Transcript Phylum Porifera

Kingdom Animalia
Animal Characteristics
• Animals are the most physically diverse
kingdom but share common characteristics.
• Most animals reproduce sexually.
Animal cells are
supported by collagen.
– three-stranded
protein
– found in bone,
skin, ligaments,
fingernails,
and hair
Most animals have Hox genes
• Homeotic genes control early development.
– Hox genes determine the position of cells’
differentiation.
– A Hox gene mutation leads to the development of a
body structure in the wrong position.
head
tail
fruit fly genes
human
HOX-B genes
head
Hox genes tell embryonic cells
which body part to become.
tail
Mutations in Hox genes led to
the vast diversity of animal
species.
How are animals grouped into phyla?
• Three criteria are used to categorize
animals.
– Body plan symmetry
– Tissue layers
– Developmental patterns
Body plan symmetry
Asymmetry
(no symmetry)
Bilateral
(left/right)
Radial (circular,
around a central
axis)
• Animals are divided into
two major groups, the
protostomes and the
deuterostomes.
– Protostomes form the mouth
end of the digestive tract first
and the anus second.
– Deuterostomes form the anus
end of the digestive tract first
and then the mouth.
A comparison of structure and genetics
reveals the evolutionary history of animals.
• Protostomes and deuterostomes are the two major
radiations on the animal phylogenetic tree.
NO TISSUES
RADIAL
lancelets,
vertebrates
sea stars,
sea urchins
crustaceans,
insects, spiders
Echinodermata
Nematoda Arthropoda
Chordata
roundworms
clams, snails,
octopuses
Segmented
worms
flatworms
Cnidaria Platyhelminthes Annelida
Mollusca
jellyfish, coral, anemones
sponges
Porifera
DEUTEROSTOMES
PROTOSTOMES
• Cells are differentiated into tissues during
development in all animals except sponges
– Cnidarians only have 2 layers
• Ectoderm (becomes skin and nerves)
• Endoderm (becomes digestive tract)
– All other animals have three layers
• Ectoderm and endoderm
• Mesoderm (becomes skeleton, muscles,
organs)
• In all except sponges and cnidarians, a body
cavity may develop
• Having a body cavity is an advantage, as it allows
for more internal space
Gut
Flatworms
Roundworms
All others
Animal Orientation
dorsal
anterior
posterior
ventral
Phylum Porifera
Sponges
Sponges are
asymmetrical
filter-feeders
Sponges are
hermaphrodites.
They are able to
produce both egg
& sperm cells.
But they DO NOT
self-fertilize.
Phylum Cnidaria
Jellyfish
Hydra
Sea Anemones and Coral
cnidocyte or
nematocyst
Cnidarians are NOT hermaphrodites. They have
separate males & females. They have external
fertilization.
Jellyfish
Hydra are much smaller than jellyfish
(almost microscopic). They use their
stinging tentacles to catch protozoans.
Sea
anemones
Coral
Coral live in colonies
that secrete a calcium
“shell” for protection
(reefs)
Phylum
Platyhelminthes
“Flatworms”
Planaria
Tapeworms
Flukes
 Acoelomate
 Protostome
development
 Cephalization
 Bilateral symmetry
 Two-way gut
Planaria live in
freshwater or in
soil.
Very small and have
eye spots to sense
light changes.
Tapeworms and flukes are entirely
parasitic. They typically live as larvae in
one host and as adults in another host.
Phylum Nematoda
“Roundworms”
• Pseudocoelomate
• Thickened exterior cuticle
• One-way gut
Many live in the soil
and freshwater.
Most are parasitic.
Phylum Annelida
“Segmented Worms”
Earthworms
Leeches
Ragworms
True coelomates
5 beating hearts– closed
circulatory system
Setae—bristles (for
anchoring & traction)
Earthworms
(terrestrial)
Leeches
(mostly freshwater)
Ragworms (marine)
Earthworms are
hermaphrodites– but
remember, they do
NOT self-fertilize.
They fertilize each
other.
The clitellum becomes
a cocoon for the eggs.
Phylum Mollusca
“Soft-bodied Animals”
Clams, mussels, oysters
Snails and slugs
Octopus and squid
•Many have shells
(“valves”)
•Three-part body
plan: head, visceral
mass, muscular foot
•Mucus-covered mantle
•Gills
•Contains smartest group of invertebrates
Bivalves
Gastropods
Cephalopods
Phylum
Echinodermata
“Spiny-skinned Animals”
Sea Lilies
Seastars and Brittlestars
Sea Urchins and Sea Cucumbers
•Deuterostome
development
•Five-part radial
symmetry
•Water-vascular
system
•Endoskeleton
Sea Lilies (sessile)
Seastars and
Brittlestars
Sea Urchins
Sea Cucumbers
Phylum Arthropoda
Myriapods
Crustaceans
Arachnids
Insects
Trilobites (ancient/extinct)
Chelicerates (arachnids, horseshoe crabs)
Myriapods (millipedes, centipedes)
Crustaceans (barnacles, lobsters, crabs)
Hexapods (insects)
• Chitinous exoskeleton
which is shed (molted)
during growth
• Jointed appendages
Centipedes
Mostly harmless
Carnivores– eat
insects, grubs, other
centipedes
1 pair of legs per
segment
Millipedes
Herbivores
Eat decaying material or
plant material
Some secrete poisonous
chemicals through their skin
as a defense
2 pairs of legs per segment
Crustaceans
2 or 3-part body (head-thorax-abdomen)
2 pairs of antennae
Biramous appendages
Up to 5 pairs of walking legs
Chelicerates
2-part body (cephalothorax and abdomen)
6 pairs of appendages
1st pair often modified into fangs
2nd pair modified to sense or grab (claws)
4 pairs of walking legs
No antennae
Black Widow
more aggressive
neurotoxin
Brown Recluse
less aggressive
necrotoxin
Insects
3 body segments
3 pairs of walking legs
Up to 2 pairs of wings
1 pair of antennae
Incomplete metamorphosis
•Grasshoppers
•Dragonflies
•Mayflies
No larva is formed.
Complete metamorphosis
•Butterflies
•Bees/wasps/ants
•Caddisflies
•Mosquitoes
A Butterfly comes from a
chrysalis—thin,
membranous.
Moths usually come
from fluffy cottony
cocoons.
Phylum Chordata
Tunicates
Lancelets
Vertebrates
All chordates have (for at least part
of the life cycle)…
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Notochord (stiff rod of cartilage)  spine
Hollow dorsal nerve cord  spinal cord
Pharyngeal slits  gills
Post-anal tail
Endostyle
Tunicates -- “sea squirts”
Lancelets -- “sea squirts”
• Adults are sessile filter feeders
• Larvae have typical chordate
features
• Adults are burrowing filter
feeders that show primitive
chordate features
Subphylum Vertebrata
• Built along the basic chordate body plan
• Defining characteristic is the vertebral column
– Notochord  segmentation + stiffness
• Gills appear in all, lost in advanced forms
• Highly developed dorsal nervous system
– Invertebrates have ventral nervous system
Subphylum Vertebrata
Class Agnatha – “jawless fishes”
Class Chondrichthyes – “cartilaginous fishes”
Class Osteichthyes – “bony fishes”
Class Amphibia – amphibians
Class Reptilia – reptiles
Class Aves – birds
Class Mammalia – mammals
Jawless Fishes
• No paired appendages
• Sharp teeth in open mouth
• Exclusively aquatic
hagfish
lamprey
Covered in
copious
amounts of
slime
Cartilaginous Fishes
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Jawed
Cartilage skeletons (no ribs)
Paired fins
Skin with “teeth”
Unprotected gills
Upper movable jaw
Several rows of teeth
Internal fertilization (oviparity or
ovoviviparity)
sharks
chimaeras
skates and rays
Bony Fishes
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Bone skeletons (no ribs)
Skin with scales
Swim bladders
Gills protected
External fertilization
(ovuliparity)
Amphibians
• Metamorphosis from aquatic
larva with gills to terrestrial
tetrapod with lungs
• Require water for external
fertilization (ovuliparity)
• Evolved from lobe-finned fish
• Separate pulmonary and
systemic circulation
salamanders and newts
caecilians
-legless
sirens -external gills
frogs and toads
Pulmonary refers to the lungs.
Amphibians (as well as other vertebrates) have a separate
circulatory circuit to the lungs.
Reptiles
• No aquatic larval stage, only
tetrapodal adult
• Dry, watertight skin
• Internal fertilization (oviparity
or ovoviviparity)
turtles, terrapins and tortoises
• Amniotic egg allows
reproduction on land
tuatara
lizards and snakes
crocodilians
Birds
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Endothermic
Feathers
Upper limbs modified into wings
Toothless beak
Amniotic egg with hard, oblong shell
Internal fertilization (oviparity)
Hollow bones
Evolved from reptiles
Heart chambers complete separate
oxygenated-deoxygenated blood
In fish & amphibians – kidneys are adapted to rid excess water
In reptiles & birds – adapted to conserve as much water as
possible
In mammals – kidneys are adapted to maintain water balance
Mammals
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Hair
Mammary glands
Middle ear bones
Internal fertilization (oviparity
or viviparity)
• Evolved from reptiles
Marsupials
-Born undeveloped
-Further development
occurs in pouch
-Kangaroo, opossum, koala
Monotremes
-Lay eggs
-No nipples
-Echidna and
platypus
Placentals
-Born fully developed
-Young attached within
via placenta to receive
nutrients