BIOL 112 Lab Exam 3: Lab 7 Protostomes

Be able to identify * terms. Refer to Lab 6 Flashcards for general background on key characteristics of Kingdom Animalia, 3 types of body symmetry, and tissue layers (& which phylum lack).

What is a coelom?

A fluid-filled body cavity lined with mesoderm

What is the function of a coelom?

-Fluid within body cavity cushions suspended organs

• Prevents internal injury

-Allows internal organs to grow and move independently of outer body

Three types of body cavities

-Acoelomate

-Pseudocoelomate

-Coelomate

Acoelomate*

No body cavity

Pseudocoelomate*

-Body cavity between mesoderm & endoderm

-Organs attached at mouth & anus

Coelomate*

Body cavity completely lined with mesoderm

In Protostomes, the blastopore becomes

the mouth

In Deuterostomes, the blastopore becomes

the anus

In Protostomes, the coelom formation is

schizocoelous (splitting of mesodermal bands)

In Deuterostomes, the coelom formation is

enterocoelous (outpocketing of the gut)

In Protostomes, the embryo development is

determinate

In Deuterostomes, the embryo development is

indeterminate

Both Protostomes and Deuterostomes have how many germ layers?

Three (triploblastic)

Examples of organisms in Phylum Nematoda

-Round worms

-Vinegar eels

-Ascaris

Phyla Nematoda & Arthopoda belong to

Ecdosozoan Protostomes

How many ecdysozoan species are there?

More than all other animals combined

Level of organization of Nematodoa

Organ system level

Are Nematodoa diploblastic or triploblastic?

Triploblastic

Nematodoa exhibit this type of symmetry

Bilateral symmetry

Which body cavity (if any) do Nematodoa produce?

Pseudocoelom

Characteristics of Phylum Nematadoa

-Complete digestive tract

-Only longitudinal muscles (whip-like motion)

-Dioecious (separate sexes)

-Cuticle that molts

Characteristics of Phylum Arthropoda

-Jointed appendages

-Segmented body (head, throat, abdomen in many)

-Exoskeleton made of chitin

-Open circulatory system

-Specialized respiratory systems (gills, book lungs, spiracles)

Subphyla of Arthropoda

-Myriapoda

• Centipedes (1 pair of legs per segment)

• Milipedes (2 pairs of legs per segment

-Chelicerate

• Horseshoe crabs

• Spiders

• Scorpions

-Pancrustacea

• Hexapoda (insects like grasshoppers)

• Crustacea (crayfish)

Anatomy of a Crayfish*

-Antennae

-Antennules

-Compound eyes

-Chelipeds

-Rostrum

-Swimmerets

-Head

-Thorax

-Abdomen

-Tail

-Walking legs

-Carapace

Anatomy of a Grasshopper*

-Compound eyes

-Antennae

-Head

-Thorax

-Abdomen

-Tympanic membrane

-Spiracles

-Wings

-Walking legs

Lophotrochozoans

Bilaterally symmetrical, triploblastic protostome organisms that may have a lophophore feeding structure, a trocophore larval stage, and/or spiral cell division in the embryo

What phyla belong to Lophotrochozoan Protostomes?

-Platyhelminthes

-Brachiopoda

-Mollusca

-Annelida

Examples of Platyhelminthes

-Planaria

-Tapeworm

-Flatworms

Eye spots/Ocelli*

-Two dark spots on head

-Light-sensitive structures that help the flatworm detect light and dark (NOT true eyes

-Found in Planaria

Auricles*

-Triangular projections on either side of the head

-Chemoreceptors used to detect food or chemicals in the environment

-Found in Planarians

Pharynx*

-On mid-ventral side (but can be extended out of the body)

-Muscular tube used to ingest food and expel waste (same opening)

-Found in Planarians and some parasitic flatworms

Incomplete gut*

-Digestive system with only one opening

• Food goes in and waste goes out of same hole

-Found in all Flatworms (except tapeworms who lack a gut entirely)

Characteristics of Flatworms

-Acoelomate

-Triploblastic

-Bilateral symmetry

-Cephalization

-Hermaphroditic

-Simple nervous sytem

-Protonephridia (flame cells)

Cephalization

Beginning of a defined head

Simple nervous system

Has longitudinal nerve chords and small brain-like ganglion

Protonephridia (flame cells)

Excretory/osmoregulatory system

Characteristics of Phylum Mollusca

-Bilateral symmetry

-Triploblastic

-Coelomate

-Soft-bodied (many with calcium carbonate shell)

Most have:

• Foot, visceral mass, mantle, radula

-Trochophore larvae

Which specific Mollusc class has a closed circulatory system?

Class Cephalopoda

What organisms belong to Class Cephalopoda?

-Squid

-Snails

-Clams

-Brachiopods

-Chiton

-Octopus

-Shells & bivalves

-Octopus

Characteristics making Cephalopods the most advanced invertebrates?

-Closed circulatory system

• With 3 hearts

-Highly developed brain & complex nervous system

-Excellent vision

-Camouflage abilities with chromatophores

-Jet propulsion

-Internalized shell

Chromatophores

Color changing cells

Jet propulsion

-Ability to use a siphon to allow Cephalopods to move through water quickly

-Typically used for hunting or fleeing

Anatomy of a Squid*

-Suckers

-Tentacle

-Arm

-Head

-Eyes

-Mouth (including beak)

-Siphon

-Ink sac

-Mantle

-Gills

-Pen (may not be shown in diagram)

Organisms belonging to Phylum Annelida

-Leeches

-Earthworm (disected)

Anatomy of an Earthworm*

-Mouth

-Anus

-Pharynx

-Crop

-Gizzard

-Intestine

-Septa

-Clitellum