Transcript Animal Presentation

Videos - animal
intro
D:\Sponges__Porifera.asf
porifera
• Chimney sponge
Cnidaria
• Feeding
• Examples
• Anemone eating jellyfish
Cnidaria
• D:\Jellyfish.asf
• D:\_Stingers___Cnidaria_and_Coral.asf
Platyhelminthes - Flatworms
• D:\Worms__Benefits_and_Problems.asf
General Characteristics
• They exhibit bilateral symmetry: anterior and
posterior ends are different; so are the dorsal (top) and
ventral (bottom) surfaces
• The platyhelminths also exhibit some degree of
cephalization Commonly referred to as the 'flatworms'
because their bodies are dorsoventrally flattened.
• They are acoelomates
• This phylum (and all remaining phyla) possess 3
germ layers (=triploblastic)
• The mesoderm (third germ layer) gives rise to
muscles, various organ systems, and the parenchyma,
a form of solid tissue containing cells and fibers
Outer Body Covering
• The body of some platyhelminthes (e.g.,
turbellarians) is covered by a ciliated epidermis
• Epidermal cells contain rod-shaped structures
called rhabdites that when released into the
surrounding water, expand and form a protective
mucous coat around the animal
• The outer body covering of other
platyhelminthes (e.g., parasitic forms) is a nonciliated tegument
• The tegument is referred to as a syncytial
epithelium
Organ Systems of the Platyhelminthes
Digestive System
• Some of the flatworms possess a digestive system, with a mouth, pharynx, and a
branching intestine from which the nutrients are absorbed
• The intestine, with only one opening, is a blind system
Organ Systems of the Platyhelminthes cont.
Excretory System (osmoregulation)
• A network of water collecting tubules adjacent to flame cells or a protonephridia
• When cilia beat they move water into the tubules and out the body through pores
called nephridiopores
Organ Systems of the Platyhelminthes con’t
Muscular System
• Below the epidermis are layers of circular and
longitudinal muscle fibers; used in locomotion
Nervous System
• Includes: anterior cerebral ganglia,
longitudinal nerve cords, and some lateral
nerves
• Most free living planarians and parasitic larval
forms possess a variety of sensory organs (e.g.,
eye spots, statocysts, rheoreceptors)
Organ Systems of the Platyhelminthes cont.
Reproductive System
• Most are capable of some form of
asexual reproduction (e.g., many
turbellarians reproduce by fission)
• Most flatworms are
hermaphroditic; however, they
often pair with other individuals to
exchange gametes
Class Turbellaria
• Free-living flatworms; mostly marine organisms
• Range in size from microscopic (interstitial species between sand grains) to extremely
large (two feet)
Locomotion
• Most move by means of cilia and
mucous
• Muscle contractions also permit
turning, twisting and folding of the
body
Class Turbellaria con’t
Nutrition
• Turbellarians are carnivores and prey on other animals or eat dead animal remains.
• Planarians have a muscular pharynx that they can insert into their prey and then pump to
bring in food fragments
• These animals have a highly divided gut to greatly increase the surface area for digestion
and absorption
Senses
• They have well developed sensory structures, including eyespots, mechanoreceptors, and
chemoreceptors
Class Turbellaria con’t
Reproduction
• Planarians are capable of asexual reproduction
via fission
• Also capable of regeneration; exhibit both
anterior- posterior and lateral polarity
• They are hermaphrodites but usually exhibit
cross-fertilization
• The penis of some turbellarians is modified as a
hollow stylet; sperm tranfer is by hypodermic
impregnation, in which the copulating partners
stab each other and inject sperm
Class Trematoda
• Flukes that live as parasites either on or in other organisms.
• Outer body lacks cilia; tegument has a layer of glycoproteins that are important in protection
and absorption
• Possess 2 suckers:
1. Oral sucker which attaches to organs of the host
2. Ventral sucker or acetabulum; used to attach to host tissues
Types of Hosts
• Often have complex life cycles that alternate between sexual and asexual stages.
• Most require at least 2 different kinds of hosts to complete their life cycle:
1. Definitive host (primary host)
• The host in which the parasite matures and reproduces (sexually)
• The host in which eggs are released
2. Intermediate host
• Hosts in which larval stages develop and undergo asexual reproduction
• Results in an increase in the number of the individuals
General Life Cycle - Chinese liver fluke, Clonorchis sinensis
• Adults live in the bile ducts of humans, dogs, and cats
• There are 2 intermediate hosts: a snail and a fish
• Eggs are passed out of the definitive host and hatch as ciliated larvae called miracidia
• The miracidia penetrates a snail molluscan host and becomes a sporocyst
• They undergo asexual reproduction producing larvae called rediae
• Rediae often asexually produce more rediae, but will eventually give rise to larvae called
cercariae
• They leave the molluscan host and penetrate fish
• They encyst in the fish tissues as the metacercaria
• Consumption of infected fish results in the metacercaria excysting in the gut and migrating
to the bile duct
Schistosoma
• Schistosoma spp. is a common blood fluke
of Southeast Asia that causes shistosomiasis
• Humans are the definitive host; snails are
the intermediate host
• In humans its eggs ultimately penetrates
and damages intestinal tissue and tissue of
the bladder
• A source of constant inflammation and
eventually leads to deterioration of liver,
spleen and other organs
Class Cestoda
General Morphology
• Nonciliated tegument composed of glycoprotein
• The anterior region is called a scolex; often armed with suckers and hooks
• Extending from the neck is a series of
proglottids; contain the sex organs and
eggs; no digestive system
• Mature eggs released through an opening
in the proglottid or leave the host when the
proglottids are separated from the main
body of the worm.
Beef Tapeworm, Taeniarhynchus saginatus
• Definitive host humans; intermediate host cattle
• Eggs are shed with human feces; infected persons defecate in a pasture and the eggs are
ingested by cattle
• Eggs hatch giving rise to oncosphere larvae that bore into the intestinal wall and get into
the circulatory system to be transported to muscle
• Here the larvae develop into the cysticercus stage (=the bladder worm) with the inverted
scolex
• If uncooked beef is consumed the cysticercus is freed and the scolex everts, forming the
adult
• Symptoms include loss of weight, chronic indigestion, diarrhea
Platyhelminthes
• Blue free-living flatworm
• Figi flatworm chases crab
• Monsters inside me - tapeworm
Roundworms
 Common name for phylum Nematoda is roundworms.
 They are among the most numerous of all animals.
 A single rotting apple can contain as many as 90,000.
 Pseudocoelomates (“pseudo” = false)
 No true coelom.
 They do have the peritoneal cavity (or gut), but it is not lined with
mesoderm.
Nematode = Thread?
Roundworms got their
name nematode because
they resemble a thread.
In Greek, ”nematos”
actually means thread
About 20,000 described
organisms
What is a Roundworm?
Slender, unsegmented worms.
Microscopic or up to a meter in
length.
Most are free-living
 inhabiting soil, salt flats, aquatic
sediments, and water from polar to
tropical regions.
Parasitic
Live in hosts
 almost every kind of plant and animal.
What is a Roundworm?
 The effects of nematode infestation on crops, domestic animals, and
humans make this phylum one of the most important of all parasitic
animal groups.
 Almost all species of vertebrates and many invertebrates serve as
hosts for one or more types of parasitic nematodes.
Digestion
Unlike the platyhelminthes,
nematodes have a digestive tract
with two openings.
The body plan is called a “tubewithin-a-tube.”
The outer tube is the body wall and
the inner tube is the digestive tract.
Food moves in one direction through
the digestive tract.
Form and Function in Roundworms
 Roundworms have specialized tissues and organ systems that carry
out essential body function.
 In general, the body systems of free-living roundworms tend to be
more complex than those of parasitic forms.
 Distinguishing characteristics of this phylum are their cylindrical
shape, flexible nonliving cuticle, lack of motile cilia or flagella, and the
muscles of their body wall run only longitudinally.
Body Covering
Outer body covering is a thick,
non-cellular cuticle secreted by
the underlying epidermis, or
hypodermis.
Feeding
 Most free-living roundworms are predators
 carnivores that use grasping mouthparts and spines to catch and eat other
small animals.
 Some soil-dwelling and aquatic forms eat algae, fungi, or pieces of
decaying matter.
 Other nematodes digest the bacteria and fungi that break down dead
animals and plants.
Respiration, Circulation,
and Excretion
Like flatworms, roundworms
exchange gases (respire) and
excrete metabolic wastes like
urea and ammonia through
their body walls. (diffusion)
They have no internal
transport system.
Response
 Nematodes have simple nervous systems, consisting of several
ganglia.
 Several nerves extend from ganglia in the head and run the length of
the body. These nerves transmit sensory information and control
movement.
 Roundworms have several types of sense organs.
Response
A ring of nerve tissue and ganglia are
found at the anterior end of their
bodies.
They have a pair of amphids
more complex sense organs that open
around their heads.
They have a pair of phasmids
similar in structure as amphids, but
open around the posterior end of the
body.
Movement
 Muscles of nematodes extend the length of their bodies.
 Together with the fluid in the pseudocoelom, create a “hydrostatic
skeleton.”
 A hydrostatic skeleton is the use of coelom fluid to maintain the shape
of the animal and allows for movement.
 Aquatic roundworms contract these muscles to move like snakes
through the water.
 Soil-dwelling roundworms push their way through the soil by
thrashing around.
Reproduction
Roundworms reproduce sexually.
They reproduce using internal
fertilization.
Female: has ovary, passes them to
the uterus, where they are fertilized.
Male: Sperm cells made in the testis
and stored in the vas deferens.
the male usually deposits sperm inside
the female’s reproductive tract.
Over 200,000 eggs can be deposited
at once in the soil once they are
fertilized.
Reproduction Cont.
Parasitic nematodes
often have complex life
cycles that involve two or
three different hosts or
several organs within a
host.
Anatomy
Classes of Nematoda
Two main classes:
Class Rhabditea – they are
both free-living and parasitic
forms.
Class Enoplea – mostly free
living, but includes some
parasites.
Roundworms &
Disease
Many nematodes are very
important pathogens of
humans and domestic
animals. Some of the
nematodes we will discuss:
Hookworms
Trichina Worm
Pinworms
Filarial Worms
Trichina Worm
They infect humans, hogs, rats,
cats, and dogs. Hogs can become
infected eating uncooked scraps of
infected meat or rats.
Heavy infections can cause death
but lighter infections are more
common.
About 2.4% of the U.S. population
is infected, mostly lightly.
Trichinosis
- cysts within the muscles
are consumed
(undercooked food)
-- worm grows in intestine
-- forms cysts in the
muscles of the new host
-- symptom: terrible pain in
muscles
Filarial Worms
 8 species of filarial nematodes that infect humans.
 About 250 million people in tropical countries are infected with Wuchereria
bancrofti or Brugia malayi, which live in the lymphatic system.
 They cause inflammation and blockage of the lymphatics.
 Females can be as long as 100 mm and can release live young, or tiny
microfilariae into the blood and lymph.
Filarial Worms cont.
Mosquitoes ingest the
microfilariae when they feed.
The worms develop to the
infective stage while inside the
mosquito and move into the
mosquito bite wound when it
feeds.
Filarial Worm Diseases
Filarial worms
cause three
main diseases
in their
definitive hosts:
Elephantiasis
River blindness
Dog heartworm
Ascarid Worms (common
roundworm)
- lives in intestine
- eggs are passed out in the feces
Most roundworms infect
dogs, but occasionally
they find their way into
human hosts
Hookworms
Hookworms are so named
because the anterior (head)
end curves dorsally, resembling
a hook.
They have large plates in their
mouths that cut into the
intestines so that they can suck
on
the host’s blood.
Hookworms cont.
 Hookworms suck more blood than they can digest. A heavy infection
can cause anemia.
 Eggs pass in feces and juveniles hatch in soil where they can live off
of bacteria.
 If human skin comes in contact with the soil, infective juveniles
burrow through the skin to blood.
 Bare foot, I think not!!!
Pinworms
Pinworms are the most
common worm parasite in the
U.S., but causes little disease.
It is estimated that 30% of
children and 16% of adults in
the U.S. have them.
Adults live in the large
intestine and cecum.
Pinworms cont.
Females, about 12 mm in length,
migrate to the anal region at
night and lay eggs, causing
itching.
Scratching the anal region
contaminates hands and bedclothes.
So how do you test for something
like this?
Scotch Tape Method
 Fecal examinations and finding the eggs, but eggs are often not found
in feces.
 Many times the female pinworm will deposit her eggs on the skin
around the anus. Doctors have started using the “scotch tape
method.”
 Truth is in fact stranger than fiction.
Scotch Tape Method
The scotch tape method consists of
placing the sticky side of cellulose
tape onto the anus overnight.
The next morning the tape is
umm...harvested and placed under a
microscope to search for eggs.
Drugs are effective against it,
all members of the family should be
treated at the same time because the
worms spread easily through a
household.
Pinworms
Eggs develop rapidly and become
infective within six hours at body
temperature.
When swallowed, these eggs hatch
in the anterior end of the small
intestine (the duodenum) and
mature in the large intestine.
Mollusks – Soft bodied
• D:\_Soft_Bodies___Mollusks.asf
• D:\Giant_Squid.asf
Echinodermata
• D:\_Spiny_Skinned___Echinoderms.asf
Arthropods – jointed “feet”
• D:\Spiders.asf
• D:\_Joint_Limbed___Arthropods_.asf
Arthropoda
• Millipede
• Crab walking
Crab eating
insect deathmatch
mosqquito larva
Echinodermata
Digestion
Why bilateria?
• Larval forms are bilateral floating in the
ocean as part of the plankton
• They convert to semi-radial symmetry as
adults when they become benthic feeders
Support and Skeleton
• Spiny skin
Why deuterstomes?
• Tubefeet
• Powerpoint
• weird man