Kingdom Animalia

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Kingdom Animalia

• Eukaryotic, multicellular heterotrophs without
  cell walls
• Animals, like all organisms, reproduce, grow, use
  energy, and respond to their environment

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Phylum Porifera

• The Latin porus means pore
• Fera means bearers
• Sponges have porous structures
• They are sessile (attached to one spot)

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• Sponges can pump water
• Many sponges have a vaselike wall around a hollow
  sac which is closed at the bottom and open at the
  top.
• The top opening is called the osculum

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• The inside of the sponge is lined with collar
  cells having flagella
• The flagella move water through the pores, into
  the central cavity, and out the osculum

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• As the water moves through, the collar cells trap
  food which is filtered out. This is called
  filter-feeding or suspension-feeding
• Food is digested in the collar cells(choanocytes)
  or passed on to amebocytes, cells that

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• move through the sponges body, bringing
  nutrients to other cells and removing wastes
• Wastes are released into the water leaving
  through the osculum

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• Structures that provide support are made of
  spongin, a network of protein fibers, or
  spicules, tiny needlelike structures made of
  silicon dioxide or calcium carbonate
• Sponges reproduce asexually by budding,
  regeneration, or by forming

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• gemmules, a dormant mass of amebocytes surrounded
  by protective layers of spicules. This occurs
  when conditions are extreme, such as freezing
  temperatures or droughts.

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• Scientists think sponges evolved from protists in
  the early Cambrian period
• The flagellated collar cells look like colonial
  protists
• Sponges lack specialized tissues or organ systems
• Most sponges do not have a body symmetry

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• Most of the approximate 8000 species live in the
  oceans. About 3 are fresh water
• Marine sponges can be many colors, including red,
  orange, yellow, or blue
• Freshwater sponges are brown or green

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• Sponges are organized into classes based on
  whether or not they have spongin, spicules, or
  both

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Cnidarians - Stinging celled animals

• Cnidarians are soft-bodied animals with stinging
  tentacles arranged in circles around their mouth
• Life cycles have stages that are different in
  appearance

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• Polyp - sessile, flowerlike stage
• Medusa - motile, bell-shaped stage
• Both have a body wall - consisting of 3 layers
• epidermis - outer layer

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• mesoglea - ranges from thin noncellular membrane
  to thick jellylike layer
• gastroderm - lines gastrovascular cavity
• Body wall surrounds the gastrovascular cavity

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• Digestion occurs in gastrovascular cavity
• Cnidarians capture and eat prey using stinging
  nematocysts

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• Nematocysts -poison-filled sac with coiled
  springloaded dart. When an animal touches it,
  the dart uncoils quickly and buries itself in the
  skin of the animal. The prey is paralyzed or
  killed by the poison.

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Endosymbiosis

• Photosynthetic protists live inside the cells of
  the gastroderm in many cnidarians
• The protists use CO2 and wastes from cnidarian
  to do photosynthesis and make proteins

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• Some of the food and O2 is available to the
  cnidarian
• Mutualistic relationship
• Some cnidarians are so dependent on the protists
  that they cant survive where its dark

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• Since cnidarians live in moving water, they can
  get rid of wastes by diffusion through the body
  wall
• Simple nervous system - a nerve net which is
  concentrated around the mouth
• Sensory cells get info. about the environment

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• Medusa form - has simple sensory organs -
  statocysts for balance and ocelli to detect light
• Reproduce sexually and asexually
• asexually by budding

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• sexually when a medusa matures it releases
  gametes into the water
• fertilization varies - in some species it is in
  open water in others - its inside an
  egg-carrying medusa

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• The fertilized egg (zygote) grows into a ciliated
  larva that swims
• Eventually larva attaches to a surface and
  changes into a polyp and the cycle continues

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Class Hydrozoa

• Spend most of life cycle as polyps
• Usually have short medusa stage
• Hydras are hydrozoans with only polyp stage
• Hydras reproduce sexually and asexually

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Hydra
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• Most hydra species have males and females some
  have hermaphrodites
• Portuguese man-of-war is a hydrozoan
• form floating colonies with several types of
  polyps

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• one polyp forms balloonlike float to keep it on
  the waters surface
• some polyps produce stinging tentacles
• some polyps digest food
• other polyps make gametes

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ClassScyphozoa - true jellyfish

• Have large, long-living medusa
• Polyp is a tiny larval stage

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• Toxin from jellyfish varies in strength - a tiny
  Australian jellyfish toxin can kill people in 3 -
  20 minutes
• Most species are harmless to people
• Others cause a sting

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Class Anthozoa - Sea Anemones and Corals

• Only polyp stage
• Reproduce sexually - gametes released in water
• zygote to ciliated larva to new polyp

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• Reproduce asexually by budding
• Sea anemones come in different colors
• Corals have skeletons of calcium carbonate -
  limestone

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• Most corals live in colonies. As colony grows new
  polyps are produced by budding
• Great Barrier Reef off the Australian coast is a
  famous coral reef made from coral colonies - over
  2000 km long and 80 km wide
• Reefs are sensitive to pollution

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Importance of Cnidarians

• Coral reefs are important ocean habitats - many
  species live there
• protect land from wave action
• if reef damaged, shoreline may be washed away
• some cnidarians used in medical research

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• Clownfish have mutualistic symbiotic relationship
  with sea anemones - both protect each other from
  predator species

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Platyhelminthes - flat worms

• Platy - flat, helminth - worm
• Unsegmented
• bilateral symmetry
• most species show cephalization development of
  anterior end, or head

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• Free-living aquatic flatworms
• Have gastrovascular cavity with one opening at
  end of muscular tube called a pharynx
• Use pharynx to suck food into gastrovascular
  cavity

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• Gastrovascular cavity forms an intestine with
  many branches along length of worm
• Enzymes in intestine break down food
• Digested food diffuses to body tissues

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• Undigested food leaves through the mouth
• Other flatworms are parasites
• Tapeworms live in the hosts intestines and dont
  have a digestive tract
• Tapeworms have hooks/suckers to attach to
  intestinal wall of host

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• Flatworms dont have specialized respiratory or
  circulatory system
• So flat that they use diffusion to transport
  oxygen, and nutrients, and get rid of carbon
  dioxide and waste

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• Planarians and freshwater flatworms have flame
  cells, excretory structures
• Have a head end with simple brain
• Brain is control center of simple nervous system

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• Nerve cords from brain run down length of body on
  both sides
• Many flatworms have one or more pair of ocelli,
  or eyespots, that are light-sensitive
• They prefer dark places and avoid light

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• Parasitic flatworms dont have much of a nervous
  system - they dont need it
• they attach to the hosts intestine and absorb
  nutrients

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• free-living flatworms move with cilia through
  water and with muscle cells that let them twist
  and turn
• reproduction - sexual or asexual
• Most are hermaphrodites

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• During sexual reproduction, one worm delivers
  sperm to other worm and receives sperm from the
  other worm
• Eggs are laid in clusters and hatch in a few
  weeks
• Asexual reproduction by fission regeneration

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Planarian - Class Turbellaria

• Free-living flatworm
• most less than 1 cm
• in moist tropical regions some giant land
  flatworms can get to 60 cm

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Flukes - Class Trematoda

• Parasitic flatworms
• some external - on mouth, gills, skin
• most are internal - infest blood, organs
• Internal parasites may have 2 or more hosts

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• Blood flukes - Schistosoma
• When people walk into contaminated river, fluke
  larvae that have left a snail host, can break
  through the persons skin and the flukes mature
  in the human host
• Person becomes very ill and may die

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Tapeworms - Class Cestoda

• Head region called scolex has suckers and ring
  of hooks
• Attaches to intestinal walls of humans and other
  animals
• Absorb food through body walls
• Human tapeworms can be up to 18 meters long!

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• Tapeworms usually do not kill the host but they
  use up a lot of food and the host may lose weight
  and weaken
• Proglottids - are the sections behind the scolex
  that make up most of the tapeworm

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• Proglottids made up mostly of male and female
  reproductive organs
• sperm can fertilize eggs in the proglottids of
  the same or other tapeworms

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• One worm can produce more than half a billion
  eggs each year
• One proglottid can have 100,000 eggs
• If food or water is contaminated with eggs and is
  eaten by cows, pigs, fishthe eggs will hatch
  into larvae

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• Larvae grow and then a cyst forms around them in
  muscle tissue
• If person eats undercooked meat with cysts, the
  larvae start to grow into adult worms

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Nematoda - roundworms

• Digestive system with 2 openings - food enters at
  mouth undigested food through anus
• species vary in length - microscopic to a meter

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• Most are free-living but there are many parasitic
  roundworms

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• Like flatworms, use diffusion to carry nutrients
  and wastes through body
• simple nervous systems - several ganglia (groups
  of nerve cells in head region)

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• muscles for movement run in strips down body
  walls

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• Sexual reproduction
• most species have males and females some are
  hermaphrodites
• Fertilization occurs inside female
• Have complex life cycles, usually with several
  host species

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Roundworm diseases

• Hookworm - burrow into skin between toes
• Trichinosis - from undercooked pork
• Elephantiasis - filarial worms -insect vector -
  block lymph vessels - cause huge swelling

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• Ascaris - fecal contamination of food or water
• Guinea worm - contaminated water - huge
  roundworms
• Pinworm - small children often get this from
  putting dirty hands in mouth (eggs are
  microscopic and persist in soil)

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Mollusca Classes

• 1. Gastropoda - univalves - snails, slugs
• 2. Pelecypoda - bivalves - oysters, clams,
  scallops
• 3. Cephalopoda - squid, octopus
• 4. Amphineura - chitons

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Arthropod Classes