Kingdom Anamalia
Characteristics of Animals
• Multicelled heterotrophic eukaryotes
• Require oxygen for aerobic respiration
• Reproduce sexually, and perhaps
asexually
• Motile at some stage
• Develop from embryos
Chordates
Echinoderms
Major
Animal
Phyla
Arthropods
Annelids
Coelomate
Ancestry
Mollusks
Rotifers
Roundworms
Bilateral
Ancestry
Radial
Ancestry
Multicelled
Ancestry
Figure 25.2
Page 415
Flatworms
Cnidarians
Sponges
Single-celled, protistanlike ancestors
Symmetry
Radial
Bilateral
Figure 25.3
Page 416
The Gut
• Region where food is digested and then
absorbed
• Saclike gut
– One opening for taking in food and
expelling waste
• Complete digestive system
– Opening at both ends; mouth and anus
Body Cavities - Acoelomate
epidermis
gut cavity
no body cavity; region between gut
and body wall packed with organs
Figure 25.4a
Page 417
Body Cavities - Pseudocoel
epidermis
gut cavity
unlined body cavity
(pseudocoel) around gut
Figure 25.4b
Page 417
Body Cavities - Coelom
gut cavity
lined body cavity
(coelom)
peritoneum
Figure 25.4c
Page 417
Body Cavities - Coelom
gut cavity
lined body cavity
(coelom)
peritoneum
Figure 25.4c
Page 417
Animal Origins
• Originated during the Precambrian (1.2
billion - 670 million years ago)
• From what? Two hypotheses:
– Multinucleated ciliate became
compartmentalized
– Cells in a colonial flagellate became
specialized
Kingdom Anamalia
•
•
•
•
•
Multicellular
Heterotrophic
Sexual reproduction
Produce gametes in sex organs, gonads
95% lack a backbone and are called
invertebratees
• Vertebrates aare a subphylum within the phylum
chordata
• Aquatic and terrestrial
• tissues organized into organs
Internal Organization
The Protostomes
Molluscs (Phylum Mollusca): shellfish such as clams
and limpets, snails, slugs, octopus, and squid.
segmented worms (Phylum Annelida): earthworms,
many marine worms that may be free-swimming or live
in tunnels or tubes, and leeches
arthropods (Phylum Arthropoda): the most diverse
group of animals, which includes insects, spiders,
scorpions, ticks, mites, centipedes, millipedes, and
crustaceans (aquatic organisms like shrimp and
lobster.)
Phylum Mollusca
Mollusks have 3 body regions: a head, a visceral mass,
and a "foot.“
Mollusks: Phylum Mollusca
• Bilateral, soft-bodied, coelomate
• Most have a shell or reduced version of
one
• Mantle drapes over body and secretes
shell
• Most have a fleshy foot
• Many have a radula for shredding food
Molluscan Diversity
• Gastropods
• Chitins
• Bivalves
• Cephalopods
Torsion
• Twisting of body
parts during larval
development
• Occurs only in
gastropods
mouth
gill
anus
Figure 25.18
Page 426
Body Plan of a Snail
heart
mantle cavity
anus
gill
mantle
digestive
gland
foot
radula
Figure 25.18
Page 426
Body Plan of a Clam
mouth
left mantle
retractor muscle
retractor muscle
foot
palps
left gill
shell
Figure 25.21
Page 429
The coelom is a body cavity, within which internal
organs can develop, which is completely lined with a
middle layer of tissue in the body called mesoderm and
distinct from the outer layer that makes up the skin (the
ectoderm tissue) and the inner layer that makes up the
digestive tract (the endoderm tissue.)
Class Amphineura
“Chitons”
Characteristics
•
•
•
•
Eight dorsal plates
Reduced head
One Foot
Radula for scraping rocks
Class Gastropoda
“Snails, limpets, abalones, slugs”
Spiraled Shell
Class Bivalvia (Cephalopoda)
“clams, oysters and mussels”
Bivalvia
•
•
•
•
Shell of two valves
Head Reduced
Gills
No radula and filter feeders
Class Cephalopoda
“Squid,octopi, chambered nautilus”
• Shell external, internal or absent
• Foot modified into eight arms and some
with two tentacles
• mantle muscular and forms a siphon for
“jet” propulsion
• radula modified as a beak
• excellent vision
• All marine
Cuttlefish Body Plan
Closed circulatory system with heart and
accessory heart
esophagus
digestive
kidney stomach
gland
Figure 25.22
Page 429
brain
arm
jaw
tentacle
mantle
reproductive internal
siphon
ink sac heart accessory organ
shell
radula
anus
gill
heart
Annelids: Phylum Annelida
Segmented, coelomate worms
• Class Polychaeta
• Class Oligochaeta
• Class Hirudinea
Phylum Annelida
“segmented worms”
Class Polycheata
“Bristle Worms”
•
•
•
•
•
Many setae born on parapodia
Relatively well devloped head
Sedentary (tube dwelling)
Errant (Swimmers or crawlers
All are marine
Polychaetes
• Most are marine
• Bristles extend
from paired, fleshy
parapods on each
segment
• Head end is
specialized
“jaws”
toothlike
structures
pharynx
(everted)
antenna
palp
(food handling)
tentacle
eyes
chemicalsensing pit
parapod
Fig. 25.24c
Page 430
Class Oligochaeta
“Earthworms and Freshwater
Annelids”
• Few setae borne on parapodia
• Reduced head
• Terrestrial and Fresh water
Earthworm - An Oligochaete
No parapodia, few bristles per segment
Dorsal blood vessel
Circular muscle
Coelom
Longitudinal
muscle
Nephridium
Nerve cord
Figure 25.25a
Page 431
Seta (retracted)
Nerve cord
Earthworm Nephridium
bladderlike storage
region of nephridium
nephridium’s thin loop reabsorbs some
solutes, relinquishes them to blood
blood
vessels
body
wall
funnel (coelomic fluid
with waste enters here)
external pore (fluid containing
wastes discharged here)
Figure 25.25b
Page 431
Earthworm Circulatory System
Hearts
Figure 25.25c
Page 431
Earthworm Digestive System
Coelomic chambers
Esophagus
Crop
Gizzard
Pharynx
Mouth
Figure 25.25d
Page 431
Earthworm Nervous System
Brain
Nerve cord
Figure
25.25e
Page
431
Class Hirudinea
“Leeches”
•
•
•
•
•
•
•
Body Flattened
Anterior and Posterior Suckers
Constant number of segments (32 or 33)
Predatory or parasitic
Anticoagulant
No setae
Most freshwater, Few terrestrial
Leeches - Class Hirudinea
• Predators and parasites
• Less obvious body segmentation
• Most have sharp jaws