lec 142 arthropods (5+6)

phylum arthropoda species

more than 1M

phylum arthropoda symmetry and body plan

• bilateral

• coelomates

• exoskeleton

• segmented body, paired joint appendages

phylum arthropoda systems

well developed

• excretory

• respiratory

• blood

• sensorial

phylum arthropoda reproduction

sexual reproduction with seperate sexes

exoskeleton advantages

• independence from environment

• protection

• reduces water loss

• more efficient locomotion

exoskeleton disadvantages

• limits growth / needs to be shed

• limits gas exchange

• limits movement

exoskeleton

• chitin and proteins

• segregated by epidermis

moulting process order

intermoult, premoult, moult, postmolt

intermoult

has epicuticle on top, exocuticle inside, endocuticle beneath

premoult

proculicle seperates and new epicuticle produced beneath old epidermis. moulting fluid dissoved old endocuticle and products reabsorbed

body segments

head, thorax and abdomen

gas exchange

• through skin in small

• gills in aquatic

• book lungs in terrestrial

• trachae in terrestrial, millipedes and insects

sensorial organs

mechanoreceptors, chemoreceptors, photoreceptors

subphylum trilobitomorphia

• most primitive

• common ancestor of all arthropods

• no living species

subphylum pycnogonida

• sea spiders

• not very diverse

• deep sea

• diversified early

subphylum myriapoda examples

centipedes, millipedes

subphylum myriapoda habitat

terrestrial, waxy epicuticle = waterproof

subphylum myriapoda gas exchange by …

trachaea

subphylum myriapoda reproduction

seperate sexes, indirect or direct sperm transfer

subphylum myriapoda species

16000

subphylum myriapoda body plan

• head with antennae, mandible, simple eyes

• many segmented body

• jointed appendages

difference between millipede and centipede

• millipede has 2 pairs of legs per segment

• centipede = predator

subphylum crustacea example

shrimp, crabs, copepods, water fleas

subphylum crustacea habitat

all aquatic except woodlice

subphylum crustacea cuticle

no waterproof epicuticle

procuticle from calcium carbonate

subphylum crustacea gass exchange

gills

subphylum crustacea eyes

simple and compound

subphylum crustacea species

47000

subphylum crustacea reproduction

sexual with 2 seperate sexes

internal and external

females lay and carry eggs until hatching

subphylum crustacea body plan

2 antennae

mandible

cephalothorax, abdomen

maxiliped, cheliped (first), pereopods (marching) ,pleopods (swimming)

subphylum chelicerata examples

horseshoe crabs, scorpions, spides, harvestmen, mites, ticks

subphylum chelicerata habitat

all terrestrial except horseshoe crabs

subphylum chelicerata gas exchange

book lungs or trachaeae

subphylum chelicerata reproduction

seperate sexes, indirect sperm transfer 

parental care

subphylum chelicerata species

100000

subphylum chelicerata body

• cephalothorax and abdomen

• 4 pairs marching legs

• nio antennae

• simple and compound eyes

• chelicerae (fangs) and pedipalps

subphylum hexapoda reproduction

internal fertilisation, direct sperm transfer, sexual dimorphism, courtship

subphylum hexapoda head

• antennae

• mouthparts

• compound eyes

• simple eyes

subphylum hexapoda thorax

3p legs, 2p wings

subphylum hexapoda abdomen

digestive system, stigmata and trachaea, sexual organs

subphylum hexapoda mouthpart types

• piercing-sucking

• chewing

• sucking

• sponging-sucking

• cutting-sucking

• chewing-lapping

subphylum hexapoda wing types

• membranous

• elytra

• halter

• tegman

• hemelytra

• scaled

subphylum hexapoda life cycle

• ametabolous

• hemimetabolous

• holometabolous

ametabolous

• no metamorphosis

• young look like adults

• still moult

hemimetabolous

• incomplete metamorphosis

• 5ish moults

• young vary slightly from adults

holometabolous

• full metamorphosis

• big change between young and adults

• ecological diversity within species

subphylum hexapoda sociality

• bees, ants, rermites

• different individuals based orn role

• only queen reproduces

subphylum hexapoda services

+ pollination, pest control, nutrient recycling

- crop pests, livestock ectoparasites, disease vectors