Invertebrate Diversity

1
InvertebrateDiversity

• Comparison of Increasing Complexity
• Highlight what is bold/underlined

2
What is an invertebrate? Name some common
invertebrates? Are snakes invertebrates?
3
Introductory Vocabulary Invertebrate animal
without a backbone Coelom fluid-filled space
between body wall and intestine Cephalization
sensory organs concentrated at the anterior end
of the organism Sexual reproduction gametes are
produced and fuse to form unique diploid
offspring Asexual reproduction single parent
produces offspring genetically identical to
itself Hermaphrodite animals with both ovaries
and testes
4
Sessile nonmotile animal that doesnt move on
its own Open circulatory system vessels empty
into body spaces called sinuses Closed
circulatory system blood never leaves vessels
as it flows through the body Compound eye eye
with many lenses found in arthropods Notochord
stiff rod found in chordates that becomes the
vertebral column in vertebrates Dorsal nerve cord
bundle of nervous tissue found in chordates
that becomes the spinal cord in
vertebrates Pharyngeal slits openings in the
pharynx found in chordates that give rise to many
structures in vertebrates
5
Kingdom Animalia Invertebrate phyla Porifera
-sponges Cnidaria-sea anemones,coral and jelly
fish Platyhelminthes-flatworms (planaria, flukes,
tapeworms) Nematoda -roundworms
6
Mollusca-slugs, snails, seashell animals,
octopii and squid Annelida segmented worms
(marine worms, earthworms leeches) Arthropoda
insects, arachnids crustaceans Echinodermata
starfish, sand dollars, sea urchins, sea
cucumbers
7
Porifera

• Sponges
• Multicellular no true tissues asymmetric
  sessile
• spongin- protein fibers for structure spicules
  for skeleton
• individual cells acting together as an organism
• filter feeders using collar cells (choanocytes)
  amoebocytes
• Water enters pores and exits osculum
• Asexual reproduction
• fragmentation
• sexual reproduction (hermaphroditic)
• External fertilization

8
Cnideria

• Radial symmetry true tissues sessile and/or
  motile
• Cnidocytes - stinging barbs to capture prey
• Tentacles to bring prey into gastrovascular
  cavity
• Two body forms
• Polyp sessile with mouth dorsal
• Medusa motile with mouth ventral (adult)
• Asexual reproduction - budding
• Sexual reproduction - external fertilization
  resulting in planulae larvae

Classes of cniderians Hydrozoa hydra, Obelia,
Portuguese man-of-war Scyphozoa
jellyfish Anthozoa sea anemones coral
9
Platyhelminthes - flatworms

• bilateral symmetry cephalization acoelomate
  organs
• Nervous system ganglia nerve cords
• Excretory system flame cells
• Digestive system two-way digestive tract with
  common mouth/anus gastrovascular cavity
• Respiratory system diffusion through epidermis
• Circulatory system none (diffusion)
• Reproductive system
• Sexual internal fertilization hermaphroditic
  lay eggs
• Asexual - fragmentation

10
Class Trematoda - endoparasites OR
ectoparasites - complex life cycle with more
than one host - primitive or no digestive
system Schistosoma major public health threat
cause liver damage

• Class Cestoda
• Tapeworms
• Parasites
• Attach to intestinal wall of host with scolex
• proglottids segments packed with reproductive
  organs
• absorb nutrition from host dont need digestive
  system

Class Turbellaria - planaria - freeliving -
one of few freshwater species typical flatworm
11
Phylum Nematoda - roundworms

• - pseudocoelomate
• - hydrostatic skeleton
• one-way digestive system with separate
  mouth/anus
• Respiration and circulation by diffusion
• Have longitudinal muscles
• Reproduction sexual complex life-cycle with
  multiple hosts
• Most are free-living predators in the soil
• Some are parasitic hookworms, pinworms,
  Trichinella

12
Mollusca

• Coelomate bilateral symmetry organs
  exoskeleton (shell)
• 3-part body plan
• Visceral mass contains organs
• Mantle secretes shell
• Foot locomotion
• Radula for feeding
• cephalization
• Open circulatory system
• One-way digestive system
• Nephridia excretory organs
• Respiration gills, mantle cavity, and/or
  diffusion across skin
• Reproduce sexually many hermaphroditic form
  trochophore larvae

• Classes of mollusks based on body plan
• Gastropoda stomach-foot snails and slugs
• Bivalvia two-shells clams, oysters, mussels
• Cephalopoda head-foot nautilus, squid,
  octopi, cuttlefish

13
ANNELIDA

• Oligochaeta earthworms
• Hirudinea leeches
• Polychaeta marine worms

14
Major characteristics of all annelids

• Segmentation separated by septa each segment
  has organs of each major system
• Cephalization including cerebral ganglia
• Ventral nerve cord
• Coelom hydrostatic skeleton
• Organ systems
• Setae bristles for movement
• Parapodia fleshy appendages for movement /or
  respiration

15

• Earthworms
• Ecologically important scavengers
• Two layers of muscle longitudinal circular
• 5 hearts closed circulatory system
• Nephridia for excretion
• Respiration through epidermis
• Complex digestive system with mouth, pharynx,
  esophagus, crop, gizzard, intestine, and anus
• Sexual reproduction hermaphroditic clitellum
  forms mucus cocoon to protect fertilized eggs

16
How are HUMANS separated into body segments?

• Remnants of segmentation are visible in the
  embryo as repeated blocks of tissue called
  somites and in the vertebral column

17
Arthropods

• largest and most diverse phylum includes
  insects, crustaceans, spiders
• segmented bodies head, thorax, abdomen or
  cephalo-thorax abdomen segmentation apparent
  on abdomen
• jointed appendages (3, 4 or 5 pairs of walking
  legs plus assorted other specialized appendages)
• Respiration spiracles into trachea gills book
  lungs
• Excretion through Malpighian tubules
• Incomplete or complete metamorphosis
• exoskeleton of chitin complex muscular system
• ventral nerve cord brain open circulatory
  system
• compound eyes ecdysis (molting)

18
Millipedes 2 pairs of legs per segment -
herbivores or detritovores,
but can be really smelly! -
one pair of antennae Centipedes 1 pair of legs
per segment - predators with jaws
- one pair of antennae
19
Insects 3 body regions head, thorax,
abdomen - 3 pairs of legs attached to
thorax - exoskeleton of chitin - jaws
(mandibles)modified for particular feeding
method - wings are extensions of the
exoskeleton 0, 1 or 2 pairs - 1 pair of
antennae - compound eyes
20

• Arachnids spiders, scorpions, ticks, mites
• Chelicerae mouthparts modified into pincers or
  fangs
• Cephalothorax abdomen
• 4 pairs of walking legs
• No antennae
• Simple eyes
• Spinnerets silk glands in spiders
• Book lungs in spiders
• Predators that consume liquified food
• Distantly related to horseshoe crabs

tick
mite
21
Crustaceans
Ecologically important copepods krill are
planktonic crustaceans that form the basis of
many marine food chains Crabs, lobsters, shrimp,
crayfish are other well-known crustaceans
called decapods 10 feet First pair of walking
legs often modified into chelipeds (pincers) 2
pair of antennae Compound eyes Sexual
reproduction Cephalothorax covered by
carapace Small appendages on abdomen of of some
called swimmerets Barnacles are sessile
crustaceans Pill bugs (isopods) are terrestrial
crustaceans with gills
22
ECHINODERMS most complex of the invertebrates

• Only live in salt water (oceans)
• Five-part radial symmetry in adults larvae are
  bilaterally symmetrical
• Hard, bumpy, spiny ENDOskeleton composed of
  ossicles
• Water vascular system with 5 rows of tube feet
  that aid them in movement, gas exchange, food
  capture and waste excretion.
• Skin gills increase respiratory surface area
  function in excretion
• Feeding in starfish involves everting stomach out
  of mouth, digesting prey outside of body, and
  then pulling the digested material into the body
  other echinoderms tend to be filter feeds or
  detritivores
• Ex starfish, sand dollar, sea cucumber, sea
  urchin, sea cucumber, sea biscuit, brittle stars,
  sea lilies, sea daisies, sea pens, feather stars

23
Invertebrate Chordates 4 characteristics of all
chordates Notochord Dorsal hollow nerve
cord Pharyngeal gill slits Postanal
tail Invertebrate chordates include tunicates
lancelets all other chordates are vertebrates
tunicate
lancelet