Introduction to Animal Bodies

Question 1

What key animal characteristics make them such efficient consumers?

Answer 1

-heterotrophic
-tissues formed from layers of embryonic cells
-efficient digestive system
-nerve and muscle cells
-can move, detect, and capture potential prey

Question 2

What do animal cells have instead of cell walls?

Answer 2

Support from structural proteins such as collagen

Question 3

What type of division produces sperm and egg cells in animals?

Answer 3

Meiotic

Question 4

Is the animal life cycle dominated by haploid or diploid stage?

Answer 4

Diploid

Question 6

Cleavage

Answer 6

A succession of cell division without growth between divisions that occurs in animal zygotes

Question 7

What does cleavage lead to?

Answer 7

The formation of a blastula that will undergo gastrulation

Question 8

Gastrulation

Answer 8

When a blastula undergoes gastrulation, it forms a gastrula with different layers of embryonic tissues

Question 9

Larva

Answer 9

Sexually immature, and morphologically and behaviorally distinct from the adult stage

Question 10

What happens after metamorphosis?

Answer 10

Larvae become juvenile that resemble adults but are sexually immature

Question 11

What are Hox genes?

Answer 11

Regulatory genes that control the expression of lots of other genes influencing morphology (where eyes should go, etc)

Question 12

What is believed to be the closest living relatives to animals?

Answer 12

Protists called choanoflagellates; the common ancestor may have resembled modern choanoflagellates

Question 13

Bilaterian

Answer 13

Organisms with:
-bilaterally symmetric form
-complete digestive tract
-efficient digestive system with a mouth and an anus at opposite ends

Question 14

What animals were the first to adapt to life on land?

Answer 14

Arthropods; began influencing plants

Question 15

What two groups of early land vertebrates live today?

Answer 15

Amphibians and amniotes

Question 16

What happened to reptiles during animal evolution?

Answer 16

Some returned to aquatic habitats, while others remained on land and became adapted for flight

Question 17

How do radially symmetrical and bilateral animals move?

Answer 17

Radially symmetrical: sessile/planktonic; drifting or weakly swimming
Bilateral: actively move and have a CNS

Question 18

What is the morphology of a bilaterally symmetrical animal like?

Answer 18

They have a dorsal (top) side and a ventral (bottom) side, a right and left side, a head end and tail end.
Many have sensory equipment (like a brain) in their anterior end

Question 19

What are the four main types of animal tissues?

Answer 19

Connective, epithelial, muscle, and nervous

Question 20

What animal(s) lack tissues?

Answer 20

Sponges and a few other groups

Question 21

What are the two germ layers that give rise to tissues and organs of embryo?

Answer 21

Ectoderm and endoderm

Question 22

Ectoderm

Answer 22

Covers the embryo’s surface and gives rise to exoskeleton and CNS

Question 23

Endoderm

Answer 23

Innermost layer, will form the gut and gives rise to the lining of organs and digestive tract

Question 24

What’s the difference between diploblastic and triploblastic animals?

Answer 24

Diploblastic animals only have ectoderm and endoderm, while triploblastic have a third germ layer called mesoderm

Question 25

Triploblastic animals

Answer 25

Include all bilaterally symmetrical animals

Question 26

Mesoderm

Answer 26

Fills space between ectoderm and endoderm, gives rise to muscles and most organs

Question 27

Body Cavity

Answer 27

Most triploblastic animals have one fluid- or air-filled space b/w digestive tract and outer body wall

Question 28

What are the functions of a body cavity?

Answer 28

-Internal fluid cushions suspended organs -Enables internal organs to grow and move independently of the outer body wall -acts as a skeleton the muscles of soft-bodied animals can work against

Question 29

What are the two types of body cavities?

Answer 29

Hemocoel and coelom

Question 30

Hemocoel

Answer 30

Body cavity formed between mesoderm and endoderm; filled with hemolymph that transports nutrients and waste through body cavity

Question 31

Coelom

Answer 31

Body cavity surrounded by tissues derived from mesoderm

Question 32

What are the two developmental modes?

Answer 32

Protostome development and deuterostome development

Question 33

What types of cleavage are prominent in protostome development?

Answer 33

Spiral cleavage and determinate cleavage

Question 34

Spiral Cleavage

Answer 34

Planes of cell division are diagonal to the vertical axis of embryo

Question 35

Determinate Cleavage

Answer 35

Rigidly determines developmental fate of each embryonic cell very early

Question 36

What types of cleavage are found in deuterostome development?

Answer 36

Radial cleavage and indeterminate cleavage

Question 37

Radial Cleavage

Answer 37

Planes of division are either parallel or perpendicular to the embryo's vertical axis

Question 38

Indeterminate Cleavage

Answer 38

Each cell produced by early cleavage is able to form a complete embryo

Question 39

Archenteron

Answer 39

Blind pouch formed during gastrulation that becomes the gut

Question 40

Blastopore

Answer 40

Indentation in gastrula that leads to the formation of the archenteron

Question 41

What does the blastopore form in the different developments?

Answer 41

Protostome: blastula becomes mouth Deuterostome: blastula becomes anus

Question 42

How is coelom formed in the different developments?

Answer 42

Protostome: solid masses of mesoderm split and form coelom Deuterostome: folds of archenteron form coelom

Question 43

What data sources are used to infer evolutionary relationships between animal phyla?

Answer 43

Whole genomes, morphological traits, ribosomal RNA (rRNA) genes, Hox genes, protein-coding nuclear genes, and mitochondrial genes

Question 44

What is the sister group to all other animals?

Answer 44

Sponges

Question 45

Eumetazoa

Answer 45

Clade of animals with tissues; means "true animals", includes all except for sponges and a few others

Question 46

Bilateria Clade

Answer 46

Most animal phyla belong here; most bilaterians are invertebrates, and Chordata is the only phylum that also includes vertebrates

Question 47

What three clades are bilaterians divided into?

Answer 47

Deuterostomia, Ecdysozoa, and Lophotrochozoa

Question 48

Deuterostomia

Answer 48

May be invertebrates or vertebrates; includes hemichordates, echinoderms, and chordates

Question 49

Hemichordates

Answer 49

Acorn worms

Question 50

Echinoderms

Answer 50

Sea stars and relatives

Question 51

What do ecdysozoans and lophotrochozoans have in common?

Answer 51

They are all invertebrates

Question 52

What bilaterian clade do nematodes and arthropods belong to?

Answer 52

Ecdysozoans

Question 53

What's special about ecdysozoans?

Answer 53

They secrete an exoskeleton that is shed to allow for growth (process called ecdysis)

Question 54

What two different features are observed in Lophotrochozoa?

Answer 54

Development of lophophore or developmental stage called trochophore larva

Question 55

Lophophore

Answer 55

Crown of ciliated tentacles used for feeding