Download Phylum Porifera (from the Greek poros "pore" and Latin ferre "to bear

Phylum Porifera
(from the Greek poros "pore" and Latin ferre "to bear")
•Sessile, mostly marine, filter-feeders, > 5000 marine spp but only a few freshwater
•Pump water through their bodies to filter out particles of bacteria and algae and other
organic matter
•simplest multicellular animals—lack tissues (eg muscles, nerves, internal organs)
•body of a sponge has 2 layers of cells separated by a gelatinous mesohyl
•believed to have originated from choanoflagellataes—a unicellular protist
•Size a few cm to 2m
•Reproduce sexually—gametes produced by the choanocytes or amoebocytes
eggs retained inside the mesohyl and motile sperm washed out by water
currents—zygote develops into small flagellated larvae that disperse and settle
•Also reproduce asexually by gemmules—small packs of tissue in a protective capsule
A comparison of unicellar and multicellular choanoflagellates to the body wall of a sponge
epidermis
Spicules
(skeletal elements)
Amoebocytes
(undifferentiated cells)
http://universe-review.ca/I10-82-choano.jpg
Mesohyl
(separates collar cells from
epidermis)
Development of a sponge from a flagellated larva
Anatomy of a sponge—showing the pattern of water circulation
Water enters through tiny ostia (pores), collects in the
spongocoel (body cavity) and leaves through the osculum
To obtain enough food to grow 100 g, a sponge must filter
1000 kg of water
From Campbell and Reece: Biology, Ch. 33, p 648
Sponges have amazing
regenerative ability
They can completely
regenerate themselves if
broken apart
In this experiment the
sponge is strained through
cheesecloth to break the
cells apart (1,2)
Over a period a week it
reattaches itself to the
substrate gradually
reorganizes itself into an
adult sponge (4-6)
http://www.eeob.iastate.edu/faculty/DrewesC/htdocs/spongeREAGG.jpg
A freshwater sponge gemmulating
--they usually do this in the fall
http://psteinmann.net/bilder_spongilla/gemmulae.jpg
http://rydberg.biology.colostate.edu/Dissections/CPspongillagemmules.htm
http://biology.about.com/library/weekly/aa090700a.htm
Spongilla lacustris—the most common freshwater sponge—generally green in shallow
water (contain intracellular Chlorella)
Often found attached to
sticks and rocks, but
may grow directly on
sand or even mud
http://cichlidpark.agava.ru/Images/plan2.jpg
http://botany.upol.cz/images/galerie/photos/spong.jpg
In softwater lakes where macrophytes don’t do well Spongilla can grow several feet tall, and essentially take over
the macrophyte niche in the lake
http://images.google.ca/imgres?imgurl=http://www.water-vision.de/Video-Dateien/Bilder/V00061_1.jpg&imgrefurl=http://www.water-vision.de/VideoDateien/vdeu_schwaemme.htm&h=300&w=400&sz=41&hl=en&start=35&tbnid=I8myP7i0xpzs_M:&tbnh=90&tbnw=120&prev=/images%3Fq%3Dspongilla
A good closeup of Spongilla growing on a rock near shore, where you can see the oscula very clearly, the ostia are
microscopic
http://shop.uwphoto.no/500/rsv066cd036.jpg
Spongilla growing in deep water is generally a pale
brown colour—no Chlorella
Freshwater sponge spicules (made of silica)
http://www.acadweb.wwu.edu/courses/envr429-rm/Robin/images/envr429/77_spongilla_spicules_4
http://images.google.ca/imgres?imgurl=http://www.superiortrips.com/images/stickelback.jpeg&imgrefurl=http://www.superiortrips.com/life_on_a_shipwreck_pag
e3.htm&h=480&w=720&sz=41&hl=en&start=15&tbnid=vwbOUlXr9EvT9M:&tbnh=93&tbnw=140&prev=/images%3Fq%3Dfreshwater%2Bsponge%26svnum%3
D10%26hl%3Den%26lr%3D%26sa%3DG
The adult fly that emerges from the sponge
Spongilla generally harbour the larvae of Sisyra (Class Insecta, Order Neuroptera) as an internal
parasite
http://www.nanfa.org/akiweb/794.JPG
http://home.hccnet.nl/d.van.vliet/foto_02/zoetwaterspons.jpg
Ephydatia muelleri. Photo:Henry M. Reiswig
http://www.ittiofauna.org/webmuseum/invertebrati/microinvertebrati/images/ephydatia-500.jpg
http://www.canadianbiodiversity.mcgill.ca/english/species/sponges/spongepages/eph_mue.htm
Phylum Cnidaria
(from the Greek word "cnidos," which means stinging nettle)
•Very diverse phylum containing well known marine species (>10,000 marine spp)
such as sea anemones, hydras, a wide variety of jellyfish, and all of the corals
•all carnivores and capture prey with tentacles that contain nematocysts
•body plan is simple—a radially symmetrical sac with a central cavity, the
gastrovascular cavity with a single opening serving as both mouth and anus
•two variations, the sessile polyp and the motile medusa
•two tissue layers in the body, gastrodermis and epidermis, separated by mesogloea
•Reproduction can be sexual, usually gonads developing either on the medusa or the
polyp—many species have both polyp and medusa in their life cycle
•Asexual reproduction occurs by “budding”
From Campbell and Reece: Biology Chapter 33
A cnidocyte of a hydra—contains a stinging capsule (nematocyst) containing an inverted thread which
everts under pressure when triggered by touch or chemical stimuli. The spiny thread shoots out from the
nematocyst and injects poison into the prey. Other types of nematocysts have different types of threads,
some entangle prey and some just stick to prey that bump into the tenctacles
A tentacle of Chlorohydra, showing nematocytes and also, many chlorella living
inside the animal
http://images.google.ca/imgres?imgurl=http://micrographia.com/specbiol/cnidari/hydrozo/hydr0100/hydvir04.jpg&imgrefurl=
http://micrographia.com/specbiol/cnidari/hydrozo/hydr0100/hydvir04.htm&h=296&w=480&sz=32&hl=en&start=4&tbnid=ug
cZYiBlt4U3hM:&tbnh=80&tbnw=129&prev=/images%3Fq%3Dhydra%2Bnematocysts%26svnum%3D10%26hl%3Den%26l
r%3D%26sa%3DG
A tentacle squashed under the
comound microscope shown
many nematocysts
http://www.ville-ge.ch/musinfo/mhng/hydrozoa/intro/nematocysts.jpg
http://images.google.ca/imgres?imgurl=http://www.visualsunlimited.com/images/water
marked/319/319205.jpg&imgrefurl=http://www.visualsunlimited.com/browse/vu319/vu3
19205.html&h=235&w=350&sz=11&hl=en&start=7&tbnid=WSRmOdEIs6JelM:&tbnh=7
7&tbnw=116&prev=/images%3Fq%3Dhydra%2Bnematocysts%26svnum%3D10%26hl
%3Den%26lr%3D%26sa%3DG
From Campbell and Reece: Biology Chapter 33
Polyp and medusa are variations
on the same body plan—a radially
symmetrical sac (gastrovascular
cavity) with a single opening
(mouth/anus) surrounded by
tentactles.
The polyp has its aboral end
attached to the substrate, and
feeds passively on prey that
“bump” into the tentacles.
The medusa swims freely by jet
propulsion—expelling water out the
opening, with its aboral end
upwards
The generalized life cycle of a hydrazoan alternating between the polyp and medusa stage
http://www.biol.andrews.edu/fb/spring/chap.%2033/3306%202.jpg
Hydra and Chlorohydra are the most common freshwater genera—no medusal stage
Sexual and asexual reproduction in Hydra
A hydra “budding” off new polyps asexually
http://www.eeob.iastate.edu/faculty/DrewesC/htdocs/hydra-mature.jpg
http://z.about.com/d/biology/1/0/P/2/hydrabud.gif
Chlorohydra showing the green colour they get from harbouring Chlorella as symbionts
Chlorohydra budding
http://www.microscope-microscope.org/gallery/hydra-187h.jpg
Hydras feed mainly on Cladocera, which often bump into their tentacles—this one has captured and swallowed a Daphia
http://www.worth1000.com/entries/34500/34986vopr_w.jpg
The life cycle of
Craspedacusta
http://sites.estvideo.net/sub.club.stbg/images/bio/craspedacusta.gif
Craspedacusta sowerbyi—the freshwater jellyfish
http://images.google.ca/imgres?imgurl=http://jellieszone.com/images/craspedacusta.jpg&imgrefurl=ht
tp://jellieszone.com/craspedacusta.htm&h=216&w=288&sz=22&hl=en&start=3&tbnid=cLKqaQBnwcg
YdM:&tbnh=86&tbnw=115&prev=/images%3Fq%3DCraspedacusta%26svnum%3D10%26hl%3Den
%26lr%3D%26sa%3DG
http://www.niwascience.co.nz/pubs/wa/10-2/alien1_large.jpg
Oral (ventral) view of Craspedacusta
medusa. You can see up into the
medusa to see the 4 gonads showing
at roughly 10, 1, 4, and 7 o'clock. The
tissue extending inward from the
margin of the umbrella toward the
center is called the velum. The
crenulated structure in the center is
the end view of the manubrium
(projection extending below the
umbrella on the underside and
containing the gastric or stomachal
cavity.) The opening in the center of
the manubrium is the mouth.
http://images.google.ca/imgres?imgurl=http://nsm1.nsm
.iup.edu/tpeard/images/Craspedacusta_oral.jpg&imgref
url=http://nsm1.nsm.iup.edu/tpeard/picture21.htm&h=1
024&w=1280&sz=298&hl=en&start=12&tbnid=nGmrvV
5RGnJw9M:&tbnh=120&tbnw=150&prev=/images%3F
q%3DCraspedacusta%26svnum%3D10%26hl%3Den%
26lr%3D%26sa%3DG
Phylum Bryozoa: “moss animals”
•Colonial coelomate animals, encased in a
hard exoskeleton with openings from which
the lophophore—its feeding organ extends.
•The lophophore bears a crown of ciliated
tentacles, which are hydraulically extended
outgrowths of the body wall communicating
with the coelomic cavity.
•The cilia on the tentacles drive a current of
water through the lophophore (filter-feeding)
and move a mucous thread filled with food to
the centrally located mouth
•Freshwater bryozoans have a horseshoeshaped lophophore with a central mouth and
an exterior anus.
•Reproduce sexually during summer
•Form statoblasts--dispersal/resting stage,
asexual reproduction during autumn
http://bio.classes.ucsc.edu/bio136/bryozoa/bryozoana.gif
About 5000 species, mostly marine but some
freshwater spp exist
The lophophore of a bryozoan, showing the gut filled with algae
A picture of a colonly of Plumatella growing on substrate—aquatic macrophytes are the most common substrate
A colony of Plumatella releasing statoblasts
http://www.senckenberg.de/images/content/forschung/abteilung/aquazool/mev3/statoblast.jpg
Statoblast formation in a bryozoan colonly
http://www.flmnh.ufl.edu/malacology/IZ2005/LabNotes/Lab10/Image4.jpg
Statoblast germinating to
release a small polyp,
which will branch off more
polyps to form a
branching colony
Some freshwater bryozoan can get very large
A colony of Pectinatella magnifica, attached to a stick
http://www.magma.ca/~syatabe/water_brains/water_brains.html
The freshwater bryozoan Lophopus
http://www.micrographia.com/specbiol/bryoz/bryo/loph0100.htm
Phylum Platyhelminthes—platy means flat and helminth means worm
•the simplest animals that are bilaterally symmetrical and triploblastic
•acoelomate—no internal fluid skeleton
•mesoderm fills the space between the endoderm (gut lining) and the ectoderm, body wall
•well differentiated tissues and organs, eg brain, bilateral nervous system, muscles, excretory
organs, reproductive organs
•In addition to free living flatworms this phylum also includes tapeworms and flukes
Class Turbellaria—means whirlpool (named for the whirling appearance of their cilia)
•free living flatworms> 4000 spp mostly marine and benthic, > 200 freshwater spp
•<1 mm to > 1cm long
•carnivores with an intestine and an extrudable muscular pharynx located in the center of the
body—the single opening to the pharynx also serves as the anus
•move by coordinated waves of cilia on a secreted mucus trail, though some species can
swim by rhythmic muscle contractions.
•simultaneous hermaphrodites and lay eggs bundled into cocoons.
• young undergo direct development and hatch as juveniles.
• Some turbellarians can reproduce asexually by fission.
•Regeneration of somatic parts is well documented in Dugesia.
Order Tricladida—means three branches
•gut has three branches one anterior and two posterior, each with many branched diverticula
•Anterior region with tactile auricles and eyespots arranged in a characteristic pattern
Order Rhabodocoela—means rod-shaped gut
•Straight (unbranched) gut
The common freshwater triclad Dugesia tigrina
http://animaldiversity.ummz.umich.edu/site/resources/Grzimek_inverts/Turbellaria/v01_id222_con_turanat.jpg/medium.jpg
Internal anatomy of Dugesia showing digestive, nervous, and reproductive systems
Dugesia with extruded pharynx
Flatworm feeding on a mayfly larva
Extruded muscular pharynx
http://images.google.ca/imgres?imgurl=http://www2.una.edu/microaquarium/images/Flatworms/Planaria_3cm.jpg&imgrefurl=http://w
ww2.una.edu/microaquarium/flatworms.htm&h=413&w=298&sz=24&hl=en&start=7&tbnid=PkrURffBKV83kM:&tbnh=125&tbnw=90&p
rev=/images%3Fq%3DMesostoma%26svnum%3D10%26hl%3Den%26lr%3D%26sa%3DG
mating flatworms. Although flatworms are usually simultaneous hermaphrodites they will not
self fertilize
During copulation worms were observed to move towards each other, touch, then wind themselves around each other. Then
they rear up and try to stab each other anywhere, sometimes causing considerable damage to their partner. During that time,
spermatozoa are injected into the partner.
http://www.rzuser.uni-heidelberg.de/~bu6/mate09.jpg
A flatworm egg cocoon
http://www.ncdc.noaa.gov/paleo/parcs/atlas/beringia/images/fossils46.jpg
Turbellarian species differ in regards to the shape of the anterior region,
shape of the auricles, placement and size of the eyespots, general
body colour and characteristics of the gut diverticula
Polycelis felina
Planaria gonocephala
Dendrocoelium lacteum
Polycelis nigra
http://images.google.ca/imgres?imgurl=http://www.bioweb.lu/sapro/felina.gif&imgrefurl=http://www.bioweb.lu/sapro/strudel.htm&h=261
&w=161&sz=13&hl=en&start=2&tbnid=2aZ0rcL3vhTS6M:&tbnh=112&tbnw=69&prev=/images%3Fq%3Dpolycelis%26svnum%3D10%
26hl%3Den%26lr%3D%26sa%3DG
Order Rhabdocoela, Mesostoma ehrenbergi—an efficient predator on mosquito larvae and
zooplankton (copepods and cladocera) in small fishless ponds
Mesostoma occasionally harbours endosymbiotic Chlorella
Phylum Tardigrada—means slow walker
•tiny slow moving animals < 1 mm,
found in virtually any type of ecosystem
•bodies roughly cylindrical and divided
into segments,
•posses four pairs of lobe-like limbs
terminating in 4-8 claws or discs
•Crawl slowly around on moss or other
plant material, sand or mud
http://www.museums.org.za/bio/tardigrades/index.htm
Common name is water bear
•Their mouths contain piercing stylets
which they use to suck juices from
mosses, algae, rotifers or other small
animals
•Over 800 spp known, most with a
world wide distribution
Tardigrades like the mosses they live on are able to dry up completely and enter a state of
suspended animation (cryptobiosis) called a tun. The tun rehydrates quickly and resumes
activity within a few minutes after the moss is wetted.
Tun formation
The limbs invaginate, the body contracts and becomes folded.The tun formation is an active process
requiring metabolism and synthesis of a protective sugar Trehelose. After the tun is formed further
desiccation can take place in 0 % relative humidity and the tardigrade can still survive. Revival typically
takes a few hours from natural habitats but depends upon how long the tardigrade has been in the
anhydrobiotic condition.
While in a state of cryptobiosis tardigrades are able to resist environmental extremes that would be instantly letha to
animals if in the active state. In 1842, the French naturalist Doyere first discovered tardigrades were able to withstand
being heated for a few minutes to 125 °C, later Rham in 1929 increased this figure to 150°C. Adults have been able to
survive being cooled to temperatures of almost absolute zero (-272.8°C) where there is no free molecular vibration and so
no metabolism can exist. While in this state the organisms are also greatly resistant to X-Rays of 570,000 Roentgens
(only 500 Roentgens would be fatal to a human). Water bears are also resistant to a vacuum (like outer space), some
noxious chemicals, boiling alcohol, and pressures six time greater than the bottom of the deepest ocean etc.
http://www.museums.org.za/bio/tardigrades/index.htm
Ovary containing eggs
gut
Salivary gland
Pharyngeal bulb, muscular
Retractable piercing stylets
Nerve ganglion on ventral nerve cord
Typically tardigrades are dioecious, sexually reproducing with both male and females. Each has a single
gonad which lies dorsally to the gut. However, some species are hermaphrodite and the absence of males
has been reported in many populations, the females then reproduce asexually by parthenogenesis.
Tardigrades express eutely, which means that the number of cells in some organs of the body is fixed from
birth, growth occurring by increase in size only and not cell division. They do not have circulatory and
respiratory systems and the excretory system may also be minimal.
http://biodidac.bio.uottawa.ca/ftp/BIODIDAC/ZOO/TARDIGRA/DIAGCL/TARD002C.GIF
Tardigrade eggs
http://www.hydro-kosmos.de/mikmak/wmic12.jpg
Eggs are laid when the animal moults its skin—the
eggs are deposited in the exuvium
The widespread distribution of tardigrades may be attributed to the fact that their eggs, and tuns are
light enough to be distributed by wind or animals for great distances possibly in the upper atmosphere.
http://www.bumblebee.org/invertebrates/images/Tardigra.gif
http://zooex.baikal.ru/pictures/izba/tard4.jpg
Flatworm- reproductive and nervous systems
A
B
1
2
3
4
5
6
7
8
9
10
11
12
13
Reproductive system
Nervous system
Ovary
Oviduct (ovovitelline duct)
Yolk gland
Sperm duct (vas deferens)
Testis
Seminal receptacle
Penis
Reproductive opening (ventral)
Entrance to oviduct
Genital chamber
Brain (cerebral ganglion)
Lateral nerve cord
Sensory lobe