The Simplest Animals Sponges Jellyfish Flatworms Roundworms Many images from: .
-
Upload
barbara-gregory -
Category
Documents
-
view
220 -
download
3
Transcript of The Simplest Animals Sponges Jellyfish Flatworms Roundworms Many images from: .
The Simplest Animals
Sponges
Jellyfish
Flatworms
Roundworms
Many images from: www.oceanicresearch.org/.../cnidarian.html
The Simplest Invertebrate Phyla are: -without a skeleton
-without segmentation:
• Porifera (sponges)
• Cnidaria (jellyfish, hydras, sea anemones, Portuguese man-of-wars, corals)
• Platyhelminthes (flatworms, including planaria, flukes, and tapeworms)
• Nematoda (roundworms, including rotifers and nematodes)
http://sps.k12.ar.us/massengale/images/brac-sponges-21.jpg
I. SpongesI. Sponges
Why areWhy are sponges sponges considered considered animals?animals?
• Early biologists thought they were
plants!
The most primitive of the
simplest animals: SpongesSponges• Phylum: Porifera-
• Invertebrate (no backbone)
• Asymmetrical
• No true tissues or organs• All species -Aquatic
• Adult is Sessile Sessile (do not move)
Sponges have key Sponges have key characteristics of animals:characteristics of animals:
• Heterotrophic
• Multicellular• Adults are sessile- but some
species can move up to 4mm/day (http://www.ucmp.berkeley.edu/porifera/poriferalh.html) –And sponge larvae have flagella
Basic Body plan of a SpongeBasic Body plan of a Sponge
Asymmetrical & Sessile
Vocabulary of sponge parts:• Osculum- Hollow cylinder shape, closed at
bottom, opening at top called
• Choanocytes ( collar cells) – flagellated cells that draw water into the sponge through pores in the body wall called Ostia.
• mesohyl – jelly-like material separates 2 layers of cells
Purple Tube Sponge ColonyPurple Tube Sponge Colony on Dead Coralhead at
Rainbow Reef near Bimini, The Bahamas
www.reefnews.com/.../photos/corals/sponges.html
If Coral Reefs are in danger- are sponges that grow on them bad?• Animals that eat sponges and algae help
to keep a healthy balance on the reef.
• If there are too few of these animals, then the sponges and algae may take over.
• Examples of algae eaters are Parrotfish, Sea Urchins, and Crabs.
• Examples of sponge eaters are Hawksbill Turtles and Loggerhead Turtles.
www.reefnews.com/.../photos/corals/sponges.html
How does a sponge eat?How does a sponge eat?• Sponge cells work together, pumping water
through the body of the sponge. • The sponge eats the plankton, bacteria &
organic material it filters out of the water as the water is pumped through the body of the sponge.
• Amoebocytes- crawling cells that deliver nutrients from choanocytes to the rest of the body
• Sponges are filter feeders!www.reefnews.com/.../photos/corals/sponges.html
How does a sponge reproduce?1. Asexual
a. Budding- part of the parent pinches off & forms a new organism
b. Gemmules – a reproductive structure in sponges, -produced in harsh conditions-a food-filled ball of amoebocytes in a protective coat
c. Regeneration- regrowth of missing cells.
2. Sexuala. Sperm are released into water, enters next sponge through pores, choanocytes engulf sperm. Carry to ameobocytes, carry them to egg in mesophyl. Produces a flagellated Larvae (immature form)
b. Hermaphrodite- each sponge has both eggs & sperm
Some sponges grow quite
large. This barrel sponge is nearly large enough for the diver to climb
right inside! Other barrel sponges get
even bigger than this.
Porifera represent transition Porifera represent transition from unicellular from unicellular
to multicellular life.to multicellular life.
• Cnidarians are animals with 2 tissue layers
• Cnidarians are the simplest animals with nervous & muscle
tissue.
• They sting & eat their prey!
Giant jellyfishGiant jellyfish (6-7 feet across)
www.divester.com/.../
Pink Hearted hydroids, members of the class Hydrozoa. They look like delicate plants but they are
animals that sting and capture food.
Fire Coral has a potent sting that leaves an itchy rash on human skin. A kind of
hydroid that encrusts other objects (including other corals).
Sea AnemoneSea Anemone
library.thinkquest.org/.../01819/SeaAnemones.htm
Tealia anemone a good example of an Anthozoan. Flower-like animals resemble plants, but they have a mouth at the center of their tentacles, & a primitive digestive system.
Cnidarian Body PlanCnidarian Body Plan2 types of bodies or Stages:
Medusa –bell shaped, swims
Polyp – vase-shaped, sessile
2 cell tissue layers-
Epidermis outside layer
Gastrodermis inside layer
-with Mesoglea (jelly) in between)
1 opening Gastrovascular cavity (gut)
Many TentaclesTentacles with cnidocytescnidocytes
http://biology.unm.edu/ccouncil/Biology_203/Images/SimpleAnimals/cnidariaDiagram.jpeg
POLYP
MEDUSA
How do Jellyfish eat?1.Cnidocytes (special defensive cell) have
Nematocysts (coiled organelle with stinging filament)
2. Tentacles push prey in mouth & intogastrointestinal cavity
3. Digestion is
Extracellular, wastes
expelled through mouth.
http://www.emc.maricopa.edu/faculty/farabee/biobk/cnidaria_1.gif
Jelly fish are the 1st animals to have nervous & muscle tissue
Nerve Net -Nerve cells interconnect and form a nerve net throughout the body.
Movement – using pulsing tentacles
Cnidarians have both muscle fibers and nerve fibers, making these animals capable of directional movement.
Cnidarian classes:Cnidarian classes:
1. Hydrozoa. Hydrozoa ( 3,700 species) ex- Obelia, Portuguese Man-O War.
2. Cubozoa. Cubozoa ex- box jellies, sea wasp
3. Scyphozoa. Scyphozoa “cup-animals” jellyfish
4.4. AnthozoaAnthozoa (6,100 species) “flower animals” like sea anemones, corals
Deadly danger: Portuguese man
o'war
can in extreme cases provoke a cardiac arrest and death in particularly sensitive persons.
www.dailymail.co.uk/news/article-1050187/Pict...
Lucky escape: Jonathan Asplin was only
saved from worse harm by his wetsuit
Pictured: Horrific scars suffered by boy, 8, stung by deadly Man o' War on British coast
www.dailymail.co.uk/news/article-1050187/Pict...
The Freshwater Hydrozoan
Hydra:Polyp with early
and mature bud.
www.micrographia.com/.../hydr0100/hydra-01.htm
Sea WaspSea Wasp
The venom of an adult sea wasp is so powerful that the victim may not even have time to swim to shore.
www.jyi.org/features/ft.php?id=189
Jellyfish Sting TreatmentJellyfish Sting Treatment • Rinse with seawater. Avoid fresh water because it will
increase pain. Do not rub the wound or apply ice to it. • For classic box jellyfish stings, apply topical acetic acid
(vinegar) or isopropyl alcohol. • Remove tentacles with tweezers. • Apply shaving cream or a paste of baking soda or mud to the
wound. Shave the area with a razor or knife and then reapply vinegar or alcohol. The shaving cream or paste prevents nematocysts that have not been activated from discharging toxin during removal with the razor.
• Immobilize the extremity because movement may cause the venom to spread.
• Hydrocortisone cream may be applied 2-3 times daily to relieve itching.
• CPR may be necessary for all stings if the person stops breathing and/or no longer has a pulse.
http://firstaid.webmd.com/wilderness-jellyfish-sting-treatment
The animals we usually call jellyfish
belong to the class ScyphozoaScyphozoa.
-almost all are drifters. Some of the jellyfishes are big, measuring many feet across with long, trailing tentacles. Like other cnidarians, the tentacles are lined with stinging cells
Jelly fish Reproduction:
• Some reproduce asexually – especially in warmer temperatures.
– (Hydra-buddingbudding)
• Sexual reproduction- – lower temps
– hermaphrodites.hermaphrodites. – Motile sperm, egg in ovary.
And now for … worms…• The term "worm" has no systematic value
whatsoever. • Basically, any elongated invertebrate can be called
a "worm", regardless if it is or not related to similar creatures.
• However, two of the most primitive types of organisms receive that common name: WORMSWORMS
• Phylum PlatyhelminthesPhylum Platyhelminthes -flatworms
• Phylum NematodaPhylum Nematoda -roundworms
www.kingsnake.com
III. PlatyhelminthesIII. Platyhelminthes(flatworms)
• Planaria (free-living predators)
• Flukes (parasitic)
• Tapeworms (parasitic)
Flatworms (Platyhelminthes)
• Bilateral symmetry– Are the simplest of animals to have bilateral symmetry – Body flattened, leaf or ribbon-like (dorsal-ventral)
• All 3 tissues layers– Ectoderm, – Mesoderm– Endoderm
• Acoelomate (No body cavity) – solid body– completely filled in with tissue.
A marine turbellarian
flatworm
• ribbonlike movement
• body surface covered in mucus-covered cilia• The ripples create waves of mucus, through which the
creature pulls itself smoothly forward, using the hairlike projections.
encyclopedia.farlex.com/Platyhelminthe
Three common marine flatworms
from south-eastern Australia.A: Paraplanocera oligoglena.B: Pseudoceros sp.C: Eurylepta fuscopunctatus.Photo: Bill Rudman.
A Planarian is a free living hunterA Planarian is a free living hunter
-hunts small organisms
-eats with it’s Pharynx (a muscular feeding tube/opening)
- 1 opening gastrovascular cavity
-sac body plan, with mouth serving as both a mouth and anus (there is no anus).
Body of a planarianBody of a planarian
No true Circulatory / Respiratory systems-cells exchange oxygen & CO2 directly from environment
It looks like it has eyes: but these are just EYESPOTSEYESPOTS
Nervous System- cerebral ganglia serves as a simple brain- transmits signals down “ladder-like” nerve network.
Can respond to light, chemicals, touch & water currents in the environment
Excretory SystemPlatyhelminthes are the simplest animals to have a dedicated excretory
system.
-Flame cells -a specialized excretory cell to eliminate excess water
-function like a kidney, removing waste materials.
-are "cup-shaped", with cilia covering the inner surface
The beating cilia resemble a flame, giving the cell its name.
-Excretory tubules -Beating of the cilia moves liquid through the excretory tubule & pores-out of the organism.
Infestation in a fishtank w/ flatworms
Owners have tried poison, cleaning, etc but can’t get rid of them
www.neilcreek.com/.../
Testimony on flatworms infestation in the fish tank…
• These hideous creatures are a huge pest in our marine aquarium. They are called flatworms and they have overrun our tank.
• They must have come in to our tank from a bought coral, and found the conditions to their liking.
• They are in huge numbers, and any exposed surface is about 30% covered by them.
• On three seperate occasions we’ve poisoned them and syphoned out all that we could see, but within a month they’re back to the same population level.
• We hate them, they make the tank ugly and we have no idea how to get rid of them… :(
4 Classes of Flatworms:
-Class Turbellaria (free-living flatworm predators)
-Class Trematoda & Monogenea (flukes)
-Class Cestoda (tapeworms). flukes and tapeworms are adapted to a parasitic mode of life
COOL THING ABOUT FLATWORMS:– If cut- they will re-grow parts missing (regeneration)
RegenerationPlanarian morphogenesis is complicated & mysterious. When its part of body is cut, each piece of the part regenerates itself. In some cases, it gets 2 heads or tails.
users.design.ucla.edu
Class Turbellaria
• 4, 500 species (ocean or fresh water)• Scavenger lifestyle, eat with pharynx• Flame cells (cilia- aids excretion)• eyespots sense light on “Spade” shaped head.• Example is Dugesia, freshwater (family Planariidae)
www8.nos.noaa.gov/.../index.aspx?letter=e http://www.discoveryscope.net/images/circleworm.gif
The classes Trematoda and Monogenea consist of parasitic flukes.
• Some are endoparasites;
• others are ectoparasites.
Structure of Flukes• clings to the tissues of its host by an anterior
sucker and a ventral sucker.
• External surface is covered by a protective layer called the tegument.
Reproduction & Life Cycle of Flukes
• Most flukes are hermaphroditic.• Complicated life cycles
– involve more than one host species.
• For example, the trematode blood flukes of the genus Schistosoma – use humans as a primary hosts
–snails as intermediate hosts. – They can cause schistosomiasis.
Class Cestoda. • 5,000 species of tapeworms • Tapeworms can live in the intestines of
almost all vertebrates.
Structure of Tapeworms• surrounded by a tegument.• attach to the host with a scolex.• series of many sections: proglottids.• have no light-sensing organs, no mouth,
no gastrovascular cavity, and no digestive organs.
Life cycle of a human beef tapeworm, Taenia saginatus
• A man eats a poorly cooked piece of beef containing the encysted bladderworm (tapeworm cyst) in the skeletal muscle tissue.
• Tapeworm attaches to the intestinal wall by its anterior end called the scolex. (anchors it to the host's intestinal wall by four suckers.)
• Grows by budding as the scolex produces flattened segments called proglottids. – A human tapeworm may contain hundreds of proglottids and be
several feet in length. • Tapeworms compete with their host for nutrients. • Large tapeworms may obstruct food passages.• Excreted eggs in feces continues cycle for next host.
Want to lose weight?
• Note: Some early diet pills actually contained a tapeworm cyst enclosed in a gelatin
capsule, before they were banned by the Food & Drug Administration. You could take the pill and eat as much as you want without gaining weight! You were actually feeding a
large tapeworm which could be very dangerous.
• **The largest flatworm on record was 91 ft long
• several feet long. • San Diego Clinic case- A
man noticed a long white ribbon in his feces and thought he had swallowed his pajama draw strings during the night. The white ribbon turned out to be a tapeworm!
Story & photo from: http://waynesword.palomar.edu/trnov01.htm
Human tapewormsHuman tapeworms
II. Nematoda (Roundworms)
• Nonsegmented round worms that include many common parasites
• Long, slender bodies that taper at both ends.• Most species are free-living; some are parasites.
• A. Structure-Bilateral symmetry
-3 tissue layers-Pseudocoelomates • body cavity not completely lined by mesoderm• where organs are found • can serve as a hydrostatic skeleton.
• Roundworms have a ONE WAY digestive tract with two openings.
• Most roundworms have separate sexes
• are covered by a protective cuticle.
Most roundworms are free living • See following examples of parasites:
Ascaris (from page 696 Holt biology textbook)• The genus Ascaris infects pigs, horses, and humans. • The eggs enter hosts through contaminated food or
water, develop into larvae in the intestines, and can infect the lungs.
• The eggs are spread in the hosts’ feces.
Hookworms Intestinal parasites that feed on blood.• The eggs produce larvae in soil, and the larvae enter
hosts through the feet.• Infect about one billion people worldwide.
Trichinella Genus Trichinella infects humans, other mammals.
• Adults live in intestines and larvae form cysts in muscles. • People usually become infected from undercooked pork.
• Infection causes the disease trichinosis.
Other Parasitic Roundworms• Pinworms, genus Enterobius, are common parasites of
humans. They cause itching but do not cause any serious disease.
• Filarial worms infect many people in tropical countries. The most dangerous ones infect the lymphatic system & may cause elephantiasis.
hookworm
courses.bio.psu.edu/.../tutorials/tutorial39.htm
www.med-chem.com
Trichinella spiralis encysted larva
www.reuk.co.uk
Large roundworm of man(ascaris infection )
March 09, 2007: A guinea worm is extracted by a health worker from a child's foot at a containment
center in Savelugu, Ghana. foxnews.com
Guinea Worm
• occurs when people drink water contaminated with worm larvae.
• can grow to the size of a 3-foot-long spaghetti noodle.
• they emerge through the skin, often causing searing, debilitating pain for months.
PINWORMS!PINWORMS!• It is estimated that 40 million people in the U.S.
have pinworms at any given time.
• Approx.10 percent of children in daycare10 percent of children in daycare are likely to be infected with pinworms.
• Caregivers also can become part of the transmission cycle as you pick up toys and play with an infected child. Caregivers also may come in contact with the pinworm eggs during diapering or assisting with toileting.
http://www.healthychild.net/articles/sh35pinworms.html
Elephantiasis
http://www.smith.edu/news/2007-08/images/elephantiasis2.jpg
en.wikipedia.org/wiki/Elephantiasis www.answers.com
www.viewimages.com