ecdysozoans and arthropoda part 1

super phylum ecdysozoa clade panarthropoda contains phylums

onychophora, tardigrada, arthropoda

superphylum ecdysozoa clade panarthropoda characteristics

segmented, reduced coelom, hemocoel and open circulatory system, ecdysis

ecdysis is

life long molting

ecdysis hormone

ecdysone

phylum onychophora means

claw bearer

onychophora are the

velvet or walking worms

velvet or walking worms have what system

tracheal

velvet or walking worms have

spiracles with no valve, restricted to moist leafy habitats in tropics and subtropics

velvet or walking worms have

slime glands and unjointed legs

tardigrada means

slow step

tardigrada are

water bears

tardigrada live in

water films

tardigrada stylet for

piercing

tardigrada does not have what systems

circulatory or respiratory

tardigrada reproduction

dioecioius some parthenogenic

tardigrada are

cryptobiosis - resist temperature extremes (149C to -272C), radiation, alcohol preservation

tardigrada eggs shed with

cuticle

phylum arthropoda has a

jointed foot

phylum arthropoda largest phylum

of animals

arthropoda over

900,000 species described

arthropoda includes

spiders, scorpions, mites, ticks, insects, millipedes, centipedes, crabs, shrimp, lobsters, crayfishes

arthropoda are very

adaptive - found in virtually every habitat

phylum arthropoda higher classification subphylums

trilobita, chelicerata, crustacea, hexapoda, myriopoda

arthropoda when compared to annelids both are

metameric

arthropoda when compared to annelids primitively have

single pair of appendages/segment

arthropoda when compared to annelids nervous system along

the same plan

arthropoda when compared to annelid have similar

embryonic development

arthropoda body plan

metameric, divided into tagmata (tagmatization), somites fused into functional units (head, thorax, abdomen or cephalothorax, abdomen)

appendages have lots of

specialization

specialization of appendages includes

locomotion, reproduction, feeding, and respiration

locomotion appendages include

simmerets and walking legs

reproduction appendages include

gonopods

feeding appendages include

maxillipeds, maxilla, mandibles

appendages primitively with

one pair per segment

exoskeleton of arthropoda made of

protein, lipids, chitin (a polysaccharide), calcium carbonate

advantages of an exoskeleton

protection, fights water loss, most successful terrestrial invertebrate group, allows for effective movement on land

disadvantages of exoskeleton

heavy and bulky, takes energy to move, needs to be periodically replaced, molting, vulnerable during molting

selected system summaries of arthropoda

complex muscular system that is segmentally arranged, reduced coleom; mostly a hemocoel filled with blood, complete digestive tract with mouthparts as modified appendages, open circulatory system with dorsal contractile heart

respiratory system of arthropoda body surfaces

primitive or early larval forms

respiratory system of arthropoda gills

crustaceans, larval insects

respiratory system of arthropoda tracea

insects, myriapods

respiratory system of arthropoda book lungs

most chelicerates

respiratory system of arthropoda book gills

horseshoe crabs

excretion of arthropoda most with paired

glands, coxal, antennal or maxillary

excretion of arthropoda insects and spiders have

malpighian tubles

arthropoda nervous system similar to that in

annelids

nervous system in arthropoda

dorsal brain (cerebral canglia) around esophagus, double ventral nerve cords, well developed sensory organs

reproduction of arthropoda

usually dioecious, usually internal fertilization, oviparous or ovoviviparous, often with metamorphosis, some with parthenogenesis

reproduction of arthropoda oviparous

producing young by means of eggs that are hatched after they have been laid by the parent.

reproduction of arthropoda ovoviviparous

producing young by means of eggs which are hatched within the body of the parent

why arthropods are so successful

versatile exoskeleton, segmentation and appendages for efficient locomotion, air piped to cells directly (tracea in insects), highly developed sensory organs, complex behavior patters, reduced competition through metamorphosis

trlobita have

three lobes

trilobita are all

extinct by 250 MYA (permian) abundant in mid-cambrian

trilobita body divided by

2 longtiduinal furrows at three lobes, distinct head, thorax, abdomen

trilobita have biramous

appendages, 2-branched

chelicerata means

claw, horn, group

chelicerata are the

horseshoe crabs, spiders, ticks

chelicerae 1st pair of appendages modified for

feeding

chelicerae 1 pair of

pedipalps

chelicerae have how many legs

4 pairs

chelicerata lack

antennae and mandible

chelicerata body divided into

2 regions, abdomen and cephalothorax

chelicerata characteristics have specialized

appendages

the specialized appendages in chelicerata are the

chelicera and pedipalps

chelicera are used for

sucking body fluids from prey or tearing

pedipalps are used for

handling food, and in some for copulation

chelicerata class merostomata called

thigh mouth

class merostomata are all

marine

merostomata body segments

cephalothorax and abdomen

merostomata compound

lateral eyes

merostomata appendages with

gills/ book gills

merostomata have a sharp

telson

chelicerata class pycnogonida are the

sea spiders

sea spiders have how many legs and body type

4 pairs of walking legs, body thin and elongate

sea spiders gonads

and digest tract in legs

sea spiders are all

marine

sea spiders males carry

eggs

chelicerata class archnida are the

spiders, scorpions, mites, ticks

arachnida have how many legs

4 pairs

arachnida have no

antennae or mandible

arachnida body divided into

cephalothorax and abdomen

arachnida mouthparts for

sucking

arachnida are very

successful; 70,000 species

arachnida are major orders -

all terrestrial

class arachnida order araneae are the

spiders

class arachnida order scorpiones are the

scorpions

class arachnida order opiliones are the

harvestman

class arachnida order acari are the

ticks and mites

class arachnida order pseudoscorpiones are the

pseudoscorpiones

class arachnida respiration through

trachea, or more commonly book lungs

book lungs are unique in

spiders

book lungs many parallel

air pockets extending into blood filled chamber

book lungs air enters

chamber via body wall slits

arachnida excretion through

malpighian tubules

malpighian tubules work in

conjunction with specialized rectal glands

the malpighian tubules that work with the rectal glands have the

K and other solutes and waste secreted into tubes

the malpighian tubules are tubes that drain

fluids into intestine

the malpighian tubules are the rectal glands that reabsorb

most K and water, waste left as uric acid

malpighian tubules have the conservation of

water and K in dry environments

arachnida excretion may have

coxal glands as well as nephridia and open at the base of 1st and 3rd walking legs