Organismal Diversity Week 7 3/23/26-3/27/26

Important orders of insects

Lepidoptera, coleoptera, odonata, orthoptera, hemiptera, homoptera, hymenoptera, diptera, mantodea, blattodea

Lepodoptera

butterflies and moth

Coleoptera

beetles

Odonata

dragonflies and damselflies

Orthoptera

grasshoppers and crickets

Hemiptera

True bugs. Like wheelbugs

Homoptera

cicadas, leafhoppers, aphids

Hymenoptera

Bees, wasps, and ants

Diptera

Flies

Mantodea

Mantids and walking sticks

Blattodea

roaches and termites

Deuterostomia

Phyla Echinodermata and Chordata

Phylum Echinodermata

Sea stars, urchins, sea lilies, bilateral symmetry as larvae, pentaradial symmetry as adults, have a water vascular system, spiny endoskeleton pokes through soft epidermis, has 5 classes

pentaradial symmetry

radial symmetry on five axis

Water vascular system

System of hydraulic tubes that draw in seawater through madreporite to move tube feet

Tube feet

Adhesive extensions for moving

Class Asteroidea

Sea stars, highly mobile predators; oral surface directed down, 5 arms radiate from central disk and touch each other

Class Ophiuroidea

Brittle stars, highly mobile predator; oral surface directed down, five highly flexible arms radiate from central disk but don’t touch

Class Echinoidea

Sea urchins and sand dollars, mobile predators; oral surface directed down, no arms-central disk may moveable long spines, well-developed jaw-like structure in mouth to feed on seaweed

Class Crinoidea

Sea lilies and feather stars, sea lilies: sessile on long stalk: oral surface directed up. feather stars: mobile; oral surface directed up. Use arms for suspension feeding (collecting suspended food from water)

Class Holothuroidea

Sea cucumber, sideways echinoderms: oral surface on anterior end. Not spiny; tube feet near mouth may form tentacles

Phylum Chordata

Sea squirts, lancelets, hagfishes, vertebrates. Four shaved derived characteristics A. dorsal, hollow nerve cord (derived from ectoderm) develops into central nervous system B. notocord C. pharyngeal gill slits D. Muscular gill slits E. endostyle

Notochord

Firm rod that runs between nerve cord and digestive tract

Pharyngeal gill slits

Openings in pharynx allow water entering mouth to exit before going into digestive tract

Muscular post-anal tail

Used to propel aquatic species; lost in many adult forms

Endostyle

Chordate liver. Highly diverse sizes and morphologies within and among major clades

Subphylum of Chordata

Contains multiple subphylum, subphylum Cephalochordata, Urochordata, and Craniata

Subphylum Cephalochordata

Lancelets, retain all chordate characteristics as adult, serially repeated units of chevron shaped muscle down the length of body, derived from repeated units of mesoderm, produce wave-like swimming action

Somites

Derived from repeated units of mesoderm

Subphylum Urochordata

Tunicates and seasquirts, free swimming larva exhibits chordate characteristics, sessile adults retains pharyngeal gill slits only, filter feeder with incurrent and excurrent siphons to move water through gill slits

Subphylum Craniata

Hagfish and vertebrates, chordates with heads brains protected by skulls many features derived from neural crest cells, contains Mixini group

Mixini

Hagfishes are an invertebrate basal group, only group with a skull but no vertebrae, nearly all are bottom-feeding and marine, produce a huge quantity of slime when attacked

Subphylum Vertebrata

Skeletal protection (vertebrae) along a complex nervous system, skeleton may be cartilaginous or mineralized. Contains Class Petrimyzontida and Gnathostomata (contains the groups chondrichthyes and osteichthyes).

Class Petromyzontida

Lampreys, jawless vertebrates with primative cartilage spine, cartilage without colagen (unlike higher vertebrates), parasites of fish: sucker like rasping mouth attaches to fish body, important invasive species in Great Lakes

Gnathostomata

Jawed vertebrates, jaw derived from bony supports of gill slits, aquatic Gnathostomata have a lateral line. Two major groups Chondrichthyes and Osteichthyes

Lateral line system

Sensory receptors along lateral side of body to detect vibrations in water

Chondrichthyes

Sharks, rays, chimeras, has a cartilaginous skeleton. More dense that water, so must swim or sink. Continual swimming increases gas exchange in gills. Special spiral valve increases surface area in short digestive tract. Have internal fertilization with young born in three ways: oviparous, ovoviviparous, or viviparous.

oviparous

young hatch from eggs laid outside the body

ovoviviparous

young hatch from eggs retained in uterus

viviparous

young nourished through mothers blood in uterus or by eating each other eggs/young in uterus