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What can be found under phylum Platyhelminthes
Flatworms with over 20,000 species which are very diverse
What are the general characteristics of Platyhelminthes
Dorsoventrally Flattened
Triploblastic Acoelomates
Unsegmented
Incomplete Gut
Monoecious
Parenchyma Cells
What does Dorsoventrally Flattened Mean?
They are Flattened from the Dorsal and Ventral Plane
What does being an Acoelomate mean?
They have no body cavity
The unsegmented and incomplete gut characteristics of Platyhelminthes are not present under what class?
Cestoda aka Tapeworms
What are the characteristics of Class Turbellaria
Free Living Flatworms
They are mostly marine or freshwater [but there are a few terrestrial ones]
Very diverse and commonly found
They breathe through their skin
What does Cutaneous Respiration mean?
Breathing through skin
What are the 3 germ layers present in Turbellarians
Ectoderm [Turns into Epidermis]
Mesoderm
Endoderm [Turns into the Gastrodermis]
What is the function of the ectoderm / epidermis in turbellarians
It is ciliated for movement
What are the functions of the mesoderm in turbellarians
Separated from epidermis with basement membrane [basement membranes are made from connective tissue]
Muscles and other organs
What parts of Turbellarians are used for Locomotion
Cilia and Muscle Undulations for Movement
Adhesive Glans and Releaser Glands
How does feeding and digestion work in Turbellarians?
Free-living - predatory, herbivorous or scavengers
From a simple chamber to a breached digestive tract
Pharynx for ingestion, can be used in conjunction with mouth
How does Respiration and Osmoregulation function in Turbellarians
Gas and Waste diffusion
Protonephridia which are found in flame cells - for osmoregulation
What can flame cells also be used for ?
waste removal
What is osmoregulation
the ability to maintain homeostasis
What are the nervous functions of Turbellarians
Nervous system resembles nerve net, some have ganglia
What are the sensory functions of Turbellarians
Sensory Organs
Detect chemical changes, touch, water currents, light and gravity
examples : Auricles (chemo), Ocellus (photo)
What type of reproduction can Turbellarians undergo?
Sexual and Asexual
How do Turbellarians undergo Asexual Reproduction
They undergo Transverse Fission
How do Turbellarians undergo Sexual Reproduction?
They are Monoecious, but usually cross-fertilize, some do penile fencing.
What is penile fencing?
Some worms engage in a fence with their penises, and the loser of the fence is the one that gets penetrated and becomes a woman
What does traumatic insemination mean and what is an example of an event with traumatic insemination
When the body wall is pierced it is traumatic insemination, an example is penile fencing
What is Batesian Mimicry
Some flatworms can mimic other animals
Examples:
Pseudoceros Imitatus
Phylidiella Pustulosa
What is Aposematic Coloration
Using the color of skin to warn about poison / is for deterrence
What are the descriptions of Class Trematoda
Example : Schistosoma
Parasitic Flukes
Highly dependent on hosts
What are the two types of hosts in parasites
Intermediate Hosts
Definitive Hosts
What differentiates Intermediate and Definitive Hosts
The definitive host are where the reproductively mature parasite is found
What is the Tegument and its functions
It is the outermost layer of Platyhelminthes
Functions :
Protection, Absorption, Waste disposal, respiration and defense against host defenses
How does feeding work in Trematoda
They have Highly specialized organs to adapt to parasitic lifestyle
An example of this organ would be : suckers
What are parasitic infections that can infect humans?
Chinese Liver Fluke (Clonorchis Sinensis)
Sleep Liver Fluke (Fasciola Hepatica)
Schistosoma
Japanese Flu (Paragonimus Westermani)
In some special cases where can the sheep liver fluke (fasciola hepatica) be found
In some cases it may be found in the eyes
Where can Schistosoma be found in the Philippines
Could be found in Bohol, Samar, Negros, Leyte, Cagayan Valley, Davao Del Norte
How many tapeworms can be found per each host
Depends, can be 1 per host, 2 per host or more
What are the general characteristics of Class Cestoda
Around 3500 species
Parasitic
No Mouth, No Digestive Tract (nutrients purely from the skin)
Presence of Proglottids
What is the head of a tapeworm called
Scolex
The Tapeworm Body
Note : Gravid Proglottid is the largest and oldest
How do Cestoideans have Specialization for Parasitism
Their teguments can also function
for nutrient absorption
“Enzyme Stealing”
hooks and suckers
How does Reproduction occur in Cestoideans
They are Monoecious
Each Proglottid contains male and female organs
They can reproduce by itself or with another tapeworm
Descriptions of the Proglottids
As the worm grows, new proglottids are added
Gravid proglottids have a blind-ending uterus
Types of Tapeworm Infections
Beef Tapeworm (Taenia Saginata)
Pork Tapeworm (Taenia Solium)
How does a human get infected by Beef Tapeworms (Taenia Saginata) and where are they found in the body
Gotten by eating infected cows
They are then found in the small intestines around 25m long
How does a human get infected by Pork Tapeworms (Taenia Solium) and where are they found in the body
By eating infected pigs
they will then be found in the Small intestine, around 10m, 2-3m are the most common
What condition can Pork Tapeworms (Taenia Solium) cause?
It can cause Aysitcecous where the larvae encysts and causes a condition called Cysticercosis
What are the general descriptions of the Phylum Nematoda
They are roundworms
Not dorsoventrally flattened
Around 500,000 species | very common | highly diverse
Estimate : for every acre of fertile soil 5,000,000,000 individual nematodes could be found
What are the characteristics of Nematoda
Triploblastic, bilateral symmetry
Molting in Juveniles
Cuticle as an outer covering
Complete Digestive Tract
Longitudinal Muscles on body wall for movement
Molting in Juveniles in Nematoda can also be known as?
ecdysis
ecdysis : when nematodes shed their outer layer for them to be able to grow
How does movement work in the longitudinal muscles in nematodes?
They move with a thrashing motion due to the longitudinal muscles
Description and Functions of the Cuticle in Nematodes
Can have modifications as needed by nematodes
Mechanical Protection
Protects the worm against injury
Digestion Resistance
Attachment
May contain bristles, spikes, warts, etc.
How does feeding work in Nematodes
Carnivores, herbivores, omnivores, saprotrophs, parasites
Complete digestive system from mouth to anus
What does saprotrophic mean?
eats nonliving organic matter
How does the nervous system work in Nematodes
Nerves extend throughout the body
Nerves are connected to each other
Nerve Ring
Used for signal relaying and response
Nervous and Endocrine secretions play a role in molting, cuticle formation and growth
How does reproduction work in Nematodes
Sexual Dimorphism
Diecious
Males have a Bursa which releases sperm | Females have gential pores which receive sperm
What does Sexual Dimorphism mean?
It is a difference in the appearance of male and females
What does Diecious mean?
The different gametes are found in different organisms | male or female
Characteristics of Ascariasis - Ascaris Lumbricoides
their outer layer of ascariasis are highly resilient against host defenses
They are large Roundworms that can infect the respiratory and digestive system in humans
Severe cases lead to organ damage
What is the life cycle of Ascariasis - Ascaris Lumbricoides
Humans are infected by eating the eggs of Ascariasis
Do not need an intermediate host to affect humans
Can be found in areas with no proper plumbing, hygiene
What are the characteristics of Enterobiasis - Pinworms
Aka enterobius vermicularis
Auto Infectious
It can keep reinfecting itself
the eggs are very sticky
Life Cycle of Enterobiasis - Pinworms
Larvae hatches in a small intestine and will move to the large intestine when they are adults
At night adult worms can end up in the anus
What can Necator Americanus - Hookworm cause?
Causes necatoriasis
Can cause weight loss hemoglobin deficiency, and brain damage or mental retardation
What is the Life Cycle of Necator Americanus
Larva can pierce skin, that is how humans catch it
What conditions can Trichinella Spiralis - Pork Worm cause
Causes trichinosis
Causes edema, in server cases can cause nervous system damage and death
What is the Life Cycle of Trichinella Spiralis
Can encyst in Pig’s Muscles
Once encysted larva is consumed by a human, it turns into an adult in the small intestine, then it will encyst in humans
Female porkworms can create larvae that migrate and encyst
What are the characteristics of Loa Loa Filariasis - Filarial Worms
They are Transmitted by the worm Loa Loa
Eye worms
Transmitted by Flies (dear flies)
Not just an eye disease can also be a skin disease
Causes a condition called Lymphatic Filariasis, eventually leading to elephantiasis
Transmitted by mosquitoes by the worm Wuchereria Bancrofti
Worms migrate and develop in the Lymphatic System which causes a build up of Fluid
What are organisms that transmit diseases to other organisms called
Vectors
What are the descriptions of Mollusca
Around 100,000 known species | very diverse
True Coelom (Euceolomates)
Characteristics of Mollusca
Two Part Body Plan
Presence of a Mantle & Radula
Bilateral Symmetry
True Coelom
Open Circulatory System
What are the two parts of the two part body plan in Molluscans
Head - Foot and visceral mass
What is the Mantle of a Mollusca
it is a soft tissue that produces the mollusc shell
All classes under Mollusca have an open circulatory system besides?
cephalopods
What is the radula in Molluscans used for?
For Feeding
What are the characteristics and functions of the Head-Foot in Molluscans
Head-Foot : Elongate head located anterior
Contains feeding, nervous and sensory structures
What are the characteristics and functions of the Visceral Mass in Molluscans
Visceral Mass : Dorsal to Head-Foot
Contains digestive, circulatory, excretory, and reproductive organs
What are the functions of the Mantle in Mollusca, and where is it attached to?
Usually attached to the visceral mass
May secrete shells in many molluscs
What are the 3 shell layers in Mollusca
Periostracum - Proteins
Prismatic - Calcium Carbonate with organic material
Nacreous - Calcium Carbonate with organic material
What is the difference Prismatic and Nacreous
The difference is the organic material that is being used
What does Nacre make up
Pearls and Mother of Pearls
What is Ocean Acidification and what are it’s effects
When the pH level of an Ocean drops and turns the ocean acidic
Happens from excessive carbon dioxide, carboxide in the water
Stops calcium carbonate from forming
What are the functions and characteristics of the Radula in Mollusca
Feeding Structure
Rows of teeth that are carved posteriorly
Chitinous
Supported by the Odontophore
Description of Class Gastropoda
Largest Molluscan class
can be Marine, freshwater and terrestrial
How does Locomotion work in Gastropods ?
Smaller Gastropods : ciliary movement over a mucus trail secreted by Glands
Larger Gastropods : muscular contractions to move foot
Modifications : attachment, swimming
How does Feeding and Digestion work in Gastropods?
Herbivores, Carnivores, Scavengers, Parasites
Projectable radula through proboscis
proboscis is also used for feeding
What is a notable gastropod and its notable function?
Conus Snails
1 sting could kill a human
How does maintenance occur in Gastropods ?
Siphon
Open Circulatory System
Hydraulic Skeleton
Nervous System - Ganglia
Excretion of Waste
How does excretion of waste work in Gastropods | Marine & Terrestrial?
Ammonia (Marine)
Ammonia is cytotoxic
Can be diluted and washed away by water in marine life
Uric Acid (terrestrial)
Note : they do not excrete both at once
What are the sensory organs of Gastropods?
Eyes
Can be simple photoreceptors or more developed
Statocysts for balance
Osphradia for chemosensing
How does reproduction occur in Molluscans
Some are dioecious other monoecious
Love Darts
Marine Gastropods
Metamorphosis : trochophore larva, veliger larva
What are the description of the Class Bivalvia
Around 30,000+ Species
Contains Clams, Oysters, Scallops and Mussels
What are the characteristics of the Bivalve Shell
Each shell is called a Valve
Teeth are formed near the hinge
The oldest part is called the umbo
Adduction muscles at the dorsal end close the shell
How does Gas Exchange work in Bivalvia
Gills for gaseous exchange, attached to the foot and the Mantle
Mantle is cilliated to move water inwards
Some bivalves have a siphon that can take in water
How does feeding work in Bivalvia
Filter Feeding
Incurrent water, food is moved by the cilia and moved towards the mouth
What do Bivalvia eat
They eat : Algae, Microplankton, Organic Material (including Feces)
What are the Other Body Systems of Bivalvia
Open circulatory system
Mantle is lined with sensory organs
Osphradium, Photoreceptors and statocysts (for balance)
How does reproduction work in Bivalvia
Mostly dioecious, some protandric, some monoecious
External Fertilization
Trochophore and Veliger Stages
Glochidium
What does protandric mean?
male first then female
Human Interactions with Bivalvia
Can reduce water turbidity
Many are used as a food source (we eat them)
Some are invasive species
What is the description of Class Cephalopoda
One of the most complex invertebrates
Octopus, squid, nautilus, cuttlefish
The Cephalopod Shell
Present in nautilus, reduced in squid, absent in Octopi
What are the reduced shells of squids and cuttlefish called?
For squid it is called a pen
For cuttlefish it is called cuttlebone
How does movement and locomotion work in Cephalopods?
Jet propulsion system
The mantle contains radial and circular muscles
Stabilizing fins for balance
Octopi normally crawl on substrate
Differentiate between Squid and Cuttlefish
Small Stabilizing Fin : Squid
Large Stabilizing Fin : Cuttlefish
Note 
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