears or clubs instead of claws.

Order Stomatopoda -Mantis shrimp

These crustaceans are very territorial. Their brightly colored legs help to warn other mantids that the area is occupied. If mantids grew to a meter or more in length, I wouldn’t go in the water! They have spears or clubs and use them t hunt prey, for protection from predators, or against invading mantids. The have the fastest reflexes in the animal kingdom, and they will use those reflexes to deliver blows with the clubs or spears that can shatter the shell of a crab or snail (their preferred prey, spear fish, or crush fingers. The rapid motion cause the formation of cavitation bubbles which do considerable damage.

Mantis shrimp appear to be highly intelligent, are long-lived and exhibit complex behavior, such as ritualized fighting. Scientists have discovered that some species use fluorescent patterns on their bodies for signaling with their own and maybe even other species, expanding their range of behavioral signals. They can learn and remember well, and are able to recognize individual neighbors with whom they frequently interact. They can recognize them by visual signs and even by individual smell. Many have developed a complex social behavior to defend their space from rivals.

In a lifetime, they can have as many as 20 or 30 breeding episodes. Depending on the species, the eggs can be laid and kept in a burrow, or carried around under the female's tail until they hatch. Also depending on the species, male and female come together only to mate or bond in monogamous long-term relationships.

Page 1
Page 2
Page 3
Page 4
Page 5
Page 6
Page 7
Page 8
Page 9
Page 10
Page 11
Page 12
Page 13
Page 14
Page 15
Page 16
Page 17
Page 18
Page 19
Page 20
Page 21
Page 22
Page 23
Page 24
Page 25