Chapter 29

The Animal KingdomThe Protostomes

Invertebrates Video

Coelom

• Fluid-filled space lined w/mesoderm; between digestive tube and outer body wall

• Tube-within-a-tube plan• Inner tube no longer attached to body wall

Advantages of Coelom

• Can serve as hydrostatic skeleton (fluid under pressure)– Contracting muscles push against tube of fluid– Greater range of movement– Swim, crawl, walk

• Space, cushion for internal organs, gonads• Transport of food, O2, waste

Phylum Nemertea

• Ribbon worms, proboscis worms• Proboscis = long, hollow muscular tube– Can be everted from anterior end of body– Wrap around prey– Sharp, sticky or toxic

• Functionally acoelomate (chamber around proboscis is true coelomic space = rhynchocoel)

• Circulatory system – blood vessels, no heart

Fig. 33-3l

A ribbon worm

Phylum MolluscaClams, oysters, octopods, snails, slugs, giant squid

• Basic characteristics– Soft body – usually covered by shell– Foot – locomotion– Visceral mass – above foot– Mantle – cover visceral mass– Radula – rasplike, belt of teeth– Coelom – reduced, small around certain organs• Hemocoel - blood

Fig. 33-15

Nephridium Visceral mass

Coelom

Mantle

Mantlecavity

Heart

IntestineGonads

StomachShell

Radula

MouthEsophagusNerve

cordsFoot

Gill

Anus

Mouth

Radula

Phylum Mollusca

• Digestive – Mouth, buccal cavity, esophagus, stomach,

intestine, anus– Radula in buccal cavity

• Circulatory – open (most)– Blood = hemolymph – bathes tissues– Heart – aorta – blood vessels – sinuses (make up

hemocoel) – blood vessels – gills – heart– Closed system – active squid, octopods• Blood in blood vessels completely

Phylum Mollusca

• Excretory– Metanephridia – funnels waste from fluid in

coelom to excretory pore

4 Classes of Mollusks• 1. Polyplacophora – “many plates”– Chitons – Shell of 8 dorsal plates, head reduced, no eyes or

tentacles• 2. Gastropoda – Well-developed head w/tentacles, 2 simple eyes, foot– Torsion – twist visceral mass; allows head to enter

shell 1st before foot– Snails – single, spiral coiled shell– Limpets – shells like flat dunce cap– Nudibranchs (sea slug) – no shell

Fig. 33-16

Fig. 33-17

(a) A land snail

(b) A sea slug

Fig. 33-18

Mouth

Anus

Mantlecavity

Stomach Intestine

Nudibranch (Sea slug)

• 3. Bivalvia– Clams, oysters, mussels, scallops– 2 part shell– Nervous – 3 pair ganglia, 2 pair nerve cords– Eyespots– Suspension feeders – water in through siphon (no

radula)

Fig. 33-19

Fig. 33-20

Mouth

Digestivegland

MantleHinge area

GutCoelom

Heart Adductormuscle

Anus

Excurrentsiphon

Waterflow

IncurrentsiphonGillGonad

Mantlecavity

FootPalp

Shell

• 4. Cephalopoda – “head foot”– Swim fast, predators– Mouth w/tentacles (suckers to seize prey)– Radula + 2 beaks– Mantle has siphon– Jet propulsion– Head – well-developed eyes– Octopus – no shell– Squid – reduced shell inside body– Nautilus – coiled shell– Defense• Chromatophores – change color• Ink sac – black liquid

Fig. 33-21

Octopus

Squid

Chambered nautilus

Phylum Annelida – “ringed”

• Segmented worms– Facilitates locomotion– Coelom divided – each segment own muscles– Setae – bristle-like structures - traction

• Bilateral symmetry• Tubular body• Nervous– Simple brain (paired ganglia) + ventral nerve cord– Each seg. = pair ganglia + lateral nerves

Phylum Annelida

• Closed circulatory system• Complete digestive tract– Mouth - anus

• Respiration– cutaneous

• Excretion – Pair metanephridia in each segment

Class Polychaeta – “many bristles”

• Marine• Parapodia – pair of paddle-shaped

appendages on each body segment– Locomotion, gas exchange, bear setae

• Head w/eyes and antennae• Optional – tentacles, palps• Separate sexes– Gametes in water same time (lunar, tides)

Fig. 33-23

Parapodia

Tubeworms - Polychaetes

Class Oligochaeta – few bristles

• Fresh water/terrestrial• No parapodia, few bristles• Lack well-developed head• Hermaphrodites

Class Oligochaeta - Lumbricus terrestris

• Cuticle• Mucus layer• Muscles in body wall• Relationship with soil• Complex digestive system– Pharynx – esophagus – crop (store) – gizzard

(grind) – intestine (digest, absorb) – anus • Circulatory system – closed– Dorsal and ventral BV; BV in segments– 5 pair BV by esophagus

Earthworm Locomotion

Class Oligochaeta - Lumbricus terrestris

• Gas exchange– Moist skin

• Excretion – Paired metanephridia – almost every segment

• Nervous – Simple brain (pair cerebral ganglia above pharynx

and subpharyngeal ganglia below pharynx)– Ventral nerve cord– Pair fused ganglia – each segment – coordinate

muscles

Class Oligochaeta - Lumbricus terrestris

• Reproduction– Hermaphroditic– 2 worms exchange sperms– Clitellum - ring of epidermis, secretion

Fig. 33-22Epidermis

Circularmuscle

Longitudinalmuscle

Dorsal vessel

Chaetae

Intestine

Nephrostome

Fusednervecords

Ventralvessel

Metanephridium

Septum(partitionbetweensegments)

CoelomCuticle

Anus

Metanephridium

Crop

Intestine

Gizzard

Ventral nerve cord withsegmental gangliaBlood

vessels

Subpharyngealganglion

MouthCerebral ganglia

Pharynx

Esophagus

Clitellum

Giant Australian earthworm

Class Hirudinea - leeches

• Blood-sucking parasites (some nonparasitic)– Suck out blood and store in digestive tract– Hirudin – anticoagulant – from crop; ensures full

meal• No setae or parapodia• Muscular suckers both body ends

Fig. 33-24

Lophophorate phyla

• Ring of tentacles around mouth for capturing particles in water

Fig. 33-14

Lophophore

(a) Ectoproct (sea mat)

Lophophore

(b) Brachiopods

Phylum Rotifera

• “wheel animals”• Crown of cilia on anterior end– Beat rapidly – swim / feed

Fig. 33-13

Jaws Crownof cilia

AnusStomach 0.1 mm

Phylum Nematoda - roundworms

• Decomposition, nutrient recyclers• Free-living; parasites• Body – point both ends, cuticle• Epidermis unusual – no composed of distinct

cells• Pseudocoelom – fluid – muscle contraction,

nutrient distribution• Bilateral symmetry

Fig. 33-25

25 µm

Phylum Nematoda

• Complete digestive system – 3 tissue layers• Lack specific circulatory parts• Sexes usually separate• No well-define head

Crawling Nematode

Examples of Nematodes• Ascaris – intestinal human parasite– Eggs in feces– Poor sanitation – eggs soil (fertilizer)– Ingest eggs on unwashed fruit/veg. OR hands

• Hookworm – lining human intestine, suck blood– Eggs – feces – host barefoot – larvae into skin / blood

• Trichina – small intestine mammals– Undercooked, infected meat– Encyst in skeletal muscle; cysts calcify

• Pinworm - large intestine, kids– Eggs ingested – dirty hands– Female worms – anal region – deposit eggs - itching

Fig. 33-26

Encysted juveniles Muscle tissue 50 µm

Phylum Arthropoda - “jointed foot” – very successful

• Segmented body – specialization• Exoskeleton – chitin + protein– Protection, water loss, molting (disadvantage)

• Paired, jointed appendages– Swim, walk, get prey, sensory, reproduction

• Nervous system – sense organs – Antennae, eyes, ganglia

• Open circulatory system - hemocoel

Phylum Arthropoda

• Gas exchange – Water – gills– Land – tracheal tubes, book lungs

Onychophorans - “missing link” between annelids and arthropods; “velvet worms”

• Like Annelids– Internal segments

• Like Arthropods– Open circulation– Tracheal tubes– Unbranched legs– Jaws from appendages

3 Subphyla of Arthropods:Subphylum Chelicerata

• Horseshoe crabs, arachnids• No antennae• Chelicerae (1st pair) – fanglike feeding

appendages• Body = cephalothorax + abdomen• Pedipalps (2nd pair) = locomotion, food,

defense or copulation• 4 pair legs on cephalothorax - walking

Fig. 33-3r

An onychophoran

Subphylum Chelicerata – Horseshoe Crabs

• Living fossil• Tail for locomotion• 5 pair walking legs

Fig. 33-30

Subphylum Chelicerata - Arachnids

• Spiders, scorpions, ticks, harvestmen, mites• Most carnivorous• 6 pair jointed appendages

Fig. 33-31

Scorpion

Dust mite

Web-building spider

50 µm

Arachnids - Spiders

• 1st pair – chelicerae – penetrate prey• 2nd pair – pedipalps – hold, chew food• Next 4 pairs – walking• 8 eyes – 2 rows, 4 each• Gas exchange– Tracheal tubes, book lungs or both

• Glands – abdomen – silk (spinnerets)• All spiders – poison glands (few toxic to

humans)

Fig. 33-32

Intestine

HeartDigestivegland

Ovary

Anus

SpinneretsSilk gland

Gonopore(exit for eggs) Sperm

receptacle

Book lung

Chelicera Pedipalp

Poisongland

Eyes

Brain

Stomach

Arachnids - Mites and Ticks

• Nuisance– Eat crops, infest livestock, pets, us– disease

• Mites – chiggers – red itchy welts

• Ticks – Rocky Mountain spotted fever, Texas cattle fever,

relapsing fever, Lyme disease

Trilobites

• Early arthropod – extinct now• 3 lobes of exoskeleton• Led to chelicerates

Fig. 33-27

Subphylum Crustacea

• Lobsters, crabs, shrimp, barnacles– Consume algae detritus– Compose much zooplankton

• Mandibles – jaw like, no chelicerae– Hard, 3rd pair appendages, sides of mouth, bite/grind food

• Biramous appendages – 2 jointed branches• 2 pair antennae (sensory)• Nauplius larva – 1st stage after hatching; has only most

anterior 3 pair of appendages• 1st and 2nd Maxillae – after mandibles; 2 pair;

manipulate, hold food• Other appendages – walk, swim, transmit sperm,

carry eggs/young/sense

Subphylum Crustacea

• Gas exchange - gills• Excretion – 2 large antennal (green) glands • Compound eyes• Statocysts – detect gravity• Reproduction - separate sexes– Male sperm to female; fertilized egg carried on

female– New animals – resemble adult or many larval

stages w/molting

Orders of Subphylum Crustacea

• Isopods – pill bugs, sowbugs (5-15 mm)• Copepods – zooplankton (microscopic)• Decapods – lobster, crayfish, crab, shrimp

Fig. 33-38

(a) Ghost crab

(b) Krill (c) Barnacles

Fig. 33-29

Cephalothorax

Antennae(sensoryreception) Head

Thorax

Abdomen

Swimming appendages(one pair locatedunder eachabdominal segment)

Walking legs

Mouthparts (feeding)Pincer (defense)

Lobster Anatomy – a decapod crustacean

• Carapace– Covers cephalothorax– Chitin w/ calcium salts

• Antennae – 2 pair– sensory

• Mandibles – 1 pair– Bite/grind food

• Maxillae – 2 pair– feeding

• Maxillipeds – 3 pair– Chop food, pass to

mouth

Lobster Anatomy – a decapod crustacean

• Chelipeds – 1 pair– Pinching claws

• Walking legs – 4 pair• Reproductive appendages

– Male – sperm transfer

• Swimmerets– Small, paddle like – swim, hold eggs

• Uropods– Large, flattened structure

• Telson– Flattened posterior end of

abdomen

• Uropod + telson – fan –shape; swim backward

Lobster Mouth

Subphylum Uniramia

• Insects, centipedes, millipedes• Uniramous appendages – unbranched• 1 pair antennae• Jawlike mandibles

Class Insecta of Subphylum Uniramia

• Most successful animals– Diverse, geographic distribution, # species, #

individuals• Articulated = jointed• Tracheated = having tracheal tubes (gas

exchange)• Hexapod – have 6 feet

Class Insecta

• Body – 3 distinct parts– Head • 1 pair antennae• Simple OR compound eyes (sensory)• Mouthparts – piercing, chewing, sucking, lapping

– Thorax• 3 pair legs, 1-2 pair wings

– Abdomen

Fig. 33-35

Abdomen Thorax Head

Compound eye

Antennae

Heart

Dorsalartery Crop

Cerebral ganglion

Mouthparts

Nerve cords

Tracheal tubesOvary

Malpighiantubules

Vagina

Anus

Class Insecta

• Tracheal system– Spiracles = opening in body wall, air enters– Spiracles – tracheal tubes – internal organs

• Open circulation• Excretion– 2+ Malpighian tubules – receive waste from blood,

concentrate waste, discharge to intestine; conserve water

Class Insecta

• Reproduction– Separate sexes– Internal fertilization– Direct development (hatch as small adult) OR– Molt during development metamorphosis• Incomplete metamorphosis

– Egg – larva – adult– Grasshopper, cockroach

• Complete metamorphosis – 4 stages– Egg – larva – pupa – adult– Butterfly, bee, flea

• Exoskeleton – water loss, protection• Flight

Fig. 33-36

(a) Larva (caterpillar)(b) Pupa

(c) Later-stage pupa (d) Emerging

adult

(e) Adult

Butterfly Metamorphosis

Class Insecta – Impact on Humans

Good• Pollination• Destroy harmful insects• Food webs• Nutrient recyclers• Products

– Honey, beeswax, shellac, silk

Bad• Destroy crops, buildings,

clothing• disease

Class Chilopoda - centipedes

• “hundred-legged”• 1 pair legs/segment (average 30 total)– Long = fast

• Uniramous appendages• carnivorous

Fig. 33-34

Class Diplopoda - millipedes

• “thousand-legged”• 2 pair legs/segment– slow

• herbivorous

Fig. 33-33

Both Chilopoda and Diplopoda

• Terrestrial• Head + elongated trunk– Many segments– Uniramous legs

Fig. 33-37a

Fig. 33-37b

Fig. 33-37c

Fig. 33-37d

Fig. 33-37e

Match the Order of Insect with the Correct Example

Order• Thysanura• Orthoptera• Isoptera• Odonata• Hemiptera• Anoplura

Example• Sucking lice• Grasshopper• Damselfly• Chinch bug• Silverfish• termite

Match the Order of Insect with the Correct Example

Order• Syphonaptera• Homoptera• Diptera• Lepidoptera• Hymenoptera• coleoptera

Example • Moth• Aphid• Ant• Housefly• Beetle• flea