Invertebrates

Section Outline

29–1 Invertebrate EvolutionA. Origin of the

Invertebrates1. The First

Multicellular Animals2. Beginnings

of Invertebrate Diversity

Section 29-1

B. Invertebrate PhylogenyC. Evolutionary Trends

1. Specialized Cells, Tissues, and Organs

2. Body Symmetry3. Cephalization4. Segmentation5. Coelom Formation6. Embryological Development

Comparing InvertebratesComparing Invertebrates

Major Characteristics

Germ Layers

BodySymmetry

Cephalization

Coelom

Early Development

Major Characteristics

Germ Layers

BodySymmetry

Cephalization

Coelom

Early Development

Section 29-1

Sponges

Absent

Absent

Absent

Absent

—

Sponges

Absent

Absent

Absent

Absent

—

Cnidarians

Two

Radial

Absent

Absent

—

Cnidarians

Two

Radial

Absent

Absent

—

Flatworms

Three

Bilateral

Present

Absent

Protostome

Flatworms

Three

Bilateral

Present

Absent

Protostome

Roundworms

Three

Bilateral

Present

Pseudocoelom

Protostome

Roundworms

Three

Bilateral

Present

Pseudocoelom

Protostome

Compare/Contrast

Pg. 748-749

Comparing InvertebratesComparing Invertebrates

Major Characteristics

Germ Layers

BodySymmetry

Cephalization

Coelom

Early Development

Major Characteristics

Germ Layers

BodySymmetry

Cephalization

Coelom

Early Development

Section 29-1

Annelids

Three

Bilateral

Present

True coelom

Protostome

Annelids

Three

Bilateral

Present

True coelom

Protostome

Mollusks

Three

Bilateral

Present

True coelom

Protostome

Mollusks

Three

Bilateral

Present

True coelom

Protostome

Arthropods

Three

Bilateral

Present

True coelom

Protostome

Arthropods

Three

Bilateral

Present

True coelom

Protostome

Echinoderms

Three

Radial (adults)

Absent (adults)

True coelom

Deuterostome

Echinoderms

Three

Radial (adults)

Absent (adults)

True coelom

Deuterostome

Compare/Contrast

Section 29-1

RadialSymmetry

Deuterostome Development

Coelom

Pseudocoelom

Protostome Development

RadialSymmetry

Three Germ Layers;Bilateral Symmetry

Tissues

Multicellularity

Chordates Echinoderms Arthropods

Annelids Mollusks

Roundworms

Flatworms

Cnidarians

Sponges

Single-celled ancestor

Invertebrate Cladogram

Pg. 747

Section OutlineSection 29-2

29–2 Form and Function in InvertebratesA. Feeding and Digestion

1. Intracellular and Extracellular Digestion

2. Patterns of Extracellular Digestion

B. Respiration

1. Aquatic Invertebrates

2. Terrestrial Invertebrates

C. Circulation

1. Open Circulatory Systems

2. Closed Circulatory Systems

D. Excretion

1. Aquatic Invertebrates

2. Terrestrial Invertebrates

E. Response

1. Centralization and Cephalization

2. Specialization

F. Movement and Support

1. Hydrostatic Skeletons

2. Exoskeletons

3. Endoskeletons

G. Sexual and Asexual Reproduction

Type of Skeleton

Hydrostatic

Exoskeleton

Endoskeleton

Type of Skeleton

Hydrostatic

Exoskeleton

Endoskeleton

Section 29-2

Sponges

Simple (spicules or spongin)

Sponges

Simple (spicules or spongin)

Cnidarians

X

Cnidarians

X

Flatworms

X

Flatworms

X

Roundworms

X

Roundworms

X

Types of Invertebrate Skeletons

Section 29-2

Type of Skeleton

Hydrostatic

Exoskeleton

Endoskeleton

Type of Skeleton

Hydrostatic

Exoskeleton

Endoskeleton

Annelids

X

Annelids

X

Mollusks

Some

Some(shells)

Mollusks

Some

Some(shells)

Arthropods

X

Arthropods

X

Echinoderms

X

Echinoderms

X

Types of Invertebrate Skeletons continued

Section 29-2

Arthropod

Annelid

Flatworm

Cnidarian

Mouth/anus

Mouth/anusMouth

Mouth

Gastrovascularcavity

Gastrovascularcavity

Pharynx

Pharynx

PharynxCrop

Crop

Gizzard

Intestine

Intestine

Rectum

Anus

Anus

Stomachand

digestive glands

Invertebrate Digestive Systems

Section 29-2

Mollusk

Insect

Spider

Gill

Siphons

Movement of water

Booklung

Airflow

Trachealtubes

Spiracles

Invertebrate Respiratory Systems

Section 29-2

Insect:Open Circulatory System

Annelid:Closed Circulatory System

Heartlikestructures

Bloodvessels

Heartlike structure

Small vessels in tissues

Bloodvessels

Hearts

Heart

Sinusesand organs

Invertebrate Circulatory Systems

Section 29-2

Annelid

Arthropod

Flatworm

Malpighian tubules

Digestive tract

Nephridia

Excretory pore

Excretory tubule

Flame cell

Flamecells

Excretorytubules

Nephrostome

Invertebrate Excretory

Systems

Section 29-2

GangliaGanglia

Brain

BrainNerve Cells

Arthropod

Mollusk

CnidarianFlatworm

Invertebrate Nervous Systems

Video

Circulatory Systems

Sponges & Cnidarians

Worms & MollusksArthropods & Echinoderms

Characteristics of Animal Kingdom

Heterotrophs Mobile Multicellular Lacks cell walls Sexual

reproduction

Radial (radiate outward from center)

Bilateral (two sides) Dorsal = top side Ventral = belly (bottom)

side Anterior = front end Posterior = rear end

Asymmetrical (no plane dividing body into equal halves)

Body symmetry

Which Type of Symmetry?

A DCB

FFE

B C

G

Development & Body Cavities

Zygote (fertilized egg) blastula (hollow ball) gastrula (inward folding creating layers)

Ectoderm Endoderm Mesoderm

Germ Layers form embryonic layers.

Endoderm: inner layer digestive tract and respiratory system

Mesoderm: middle layer muscles, circulatory, reproductive and excretory organs

Ectoderm: outermost layer sense organs, nerves, and epidermis

Body plansBody plans

No body cavity

Fluid filled body cavity fully lined with mesoderm

Fluid filled body cavity partially lined with mesoderm

Protostomes vs Deuterostomes

Phylum Porifera, the sponges

Asymmetrical

Lacks tissues = cells embedded in matrix

Sessile adults

sponges

Phylum Cnidaria

Examples: jellyfish, coral, hydra,

sea anemones, man-o-war

Radial symmetry True tissues 2 cell layers

endoderm, ectoderm

Polyp (tubular body) & Medusa (bell-shaped body)

Feeding

Body tissue surrounds gastrovascular cavity, a single opening space, where digestion takes place.

Phylum Platyhelminthes, the flatworms

Examples: planarians, flukes, tapeworms

Acoelomates (no cavity)

Organs & systems Three germ layers Bilateral symmetry Cephalization

(concentration of nervous

tissue in head)

Flatworms

Planeria

Intermediate hosts•Tapeworm larvae burrow into cow or fish muscle tissue, which infects the animal that eats this tissue.

Rat tapeworm

Parasites have a complex life history with several hosts

Parasitic tapeworm from a fish

Human tapeworm

•Scolex: head with suckers or hooks

Tapeworm

Phylum Nematoda, the roundworms

Examples = heartworms,

hookworms, pin

worms

Roundworm Anatomy Pseudocoelom false body cavity

between endoderm & mesoderm

2 body openings (mouth and anus)

Guinea worm disease

Preventive Measures

Health education and low-technology measures to promote behavioral change are used to prevent Guinea worm disease.

The most effective way to prevent it is to filter the tiny water fleas out of drinking water. The Carter Center provides families with fine-mesh filter cloths that fit over clay pots used to hold water. 

Some people, especially nomadic groups, receive pipe filters, which are small straw-like personal filters that can be worn around the neck.  These simple but revolutionary devices enable people to drink water safely no matter where they are.

http://www.cartercenter.org/news/multimedia/media_console/console.aspx?sectionID=H&directoryEXT=h07&linkEXT=CC_video.swf

Pinworm infection in child’s intestine

Roundworms A report by the Centers for

Disease Control and Prevention found that about 14 percent of Americans are infected with Toxocara – a parasite commonly known as the round worm.

The disease is zoonotic – which means you can get it from your pet. The CDC says the parasite is most commonly found in children from low socioeconomic areas.

For the most part there aren't any symptoms. But in rare cases it can cause blindness, especially in children.

Researchers say the worms are transferred through cat and dog fecal matter – in yards and sand boxes – places where children often play.

Filarial worms

•Primary cause of elephantiasis condition where parts of the body are swollen

•Requires arthropod intermediate host to complete life cycle

Filarial worms

Elephantiasis is a condition of extreme edema that occurs when lymph vessels become blocked by filarial worms. Here the left leg is swollen with the fluids accumulated in the tissues as a result of the blockage.

Phylum Annelida

Examples: leeches, earthworms & marine worms

Segmented worms Separated by septa = dividing walls

Bilateral symmetry Coelomates 3 cell layers Advanced

organ systems

Annelids

Leeches release a chemical that prevents the prey from forming scabs. A leech bite is less painful than it is just messy with the profuse bleeding.

Phylum Mollusca

Coelomates=true body

cavity (between mesoderm)

Soft body Unsegmented 2nd most successful

land animal (after insects)

Mollusks

Mollusk Anatomy

3 body parts: Visceral mass = houses

body organs Mantle = heavy fold of tissue

surrounding visceral mass Foot = ventral surface for

locomotion Respiratory structure:

Gills = filamentous projections that capture oxygen from the water

Mollusk Groups

Cephalopod = “head-footed” little or no shell most advanced eye Jet propulsion Octopus, squid,

nautilus

Cuttlefish

Mollusk Groups

Bivalves = “2 shells” “hatchet-footed” Clams, oysters,

etc

Mollusk Groups

Gastropods = “belly-footed” One shell Snails, slugs, etc

Groups of mollusks

Gastropods: shell-less or single-shelled mollusks with muscular feet

Sea snail

Movement Snails: secrete

mucus and crawl slowly

Cephalopods: fast moving, drawing water into mantle cavity and forcing water out of siphon (like jet propulsion)

excessive amount of snail mucus secreted

Snail Trail

Mexican turbo snail

Phylum Arthropoda

Jointed appendages

Segmented bodies

Exoskeleton

Largest phylum in Animal Kingdom

Metamorphosis

Undergoes morphological changes during life history

Incomplete = 3 stages Egg, nymph, adult

Complete = 4 stages Egg, larva, pupa,

adult

Arthropod Groups

Arachnids = spiders,

scorpions Crustaceans =

lobsters, shrimp

Insects = grasshoppers,butterflies, bees

Diplopoda = millipedes

Chilopoda = centipedes

Specialized appendages

Mouthparts Antennae Legs Pincers Wings Swimmerets

Phylum Echinodermata

Spiny skinned Radial symmetry (as

adults) Endoskeleton made

of plates, ossicles Water vascular

system for moving & feeding

Regeneration

Water Vascular System,for feeding & locomotion

Echinoderm groups

Sea Stars (starfish)

Sand dollars & sea

biscuits

Sea urchins

Echinoderm groups

Sea cucumbers

Brittle stars (serpent stars)

Sea lilies

Echindoerms

Subphylum Arachnida – black widow spider

Brown Recluse Spider

Scorpion

Wolf Spider

Subphylum Crustacea – hermit crab

Subphylum Crustacea –crab

Subphylum Crustacea – fire shrimp

Subphylum Insecta – lady bug

Subphylum Insecta – bee moth

The purple Sea urchin has sharp spines to protect against predators.

A close-up of the mouth of a Green Sea urchin, called Aristotles lantern.

Diversity of Echinoderms

Sea cucumbers

Sea lilies & feather stars

Red Prickly Sea Cucumber

Yum Tasty!!!!!!!!

Sea Lilies