Lecture 18: Animals

Question 1

5 key transitions for animal body plan

Answer 1

• symmetry
• embryonic tissue layers
• specialization of tissues and cell types
• coeloms
• segmentation

Question 2

traits that unify animals

Answer 2

• mobility
• no cell walls
• sexual reproduction
• developed specialized tissues
• heterotrophic
• multicellular

Question 3

radial symmetry

Answer 3

• can divide in half through multiple axes from center
• usually basal
• leads to spherical or circular organisms

Question 4

bilateral symmetry

Answer 4

-right and left halves are mirror images

Question 5

cephalization

Answer 5

• with half and half symmetry, different cultures can cluster in different parts of the body
• over time sensory organs are concentrated at anterior end of bilateral symmetry
• evolution of brain area

Question 6

diploblastic development

Answer 6

-2 layers: endoderm and ectoderm

Question 7

triploblastic development

Answer 7

• 3 layers: endoderm, mesoderm, and ectoderm

- More tissues increases complexity

Question 8

endoderm

Answer 8

• digestive organs

- intestines

Question 9

ectoderm

Answer 9

• outer body covering

- nervous system

Question 10

mesoderm

Answer 10

• muscle system

- skeletal system

Question 11

benefits of variable tissue

Answer 11

• increases complexity and specialization
• allows for differentiation of cell types which allows for more function like movement
• allowed for increased complexity of form and function of animals to become really big in size

Question 12

protostome

Answer 12

-mouth 1st, anus 2nd “first mouth”

Question 13

deuterostome

Answer 13

-anus 1st, mouth 2nd “second mouth”

Question 14

acoelomates

Answer 14

• no space btwn tissue layer

- move by cilia

Question 15

pseudocoelomates

Answer 15

• have cavity that’s fluid filled (gives them rigidness)

- fluid can also function as a hydrostatic skeleton and a circulatory system

Question 16

coelomates

Answer 16

• have cavity inside mesoderm

- organs are lined in muscle (gives them a lot of control)

Question 17

segmentation

Answer 17

-allow for redundancy of function and specialization

Question 18

locomotion

Answer 18

• more efficient when segments move independently

- further protects individual organs

Question 19

how has the DNA based tree changed from the old morphological tree?

Answer 19

• says differentiating based on coeloms isn’t correct bc both coeloms and pseudocoeloms are homoplasious
• we do still look at different types of symmetry and protostome vs. deuterostome

Question 20

lophotrochozoans

Answer 20

-grow by adding mass to already existing bodies

Question 21

edysozoans

Answer 21

• molt/shed hard exoskeleton in order to grow

- (NOT SNAKES)

Question 22

sponges

Answer 22

-most basal lineage of animals
-don’t have tissues, but considered animal bc of their specialization of cells and their larvae are free moving
-can form colonies or be independent
they have a lose body structure and can vary greatly in size

Question 23

ctenophores

Answer 23

• aka comb jellies

- homoplasious traits with more diverged animals (evolved independently)

Question 24

homoplasious traits found in ctenophores​​

Answer 24

• radial symmetry
• diploblastic
• complete gut
• nerve nets

Question 25

spone morphology

Answer 25

-contains choanocytes and water pores

Question 26

choanocytes

Answer 26

- highly specialized cells | - long and flagellated to help sponge collect food particles as they pass

Question 27

water pores

Answer 27

- pump water | - bring food and O2 in and waste out

Question 28

cnidarians

Answer 28

- marine predator - radial symmetry - true tissues (2 layers) & nerve nets have not yet developed true organs - incomplete gut (gastrovascular cavity)

Question 29

polyps

Answer 29

- cnidarians - cylindrical shaped - usually attached to substrate like sponges - few free swimming solitary or colonial

Question 30

medusae

Answer 30

- cnidarians - umbrella shaped with tentacle existing around mouth - free swimming

Question 31

cnidarian digestion

Answer 31

-in medusae: in gastrovascular cavity -external digestion b/c it takes place outside of body the gut can then engulf those fragments

Question 32

bilaterians

Answer 32

bilateral symmetry: protostomes and deuterostomes | -echinoderms only has radial symmetry

Question 33

arrow worm placement of bilaterian tree

Answer 33

-deuterostome but placed with protostome | bc DNA and has a nerve cord

Question 34

bryozoans and entoprocts

Answer 34

- colonial - excrete protective membrane - sexual

Question 35

flatworms

Answer 35

- acoelomates, internal parasite, clear heads, have eyespots incomplete guts with single opening - absorb food through body wall(diffusion) - lack organs that transport O2 that's why they're flat - have cilia, hermaphroditic, can often regenerate

Question 36

tapeworm

Answer 36

- type of flatworm - has no gut at all - absorb food through body wall

Question 37

rotifers

Answer 37

- pseudocoelomates - complete gut - top of lead corona - move through cilia and depend o water to survive

Question 38

rotifer corona

Answer 38

- circle of cilia sweep food into mouth | - cilia helps with movement and requires water to survive

Question 39

ribbon worms

Answer 39

- similar to flatworms - acoelomate - complete digestive tract (both mouth and anus) have specialized feeding appendages(proboscis)

Question 40

proboscis

Answer 40

-typically length of worm; when worm counters prey, proboscis shoots and stabs into prey so ribbon worm can eat prey

Question 41

annelids

Answer 41

- coelomate, segmented worms (i.e. earthworms) - segmentation allows for specialization in reproduction, digestion, excretion, feeding, respiration & locomotion - its segments protects itself from physical damage to real brain

Question 42

sea jellies and box jellies

Answer 42

-found in cnidarians & medusae

Question 43

anemones and corals

Answer 43

found in cnidarians, polyp, ectoderm, and endoderm

Question 44

clitellates

Answer 44

- aka earthworms and leeches - annelids - hairless - used for wounds

Question 45

polychaetes

Answer 45

- aka tube worms - annelids, marines - have a lot of hairs - unusual forms more than 1 pair of eyes & tentacles to filter food out of water