ecdysozoa: arthropoda

Question 1

what are athropod’s exoskeleton made of

Answer 1

polysaccharide chitin,
strengthened by calcium carbonate (CaCO3) in crustaceans

Question 2

arthropods body plan

Answer 2

tagma (body segments) as well as jointed appendages for movement

Question 3

coelomate type

Answer 3

hemocoel (reduced coelom)

Question 4

circulatory system type

Answer 4

open

Question 5

show that small
changes in the timing and location of gene expression can
result in novel shapes and sizes

Answer 5

studies of Hox genes

Question 6

what led to the
diversification of arthropod body segments and appendages

Answer 6

Variation in gene expression, combined with ecological
opportunity through natural selection

Question 7

first animals to fly

Answer 7

insects

Question 8

independent wing origin hypothesis:

Answer 8

Wings arose as outgrowths from the thorax independent from the legs

Question 9

gill co-option hypothesis

Answer 9

Wings arose from gill-like projections on the branched legs of a wingless ancestor

Question 10

developmental genetics supported which hypothesis?

Answer 10

gill co-option

Question 11

lineages of arthropods:

Answer 11

1. Myriapods
2. Insects
3. Crustaceans
4. Chelicerates

Question 12

myriapod body

Answer 12

• A head region
• A long trunk with segments that each have one pair of legs
  (centipedes) or two pairs of legs (millipedes)
• Some species have no eyes, but others have from a few to many
  simple eyes clustered on the sides of the head

Question 13

insect body

Answer 13

three tagmata—a head, thorax, and abdomen

Question 14

insect legs

Answer 14

Three pairs of walking legs extend from the sides of the thorax

Question 15

insect eye

Answer 15

compound eye contains many lenses, each associated with a light-
sensing, columnar structure (ommatidium)

Question 16

insect head

Answer 16

our pairs of mouthpart structures, one pair of
antennae that are used to touch and smell, and a pair of compound eyes

Question 17

crustaceans ecological role

Answer 17

consume phytoplankton and, in turn, are an important food source for fish and marine
mammals

Question 18

are there any terrestrial crustaceans?

Answer 18

Just a few species of crabs and some isopods

Question 19

crustacea body

Answer 19

divided
into three tagmata: the head, thorax, and abdomen

Question 20

carapace

Answer 20

covers and protects head and thorax (some crustacea species have this)

Question 21

Chelicerate body

Answer 21

consists of two tagmata: the cephalothorax
(prosoma) and abdomen (opisthosoma)

Question 22

chelicerate tagmata

Answer 22

not homologous to those in other arthropods, even though they are functionally similar

Question 23

chelicerate sensory

Answer 23

Cephalothorax lacks antennae, but usually has eyes

Question 24

two types of insect metamorphosis

Answer 24

1. Holometabolous metamorphosis
2. Hemimetabolous metamorphosis

Question 25

Holometabolous metamorphosis

Answer 25

There is a distinct larval stage

Question 26

Hemimetabolous metamorphosis

Answer 26

Form of direct development. Juveniles called nymphs look like smaller versions of the adult

Question 27

why do insects metamorhpose

Answer 27

Biologists hypothesize that this is because of feeding efficiency. If adults and juveniles feed on different resources in different ways, they do not compete with each other for resources