Chapter 34

Question 1

what charts the the evolutionary relationships among more than a million animal species?

Answer 1

Phylogeny

Question 2

How many animals are there ?

Answer 2

1.5 million species have been described ( An estimated 5-30+ Million species exist)

Question 3

Where do animals occur?

Answer 3

Everywhere
-Caves
-deep rift vents
-moss on tress
-beer coasters
-intestines
YOUR BODY

Question 4

From what did animals evolves?

Answer 4

Fungi plantae and Animalia separately evolved from single- celled eukaryotes.
- Eukarya is a monophyletic taxon with multiple SYNAPOMORPHIES of CELL STRUCTURE
-EURKAYA includes both single- and multi-celled organisms

Question 5

What resembles a cell type in basal animals, reflecting a sister taxon relationship?

Answer 5

Choanoflagellates

Question 6

What is monophyletic:

Answer 6

Animalia is monophyletic: Molecular and structural characters and common features of development strongly support the common evolutionary history of all animals

Question 7

What are the earliest branches of the animal tree?

Answer 7

sponges, cnidarians, ctenophores, and placozoans.

Question 8

sponges

Answer 8

• which are widespread in the oceans have a simple anatomical organization.
• they feed by drawing water containing food particles and dissolved organic molecules into their interiors.

Question 9

What are the most basal metazoans

Answer 9

• sponge bodies lack organized tissues and therefore, guts - multiple cell types scattered throughout a sponge body.
• mostly marine with a few freshwater species
• suspension feeders
• Benthic ( bottom-dwelling)
• Specialized cell types (food collection, skeleton secretion, etc)
• Lack organized tissues
• They come in a wide variety of body forms.
  . Some are vase-shaped & hollow in the center
  . Some are full of chambers and passages
• fans, globe etc.

Question 10

What are diploblastic and triploblastic

Answer 10

Sponges have not tissue layers therefor not a Eumetazoan
Eumetazoans are diploblastic or triploblastic

Question 11

Diploblastic

Answer 11

are cnidarians

Question 12

Triploblastic

Answer 12

Bilarians

Question 13

Eumetazoa means

Answer 13

good animals, they have tissues
Tissues arise from cell lines that differentiate early in development, in blastula or gastrula stage.

Question 14

Cnidarians

Answer 14

radial symmetry,
* a mouth surrounded by
tentacles,
* a closed gastric cavity,
* two tissue layers (endodermis
and epidermis),
* a mesoglea, surrounded by
epidermis on the outside and
endodermis on the inside.

Unlike sponges, cnidarians:
* have epithelial-lined
compartments,
* have tissues and organs,
* have a wider array of cell types,
* are predators

Question 15

Cnidarians: have nematocysts for food acquisition

Answer 15

Nematocyst = “threadlike cell” these are
special epidermal cells,
triggered by touch, that
fire out a thread-like
structure with a
harpoon on the tip with
toxins

Question 16

Cnidarian Colonies

Answer 16

Many cnidarians reproduce asexually to produce colonies. Many reproduce
sexually by releasing gametes into the water column in synchrony.

Question 17

Ctenophores: Comb-jellies

Answer 17

Like cnidarians, ctenophorans
have:
* radial symmetry
* an outer epithelium and an inner
endodermis that enclose a
gelatinous interior
* simple nerve net
* rudimentary gonads
* gastric cavity
Unlike cnidarians,
ctenophorans have:
* Movement via beating cilia.
* Digestive wastes move through
the gut and exit through an anal
pore.

Question 18

Placozoans

Answer 18

are tiny animals that lack specialized tissues.

Question 19

Eumetazoans are diploblastic or triploblastic

Answer 19

Tissue layers (= germ layers)
Ectoderm—outermost tissue layer
Forms the skin and nervous system
Endoderm—innermost tissue layer
Formed during gastrulation
Forms the gut
The diploblast body plan is based on these two tissue
layers

Question 20

Diploblasts

Answer 20

have an ectoderm and endoderm, with
gelatinous material between.

Question 21

Characteristics of Cnidaria:

Answer 21

Diploblastic
* Radially Symmetric
* Tentacles around mouth for catching prey
* Tentacles have cnidocytes (stinging cells)
* Blind Gut (single mouth/anus)
* A species can have a polyp stage,
medusa stage, or both
* Solitary or colonial