Lecture 8 - Bilaterian Animals

Question 1

Chart: Before Bilateria

Answer 1

Porifera, Ctenophora, Cnidaria

Question 2

Chart: Protostomes group 1

Answer 2

Rotifera, Platyhelminthes, Annelida & Mollusca

Question 3

Chart: Protostomes group 2

Answer 3

Nematoda, Tardigrada, Onychophora & Arthropoda

Question 4

Chart: Deutoerstomes

Answer 4

Echinodermata & Chordata

Question 5

What is a Bilaterian? (6 traits)

Answer 5

Bilateral symmetry, triploblastic, true coelom, nervous system, muscles, through-gut

Question 6

What are the two main lineages of Bilateria

Answer 6

Protostomes, Deuterostomes

Question 7

What is spiral cleavage?

Answer 7

Cells divide at oblique angles

Question 8

What is radial cleavage?

Answer 8

Cells are arranged directly on top of each other

Question 9

What is determinate cleavage?

Answer 9

Fate of cell is set in early development, isolated blastomeres cannot develop into an entire animal, cytoplasmic determinants

Question 10

What is indeterminate cleavage?

Answer 10

Fate of cells not set in early development, isolated blastomeres can develop into an entire animal, induction

Question 11

Traditional model for protostomes cleavage

Answer 11

Sprial and determinate

Question 12

Traditional model for deuterostomes cleavage

Answer 12

Radial and indeterminate

Question 13

Traditional model: formation of protostomes

Answer 13

Schizocoelous: solid masses of mesoderm split to form coelom, mouth develops from blastopore

Question 14

Traditional model: formation of deuterostomes

Answer 14

Enterocoelous: fields of archenteron form coelom, anus develops from blastopore

Question 15

Where is priapulids located?

Answer 15

Directly before protostomes group 2

Question 16

Modern model of Radial cleavage

Answer 16

Porifera, Ctenophora, Cnidaria, Rotifera, Priapulid, Echinodermata, Chordata

Question 17

Modern Model of Spiral cleavage

Answer 17

Platyhelminthes, Annelida, Mollusca

Question 18

Modern Model of Idiosyncratic cleavage

Answer 18

Nematoda, Tardigrada, Onychophora, Arthropoda

Question 19

Modern model of Determinate cleavage

Answer 19

Rotifera, Platyhelminthes, Annelida, Mollusca, Nematoda, Onychophora, Some arthropods

Question 20

Modern model of Indeterminate cleavage

Answer 20

Tardigrada, some arthropods, Echinodermata, Chordata

Question 21

Modern enterocoelic coelom development model

Answer 21

Echinodermata and Chordata

Question 22

Modern Schizocoleic coeolom devolpment model

Answer 22

Annelida, Mollusca, Oncyphora, Arthropoda

Question 23

Modern Pseudocoelom coelom development model

Answer 23

Rotifera, Nematoda, Tardigrada

Question 24

Modern Acoelomate coelom development model

Answer 24

Platyhelminthes.

Question 25

Where is Nemertea located?

Answer 25

Between Platyhelminthes and Annelida & Mollusca

Question 26

Where is Polychaeta located?

Answer 26

At Annelida

Question 27

Modern Deuterostomy Fate of the Blastopore Model

Answer 27

Priapulid, Nemertea, Oncyphora, Echinodermata, Chordata

Question 28

Modern Protstomy Fate of the Blastopore Model

Answer 28

Rotifera, Platyhelminthes, Annelida, Mollusca, Nematoda, Tardigrada, Arthropoda

Question 29

Modern Amphistomy Fate of the Blastopore Model

Answer 29

Polychaeta