Arthropods

arthropod synapomorphies

• jointed legs

• mandibles

• head/thorax/abdomen

arthorpod subphyla (Ch, Cr, H, M, T)

• chelicerata, spiders/scorpions

• crustacea, shrimp

• hexapoda, insects

• myriapoda, centipedes

• trilobita, trilobites

what has contributed to the sucess of arthropods

metamerism and tagmatazation, exoskeleton, and metamorphosis

epicuticle

waxy lipoprotein layer/outer layer of exoskeleton

procuticle

majority of exoskeleton - made of chitin

ecdysis

shedding of exoskeletonduring growth in arthropods.

precdysis

• enzymes secreted digest and seperate hypodermis from exoskeleton

• old exoskeleton splots

• animal crawls out

• new exoskeleton is inflated

• more epicuticle is formed and exoskeleton hardensthe process before shedding where

biramous appendeges

appendages with two branches, characteristic of certain arthropods such as crustaceans.

classes of chelicerata (M A P)

• merostoma, horeshoe crabs

• arachnida, spiders

• pycnogonida, pycnogonida

feeding and digestion of arachnida

• digestion partly outside of body

• inject/bathe prey in enzymes - suck of fluid

  • foregut —> midgut (absorbtion) —> hindgut (water reabsorbtion)

arachnida excretion

• malpighian tubulues - tubulues in blood sinus where water is secreted

• tubulues dump waste into digestive ract

  • guanine/uric acid NH4 waste

book lung

arachnida gas exchange

• countercurrent exchange system with cuticle covered filaments

arachnida reproduction

• dioecious

• transfer sperm packets

• courtship rituals

arachnida nervous system

• ventral nerve cord

• centralized fusion of ganglia

• strong cephalization w/ lots of sensory and vibration receptors

scorpionida defining characterisitcs

• fused prosomoa carapace

• divided opisthosoma

• postabdomen with stinger

chelicerae

fangs on arachnida with poison glands

spinnerets

used to spin webs from silk glands in arachnida

crustacea defining characteristics

• two pairs of antennae

• fused cephalothorax and abdomen

• usually biramous limbs

isopoda

all legs similar

amphipoda

modified legs

crustacea classes (M Ma B)

• Malacostraca, crabs/shrimp

• Maxillopoda, barnacles

• Branchiopoda , brine shrimp

general crustacean body head

• 5 pairs of appendeges - 2 antannea, mandible, and 2 maxilla

pleopods

swimmerets on abdominal part of crustacea

pereopods

walking legs on carapace part of crustacea

crustacea circulatory system

heart, dorsal artery, blood sinus

crustacea digestive tract

complete digestoim, absorbtion in midgut

crustacea nervous system

• fusion of ganglia

• centralization, cephalization,

• ventral nerve cord

crustacea gas exchange

gills/respirtory pigments

crustacea excretion

crustacea excretion

crustacea reproduction

dioecious (except for barnacles)

copepods

primary consumbers - base of marine food chains

myriapoda defining characteristics

• millipeds.centipedes

• head + trunk

• two body tagma

hexapoda/insecta defining characteristics

• three body tagama (head throax abdomen)

• only invertebrate that can fly

insecta gas exchange

tracheal system

diffusion

chitin lined tubes

insecta feeding

diversity related to feeding mode

insecta flight mechanism

tergum depresses for outside muscles to relax, and dorsal muscles to flex— tergum is rasied for vise versa

insecta excretion

malpighian tubules

rectum

uric acid

insecta reproduction

dioecious

internal fertalization

ametabolous

a developmental type in insects where they do not undergo metamorphosis and the young resemble miniature adults.

hemimetabolous

a type of insect development characterized by incomplete metamorphosis, where young nymphs resemble small adults and gradually develop into mature forms.

holometabolous

a type of insect development characterized by complete metamorphosis, where the organism undergoes distinct life stages: egg, larva, pupa, and adult.