Chapter 32: Overview of Animal Diversity

Question 1

Definition of animal?

Answer 1

• Multicellular, heterotrophic eukaryotes with tissues that develop from embryonic layers

Question 2

Nutritional mode of plants

Answer 2

Autotrophs

Question 3

Nutritional mode of fungi

Answer 3

Absorb nutrients from their surroundings; grow on their food and feed by absorption

Question 4

Nutritional mode of animals

Answer 4

Heterotrophs; ingest nutrients and use enzymes to digest within bodies

Question 5

Tissues

Answer 5

Groups of similar cells that act as functional unit

Question 6

Development Stages

Answer 6

• Zygote (unicellular) forms from sperm + egg
• Eight-cell embryo is formed by 3 rounds of cell division
• Cleavage produces a blastula (cavity)
• Undergoes gastrulation
• Pouch formed creates an external ectoderm, endoderm (develops into tissue lining the animal’s digestive tract)

Question 7

What’s special about animal cells?

Answer 7

• Ability to move and conduct nerve impulses underlie many of adaptations that differentiate animals from plants

Question 8

Cleavage

Answer 8

Succession of mitotic division without cell growth between the divisions

Question 9

Gastrulation

Answer 9

Layers of embryonic tissues that will develop into adult body parts are produced

Question 10

Metamorphosis

Answer 10

Developmental transformation that turns animal into a juvenile that resembles adult but is not sexually mature

Question 11

Significance of choanoflagellates in animal development?

Answer 11

• ## Choanoflagellates marked the transition from uni-cellularity to multicellularity

Question 12

History of animals spans how many years?

Answer 12

More than 700 billion

Question 13

Paleozoic Era

Answer 13

• 542-251 MYA
• Included Cambrian explosion
• Many major groups of animals appeared at this time
• Hypothesized to have occurred as a result of more oxygen, increased intensity of predation, and evolution of new developmental genes

Question 14

Mesozoic Era

Answer 14

• 251-65.5 MYA
• Animal phyla begins to spread
• Coral reefs emerged
• Dinosaurs were dominant
• Flowering plants/insects diversified

Question 15

Cenozoic Era

Answer 15

• 65.5 MYA to present
• Mass extinctions of both terrestrial and marine animals
• Begin diversification of mammals

Question 16

Neoprotozoic Era

Answer 16

• 1 billion-542 MYA

- Earliest members of the fossil record were “Edicaran biota”

Question 17

Radial symmetry

Answer 17

• Type of symmetry found in a flower pot

- Slice through central axis to divide animal into mirror images

Question 18

Bilateral symmetry

Answer 18

• Two axes of orientation: front to back and top to bottom
• Such as a shovel
• Have dorsal (top), ventral (bottom), left/right, posterior (back) and anterior (front)

Question 19

Ectoderm

Answer 19

• Germ layer covering surface of embryo gives rise to the outer covering of the animal
• In some phyla to the central nervous system

Question 20

Endoderm

Answer 20

• Innermost germ layers; lines pouch that forms during gastrulation and gives rise to lining of digestive tract and organs

Question 21

Diploblastic

Answer 21

• Two germ layers (cnidarians and few other animal groups)

Question 22

Triploblastic

Answer 22

• All bilaterally symmetrical

- Have mesoderm

Question 23

Cephalization

Answer 23

Concentration of nerve organs during embryonic development

Question 24

Protostome Development

Answer 24

• Spiral, determinate eight cell stage (planes of cell division are diagonal to vertical axis of embryo)
• Solid mass of mesoderm split and form coelom
• Mouth develops from blastopore

Question 25

Deuterostome development

Answer 25

• Radial and indeterminate eight cell stage
• Folds of archenteron form coelom
• Anus develops from blastopore

Question 26

Blastopore

Answer 26

Indentation that during gastrulation leads to formation of archenteron

Question 27

Diversification of Animals

Answer 27

1) All animals share common ancestor
2) Sponges are basal animals
3) Eumetazoa is clade of animals with true tissues
4) Most animal phyla belong to clade Bilateral
5) Three major clades of bilateral (Deutorosomia, Lophotrochozoa, and Ecdysozoa)