Animals Unit

Question 1

what characteristics do all animals share?

Answer 1

• multicellular
• eukaryotic (no cell walls)
• motil
• heterotrophic

Question 2

what is the difference between complete and incomplete metamorphosis?

Answer 2

complete metamorphosis:
- body changes completely
incomplete metamorphosis:
- not much change

Question 3

what is bilateral symmetry?

Answer 3

when something is divided by a line that separates the halves into nearly identical halves.

Question 4

what is radial symmetry?

Answer 4

when the body plan is divisible into identical parts around a central axis

Question 5

what is asymmetrical symmetry?

Answer 5

lack of symmetry.

Question 6

what are the three germ layers, where they’re located and what do they form?

Answer 6

ectoderm- forms outer layer of body (skin, nails, feathers, etc; think exterior)
mesoderm- forms middle layer (body systems; think M for middle)
endoderm- forms inner layer of body (stomach lining; think interior)

Question 7

what is the difference between diploplast and triploplast?

Answer 7

diploplast has two germ layers wherears triploplast has three

Question 8

what are the two body plans and how are they different?

Answer 8

complete- mouth and anus are different openings, allows for specialization

sac plan- mouth and anus are the same opening; no specialization

Question 9

what is coelom?

Answer 9

fluid-filled cavity located between gut and body; is also where all internal organs are found

acoelomate (no body cavity)

Question 10

what is the difference between protosome and deuterostome?

Answer 10

protosome: blastopore is first opening
deuterostome: anus is first opening

Question 11

list the main characteristics of sponges:

Answer 11

• sac-like bodies with many pores
• sessile
• filter feeds
• monoecious
• cellular level of organization (no tissue)

Question 12

function of choanocytes

Answer 12

flagellated collar cells used for feeding

Question 13

function of epidermal cells

Answer 13

cells forming the outer layer of the animal

Question 14

function of spicules

Answer 14

rods of silica/spongin/carbonate of used for support

Question 15

function of amoebocytes

Answer 15

amoeba-like cells that transport food and make “skeletal elements”

Question 16

what material can spicules be made from?

Answer 16

silica, calcium, and protein

Question 17

how does the sponge obtain food?

Answer 17

strained by the collar and transported down, cells absorb food by endocytosis. cell either digests it or exocytoses it and another cell takes it

Question 18

what is the amoeboid responsible for?

Answer 18

• circulates nutrients through sponges
• makes gametes and spicules (internal skeleton)

Question 19

what are gemmules?

Answer 19

• sphere-shaped collection of amebocytes surrounded by a tough layer of spicules
• can exist for a very long time

Question 20

what is a cnidocyte? how do they work?

Answer 20

definition: stinging cell
- has a capsule called nematocyst which contains a long, coiled thread
- filled with paralyzing toxins
- nematocysts discharged when triggered

Question 21

how is sexual reproduction different between a hydra and a jellyfish (medusa + polyp)?

Answer 21

• medusa produces sperm and egg into the water
• hydra develops ovaries/testes in the body wall

Question 22

how is asexual reproduction done?

Answer 22

fragmentation

Question 23

cnidarians are able to move because they have muscle fibers, they can also do movements like ________ and ________.

Answer 23

expanding + shrinking

Question 24

cnidarians don’t have a brain but have a…?

Answer 24

nerve net

Question 25

medusa have specialized cells. what are their names and their functions?

Answer 25

a. statocysts (for balance + for staying upright)
b. ocelli (eyespot, detect light)

Question 26

which body plan has only one opening?

Answer 26

sac-like body plan. it’s used to obtain food as well as get rid of undigested material.

Question 27

which body plan has a separate mouth and anus, and why is it more effective than sac-like?

Answer 27

one-way system. it’s more effective because it is often specialized into organs, making it much more efficient,

Question 28

do motile animals tend to be bilaterally symmetrical, radially symmetrical, or asymmetrical?

Answer 28

bilaterally symmetrical

Question 29

define “hermaphrody”.

Answer 29

an organism specialized in both male and female reproductive organs, producing both sperm and ova.

Question 30

true or false: acoelomates have coeloms.

Answer 30

false, they do not have coeloms.

Question 31

how is an individual identified as an acoelomate? (what “parts” do they have?)

Answer 31

1. ectoderm
2. mesoderm
3. endoderm
4. digestive cavity

Question 32

how is an individual identified as a eucoelomate? (what “parts” do they have?)

Answer 32

1. ectoderm
2. mesoderm
3. endoderm
4. COELOM

Question 33

how is an individual identified as a pseudosoelomate? (what “parts” do they have?)

Answer 33

1. ectoderm
2. mesoderm
3. endoderm
4. pseudocoelom

Question 34

which germ layers do acoelomate, eucoelomate and pseudocoelomate all have in common?

Answer 34

1. ectoderm
2. mesoderm
3. endoderm

Question 35

what are some characteristics of flatworms?

Answer 35

• acoelomates
• two forms: free-living + parasitic

Question 36

what are some characteristics of nematodes (roundworms)?

Answer 36

• pseudocoelomate
• two forms: free-living + parasitic

Question 37

what are some characteristics of flatworms?

Answer 37

• eucoelomate
• two forms: free-living + parasitic