Transcript Chapter 12: Sponges and Cnidarians

 Animals are many-celled, eukaryotic
organisms that must find and digest food.
 Most can move from place to place.
 There are 9 animal phyla:
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Phylum Porifera—sponges
Phylum Cnidaria—jellyfish, corals, sea anemones
Phylum Platyhelminthes—flatworms
Phylum Nematoda—roundworms
Phylum Annelida—segmented worms
Phylum Mollusca—snails, clams, octopus, squid
Phylum Echinodermata—starfish, sea urchin
Phylum Arthropoda—insects, crabs, spiders
Phylum Chordata—vertebrates
 The first eight phyla in the
animal kingdom are
invertebrates—animals
without backbones. 95% of
all animals are invertebrates.
 The chordate phylum
represents the only group of
vertebrates—animals with a
backbone and inside skeleton
(endoskeleton).
 Characteristics:
 Simplest animals.
 Porifera means “pore-bearer” in Latin.
 Bodies covered with pores and are made
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of different types of cells but no tissues.
Over 5000 species of all shapes and
colors.
All live in water—mostly salt water.
Asymmetrical—no definite shape.
Evolved over 600 million years ago.
Sponges don’t wear
square pants!!!!
 Body structure
 Hollow, sac-like body
with a large opening
at the top called an
osculum and many
small openings on
the side called pores.
 Sponges are filter-
feeders
 Water enters through
the pores and leaves
through the osculum.
 Collar cells filter
and digest bacteria,
algae and protists.
 Sponges reproduce in two ways:
 Asexually—budding or regeneration
 Sexually—produce sperm and egg cells.
 Sponges are hermaphrodites (produce both
sperm and egg cells): However, they cannot
fertilize their own eggs.
 Sperm cells from one sponge enter another
and are taken by amoebocytes to the egg cells.
A fertilized egg develops into a freeswimming larva. The larva attaches to a rock
and becomes an adult sponge.
Commercial sponge
Tropical Sponges
 Characteristics:
 Tentacles with stinging cells called,
cnidocysts.
 “Cnidos” is Greek for “stinging nettle”.
 Over 9,000 species ranging in size from
microscopic to 70m long.
 Live in water—mostly salt water.
 Radial symmetry.
 Bodies have tissues but no organs.
 Feed as predators, killing prey with their
stinging tentacles.
 Evolved 600 million years ago.
The stinging cells (cnidocysts) come equipped with
harpoon-like stingers called nematocysts. The
stings of some jellyfish
can be quite painful,
causing reactions
ranging from a mild rash to
death. The Australian Box Jelly is the most
poisonous—killing victims in under 5 min.
Australian Box Jellyfish
Close-up showing eye spot
Wounds from the sting of a box jelly
 Cnidarians come in two shapes:
 Polyp—vase-shaped, sessile cnidarians.
 Medusa—umbrella-shaped mobile cnidarians.
Medusa
Polyp
 Examples of Cnidarians:
 Jellyfish—live as both a polyp
and medusa (mostly as a freeswimming medusa).
 Reproduce Sexually as sperm and
egg cells are released into the
water where they unite.
 Fertilized eggs develop into a
larva that attaches to a rock.
 A larva becomes a sessile planula,
which grows a mouth and
tentacles and is now called a
polyp.
 The polyp divides into a stack of
saucer-like structures that swim
away as adult medusas.
 Hydra—small polyps attached
to rocks in freshwater streams
and ponds. Can reproduce
asexually by budding.
Adult hydra with bud
 Corals and Sea Anemones—
polyps that live attached to
rocks on the ocean floor or in
large colonies called reefs.
Sea anemone
Coral Skeletons
 Coral Reefs
 A coral reef is made of billions of
skeletons of dead corals that are
covered by a layer of living coral
polyps.
 Largest = Great Barrier Reef of
Australia (1200 miles long and 48
miles wide).
 Very diverse habitats (home to 35,000
to 60,000 different species).
 All are located between 300 N and 300
S latitude.
 Types of Coral Reefs
 Fringing reef—forms close to the shoreline of islands
or continents.
 Barrier reef—located farther out. Separated from
land by a lagoon.
 Atoll—formed when fringing reef shrinks—
sometimes at the top of a mid-ocean volcano.
Fringing reef
Barrier reef
Atoll
 Importance of the Coral Reef:
 Help protect the shoreline from
storms.
 Important source of food and
shelter for many other marine
organisms.
 Easily damaged by pollution,
careless boaters and careless divers.
 Reef balls are used to repair
damage reefs.
 All have flat, legless bodies with no
internal body cavity.
 Some are free-living and feed as predators
of other small organisms, some are
parasites.
 All have bilateral symmetry.
 Three examples: tapeworms, flukes,
and turbellarians.
 Tapeworms—parasitic
flatworms that live in the
intestines of a host animal.
 Feed on the host’s digested food.
 Size: 6-12 meters.
 Humans can catch a tapeworm from
eating undercooked beef, pork or
fish.
 Flukes—parasitic flatworms
that live inside the bodies of
humans and animals.
 Shistosoma is a blood fluke found
in polluted water. It kills 200
million people a year by blocking
arteries of infected people.
 Turbellarians—free-living
flatworms.
 Most live in the ocean.
 The planarian is a fresh-
water turbellarian. It swims
using cilia and can reproduce
both asexually, by
regeneration, and sexually. It
has two eyespots on the
anterior end that respond to
light.
Ocean turbellarian
Planarian
 Long, tapered bodies with a true body cavity
between their layers of tissue.
 All have a complete, one-way digestive tract.
 Most are free-living and feed on organic material in
the soil, however, some are serious human parasites.
 Reproduce sexually
 Parasitic roundworms
include:
 Hookworms—caught by
walking barefoot in tropical
soil. Larva travel to the
intestines, lungs or brain.
 Trichina—caught by eating
undercooked pork. Causes
muscle pain and breathing
problems.
 Ascaris—caught by eating
ascaris eggs found in
contaminated food. Worms
live in intestines of host.
Common in puppies and
kittens.
Hookworm
Trichina
Ascaris
 Pinworms—caught by
ingesting pinworm eggs.
Causes an “itchy bum”. It
is the most common
human intestinal parasite.
Pinworm
 Heartworm—
roundworm parasite of
dogs only. Transmitted by
mosquitoes. Easily
prevented but difficult to
treat once diagnosed.
Heartworm
 Tube-shaped bodies with
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segments.
“Annelid” means “little rings”.
Some are free-living and feed
on organic material in the soil,
saltwater or freshwater.
Others are parasites.
Reproduce both asexually as
hermaphrodites or by
fragmentation; or sexually.
Three classes: marine
worms, earthworms, and
leeches.
 Marine Worms—over 6,000
species of segmented worms
that live in the ocean.
 Move using parapodia
 Include: giant tube worms,
sand worms, bristle worms,
and feather-dusters.
 Leeches—external parasites
that feed on the blood of a
host.
 Formerly used in blood-letting.
 Currently used in
microsurgery.
 Earthworms—free-living annelids found in the
soil.
 Have complete body systems: circulatory,
respiratory, digestive, nervous, and reproductive.
 All have soft bodies and bilateral
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symmetry.
The Latin word, “mollis” means “soft”.
Most secret hard, calcium carbonate
shells to protect themselves.
Most reproduce sexually
Three basic body parts:
 Head: containing the mouth
 Muscular foot: for crawling, digging, or
swimming.
 Visceral mass: location of main body
organs. It is surrounded by a layer of
tissue called the mantle. The mantle
secretes the shell.
 Classes of mollusks include:
 Gastropoda (stomach-foot) —snails,
slugs, and sea slugs. They carry one
shell (univalve) and live in the water or
on land. Most of the world’s most
beautiful sea shells are made by
gastropods. Some feed on plants,
others are predators
 Bivalvia—two-shelled mollusks
including; clams, oysters, scallops and
mussels. Economically important as
food and for the production of pearls.
All are filter feeders.
 Cephalopoda (head-foot) —octopus, squid,
cuttlefish, and chambered nautilus. Muscular foot
is divided into tentacles for swimming. They are
very complex and intelligent. Range in size from 160 feet. Most are predators of other small
invertebrates.
Octopus
Squid
Chambered nautilus
 6,000 species of spiny-skinned animals
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with radial symmetry.
“Echinoderm” means “spiny-skin”.
Have an internal skeleton made of
spines that extend out through the body.
All live in the ocean and reproduce
sexually.
Move using a water-vascular system
and tube feet.
Most can regenerate lost body parts and
can occasionally reproduce this way as a
type of asexual reproduction.
 Examples of echinoderms:
 Sea stars and brittle stars: have 5
or more arms lined with tube feet.
Feed as predators on clams by
inserting their stomach into the
clam and digesting it inside the
shell.
 Sea urchins and sand dollars: do
not have arms. Covered with
movable spines used for defense
and movement. Most feed as
grazers on plants and algae.
 Sea cucumbers: leathery skin with
no spines. Expels its internal
organs to confuse predators. Also
feed as grazers on plants.
 Characteristics:
 Largest group of animals with over 1 million species
known. That number may be as high as 10 million.
 Jointed appendages (legs, antenna, pinchers and
claws)
 Segmented bodies
 Exoskeleton made of chitin. Must be shed from time
to time in a process called molting.
 Open circulatory system
 Dorsal heart and ventral nervous system.
 Most reproduces sexually
 Five classes: Arachnida, Crustacea, Chilopoda,
Diplopoda, Insecta
 Arachnids: spiders, scorpions, mites and ticks.
 Most have two body regions:
abdomen and cephalothorax.
Simple eyes and 4 pair of
legs attached to the
cephalothorax
Poison glands, fangs
or stingers to capture prey.
 Spiders are found
everywhere. They spin
webs using spinnerets in
their abdomen.
–Scorpions are found in
tropical areas and hunt
insects and spiders.
–Ticks are external parasites that feed on the
blood of a host. Some transmit Lyme
disease and Rocky Mountain Spotted Fever.
–Mites are found mostly in dust and are
harmless.
 Crustaceans: crabs, lobsters,
crayfish, shrimp and pill bugs.
 Most have two body regions:
cephalothorax and abdomen.
 Five pairs of appendages including
large pinchers on most.
 Most have two pair of antenna
 Chilopoda: centipedes
 Long, flat bodies with one pair of
legs per body segment.
 Carnivores: eat snails, slugs and
worms and can bite humans.
 Diplopoda: millipedes
 Long, rounded bodies with two
pairs of legs per body segment.
 Plant eaters: will not bite humans
 Insects: largest group of arthropods
 Three body segments: head, thorax and abdomen.
 Three pairs of legs attached to the thorax.
 One pair of antenna.
 Some have one or two pairs of wings; some have no wings.
 Large, compound eyes; some also have simple eyes.
 Open circulatory system.
 Two types of metamorphosis: Incomplete and Complete.
 Stages of Incomplete Metamorphosis:
 Egg, Nymph, Adult
 Stages of Complete Metamorphosis:
 Egg, Larva, Pupa, Adult
 All chordates have the following three characteristics at
some time in their lives:
 Notochord: soft, flexible rod of cartilage. It develops into
the vertebrae in most chordates.
 Nerve cord: develops into the brain and spinal cord.
 Gill slits: paired openings in the throat. Develop into gills
in some chordates.
 All reproduce sexually
 Feed as either herbivores,
carnivores, or omnivores
 Most chordates are also
known as vertebrates.
 Seven classes of vertebrates:
Agnatha: Jawless fish: They have eellike bodies and sucker-shaped mouths.
They are external parasites of other fish.
Ex: Lamprey and Hagfish
Chondrichthyes: Cartilage fish:
Skeletons made of cartilage only. They
have uncovered gills and no swim bladder
Ex: Sharks, skates and rays
Osteichthyes: Bony fish:
Skeletons made of bone. All have
Covered gills and swim bladders.
Includes 95% of all fish.
Ex: lungfish, lobe-finned fish, and ray-finned fish
Amphibia: Amphibians:
Live a double-life: larva (tadpole) that
breaths through gills and adult that
breaths through lungs. Most have moist, smooth skin.
All must lay eggs in water.
Ex: frogs, toads, salamanders and newts.
Reptilia: Reptiles
First animals to lay amniotic eggs. All have dry-scaly skin.
All breath through lungs. First truly successful land animals.
Ex: turtles and tortoises, alligators and crocs, snakes and lizards.
Aves: Birds
Endothermic (warm blooded) animals
with a body temp. of 104-108o. All have
feathers, thin-hollow bones, 4-chambered hearts,
and specialized body systems to make them
capable of flight. They lay amniotic eggs in
groups called clutches.
Ex: eagle, chicken, parrot, robin
Mammalia: Mammals
Endothermic animals with hair or blubber
to keep warm. All have a 4-chambered heart
and a diaphragm to assist in breathing.
All produce milk from mammary glands to feed
their young. Includes over 20 different orders.
Ex; egg-laying mammals, marsupials, and
placental mammals (including humans).
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