Introduction to Animal Diversity

Question 1

what are the characteristics of animals?

Answer 1

-eukaryotic, multicellular
-no cell walls, have extracellular protein called collagen instead
-have nervous and muscle tissue

Question 2

how do animals reproduce?

Answer 2

-zygote undergoes cleavage, forms a blastula
-blastula undergoes gastrulation, forms 2-3 tissue layers (endo, ecto, meso)
-becomes a gastrula

Question 3

what happened to animal development in the cambrian explosion?

Answer 3

-created earliest fossils for most living animals and gave rise to most phylum still around

-due to hox genes, snowball earth, more atmospheric oxygen, or predator prey relationships

Question 4

what are the two forms of animal symmetry?

Answer 4

radial = can be cut into equal halves along a central plane in multiple directions

bilaterial = can only be cut into equal halves horizontally along the central axis

Question 5

what do bilaterally symmetrical animals have?

Answer 5

-a dorsal/top side and a ventral/bottom side
-a right and left side
-an anterior/head side and a posterior/tail side
-cephalization, or development of a head

Question 6

what are the three tissue layers of animals and what do they become?

Answer 6

-ectoderm = becomes outside lining, nervous tissue, glands
-endoderm = becomes gut lining, digestive organs
-mesoderm = becomes muscles, middle bits

Question 7

what is the difference between diploblastic and triploblastic animals?

Answer 7

diplo = have two tissue layers [endo, ecto] and are radially symmetrical
triplo = have all three layers and are bilaterally symmetrical

Question 8

what is a coelom?

Answer 8

the coelom is a body cavity in animals that acts as a protective cushion for inner organs

Question 9

what are the three types of coeloms?

Answer 9

-coelomate animals with a body cavity formed from the mesoderm

-pseudocoelomate animals with a body cavity formed from meso and endoderm

-acoelomate animals without a body cavity

Question 10

what is the difference between protostomes and deuterostomes?

Answer 10

protostome = blastopore forms mouth first, anus second
deuterostome = blastopore forms anus first, mouth second

Question 11

what is the cleavage pattern for proto and deuterostomes?

Answer 11

protostomes = spiral and determinate [each cell division has a determined future]

deuterostomes = radial and indeterminate [each cell has equal potential to develop]

Question 12

what is schizocoelous development and in what type of animal does it occur?

Answer 12

-occurs in protostomes
-the coelom is formed when the mesoderm layer splits into two

Question 13

what is enterocoelous development and in what type of animal does it occur?

Answer 13

-occurs in deuterostomes
-the coelom is formed when the archenteron [predecessor to GI tract] folds the mesoderm and forms the coelom

Question 14

how is the animal kingdom classified / divided into phyla?

Answer 14

-morphological and developmental similarities
-molecular DNA analysis

-bilateria: deuterostomes and two groups of protostomes

Question 15

what are the two protostome subdivisions?

Answer 15

-ecdysozoa
-lophotrocozoa

Question 16

what are ecdysozoans and lophotrocozoans?

Answer 16

-ecdysozoans shed their exoskeleton, called ecdysis

-lophotrocozoans have a feeding structure called a lophophore, OR go through a larval stage called a trocophore larva