Origin And Evolution Of Animals

Question 1

Metazoa

Answer 1

“Later animals”; shared derived traits include heterotrophic, sexual reproduction, multicellular, and movement

Question 2

Chanoflagellates

Answer 2

Not animals but have similar traits; protists; aggregate into colonies

Question 3

Poriferans

Answer 3

Simplest animals; cells not organized into tissues and move briefly in life cycle but mostly sessile; asymmetrical; filter feed using chanocytes

Question 4

Choanocyte

Answer 4

Filter feed

Question 5

Amoebocyte

Answer 5

Part of a sponge; freely move throughout the sponge body and performs any task; can also divide into other things

Question 6

What are two things that make a sponge?

Answer 6

Choanocyte and Amoebocyte

Question 7

What are the three major body plans?

Answer 7

No symmetry, radial symmetry, and bilateral symmetry

Question 8

Radial symmetry

Answer 8

Same thing on every direction/side

Question 9

Bilateral symmetry

Answer 9

Cut in half -> same layout on either side (mirror)

Question 10

Do sponges have tissues?

Answer 10

No, but other animals (eumetazoans) have tissues

Question 11

What are the four tissues?

Answer 11

Nervous, epithelial, connective, and muscle

Question 12

Cnidaria

Answer 12

Coral, jellyfish, and sea amenity; use tissue to coordinate movement; radial symmetry; carnivorous, presence of diploblastic embryo, two forms: sessile polyp and motile medusa

Question 13

Diploblastic embryo

Answer 13

Two germ layers

Question 14

Sessile polyp

Answer 14

Non-moving, tentacles on top; Ex: coral

Question 15

Motile Medusa

Answer 15

Moving; tentacles on the bottom; Ex: jellyfish

Question 16

Lophotrochoza

Answer 16

Annelids, molluscs, platyhelminths; protocols development; has two larvae stages: lophophore and trochophore; larvae stages have cilia or gills for movement and filter feeding

Question 17

Triploblastic embryos

Answer 17

Have three germ layers; ectoderm, mesoderm, and endoderm

Question 18

Gastrulation

Answer 18

Cells dive or die to create a hole/gastrule

Question 19

Gastrule

Answer 19

Infolding into embryo/a hole

Question 20

Endoderm

Answer 20

Inside layer of embryo; later forms the gastrointestinal tract

Question 21

Ectoderm

Answer 21

Outside layer of embryo; later forms skin, muscle, and nervous tissue

Question 22

Protosomes

Answer 22

Mouth developing first organisms; in eight cell stage it is spiral and determinate

Question 23

Determinate

Answer 23

Once embryo starts to develop cells cannot change even when cut (determined fate)

Question 24

Deuterostomes

Answer 24

Mouth developing second organisms; evolved from protostomes; in its eight cell stage embryo is radial and indeterminate

Question 25

Indeterminate

Answer 25

Cells can change; Ex: if cells cut in half, some cells go out and form ectoderm and others stay in and form endoderm, can also get twins

Question 26

Platyhelminths

Answer 26

Flatworms; flat body; no complex body systems; 1-2 cells thick; no body cavity, bilateral symmetry, gastrovascular cavity/no digestive tract

Question 27

Molluscs

Answer 27

Gastropods and cephalopods; bilateral symmetry, hemocoel; three main body parts: muscular foot, visceral mass, and mantle

Question 28

Gastropods

Answer 28

Part of molluscs; w/ shells; complex body systems; Ex: snails

Question 29

Cephalopods

Answer 29

Shell-less molluscs and predatory molluscs; same body arrangement as other molluscs; highly intelligent; it’s structures: mantle, visceral mass, and foot; Ex: octopus, squid

Question 30

Nautilus

Answer 30

Ancient molluscs; squid and octopus evolved from this

Question 31

Annelids

Answer 31

Segmented worms; complex body systems; coelom and bilateral symmetry; Ex: leech, tube worm, bristle worm

Question 32

Ecdysoza

Answer 32

Animals that have to molt or go through ecdysis; include arthropods, hexapoda, and nematoda

Question 33

Molting

Answer 33

Also called ecdysis; shedding exterior part of the body to grow

Question 34

Arthropods

Answer 34

Most speciose animal group; includes chelicerates, myriapods, and crustaceans; hemocoel and reduced coelom, segmented body w/ joined appendages and exoskeleton, bilateral symmetry

Question 35

Chelicerates

Answer 35

Extra arms to manipulate foods; Ex: spiders and scorpions

Question 36

Myriapods

Answer 36

Arthropods w/ many feed; Ex: centipede

Question 37

Crustaceans

Answer 37

Crabs

Question 38

Hexapoda

Answer 38

Have six feet; insects; segmented exoskeleton; complex body systems; molt and go through metamorphosis; Ex; butterfly

Question 39

Nematoda

Answer 39

Roundworms; hemocoel, no circulator system, bilateral symmetry Ex: C. elegans

Question 40

Deuterostomia

Answer 40

Mouths develop second; organs, dueterostome development, coelom; bilateral symmetry enables rapid locomotion; Ex: cheetah?

Question 41

Echinoderms

Answer 41

Are deuterostomia; re-evolved radial symmetry (juveniles have bilateral while adult has radial); water vascular system, coelom, endo skeleton ; Ex: sea star, feather star, sea cucumber

Question 42

What trait is not a shared derived trait of lophotrochozoa?

Answer 42

Ecdysis