Potts-Santone General Bio 2 Final

Parasitic Flatworrms

- Group of flatworms that include trematodes (flukes) and cestodes (tapeworms)

- Routinely engage in asexual reproduction

Flukes (Trematodes)

- Type of parasitic flatworm

- Has a well-developed reproductive system

- Usually goes through at least 2 hosts

- Usually hermaphroditic

- Endoparasite

- Has a complex life cycle

- Attachment device present

- Often target the liver because of the excess blood supply

- Ex: Schistosoma and Clonorchis

Schistosoma (Blood Fluke)

- Type of trematode

- Has 2 hosts (human [in the liver] and snails

- Likes hot, humid conditions

- Dependent on water

- Separate male and female sexes

- Found in areas with poor sanitation

- Sexual reproduction only occurs in dependent host (humans)

- Causes Schistosomiasis

Schistosomiasis

- Caused by blood flukes

- 300 million infected

- Second biggest parasitic disease

Liver Fluke (Clonorchis sinensis)

- Type of trematode

- 3 hosts: snail, fish, and humans

- Hermaphroditic

- Acquired through ingestion of raw fish (metacercariae)

- Can lead to liver cancer

- 20-30 million cases in Eastern Asia

Miracidia

- Ciliated larvae stage found in trematodes that bore into the snail

Cercariae

- Larvae with the ability to bore through human skin

Metacercariae

- Tailless encysted late larva of a trematode that is usually the form which is infective for the definitive host

- Found in trematodes with sexual reproduction as an internal parasite of a vertebrate alternates

Common Trematodes in Humans

- Blood Flukes

- Chinese Liver Flukes

- Lung Flukes

- Intestinal Flukes

- Sheep Liver Fluke

Lung Fluke (Paragonimus species)

- Type of trematode

- Acquired from eating metacercariae in raw crabs and crayfish

- Found in Asia, Oceania, Africa, and South and Central America

- Several million cases in Asia

Intestinal Fluke (Fasciolopsis species)

- Type of trematode

- Acquired from eating metacercariae on aquatic vegetation

- 10 million cases in Eastern Asia

Sheep Liver Fluke (Fasciola hepatica)

- Type of trematode

- Acquired from eating metacercariae on aquatic vegetation

- Prevalent in sheep and cattle

Tapeworms (Cestodes)

- Type of parasitic flatworm

- Have a scolex

- Body consists of a long series of proglottides

- Possess multiple sex organs

- Each segment contains a full set of male and female sex organs

- Can self-fertilize millions of eggs per day

- Complicated life cycles

- Cysticerci in muscle

Scolex

- Anterior region with modifications for attachment to intestinal wall of host found in cestodes

Common Cestodes in Humans

- Large tapeworms

1. Beef tapeworm

2. Pork tapeworm

3. Fish tapeworm

- Dog tapeworm

- Dwarf tapeworm

Unilocular hydatid

- Type of cestode

- Causes a hydatid cyst to form in humans

- Dogs are the definitive host

Hydatid Cyst

- Caused by unilocular hydatid

- Forms almost anywhere on the human body

- Only treatment is surgery

- Rupture means immediate death due to anaphylactic shock

Taeniosis

- Condition caused by pork tapeworms

- Leads to neurocysticercosis, which leads to brain cysts

- Humans are intermediate hosts

Phylum Rotifera

- Part of the lophotrochozoa

- Known as "Wheeled Animals"

- Named for corona

- Possess mastax and trophi

- Most live in fresh water

- Do no molt

- Pseudocoelomate

- Live for around one week

- Take coloration from food

- Complete digestive system

- No cuticle or chitin

- Ciliary swimming

- Lophophore larvae stage

- Possess flame cells

- Can go into cryptobiosis

- Possess spines on their body

- Dieocious

- Some only female

- 900-1,000 small cells

- Omnivores

- Function as a food source

Unique Aspects of Rotifera

- Mastax

- Trophi

- Corona

Corona

- Crown of cilia resembling a rotating wheel found on Rotifers

- Serves as both as an organ of locomotion and aids direction of food to mouth

- Aids in water flow, which helps with propulsion

Mastax

- Pharynx of Rotifers

Trophi

- Jaws for grinding found in Rotifers

Cryptobiosis

- Death-like state common in fresh

- Suspended animation that allows an organism to tough out harsh conditions

- Frequent in freshwater organisms, especially Rotifers

Rotifer Spines

- Able to change by choice

- Cyclomorphosis is a main part of the changing of these

Cyclomorphosis

- Situation where as a population changes, an organism changes its body because of the environment

- Common in fresh water

Reproduction in Rotifers

- Sexual Reproduction and Parthenogenesis

- Some swap between those two things

Sexual Reproduction in Rotifers

- Happens when conditions deteriorate

- Haploid egg becomes a haploid adult male if it stays unfertilized

- Haploid adult male fertilizes an egg, making a diploid resting egg

- Diploid resting egg becomes an adult female with a new genetic combination

Diploid Resting Egg

- Happens in Rotifer sexual reproduction

- "Winter Egg"

- Hatches in favorable conditions

Parthenogenesis

- Type of reproduction that only uses females

- Eggs are not fertilized

- Adult female produces diploid egg (amictic egg) which becomes female

- Rotifers do this

- Good for rapid population growth when conditions are favorable

- Beneficial because of efficiency, no time wasted looking for a mate

Amicitc Egg

- Diploid egg produced without fertilization

- Formed only through mitosis

- Present in parthenogenesis

Open Circulatory System

- Type of circulatory system found in arthropods and mollusks

- Low pressure

- Large fluid volume

- No arteries

Closed Circulatory System

- Type of circulatory system found in annelids

- High pressure

- Low fluid volume

- Blood remains in a series of vessels

Phylum Annelida

- Part of the lophotrochozoa

- Eucoelomate

- Has segmentation/metamerism

- Possess septa

- Has a specialized digestive tract

- Closed circulatory system

- Has a double transport system

- Has chaetae

- Ventral solid nerve cord present

- Well developed organs, muscles, and coeloms

- Circular muscle allows movement

- Ex: polychaetes, oligochaetes, and leeches

Double Transport System

- Circulatory system and coelomic fluid both carry nutrients, wastes, and respiratory gases

- Found in annelids

Chaetae

- Type of chitinous bristles found in annelids

- Help in movement

Setae

- Type of chitinous bristles found in arthropods

-Come through the exoskeleton and is connected to nervous system

- Act as sensory hairs

Ventral Solid Nerve Cord

- Nervous system of annelids

- Giant axons facilitate rapid responses

Errantia

- Type of annelid

- Most free ranging predators

- Well-developed eyes and powerful jaws

- Often brightly colored

- Long chaetae on foot like parapodia

Sedentaria

- Type of annelid

- Chaetae close to body wall to facilitate anchoring in burrows

- Ex: earthworms

Tubeworms

- Type of marine annelid

- Filter food from water with a crown of tentacles

Leeches

- Type of annelid mostly found in fresh water

- Generally blood suckers

- Known as temporary parasites

- Dorsally flattened

- No digestive enzymes

- Bacteria in the gut run digestion

- Possess kidneys for taking water out of blood

- Bite has an anesthetic quality

- No chaetae

- No head

- Triaradiate jaw: 3 slices to jaw

- Muscular body wall

- No peristalsis

- Possess hirudin

- Used medicinally in the past

- Sometimes still used in surgeries

Hirudin

- Found in leeches

- Anticoagulant that allows blood to flow freely

Chitin

- Nitrogenous polysaccaride frequently found as a protective barrier in animals and fungi

- Found especially in arthropods

Polychaetes

- 2/3 of annelids

- Have trochophore larvae

- Found in marine environments

- Colorful

- Come in sedentary and errant forms

- Some use mucus bag form of eating

- Some use epitoky

- Segmented

- Ex: Pogonophora/Siphoglinds

Sedentary Polychaetes

- Tube form of annelids

- Feature specialized body parts for a nonmotile animal

Errant Polychaetes

- Free swimming annelids

- Agile marine swimmers

Segmentation of Polychaetes

- Prostomium: 1st segment

- Peristomeum: 2nd segment found around mouth

- Parapodia

Parapodia

- Extensions of coelom that aid in respiration

- Bear many chaetae

Mucus Bag

- Type of eating used by burrowed worms or "Inkeeper Worms"

- Modified parapodia has this, which traps food

- When full, the worm wraps this up and swallows it

Epitoky

- The separation of sex organs from the normal parts of a worm

Atoke

- Normal parts of a worm

Epitoke

- Parts of a worm specialized for sexual reproduction

- Swarming can occur when these are released

Swarming

- Rapid release of epitoke

- Predators make no difference due to amount of epitokes

Pogonophora (Siphoglinds)

- Type of polychaete

- Cephalic lobe bearing a beard of 1-1000s ciliated tentacles

- Trunk with a pair of coelomic cavities

- Gut tissue forms an organ (trophosome) than becomes filled with chemosynthetic bacteria (only responsible for digestion)

- Segmentation confined to small rear portion (opisthoma)

- Live near hydrothermal vents

Oligochaetes

- No well-developed head

- Chaetae protrude in pairs directly from the body surface

- Food drawn into the mouth by suction of muscular phyarynx

- Mostly terrestital

- Digestion and absorption occur in long internal intestine

- Typhlosole for absorption, which increase the surface area

- Tube-within-a-tube body plan

- Closed circulation

- Hermaphroditic

- Clitellum present

- Have direct development

Oligochaete Structures

- Crop

- Dorsal Nerve Cord

- Clitellum

Clitellum

- Present in Oligochaetes

- Secretes mucus to protect sperm from desiccation

- Secretes cocoon`

Direct Development

- Leads to fully formed organism

- Clitellum in Oligochaetes allows this

Phylum Mollusca

- Mostly shelled invertebrates

- 110,000 living

- 35,000 fossils

- Possess a well-defined respiratory system

- Reduced coelom and is limited to the region around the heart

- Heart pumps hemolglymph through vessels into the hemocoel

- Have a complete digestive system

- Well-defined respiratory system present

- Possess feathery gills that run the blood opposite to the flow of water

- Mostly separate sexes

- Possess a radula

- Nervous system of several ganglia connected by nerve cords

- More well developed types can learn and possess a large brain

Three Parts of Mollusca

1) Visceral Mass

2) Mantle

3) Head Foot

Visceral Mass

- Contains internal organs

Mantle

- May secrete a shell

- May contribute to development of gills and lungs

- Only found in molluscs

Head Foot

- Muscle adapted for locomotion, attachment, food capture, or sensory reception

Mollusc Shell

- Provide protection for soft body

- Provide protection from harsh environments and from predators

- Come in a variety of colors and patterns

- Synthesized by using CaCO3 from H2O

- Layered

- Grow with the body

Radula

- Only found in molluscs

- Rasping, tongue-like organ found in all molluscs except bivalves

- Ribbon-like structure of chitinous teeth

- Highly modified depending on feeding style

Layers of Mollusc Shell

1) Periostracum

2) Prismatic

3) Nacreous

Periostracum

- First layer of mollusc shell

- Very thin protective layers of tough protein

Prismatic

- Second layer of mollusc shell

- Form a regular arrangement of CaCO3

Nacreous

- Third layer of mollusc shell

- CaCO3 over protein

- Can become very thick

- Forms the "Mother of Pearl"

- Keeps irritations away

Life History of Molluscs

- Spawn into the water column

- 2 larvae stages

1) Trochophore

2) Veliger

Veliger

- Second larvae stage of molluscs

Types of Mollusca

- Bivalves (Delecypoda)

- Chitons (Polyplacophora)

- Monoplacophora

- Gastropoda

- Tusk shell (Scaphopoda)

- Cephalopods

- All stem from a common ancestor

Bivalves

- Shell of 2 hinged parts with a body inbetween

- Closed by adductors

- No head or radula

- Open circulatory system

- Dorsal and ventral portions

- Anterior and posterior portions

- Possess a siphon

- Separate sexes

- Foot is good for digging

- Often lived buried under sediments

- Ciliated gills hang down within mantle cavity on either side of visceral mass

- Beating of cilia causes water to enter cavity

- Filter feeders

- Muscle fibers can contract and stay contracted

- Can concentrate toxins from water

- Ex: Clams, Oysters, Muscles, and Scallops

Adductor

- Powerful muscles that can open and close bivalve shells

Siphon

- Muscular tube used for getting water in and out of the mantle cavity

- Forms when a mantle is drawn in and out in the posterior direction

- Helps with the bivalve getting buried

- Incurrent and outcurrent types

Filter Feeders

- Capture tiny food particles suspended in water

Gastropods

- Largest group of mollusca

- Possess an operculum

- Possess a well-developed head

- Eyes and tentacles project from coiled shell

- Gills found in the mantle cavity in aquatic types

- Mantle functions as lungs in terrestrial species

- Have a wide variety of feeding strategies

- Body can be withdrawn into single piece shell

- Only mollusc that can be terrestrial

- Does torsion

- Ex: Snails, slugs, nudibranchs, limpets

Operculum in Gastropods

- Elongated, flattened foot found in gastropods

- Flap that seals a gastropod into its shell

Torsion

- Twisting of muscles on the right side of a gastropod's body

- Moves the mantle cavity from the posterior side to the anterior side

- Head and anus start on different sides and move to one side

Advantages of Torsion

- Respiratory system has better water available

- Allows a gastropod to be pulled into its shell headfirst

Drawback of Torsion

- Fowling, which puts the anus over the head

- Gastropods adapted to avoid this

Cephalopods

- Head footed mollusc

- Force water out of mantle cavity

- Move through jet propulsion

- Tentacles and arms capture prey by adhesive secretions or suckers

- Possess a chitinous beak used to tear apart prey

- Well-developed sense organs

- Only mollusc with a closed circulatory system

- Spermatophore packets passed from males to females

- Some possess chromatophores or iridocytes

- Possess accessory hearts (branchial hearts)

- Very fast, active predators

- Siphon directs movement

- Most complex and intelligent invertebrates

- Internal fertilization

- Ex: Nautilus, Cuttlefish, Squid, and Octopus

Chromatophores

- Melanin filled cells that allow them to change colors

- Often found in octopi

Iridocytes

- Iridescent cells found on squids which makes them hard to see

Nautili

- Possess an external shell

- Siphuncle connects this animal to the center of the shell as it becomes segmented off

- Used for gas exchange to maintain buoyancy

Shell of Cephalopods

- Nautili are the only one with an external shell

- Cuttlefish possess an internal shell known as a cuttlebone

- Pen is all that is left of a shell in squids

- Octopi have no shell

- As shell evolved out, ink sacs formed

Hectocotylus

- Special arm in cephalopods that is involved with the transfer of spermatocytes

Ecdysozoa

- Clade of invertebrates separated from lophotrochozoa by molecular data and morphology

- Abundant in all environments

- Named for ecdysis

- Most are protostome or protostome-like

- True coelom present in most

- Chitinous cuticle provides support and protection

- Cuticle also has calcium salts

- Some undergo metamorphosis

- Internal fertilization allows colonization of dry environments

- Sperm not flagellated

- Sperm is amoeboid and crawling

- Large size only found in water

- Exoskeleton present

Consist of

1) Arthropods

2) Nematodes

Metamorphosis

- Dramatic change in body form

- Reduces competition between juveniles and adults

- Present in ecdysozoa

Ecydsis

- Also known as molting

- Defining characteristic of ecdysozoa

- Needed for growth

- Triggered by release of ecdysone

Exoskeleton

- External skeleton that must be shed in order for growth

- Found in ecdysozoa

Nematodes

- Ubiquitous, abundant, and habitat/host specific group of ecdysozoans

- Worm-like body

- Tube within a tube body plan

- Mostly acoelomates but larger kinds are pseudocoelomates

- Look similar on the surface, but molecularly they are differnt

- Most are small and transparent

- Tapered at both ends

- Homogeneus

- Most abundant organisms on Earth

- Most are parasites

- Feed on bacteria and fungi (control decomposers)

- Fluid in pseudocoelom maintained by high pressure

- Can grow in between molts

- Have eutely of 959

- Most body cells lose genetic material as they age

- Only possess longitudinal muscles

- Thrashing, whip-like movement

- Possess spicules

- Females larger than males because of reproductive output

- Ex: Caenorhabditis elegans, roundworms, and hookworms

Caenorhabditis elegans

- Type of nematode that became the model for life

- First eukaryote to have its genome sequence

Peristalsis

- Type of movement found in most annelids, except leeches

Roundworms

- Non-segmented nematodes

- Mostly colorless worms that infect humans, animals, and plants

- Parasitic worms

- Common in rural areas of Appalachia and Southeastern US

Eutely

- When species have a set number of cells that it can grow to, after which it stops dividing

Spicules

- Male sex organs that insert amoebic sperm in females

- Found in nematodes

Hookworm

- Type of parasitic nematode

- Infects 1 billion people worldwide

- Affects 1/5 of the worlds population

- Part of the top 3 of parasitic disease in humans

- Leads to fatigue, anemia, and iron deficiencies

- Found in rural areas with poor sanitation

- Found in Southeastern US (Alabama)

- Unusual lifecycle

- Likes warm climates

- Women and children affected the most

- Juveniles can burrow into the skin

Hookworm Life Cycle