Animal Body Plans

Question 1

4 main categories of body plan organization

Answer 1

1. symmetry
2. embryonic development
3. tissue
4. body cavities

Question 2

What are animals without true tissue?

Answer 2

Parazoa

Question 3

What are animals with true tissue?

Answer 3

Eumetazoa

Question 4

What are the 2 kinds of symmetry, what are they found in, what are their distinct characteristics?

Answer 4

1. Radial -> found in sessile animals
   - have top (oral) and bottom (aboral)
   - no distinct left/right font/back
2. Bilateral -> found in actively moving animals
   - more complex
   - anterior/posterior end different
   - left/right “mirrored”

Question 5

What is the development of a head in animals called?

Answer 5

Cephalization

Question 6

What are the are the 2 kinds of tissue structures of animals, what are the layers, and what symmetry are they associated with?

Answer 6

1. diploblastic -> 2 germ layer
   - endoderm -> inside layer (develops into digestive tract)
   - ectoderm -> outside layer
   - found with radial symmetry
2. triploblastic -> 3 germ layer
   - endoderm
   - mesoderm (gives rise to muscles and organs)
   - ectoderm
   - found in bilateral symmetry

Question 7

What do body cavities do in animals?

Answer 7

1. help protect internal organs

2. help with movement of individual organs

Question 8

What are the 3 types of body cavities, where are they located, and what kind of digestive tract are they associated with?

Answer 8

1. coelomates -> cavity fully surrounded by mesoderm
   - complete digestive tract
2. pseudocoelomates -> cavity between mesoderm and endoderm
   - complete digestive tract
3. acoelomates -> no body cavities
   - incomplete digestive tract

Question 9

what are the 2 types of embryonic development?

Answer 9

1. protostome -> mouth first development from blastopore

2. deuterostome -> anus first development from blastopore

Question 10

What is a blastopore?

Answer 10

is the first opening in a blastula (that will become either the mouth or anus) as it undergoes gastrulation.

Question 11

What are animals?

Answer 11

1. organisms that made of eukaryotic cells
2. multicellular organisms
3. ingestive heterotrophs
4. have nervous/muscular tissue (movement of body/nerve impluses)
5. have no cells walls, but are held together with proteins like collagen

Question 12

What happens after a sperm fertilizes an egg?

Answer 12

Zygote -> undergoes cleavage -> becomes blastula (hollow ball) -> gastrulation begins with blastopore opening -> formation of endoderm and ectoderm

Question 13

What are choanoflagellates, and what is the hypothesis around them?

Answer 13

Choanoflagellates are present day protists that animals share a common ancestor with. the hypothesis around them is that animals likely shared a common suspension feeding ancestor with them because:

1. Cells found in choanoflagellates are same as collar cells found in sponges
2. Similar collar cells have been found in other invertebrate phyla, but never in other protists/plants/fungi
3. DNA sequence data shows choanoflagellates and animals are sister taxa

Question 14

What is a gastrovascular cavity?

Answer 14

A central cavity found in some animals with simple body plans, only one hole (meaning both mouth and anus). It is responsible for digestion, and then distribution of nutrients. found in Cnidaria, and some platyhelminthes.

Question 15

what is a larva?

Answer 15

a larva is sexually immature and morphologically

distinct from the adult

Question 16

what is a coelom

Answer 16

-a body cavity
-A fluid- or air-filled space separating the digestive
tract from the outer body wall