Transcript Marine Invertebrates_7a (Porifera, Cnidaria, Ctenophora)

Kingdom Animalia
Kingdom
Animalia
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Eukaryotic (Domain Eukarya)
All Multi-cellular (unlike Protists)
All Heterotrophic (unlike Plants)
No cell walls (unlike Fungi and Plants)
Sexual reproduction
Cells are organized into structurally-functional
tissues
Marine Animals Without A Backbone
• There are two major groups of animals: the
vertebrates, which have a backbone, and the
invertebrates, those without a backbone
• Of all the species of animals, ~97% are
invertebrates!
Marine Animals Without A Backbone
• All major groups of invertebrates have marine
representatives, and many are exclusively
marine
• Other than insects – one of the few
invertebrate groups to invade land – most
animals are marine!
– ~8/10ths of all organisms
are Arthropods!
if Facebook existed years ago…
Phylum Porifera
• Sponges are the simplest of all animals; best
described as aggregations of specialized cells
• Sponges do not have true tissues or organs;
cells are largely independent of one another
• All are sessile (non-mobile)
• Porifera means “pore bearer”
• NO body symmetry
Phylum Porifera
• Tiny pores, or ostia allow water to enter and
circulate through a series of canals where
plankton and other organic debris are filtered
out and eaten
• Sponges are suspension feeders,
animals that eat food particles
suspended in the water column
• Filter feeders; they actively
filter out food particles
Phylum Porifera
• Water is pumped into a feeding chamber lined
with collar cells, or choanocytes
• Choanocytes have a flagella that generates a
current, and a thin collar that traps food
particles
• Food is then ingested
within the cell
Phylum Porifera
• As sponges get larger, they need structural
support
• Most have spicules, supporting structures of
different shapes and sizes, made of silica or
calcium carbonate
• Many also have a ‘skeleton’ of
tough, elastic fibers made of a
protein called spongin
Phylum Porifera
• Wandering cells, or amebocytes secrete the
spicules and spongin
• Amebocytes also transport and store excess
food particles, and can change into other cell
types, quickly ‘repairing’ any damage to the
sponge
• ~80% of food particles are engulfed and
ingested by choanocytes; smaller particles,
inc. bacteria and dinoflagellates are eaten by
amebocytes
Sponges are filter-feeders
You are what you eat…
• The silica frustules of diatoms and
other phytoplankton help make the
glass spicules of sponges!
Diatoms
Sponge
Sponges are boring!
• A family of sponges known as boring sponges
bore into shells by use of an
enzyme produced by the
amebocytes
• Sponge larvae settle onto wood
and/or shells and create
burrows where they will grow
Sponge worthy?
• Unlike most animals, many sponges reproduce
asexually
• Branches or buds break off to form separate,
but identical, sponges
• Like all animals, however, sponges also
reproduce sexually
– Specialized coanocytes or amebocytes produce
eggs and sperm
– Sponge larvae is planktonic!
Phylum Cnidaria
• Cnidarians (phylum Cnidaria) are multicellular animals with tissues that perform
specific functions
• Cnidarians include the sea anemones, jellyfish,
coral, and their relatives
• Cnidarians have radial symmetry;
in fact radial symmetry evolved
in the Cnidarians!
Cnidarians are rad!
• Animals with radial symmetry look the same
from all sides and have no head, front or back
• Instead have an oral surface (where mouth is)
and aboral surface
Phylum Cnidaria
• Cnidarians have a centrally-located mouth
surrounded by tentacles, slender, finger-like
projections used to capture and handle food
• All possess stinging cells, or nematocysts
• Nematocysts employ neurotoxins which
paralyze prey; 7-17 different types
• The mouth opens up to a gut, with only one
opening
Nematocysts
http://www.youtube.com/watch?v=BpKKGBivQo&feature=related
Phylum Cnidaria
• Cnidarians occur in two basic forms: a polyp, a
sac-like attached form with its mouth and
tentacles pointed upward, and a bell-like
medusa, which resembles an upside-down
polyp adapted to swimming
• Some Cnidarians have both polyp and medusa
stages; others spend their entire lives as either
a polyp or a medusa
Phylum Cnidaria, Class Hydrozoa
• The Hydrozoans are a class of very small,
predatory Cnidarians which can be solitary or
colonial in form
Class Hydrozoa, Order Siphonophora
• Within class Hydrozoa, lies the Order
Siphonophora, the Siphonphores
– Siphonophores consist of colonies of medusa-like
and polyp-like individuals, each specialized for a
specific function
– Specialized features include a gas-filled float,
tentacles lined with nematocysts, and digestive
cells
– Very toxic!
Portuguese Man o’ War: a siphonophore
By-the-wind Sailors: a siphonophore
Physophora: my nemesis!
Actual size
http://life.bio.sunysb.edu/marinebio/plankton.html
Phylum Cnidaria, Class Scyphozoa
• The Scyphozoans (class Scyphozoa) include
most of the common medusa-like ‘jellyfish’
• Larger than Hydrozoans
• Short polyp stage; Long medusa-stage
NOAA
Phylum Cnidaria, Class Scyphozoa
• Scyphozoan polyps are very small and release
juvenile medusa
• Adult medusa have a rounded body, or bell
• Scyphozoans swim with rhythmic
contractions of their bell, but
their swimming ability is limited
– Planktonic!
– Painful stings to swimmers
Phylum Cnidaria, Class Anthozoa
• The Anthozoans (class Anthozoa) include the
corals, sea anemones, and sea fans
• Anthozoans lack a medusa stage and exist as
solitary or colonial polyps
• Many corals excrete a skeleton of calcium
carbonate, which forms reefs (‘reef-building
corals’); very important for marine ecosystem
• Anthozoans can sting and ‘attack’ each other!
Class Anthozoa
http://webs.lander.edu/rsfox/invertebrates/aiptasia.html
Confused yet?
Phylum Ctenophora
• The comb jellies, or ctenophores are
exclusively-marine
• NO nematocysts (not Cnidarians); instead of
stinging cells, ctenophores possess sticky cells,
or colloblasts
• 8 rows of cilia; Ctenophore
literally means “comb bearer”
• ‘Boom and bust’ population
dynamics
Phylum Ctenophora
• Most species are bioluminescent
• Voracious feeders on copepods, fish eggs, crab
larvae, shrimp larvae and other
meroplankton
• Self-fertilizing hermaphrodites
• Can double in size in 1 day!
• Important secondary consumers
in Long Island estuaries
Peanut butter and jellyfish
anyone?
• Ctenophores are
increasing in LI estuaries
• During peak ctenophore
abundance in Great South
Bay (in 2006), one 2minute plankton tow
yielded over 3,700
individuals (543.1
individuals m-3)!
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M. leidyi mL m^-3
Mean mesozooplankton L^-1
Total mesozooplankton L-1
M. leidyi mL m-3
Ctenophores vs. Zooplankton 2009
Ctenophores on Long Island
Spring: Sea gooseberry
Summer: Sea walnut
Fall: Beroe ovata
Understanding my ctenophore
research through Pac Man…
Bivalve larvae
(ctenophore food)
Phytoplankton
(clam food)
Ctenophore
Lots of
ctenophores!!!
GAME OVER
(for the hard clam)