kingdom anamalia. characteristics of animals multicelled heterotrophic eukaryotes require oxygen for...
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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
Major Animal Phyla
Chordates
Echinoderms
Arthropods
Annelids
Mollusks
Rotifers
Roundworms
Flatworms
Cnidarians
SpongesMulticelled Ancestry
Radial Ancestry
Bilateral Ancestry
Coelomate Ancestry
Single-celled, protistanlike ancestorsFigure 25.2Page 415
Symmetry
Radial Bilateral Figure 25.3Page 416
dorsal
posterior
ventral
anterior
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
epidermisgut cavity
no body cavity; region between gut and body wall packed with organs
Figure 25.4aPage 417
Body Cavities - Pseudocoel
epidermis gut cavity
unlined body cavity (pseudocoel) around gut
Figure 25.4bPage 417
Body Cavities - Coelom
gut cavity
peritoneumlined body cavity (coelom) Figure 25.4c
Page 417
Body Cavities - Coelom
gut cavity
peritoneumlined body cavity (coelom) 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.“
• 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
Mollusks: Phylum Mollusca
• Gastropods
• Chitins
• Bivalves
• Cephalopods
Molluscan Diversity
• Twisting of body parts during larval development
• Occurs only in gastropods
Torsion
mouth
anusgill
Figure 25.18Page 426
Body Plan of a Snail
gillanus
radula
foot
mantle cavity
digestive gland
mantle
heart
Figure 25.18Page 426
Body Plan of a Clam
mouthretractor muscle
left mantle
retractor muscle
foot
palpsleft gill shell
Figure 25.21Page 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 PlanClosed circulatory system with heart and
accessory heart
stomachkidneyesophagus
digestive gland
brain
arm
jaw
tentacle radula
siphon
anusink sac
gillheart accessory
heart
reproductive organ
mantleinternal
shell
Figure 25.22Page 429
Segmented, coelomate worms
• Class Polychaeta
• Class Oligochaeta
• Class Hirudinea
Annelids: Phylum Annelida
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
Fig. 25.24cPage 430
“jaws”
toothlike structurespharynx (everted)antenna
palp (food handling)
tentacle
eyes
chemical-sensing pit
parapod
Class Oligochaeta“Earthworms and Freshwater
Annelids”
• Few setae borne on parapodia
• Reduced head
• Terrestrial and Fresh water
No parapodia, few bristles per segment
Earthworm - An Oligochaete
Nerve cord
Nerve cord
Dorsal blood vessel
Nephridium
Coelom
Circular muscle
Longitudinal muscle
Seta (retracted)Figure 25.25a
Page 431
Earthworm Nephridiumbladderlike storage region of nephridium
nephridium’s thin loop reabsorbs some solutes, relinquishes them to blood
blood vessels
body wall
external pore (fluid containing wastes discharged here)
funnel (coelomic fluid with waste enters here)
Figure 25.25bPage 431
Earthworm Circulatory System
Hearts
Figure 25.25cPage 431
Earthworm Digestive System
PharynxEsophagus
Crop Gizzard
Coelomic chambers
Mouth
Figure 25.25dPage 431
Earthworm Nervous System
Brain
Nerve cord Figure 25.25ePage 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
• Predators and parasites
• Less obvious body segmentation
• Most have sharp jaws
Leeches - Class Hirudinea