Phylum Arthropoda:Phylum Arthropoda:ArthropodsArthropodsChapter 28: Arthropodspp. 606-631

Biology fun facts of the day:

No two human beings have the same

fingerprint; likewise, no two spider webs are

the same.

Mosquitoes dislike

citronella because it

irritates their feet. You're

more likely to be a

target for mosquitoes if

you consume bananas.

Biology fun facts of the day:

Each year, insects eat 1/3 of the Earth's

food crop.

Biology fun facts of the day:

Australian termites have been

known to build mounds twenty

feet high and at least 100 feet

wide.

Biology fun facts of the day:

Introduction to ArthropodsIntroduction to ArthropodsPhylum Arthropoda - Latin arthro = “joint”, pod =

“foot”Bilateral symmetry3 cell layers (ectoderm, endoderm, mesoderm)Have a coelom (reduced to the excretory and

reproductive systems)

Key features:Jointed appendagesExoskeleton (made of chitin)Segmented body (head, thorax, abdomen

segments)◦ Probably evolved from segmented wormlike animals, similar to

modern annelids

Subphyla of ArthropodsSubphyla of Arthropods1) Subphylum Trilobita: ex: trilobites• Oldest subphylum, all extinct now, but ubiquitous for

many era.

2) Subphylum Chelicerata: ex: spiders, scorpions, ticks, mites, horseshoe crabs, etc.• Special mouthparts called chelicerae

3) Subphylum Crustacea: ex: crabs, lobsters, shrimp, etc.

• Over 35,000 species!

4) Subphylum Uniramia: ex: millipedes, centipedes, and all insects

• Huge group!

Form and Function of Form and Function of ArthropodsArthropodsArthropods vary a lot, but share some key features:

• Jointed appendages• Exoskeleton• Segmented body•Brain located in the dorsal part of the head•Ventral nerve cord•Open circulatory system powered by a single heart

*3 most important features*

Grasshopper diagram

Form and Function of Form and Function of ArthropodsArthropodsDigestive system: • Complete digestive tract (mouth anus)• Many arthropods have specialized

feeding parts• Every mode of feeding is seen

Examples:PredatorsFilter feedersParasitesScavengers (detritivores)Herbivores

etc.

Respiratory system: 1) Gills – feathery structures (ex: crustaceans)

2) Book gills/lungs – pagelike sheets of respiratory tissue

(ex: chelicerates)3) Tracheae – network of tubes that carry air (ex:

uniramians)

Circulatory system:• Open circulatory system• Well-developed heart pumps blood through

arteries, which branch into smaller vessels which lead to open spaces called sinuses

Excretory system: 1) Malpighian tubules (terrestrial arthropods) 2) Gills or green gland (aquatic arthropods)

Nervous system:• All arthropods have a brain that consists of

a pair of ganglia• Ventral nerve cord• Ganglia along nerve cord• Many sense organs may be present

Examples: Eyes (compound or simple) Antennae Statocysts Tympanic membrane Chemoreceptors

Musculoskeletal system:• Movement only at joints• Muscles attached to inside of

exoskeleton• Arthropods moult when they grow

because exoskeleton won’t expandFreshly moulted

crabCrab moult

Cicada moult

Babies look like miniature adults. They increase in size as they grow older, but do not change overall form.

Ex: grasshopper

Eggs hatch into larvae (immature stages that do not look like adults).As larvae grow, they change shape dramatically.

Ex: butterfly, bees, wasps

Ecology of ArthropodsEcology of Arthropods Arthropods are the bottom of the food chain (ex:

copepods)

Pollination – co-evolution with flowering plants

Symbiotic relationships (ex: cleaner shrimp and fish)

Food source for humans (especially crustaceans)

Useful chemicals

Honey, silk

Disease carriers (ex: mosquitoes, mites, ticks)

Crop destruction, pesticides

Video – “Arthropods”

Homework for next class:Homework for next class:Complete Phylum Arthropoda worksheet

Read over class notes and check out the class blog: http://msoonscience.blogspot.com/

Works CitedWorks CitedImages taken from the following

sources:http://www.news.cornell.edu/releases/Oct04/insects.openhouse.ssl.html

http://www.cracked.com/funny-1934-spiders/

http://www.police.oakland.edu/fingerprints

http://www.kiwicare.co.nz/index.cfm/1,182,0,0,html/No-Mosquitoes-Citronella-Candle

http://www.dealspice.com/

http://www.gardenguides.com/789-corn-rootworm-information.html

http://www.ent.uga.edu/veg/colecrops.htm

http://www.the-discount-travel-guide.com/Kakadu-National-Park.html

http://www.bio.miami.edu/dana/160/160S10_13print.html

http://www.thepoisonforest.com/?tag=trilobite

http://www.treehugger.com/files/2010/01/deadly-scorpion-venom-used-create-new-safer-pesticide.php

http://stirwordfest.wordpress.com/book-lung/

http://www.brisbaneinsects.com/brisbane_insects/GrasshopperHead.htm

Works CitedWorks Citedhttp://www.wildsingapore.com/wildfacts/crustacea/moulting.htm

http://squirrelbasket.wordpress.com/2010/07/04/words-fledge-fletch-moult-mews-%E2%80%93-and-mould/

http://rohlenscience.pbworks.com/w/page/7859192/Insects-Notes

http://www.buyinsectcollection.com/identifying_insects

http://www.bbcgoodfood.com/content/knowhow/glossary/honey/

http://www.livingprairie.ca/livinglandscape/hikes/index.html

http://www.superstock.com/stock-photos-images/1532R-3016

http://www.raisethehammer.org/article/640

http://www.chacha.com/topic/arthropods

http://www.nooor.com/search/Invertebrate/&p=13