Name ___________________________

Morgan-Carter Lab #19 – ANIMAL DIVERSITY II:

NEMATODA, ARTHROPODA, ECHINODERMATA & CHORDATA

Ex. 19.1: Phylum Nematoda – Roundworms (Ascaris)

How would nourishment be taken into the body of Ascaris and circulated?

Do you see signs of segmentation in the body wall or in the digestive, reproductive, or excretory

systems? (Hint: compare with annelids which you analyzed in the previous lab)

What do you think supports the body of Ascaris?

Can you detect muscle, a mesodermal tissue, adjacent to the endodermal layer (the gut)?

What do we call a coelom with an outer lining of mesoderm and an inner lining of endoderm?

What do you see inside the uteri when observed in cross section under the microscope?

Sketch below a cross section of a female Ascaris and label the following: cuticle, epidermis, muscle

fibers, intestine, body cavity (indicate type), reproductive organs (uterus, oviduct, ovary), lateral lines,

and dorsal and ventral nerve cords.

List some features of Ascaris that are possible adaptations to parasitic life.

In the table below, fill in the indicated the characteristics of roundworms:

Type of Symmetry

Tissue organization

Type of Body Cavity

Digestive Openings

Circulatory System

Habitat

Respiratory Organs

Ex. 19.2: Phylum Arthropoda

Lab Study A: Crayfish (Cambarus)

As you observe the crayfish, describe the following and indicate the evolutionary advantages of each.

a. body symmetry

b. supportive structures

c. appendages

d. segmentation

Speculate about the functions of each group of appendages below.

a. head appendages

b. thoracic appendages

c. abdominal appendages

What is the function of the gills that lie under the lateral extensions of the crayfish carapace?

What name is given to the type of circulation that occurs in crayfish?

What kind of coelom does a crayfish have?

How does the pattern of segmentation differ in crayfish compared to the earthworm studied in lab 18?

In the table below, fill in the indicated the characteristics of crayfish:

Type of Symmetry

Tissue organization

Type of Body Cavity

Digestive Openings

Circulatory System

Habitat

Respiratory Organs

Lab Study B: Grasshoppers (Romalea)

What type of circulation does the grasshopper have?

Describe how each of the following structures help the grasshopper succeed in terrestrial environments.

a. exoskeleton

b. spiracles

c. tracheae

d. Malpighian tubules

e. rectum

In the table below, fill in the indicated the characteristics of grasshoppers:

Type of Symmetry

Tissue organization

Type of Body Cavity

Digestive Openings

Circulatory System

Habitat

Respiratory Organs

Ex. 19.3: Echinodermata – Sea Star

What evidence did you see in your sea star dissection that it belongs in the clade Deuterostomia?

What structures did you observe that appear to be unique to echinoderms?

Sea star and other echinoderm larvae have bilateral symmetry, however their adult forms have radial

symmetry. How might this be explained?

In the table below, fill in the indicated the characteristics of sea stars:

Type of Symmetry

Tissue organization

Type of Body Cavity

Digestive Openings

Circulatory System

Habitat

Respiratory Organs

Ex. 19.4: Phylum Chordata

Lab Study A: Lancelets (Branchiostoma, formerly Amphioxus)

Do you see evidence of segmentation in the muscles or in other organs or structures?

Look at the anterior end of the lancelet for evidence of a sensory system and describe what you see.

Think of the worms you studied in Lab 18. Where was the anus located in these animals?

Was a postanal region present?

Identify the notochord of the lancelet and speculate about its function.

Have you seen a notochord in any of the animals previously studied?

Notice the nerve cord is in the dorsal position. Have you seen a dorsal nerve cord only in any of the

animals studied previously?

Sketch below a cross section of a lancelet and label the following: segmental muscle, dorsal fin, dorsal

nerve cord, notochord, pharynx, gill bars and gill slits.

In the table below, fill in the indicated the characteristics of lancelets:

Type of Symmetry

Tissue organization

Type of Body Cavity

Digestive Openings

Circulatory System

Habitat

Respiratory Organs

Lab Study A: Fetal Pig (Sus scrofa)

Examine the fetal pig and as you do so predict the answer the following questions:

What type of symmetry does the pig body have?

How many layers of embryonic tissue are present (i.e., ectoderm, mesoderm, endoderm)?

How many digestive tract openings are present and what are they?

Is the circulatory system open or closed?

Is the body segmented?

How is the central nervous system (brain and spinal cord) positioned in the pig?

In the table below, fill in the indicated the characteristics of pigs:

Type of Symmetry

Tissue organization

Type of Body Cavity

Digestive Openings

Circulatory System

Habitat

Respiratory Organs