Unit 6: Animals

Question 1

Characteristics of the Animal Kingdom

Answer 1

1.Opisthokonta (along with Fungi and some protozoa): Single posterior flagellum (sperm cells)
Heterotrophic: Carnivores, herbivores, omnivores, parasites
2. Motility during some stage of life
3. Diplontic life cycle–> all diploids
4. Fixed Body plan: Morphology of animal determined by developmental cues (unlike a tree, limbs all same spots)
5. Complex tissue structure, Development, Hox Genes

Question 2

Complex tissue structure

Answer 2

1. Needed to find and process food
2. Can rapidly sense and respond to changes in the environment *anything from finding prey to moving from danger
   Muscle tissue: Aids in movement to seek food, Neural tissue: Communication of multiple tissues
3. Tissue cells

Question 3

how are animal cells diff from plant cells

Answer 3

Tissue cells lack cell walls (may have a supportive matrix like bone)
Epithelial tissue: protects internal and external body surfaces
Differential tissues: carry out specific functions

Question 4

group animals based on

Answer 4

tissues

Question 5

5 monophyletic Clades

Answer 5

1. Parazoa (P. Porifera) – Sponges: No specialized tissues from germ layer of embryo– 24 cell types
2. Placozoa – parasites resembling amoeba, only 4 cell types
3. Cnidaria – Jellyfish, Corals…
4. Ctenophora – Comb Jellies
5. Bilateria – All other animals

Question 6

Eumatezoa (True Animals)

Answer 6

Cnidaria, Ctenophera, Bilateria – specialized tissues derived from germ layers of the embryo

Question 7

Asexual reproduction are

Answer 7

exceptions: - Budding, Fragmentation
- Parthenogenesis
…Haplodiploidy (sex determination..ex.Bees)

Question 8

Zygote and further development

Answer 8

• Germ layers arise (ectoderm, mesoderm, endoderm)
• Cleavage: cell division with no cell growth
  Blastula–ball of cells (hallow in inverts, little yolk)
• Gastrulation: formation of primitive gut, and germ layers
• Metamorphosis – complete (holometabolous) and incomplete (hemimetabolous)

Question 9

Gastrulation in detail

Answer 9

Organogenesis: programmed development of tissue types and organ systems
* Diploblasts – have two germ layers
* Triploblasts – have three germ layers

Question 10

Role of Homeobox (Hox) genes in development

Answer 10

“Master control genes” – turn on or off large #s of genes
- Determine general body plan (# body segments, # and placement of appendages, Head-tail directionality)
* Undergone duplication throughout animal evolution (Verts 4 sets, Inverts 1 set)

Question 11

Part of body plan: Symmetry

Answer 11

Ability to divide an animal in equal halves on at least one plane (Sagittal, Coronal, Transverse)

Question 12

Asymmetrical animals

Answer 12

Parazoa and Placozoa

Question 12

Radial Symmetry

Answer 12

Divisible on two planes, or arranged around a central axis (pizza, bike wheel), no left or right sides, Cnidarians, Ctenophorans
- Experience environment equally in all directions

Echinodermata (starfish): pentaradial symmetry in adult only

Ctenophorans: rotational symmetry–2 copies of same half (oral/aboral) 180 Degrees

Question 13

Bilateral symmetry

Answer 13

division along the mid-sagittal plane
- Head and tail, right and left, front and back
–Bilateria

Question 14

what organisms are bilaterally symmetrical

Answer 14

All Eumetozoa (except those mentioned earlier…)- Echinodermata have bilateral symmetry in larval stage so are classified in
Bilateria

Promoted Cephalization: collection of a nervous system at anterior end
- active/controlled/directional mobility – resource seeking EX.STARFISH

Question 15

Germ layers formed during gastrulation are important

Answer 15

Diploblasts: 2 layers – Radial, biradial, rotational symmetry *Endoderm, ectoderm

Triploblasts (bilateria): 3 layers *Endoderm, ectoderm, mesoderm

Question 16

each layer give rise to

Answer 16

Endoderm: lining digestive tract (and organs), trachea, bronchi, lungs

Ectoderm: Epithelial covering of body, nervous system

Mesoderm: specialized muscle tissues, connective tissue, blood cells

Question 17

Triploblasts further divided by…

Answer 17

coelom type

Question 18

Coelom

Answer 18

internal fluid-filled cavity derived from & surrounded by mesoderm

• Between visceral organs and body wall (but contains organs)
• Allows cushioning, gas diffusion, independent movement & growth of organs

Question 19

Acoelomates

Answer 19

mesoderm completely filled with tissue – platyhelminthes

Question 20

Pseudocoelomates

Answer 20

Cavity lined with mesoderm & Endoderm – Nematodes

Question 21

true coelomates

Answer 21

Annelids, Mollusks, Arthropods, Echinoderms, Chordates
* Termed Eucoelomates
- is completely surrounded by muscle

Question 22

Development of the Mouth (dealing with triploblastic, Eucoelomates)

Answer 22

Development of Gut and Anus in Blastopore:

Protostome (mouth first): Mouth from Blastopore (Mollusk, Annelid, Arthropods)

Deuterostome (Mouth second): mouth from other end of tube – anus from blastopore (Chordates and Echinoderms) … we form anus first

Question 23

Differences in Development: Protosome

Answer 23

Schizocoely: 2 clumps form cavities then merge

Spiral Cleavage: cells rotated along poles – misaligned

Determinate Cleavage: Embryonic cell type determined at division