INVERTEBRATE SURVEY LAB

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INVERTEBRATE SURVEY LAB

• Spring 09

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CHARACTERISTICS OF ANIMALS

• Representatives of the animal kingdom display a
  wide diversity in appearance. Regardless, they
  do share certain characteristics
• ALL ANIMALS ARE HETEROTROPHIC
• ALL ANIMALS ARE MULTICELLULAR
• ALL ANIMALS ARE MADE OF EUKARYOTIC CELLS THAT
  LACK A CELL WALL
• The animal kingdom is divided into several phyla
  (categories). Each phylum contains animals which
  demonstrate common traits.
• These traits allow for a classification system
  that shows progressive change in the phyla from
  simple to more complex in forms.

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KEY TERMS TO KNOW

• Body Symmetry
• Asymmetry no specific shape
• Radial Symmetry body plan in which body parts
  repeat around the center of the body
• Bilateral Symmetry a single imaginary plane
  could divide the organism in to 2 equal halves

Asymmetry
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KEY TERMS TO KNOW

• Cephalization
• Cephalization is a concentration of sense organs
  and nerve cells in the front of the body (toward
  the head).

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KEY TERMS TO KNOW

• Coelom
• Coelom means body cavity (a tube within a tube).

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About the Coelom

• Coelom means body cavity (a tube within a tube).
• Acoelomates
• Have NO TRUE body cavity!
• Pseudocoelomates
• Have a fluid filled cavity BUT it is not lined
  like that of higher-order animals.
• Coelomates
• Have a body cavity that separates the body into
  an inner and outer tube (fully lined).

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KEY TERMS TO KNOW

• Early Development
• Protostomes are organisms that develop a mouth
  first and then an anus.
• Most invertebrates are protostomes
• Deuterostomes are organisms that develop an anus
  first and then a mouth.
• Echinoderms and all vertebrates are deuterostomes.

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KEY TERMS TO KNOW

• Early Development-
• During early development, the cells of most
  animal embryos separate into three layers called
  germ layers
• ENDODERM innermost layer develops into the
  lining of the digestive tract much of the
  respiratory system
• MESODERM middle layer develops into muscles and
  much of the circulatory, reproductive, and
  excretory systems
• ECTODERM outermost layer develops into the
  sense organs, nerves, and outer layer of the skin

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KEY CONCEPT TO KNOW
TRENDS IN ANIMAL EVOLUTION
As animals get more advanced, they have more
specialized features than those animals found in
the prior phyla.
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PHYLUM PORIFERA - SPONGES
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KEY CHARACTERISTICS

• Sponges are
• Multicellular, but do not have tissues!
• Filter feeders that sift microscopic food
  particles from the water.
• Asymmetrical they have no front or back end!
• Sessile they do not move!
• No cephalization!
• Early development is protostome.
• Habitat is water.
• No segmentation!
• No germ layers!
• No coelom!

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ECOLOGY OF SPONGES

• Sponges play an important part in the ecology and
  survival of numerous aquatic organisms
• They usually live attached to the sea floor.
• They form mutually beneficial relationships with
  bacteria, algae, and plantlike protists.
• They provide a habitat for snails, sea stars, sea
  cucumbers, and shrimp.

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PHYLUM PORIFERA - SPONGES
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PHYLUM CNIDARIA JELLYFISH, SEA ANEMONES,
CORALS
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KEY CHARACTERISTICS

• RADIAL SYMMETRY
• CARNIVOROUS
• NO CEPHALIZATION
• MOVEMENT
• Polyps are sessile
• Medusas are free swimming
• EARLY DEVELOPMENT protostome nerve net
• SOFT/SAC-LIKE BODY PLAN
• 2 WAY DIGESTION (ONE OPENING)
• Eat excrete through same hole!
• NO COELOM
• NO SEGMENTATION
• 2 GERM LAYERS ectoderm endoderm

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IMPORTANT FEATURES

• They typically have a life cycle that includes
  two different-looking stages a polyp and a
  medusa
• A polyp is a cylindrical body with arm-like
  tentacles.
• In a polyp, the mouth points upward.
• Polyps are usually sessile (do not move).
• A medusa has a motile, bell-shaped body with the
  mouth on the bottom.

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CNIDARIAN ACTIVITY

• Cnidarians are soft-bodied, carnivorous animals
  that have stinging tentacles arranged in circles
  around their mouths.
• They are the simplest animals to have body
  symmetry and specialized tissues.
• Cnidocytes are stinging cells that are located
  along their tentacles.
• A nematocyst is a poison- filled, stinging
  structure that contains a tiny coiled dart used
  to paralyze and kill prey.

• After paralyzing its prey, a cnidarian pulls the
  prey through its mouth into its gastrovascular
  cavity.
• Nutrients are then transported through the body
  by diffusion.
• Cnidarians gather information from their
  environment using specialized sensory cells.
• Most cnidarians reproduce both sexually and
  asexually
• Most sexual reproduction takes place with
  external fertilization (outside the females
  body).

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PHYLUM PLATYHELMINTHES - FLATWORMS
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KEY CHARACTERISTICS

• Three germ layers ectoderm, mesoderm, endoderm
• Bilateral symmetry
• Cephalization is present
• Acoelomates - No coelom
• Use diffusion to transport materials through body

• No segmentation
• Movement w/ muscles or cilia
• Early development protostomes
• Habitat ? water or moist dirt
• Basic body parts mouth, pharynx, intestine,
  ganglia, flame cells

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MOVEMENT REPRODUCTION IN FLATWORMS

• Free-living flatworms typically move in 2 ways
• Cilia help them glide through the water.
• Muscle cells allow them to twist and turn.
• Most free-living flatworms are hermaphrodites
  (have both male and female reproductive organs).
• Sexual reproduction involves joining in a pair
  and delivering sperm to each other.
• Asexual reproduction takes place by fission
  where the organism splits in two and each half
  grows into a new organism.

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GROUPS OF FLATWORMS

• Turbellarians (picture 1) free-living flatworms
  that live in marine or fresh water
• Bottom dwellers
• Flukes (picture 2) parasitic flatworms
• Infect the internal organs of their hosts
• Tapeworms (picture 3) long, flat, parasitic
  worms
• adapted to life inside the intestines of their
  hosts

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FLUKES PARASITIC FLATWORMS
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PHYLUM NEMATODA - ROUNDWORMS
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KEY CHARACTERISTICS

• Three germ layers present ectoderm, mesoderm,
  endoderm
• Unsegmented
• Bilateral symmetry
• Cephalization present
• Pseudocoelom present

• Mouth forms first protostome
• Basic body parts mouth, anus, intestines
• Examples Pinworms Nematodes

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Roundworms

• Feeding most are carnivorous with grasping
  mouthparts and spines to catch and eat other
  animals
• Respiration, circulation, and excretion occurs
  via diffusion they have no internal transport
  system
• Response simple nervous systems consisting of
  several ganglia
• Movement muscles extend the length of their body
  and allow for movement
• Reproduction sexual, non-hermaphroditic

• Roundworms are unsegmented worms that have
  pseudocoeloms and digestive systems with two
  openings a mouth and an anus
• A pseudocoelom is a false coelom a body
  cavity lined only partially with mesoderm

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ROUNDWORMS HUMAN DISEASE
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PHYLUM ANNELIDA EARTHWORMS LEECHES
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KEY CHARACTERISTICS

• Three germ layers present
• Bilateral symmetry present
• Cephalization present
• True coelom present
• Segmentation present

• Movement ? Muscles
• Mouth develops first protostome
• Basic body parts mouth, anus, crop, gizzard,
  body segments
• Ex earthworm

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FORM FUNCTION OF ANNELIDS

• Feeding Digestion range from filter feeders to
  predators
• They extend their pharynx to collect prey and the
  food moves through the crop where it is stored
  and then through the gizzard where it is ground
  into smaller pieces
• Circulation they have a closed circulatory
  system
• Blood is contained within a network of blood
  vessels

• Respiration gills (aquatic annelids) and
  diffusion (land annelids)
• Excretion digestive wastes passes out through
  the anus and liquid waste is eliminated by
  nephridia (filter fluid)
• Response have well developed nervous systems
  that include a brain and several nerve cords
• Movement have 2 major groups of body muscles as
  part of a hydrostatic skeleton
• Reproduction most reproduce sexually (although
  some use external fertilization) and some are
  hermaphroditic

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GROUPS OF ANNELIDS

• Oligochaetes Typically have streamlined bodies
  and relatively few setae (hairs) compared to
  polychaetes (most live in soil or fresh water).
• Leeches external parasites that suck the blood
  and body fluids of their host.
• Polychaetes marine annelids that have paired,
  paddlelike appendages tipped with setae (hairs).

Polychaetes
Oligochaete
Leech
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PHYLUM MOLLUSKA SNAIL, CLAM, SQUID, OCTOPUS,
ETC.
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KEY CHARACTERISTICS

• Ex. Clam, squid, octopus, snail, oyster,
  scallop...
• Three germ layers present ectoderm, mesoderm,
  endoderm
• Have an external or internal shell for support
• Bilateral symmetry Radial Symmetry (Squid)
• Cephalization present

• Segmentation present
• Movement ? with muscles
• Has a TRUE COELOM
• Mouth develops first protostome
• Basic body parts gills, specialized foot

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THE MOLLUSK BODY PLAN
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BODY PLAN OTHER PROCESSES

• Respiration breathe using gills (aquatic) or by
  diffusion (land)
• Circulation either open or closed circulatory
  system
• Open - blood is pumped through vessels by a
  simple heart and then diffusion into other
  systems
• Closed blood is transported through the body
  much quicker than an open circulatory system and
  is always contained in vessels
• Excretion nephridia
• Response complexity of nervous systems varies
• Movement secretion of mucous or jet propulsion
• Reproduction sexually by external fertilization,
  sexually by internal fertilization, and some are
  hermaphrodites

• Body Plan contains 4 parts foot, mantle,
  shell, visceral mass
• The muscular foot has many forms, including flat
  structures for crawling, spade-shaped structures
  for burrowing, and tentacles for capturing prey
• The mantle is a thin layer of tissue that covers
  most of the mollusks body
• The shell is made by glands that secrete calcium
  carbonate and has been reduced or lost in snails
  and some other mollusks groups
• The visceral mass lies just below the mantle and
  contains the internal organs

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GROUPS OF MOLLUSKS
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GIANT CLAM
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VARIOUS MOLLUSKS
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PHYLUM ARTHROPODA CRAYFISH, SPIDERS, LOBSTERS,
ETC.
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KEY CHARACTERISTICS

• Three germ layers present
• Exoskeleton present that requires molting
  (shedding)
• Jointed appendages
• Bilateral symmetry
• Cephalization present
• True coelom present

• Segmentation present
• Movement ? Yes (muscles skeleton)
• Habitat ? In or Near Water
• Early Development ? Protostome
• Ex. Insects, spiders, crayfish, millipedes, and
  centipedes

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CRUSTACEAN PARTS

• Cephalothorax formed by fusion of the head with
  the thorax (which houses most of the internal
  organs)
• Abdomen posterior part of the body
• Carapace part of the exoskeleton that covers the
  cephalothorax
• Mandible mouthpart adapted for biting and
  grinding food

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DECAPODS

• The largest group of crustaceans are the
  decapods
• They have 5 pairs of legs
• The 1st pair of legs are chelipeds and bear large
  claws
• The walking legs are the next pair
• Behind the walking legs are the swimmerets
  (flipper-like appendages for swimming)
• Examples crayfish, lobsters, crabs

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HORSESHOE CRABS

• Horseshoe crabs are among the oldest living
  arthropods!

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SPIDERS INSECTS

• Horseshoe crabs, spiders, ticks, and scorpions
  are chelicerates
• They have 2 pairs of appendages attached near the
  mouth
• One pair are the chelicerae that includes fangs
• The other pair, the pedipalps, are modified to
  capture prey
• They have two body sections, a cephalothorax and
  abdomen
• nearly all have 4 pairs of walking legs
• They lack antennae
• They respire using book gills or lungs

• The largest group of arachnids are spiders!
• Spiders are arthropods that do not have jaws for
  chewing, so they must liquefy their food to
  swallow it.
• All spiders produce silk which is stronger than
  steel!
• To spin silk into webs, spiders force liquid silk
  through spinnerets, which are organs that contain
  silk glands

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ANATOMY OF SPIDER GRASSHOPPER
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INSECT RESPONSES

• Insects use a multitude of sense organs to
  respond to stimuli
• Compound eyes are made of many lenses.
• Chemical receptors are used for taste and smell.
• Sensory hairs detect slight movements in
  surrounding air or water.
• Well developed ears detect sounds far above the
  human range.

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INSECT METAMORPHOSIS

• The growth and development of insects usually
  involve metamorphosis
• Metamorphosis is the process of changing shape
  and form
• Most insects undergo either incomplete or
  complete metamorphosis
• Incomplete metamorphosis immature nymphs look
  much like adult form
• Complete metamorphosis immature larvae look
  nothing like parents

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INSECT COMMUNICATION SOCIETIES

• Ants, bees, termites, and some of their relatives
  form complex associations called societies.
• A society is a group of closely related animals
  of the same species that work together for the
  benefit of the whole group.
• Within a society, individuals may be specialized
  to perform particular tasks in groups called
  castes.

• Many insects communicate using chemical signals
  called pheromones.
• Insects can also communicate using sound, visual,
  and other types of signals.
• Insect communication usually involves finding a
  mate.

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PHYLUM ECHINODERMATA STARFISH, SEA URCHINS,
SAND DOLLARS SEA CUCUMBERS
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KEY CHARACTERISTICS

• Movement ? Tube feet water vascular system
• Anus forms first deuterostome!!! (the only
  invertebrate deuterostome)
• Basic body parts spiny skin, endoskeleton,
  water vascular system, tube feet
• Ex starfish, sea urchins, sand dollars, sea
  cucumbers

• 3 germ layers present
• Bilateral Radial symmetry (adults)
• No cephalization in adults
• True coelom present
• Segmentation present

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ENDOSKELETON WATER VASCULAR SYSTEM

• A unique feature of echinoderms is a system of
  internal tubes called a water vascular system
• This system is filled with fluid and carries out
  many essential body functions (respiration,
  circulation, movement)
• It opens to the outside through filter-like
  structures called madreporites
• A tube foot is a structure that operates much
  like a suction cup

• Echinoderms are characterized by spiny skin, an
  endoskeleton (internal skeleton), a water
  vascular system, and suction-cuplike structures
  called tube feet.
• Most adult echinoderms exhibit five-part radial
  symmetry
• The body parts are arranged around a central body
  like the spokes of a wheel

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CLASSES OF ECHINODERMS

• Sea urchins and sand dollars
• Unique echinoderms in having large, solid plates
  that form a box around their internal organs
• Many detritivores Grazers
• Brittle Stars
• Common in coral reefs detritivores filter
  feeders
• Can shed one or more arms if attacked arm will
  distract their predators
• Sea Cucumbers
• Look like pickles detritus feeders that move
  across sea floor
• Sea Stars
• Carnivorous prey on bivalves
• Can repair itself ? when pulled apart, each
  section can become a new sea star if a portion of
  the central cavity still remains.
• Sea Lilies and Feather Stars
• Filter feeders with long, feathery arms
• Common in tropical oceans around coral reefs

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ECHINODERMS