Ch. 1: Biology of the Invertebrate Animals

Question 1

invertebrate definition

Answer 1

an animal without a skeleton or bone/cartilage (around CNS)

Question 2

biological species concept

Answer 2

a group of individuals that can repro together to create fertile offspring

Question 3

cladistics

Answer 3

searches for features (morphological/genetic) that are/were carries by all taxa that descend from a common ancestor

Question 4

4 features taxonomists study

Answer 4

1. anatomy
2. the fossil record
3. embryonic development and larval forms
4. molecular comparisons

Question 5

what group may have given rise to animals?

Answer 5

choanoflagellates

Question 6

kingdom animalia features (5)

Answer 6

1. multicellular heterotrophs
2. store carbs as glycogen
3. no cell walls
4. functionally-specialized cells
5. tissues (epithelium, connective, nervous, muscle)

Question 7

epithelium features (5)

Answer 7

1. forms sheets on body surfaces
2. secretes extracellular matric or cuticle
3. sits on thin fibrous ECM called the basal lamina
4. cells bonded to neighbours and basal lamina by desmosomes
5. commonly ciliated

Question 8

connective tissue features (2)

Answer 8

1. separated cells in a chemical ECM

2. contains a ground substance and protein fibers

Question 9

muscle property

Answer 9

is exitable and can contract via electrochemical gradients

Question 10

most inverts have smooth muscle, but insects have

Answer 10

striated muscle

Question 11

nervous tissue contains

Answer 11

neurons and may have neuroglia

Question 12

radial symmetry

Answer 12

any slice through central axis divides the body into mirror images
- have aboral and oral sides

Question 13

bilateral symmetry

Answer 13

only one slice divides the body into mirror images

- L and R sides

Question 14

what type of symmetry do sponges have?

Answer 14

none

Question 15

early embryonic development (3)

Answer 15

zygote -> blastula -> gastrula-> -derms form

Question 16

endoderm

Answer 16

inside lining of gut

Question 17

mesoderm

Answer 17

muscle, connective tissue

Question 18

ectoderm

Answer 18

skin, possibly CNS

Question 19

coelom

Answer 19

a fluid filled internal cavity

Question 20

protostome cleavage

Answer 20

spiral, determinate

Question 21

deuterostome cleavage

Answer 21

radial, indeterminate

Question 22

in protostomes, the 1st opening becomes

Answer 22

mouth

Question 23

in deuterostomes, the 1st opening becomes

Answer 23

anus

Question 24

coelom in protostomes

Answer 24

arises w/in solid mass of mesoderm

Question 25

coelom in deuterostomes

Answer 25

arises as pouches from wall of archenteron

Question 26

nerve cord in protostomes

Answer 26

ventral

Question 27

nerve cord in deuterostomes

Answer 27

dorsal

Question 28

differentiation of the body, pattern (5)

Answer 28

1. establish general anterior-posterior pattern
2. cell segmentation
3. anterior-posterior pattern formed in each segment
4. Hox genes trigger development of structures
5. differentiation and movement of various cells

Question 29

2 phyla where Hox genes are NOT found

Answer 29

1. porifera

2. ctenophora

Question 30

what does the fact that Hox genes are conserved in almost all animal phyla suggest (2)

Answer 30

1. suggests homology (derivation from a common, early ancestor)
2. may explain apparent examples of convergence

Question 31

what could “explosions” like the Cambrian explosion be due to?

Answer 31

Hox genes

Question 32

ecdysozoa

Answer 32

animals that molt

Question 33

what 2 phyla are in ecdysozoa?

Answer 33

1. arthropoda

2. nematoda

Question 34

lophotrochozoa

Answer 34

animals who don’t molt but have a trochophore larva or a lophophore feeding structure