Chapter 33:Protosomes

• 1.Lophotrochozoan
• 2.Ecdyzoan

first mouth

• a)Lophophores function in suspension feeding in adults
• b)Trochophore larvae swim and may feed

No

• 1.rotifera
• 2.platyhelminthes
• 3.annelida
• 4.Mollusca

• -Lophotrochozoans
• -Rotifers
• -Live in pond water/soil-live in damp soils
• -have coelom
• -most production by unfertilized eggs;parthogenesis
• -both asexual and sexual

• -Lophotrochozoans
• -Flatworms

• 1.Tubellarians:Free living flat worms
• 2.Cestodes:Endoparasitic tapeworms
• 3.Trematodes:Endo-orectoparasitic flukes

They have no gut, stomach, mouth or digestive system

Multiple hosts

• -Lophotrochozoans
• -Segmented worms
• -Very diverse group

• -most prey on protists or small animals
• -some swim by undulating thier bodies
• -can reproduce asexually by splitting themselves in half
• -most reproduce sexually contain both male and female organs

• 1.Polychaeta:"Feet"
• 2.Clitellata:"no feet"

Earth worms

• 1.bivalves(clams and mussles)
• 2.gastropods(slugs and snails)
• 3.chitons
• 4.cephalopods(squid and octopuses)

Leeches

• 1.Mantle-Secretes the shell
• 2.Muscular foot-used for movement
• 3.Visceral Mass-holds the organs

-Polyplacophora

• Both aquatic and terrestrial
• 1.Snails
• 2.Slugs

Aplysia

• 1.Squid
• 2.Cuttlefish
• 3.Octopus
• 4.Nautilus

shell or cuticle that sheds

• 1.Nematoda(Roundworms)
• 2.Arthopoda

• Ecdysozoan
• -Roundworms
• 1.Unsegemented
• 2.Pseudocoelom
• 3.Cuticle
• 4.Live in extremely diverse habitats
• ex.Vinegar eels

• 1. providing space for fluids to circulate and
• 2.providing a hydrostatic skeleton for movement

all ecdysozoans grow by molting

all protosomes are triploblastic and bilaterally symmetric

• 1.have segemented bodies orgnized into prominent regions called tagamta
• 2.jointed limbs
• 3.exoskelton made of polysaccharide chitin
• 4.Hemocoel
• 5.Paired appendages
• 6.Open circulatory system

arthopods have a a spacious body cavity called the hemocoel that provides space for internal organs and circulation of fluids

Tube where water is forced out during jet propulsion

the production of unfertilized eggs, by mitosis, that develops into offspring

• 1.exchange gases
• 2. avoid drying out

the coelom is much reduced in mollusks and functions only in reproduction and excretion of wastes

arthopods have reduced coelem but an extesive body cavity called hemocoel

-A flat body provides a surface area gas exchange; which compensates for their lack of gas exchange organs

they have a muscular foot and visceral mass that fufill the functions of the coelom

• -Ecdysozoans:Nematoda
• -unsegemented
• -coelem and tube within tube body plan
• -most are tiny

roundworms and earth worms exchange gases across their body surface. They have high surface area to volume ration ,which increases the effiency of gas exchange

• -Lophotrochozoan:Playthelminthes
• -flatworms lack a coelem and are unsegmented -flatworms have a digestive tract that is blind, one opening ingestion and digestion
• -flatworms do not move much

• 1.support
• 2.dessication
• 3.Dispersal

• -Resistant to water
• -No chitin

• 1.Chelicerates
• 2.Myriapods
• 3.Crustaceans
• 4.Insects

• -Ecdysozoans: Arthopoda
• 1.Centipedes:some ae venomous, 2 legs per segment
• 2.Millipedes:vegetarian, 4 legs per segment

• -3 main body parts
• 1.head
• 2.thorax
• 3.Abdomen

• -Wingless Insects
• Ex.Silverfish

• "scale-winged"
• Ex.Butterflies, moths

• "Two-winged"
• Ex.Flies
• -one functional wing
• -halters

• -Big wings "membrane-winged"
• Ex.Ants, bees, moths
• -diverse behavior;selfless

• -Ecdysozoans:Arthpoda
• -Chelicerae:Pair of appendages:used for feeding,defense, movement
• -8 legs
• ex.Spiders, scorpions-book lungs

• Ecdysozoans:Arthropoda
• Ex. Shrimps, lobsters, crabs, barnacles

• -Divided in two distinct regions
• 1.cephalothorax:combines the head and thorax
• 2.The abdomen-Only type of arthropod with two pairs of antennae-more related to insects
• 3.calcified exoskeleton
• 4.Variable number of legs;10

• 1.Spiders
• 2.Mites
• 3.Ticks
• 4.scorpions
• 5.Daddy long legs
• 6.Horshoe crabs

Insects close their respiratory passages to minimize water loss to the environment.Open/close spiracles and minimize water loss.

metamorphosis and desiccation resistant egg

reduces predation; when close it protects the mantle, visceral mass, and foot

an animal that lacks a body cavity

-Lophophore; generate small currents of water that bring in food for consumption

• -Competition between juvenile and adult forms by allowing them to exploit different resources.
• Adults concerned with reproduction.

one

heart, arteries, veins>>>>where gas exchange happens