invert arthropoda and echinodermata

arthropoda clade

panarthropoda

what is under panarthropoda?

Onychopora, tardigrada, arthropoda

Characteristics of arthropods

• external jointed skeleton

• Trachea

• compound eyes

• Malpighian tubules (Execratory organ)

• mandibles

  • heart with ostia

tardigrades and onychophorans have what?

lobopods - unjointed walking legs ( terminate in claws)

Phylum Tardigrada

“water bears”

-900 species

-4 pair of clawed appendages

-no larval stage

-apendages segmented, not jointed

-undergo cryptobiosis

cryptobiosis

can dehydrate and lower metabolic rate to survive harsh conditions

Phyum Onychophora

• less than 100 species

• free living

• terrestrial

• second pair of appendages (oral papilla) form jaw

  • have preantenna

Phylum Arthropoda

• coelomate

  • protostome complete digestive

Arthropoda bauplan

• jointed appendages

• chitinous exoskeleton

  • exoskeleton molt

Arthropoda is the ______ and ______ of all the animal phylum

abundant and diverse

arthropod cuticle

• versatile exoskeleton with multiple layers secreted by epidermal cells

• protects body without sacrificing mobility

• thin at joints

epidermal cells

epicuticle- proteins and lipids

procuticle- polysaccharide chiton and proteins

sclerotization

• formation of bonds between proteins

  • hardens cuticle

in crustaceans the cuticle is further hardened by

CaCO3

Muscle attachments ____the exoskeleton

inside

Segmented body & jointed appendages allow for

more

efficient locomotion

Each segment typically has a

pair of appendages

Segments & appendages

adapted to various tasks

Segmentation and Appendages

Phylum Arthropoda

such as

sensing, feeding,

walking, swimming, flying,

copulating,

Segments may be fused or

combined into functional groups

called

tagmata

uropod and telson

chela and cheliped

Polychaetes have some tagmatization (the

head region), but most arthropod groups have

more

Arthropod classes are defined largely by patterns of

tagmatization and the number and arrangement of limbs

In most groups, appendages on the head have been modified

into

antennae and various feeding devices

Appendages may be

uniramous

or biramous

Tracheal System

• in most terrestrial

• Network of finely branched

  air tubes

  • delivers oxygen directly to cells

Tracheae open via

spiracles

Nervous system

• Brain, ventral nerve cord are well developed

• Simple eyes (ocelli), compound eyes often present

Many arthropods undergo

metamorphosis

-greatly increases their trophic breadth

subphylum trilobita

Trilobites (extinct)

Subphylum Chelicerata

Merostomata- horshoe crab, (eurypterids (extinct))

Pycnogonida- sea spider

Arachnida- spider, scorpion, mites, tics

subphylum Myriapoda

centipedes, millipedes

Subphylum Crustacea

obsters, crabs, many otl

Subphylum Hexapoda:

insects & a few others

Subphylum Trilobita

abundant during the Cambrian & Ordovician periods

bottom dweller

Died out in Permian mass extinction

Trilobita Body divided into

3 longitudinal regions

chepalon and thorax

-legs biramous

Subphylum Chelicerata Two tagmata:

prosoma and opisthosoma

Subphylum Chelicerata have no

antennae or mandibles

Subphylum Chelicerata Six pairs of appendages on prosoma:

- 1st pair = chelicerae, used for feeding

- 2nd pair = pedipalps, variously adapted

- Four pairs of walking legs

Class Merostomata

Xiphosurids or horseshoe crabs

• Oldest fossils Ordovocian

Prosoma has dorsal

carapace

Spinelike ______on opisthosoma

telson

grind food, pass

it to the mouth

Gnathobases

flat, leaflike

appendages on opisthosoma

that function as gills

book gills

Eurypterids

-sea scorpions

-Reached length of 3 m Largest arthropods of all

Class Pycnogonida

Sea spiders

Body is mostly prosoma, opisthosoma just a stump

Mouth at tip of prominent suctorial proboscis

Suck juices from soft-bodied, sessile animals

appendages used by both sexes for grooming

Ovigers

• Males use ovigers for carrying eggs

Class Arachnida orders

Order Araneae: spiders

Order Scorpionida: scorpions

Order Solpugida: camel spiders

Order Opiliones: harvestmen

Order Acari: ticks & mites

spider order

Araneae

Chelicerae function as fangs, bear ducts from venom glands

Prosoma aka in spider

cephalothorax

opisthosoma aka in spider

abdomen

Araneae breath via

tracheae or book lungs or both

Silk from

silk glands spun into threads by spinnerets

Araneae reproduction

Male pedipalp holds a silk-wrapped sperm package

• Inserted into female genital opening after courtship ritual

• female lay eggs in silk bag

scorpion order

Scorpionida

Scorpionida Opisthosoma

long and segmented, prosoma shorter

Pedipalps bearing

chelae (pincers)

Scorpionida reproduction

-male place sperm package on ground

-dances with female while holding pedipalps

Camel Spiders

Order Solpugida

Harvestmen

Order Opiliones

Mites & Ticks

Order Acari

Acari Mouthparts on

capitulum,

modified for sucking

Phylum Arthropoda: Subphylum Myriapoda tagmata

Two tagmata: head and trunk

Mouthparts:

mandibles

& two pairs of maxillae

Centipedes Maxillipeds:

Appendages modified as venom claws

Centipedes

One pair of legs on most segments

Millipedes

Two pairs of legs per segment, 25 to 100 segments

Defensive glands secrete foul-smelling or toxic

substances

Subphylum Crustacea

More than 67,000 species

tagmata vary

primarily aquatic

Subphylum Crustacea

• 2 pairs of antennae

• Mouthparts: mandibles &

  two pairs of maxillae

• Paired appendages

  on most segments,

  often with gills

  • biramous

The ancestral larva

of crustaceans

is the

nauplius

Class Malacostraca

Crabs, lobsters, shrimp,

crayfishes, pillbugs

Largest crustacean class

Malacostraca Tagmata

head, thorax, & abdomen

Head & thorax often fused as

cephalothorax, usually

covered with a carapace

Maxillipeds:

first 3 pairs

of thoracic appendages,

for handling food

Walking legs:

5 pairs,

some chelate

Overlapping carapace protects the

branchial chambers

Class Branchiopoda

An important component

of freshwater zooplankton

Class Branchiopoda The flattened, leaf-like legs or

phyllopodia

are the chief respiratory organs

Class Maxillopoda

Copepods, Barnacles

Copepods

• small, marine, freshwater, terrestrial

• single eye

  • major part of marine zooplankton

Barnacles

Head reduced, 2nd pair of antennae absent

Protective shell of calcium carbonate

Filter-feed using modified thoracic legs

hermaphroditic

Phylum Arthropoda: Subphylum Hexapoda tagmata

Three tagmata: head,

thorax, & abdomen

Three pairs of uniramous

legs on the thorax

Class Insecta

Insects are the dominant form of animal life on Earth

in terms of:

- Number of species

- Number of individuals

- Biomass

Class Insecta lives and eats

anything and anywhere

The classification of insects is

based in part

on modifications

of the appendages:

Mouthparts

- Legs

- Wings

& in part on type of development:

- Ametabolous

- Hemimetabolous

- Holometabolous

Ametabolous

wingless,

incomplete metamorphosis

Hemimetabolous

winged, incomplete

metamorphosis

Holometabolous

winged, complete

metamorphosis

88% of insects

Each stage between molts

is called an

instar

Hemimetabolous orders

Ephemeroptera: mayflies

Orthoptera: grasshoppers & crickets

Odonata: dragonflies & damselflies

Blattodea: cockroaches

Holometabolous orders

Coleoptera: beetles

Diptera: flies, mosquitoes, & gnats

Lepidoptera: butterflies & moths

Hymenoptera: bees, ants, & wasps

NEXT CHAPTER

Two subgroups originally identified

by molecular characters:

Lophotrochozoa (16 phyla)

Extremely diverse group, no

common morphological character

- Ecdysozoa (8 phyla):

Animals that molt their cuticles

Phylum Echinodermata

-deuterostome

Sea stars, sea urchins, sand dollars,

sea cucumbers, sea lilies

All species marine

Lack ability to osmoregulate

Body plan:

- Calcareous, spiny endoskeleton

- Pentaradial symmetry

- Larvae have bilateral symmetry,

suggesting common ancestry

Class Asteroidea Anus and madreporite are located on the

aboral surface

An ambulacrum bearing rows of

tube feet (podia) and

moveable spines

An endoskeleton of small calcareous

ossicles

Spines and ___project from ossicles to surface

tubercles