Exam 2 Chapter INVERTEBRATES

Question 1

Traditional classification of animals

Answer 1

based on:
type of symmetry
pattern of embryonic development
presences or absence of a true body cavity
presence or absence of certain types of tissue

Question 2

open circulatory system vs/ closed circulatory system

Answer 2

The open circulatory system has a combination of blood vessels and large thin-walled sinuses whereas a closed circulatory system has ONLY vessels

Question 3

Symmetry

Answer 3

bilateral vs radial

Question 4

hermaphrodite

Answer 4

individual animal that can produce both sperm and eggs.

ex: worms, snails, slugs, barnacles.

Question 5

typical animal embryonic development

Answer 5

follows path of zygote –> morula –> blastula –> gastrula

Question 6

germ layers

Answer 6

embryonic layers that have different developmental potentials

The endoderm forms the gut, the ectoderm forms part of the nervous system and the epidermis, and the mesoderm forms muscles and most internal organs.

Question 7

Diploblastic and triploblastic animals

Answer 7

diploblastic have two germ layers (endoderm and ectoderm) triploblastic have three germ layers (endoderm, mesoderm, and ectoderm)

Question 8

Bilateral

Answer 8

Bilateria are characterized by a plane of symmetry that forms mirror images around a vertical plane in the midline…confers anterior and posterior areas and allows for greater efficiency in movement for seeking food and mates

Question 9

Radiata

Answer 9

Radiata are characterized with radial symmetry;

Symmetrical body plans first evolved in the phylum Cnidaria

Question 10

Parazoa

Answer 10

Parazoa lack symmetry, have no true tissues or organs.

Sponges.

Question 11

Eumetazoa

Answer 11

Eumetazoa have symmetry and more than one type of true tissues and organs

Question 12

cephalization

Answer 12

concentration of sensory organs on the anterior end of the body

Question 13

chordate

Answer 13

animal with notochord

Question 14

acoelomates

Answer 14

1 of 3 type of body plan for bilateral symmetrical animals.
have no body cavity

An acoelomate is an animal with neither a coelom nor a pseudocoelom, thereby lacking a body cavity.

Question 15

coelomates

Answer 15

1 of 3 type of body plan for bilateral symmetrical animals.

have a fluid filled body cavity lined with mesodermal cells and develops entirely within the mesoderm

Coelomates are animals with a true coelom. A true coelom is completely enclosed by mesoderm

Question 16

pseudocoelomate

Answer 16

body cavity (called a pseudocoelom) located between endoderm (inner layer) and mesoderm (outer layer)

a pseudocoelom has an outer layer of mesoderm and an inner one of endoderm

Question 17

dominant animal phyla on land

Answer 17

Mollusca, Arthropoda (phyla with the greatest number of species), Chordata

Question 18

animal evolutionary transitions

Answer 18

radial to bilateral symmetry; no body cavity to body cavity; unsegmented to segmented bodies, and protostome to deuterostome development

Question 19

protostomes

Answer 19

spiral cleavage; animals in which the mouth develops from the blastopore and the anus if present develops from the second opening

Question 20

deuterostome

Answer 20

Include Chordates and Echinoderm and evolved from protostomes; triploblastic; dividing cells on a radius from the polar axis; are bilateral symmetrical; blastopore becomes anus and mouth develops later; indeterminate development meaning any cell from embryo (up to 8 cell embryo) can develop into a complete organism; are coelomates with coelom produced by invagination of archenteron

Question 21

coelom evolution

Answer 21

led to hydrostatic skeleton development;

that led to circulatory system solving problem of barrier to diffusion created by gut surrounded by tissue

Question 22

Porifera (Phylum)

Answer 22

the sponges, means "pore bearer"
asymmetrical, no tissues, no organs, contain 2 layers of cells with a jellylike substance in between
filter feeder
sessile (does not move)
asexual and sexual reproduction

Question 23

Cnidarian

Answer 23

invertebrates that have stinging cells and take food into a central body cavity
(jellyfish, moon jelly, anemone, etc)
have cnidocytes: stinging cells only used once.

Question 24

Platyhelminthes

Answer 24

FLATWORMS
 bilaterian, unsegmented, soft-bodied
no body cavity: acoelomates
no respiratory organs
no specialized circulatory organs

Question 25

annellida

Answer 25

segmented worms
bilaterally symmetrical, triploblastic, coelomate
parapodia for locomotion

Question 26

Molusca

Answer 26

a mantle with a significant cavity used for breathing and excretion, the presence of a radula (except for bivalves), and the structure of the nervous system

coelomates
open circulatory system

Question 27

Arthropoda

Answer 27

having an exoskeleton (external skeleton), a segmented body, and paired jointed limbs

• Chelicerata: horseshoe crabs, sea spiders, and arachnids,
• Crustacea: crabs, lobsters, crayfish, shrimp, krill, woodlice, and barnacles. possession of biramous (two-parted) limbs, and by their larval forms.
• Hexapoda:a consolidated thorax with three pairs of legs (six legs). Most other arthropods have more than three pairs of legs

Question 28

Which of the following statements best compares a pseudocoelom and a coelom?

Answer 28

A coelom is completely enclosed by mesoderm whereas a pseudocoelom has an outer covering of mesoderm and an inner one of endoderm

Question 29

What is a characteristic of most animals?
A. they lack a nervous system
B. They are autotrophic
C. They have Hox genes and an extracellular matrix of proteins such as collagen
D. They have cell walls

Answer 29

They have Hox genes and an extracellular matrix of proteins such as collagen

Question 30

What was a major morphological criterion on which tradition classification of animals was based?
A. presence or absence of genetic material
B. presence or absence of specialized cells
C. presence or absence of a coelom
D. presence of absence of cell wall

Answer 30

presence or absence of a coelom

Question 31

Germ layers are
A. layers infected with bacteria
B. embryonic layers with different developmental potentials
C. Layers of cells surrounding the egg prior to fertilization
D. colonial protists arranged in layers
E. layers of gametes

Answer 31

embryonic layers with different developmental potentials