Animal biodiversity 4

Question 1

what is the sister group of the protostomes?

Answer 1

deuterostomes

Question 2

what are the 2 groups within the deuterostomes?

Answer 2

1) echinodermata

2) chordata

Question 3

in deuterostomes which forms first the mouth or anus?

Answer 3

the anus forms first then the mouth

Question 4

what species does echinodermata include?

Answer 4

starfish and sea urchins

Question 5

what symmetry do echinodermata have?

Answer 5

secondary radial and larvae bilateral

Question 6

describe echinodermata vascular system

Answer 6

has digestive, reproductive and water vascular systems- WVS derived from coelom

Question 7

what is the notochord and where is it found?

Answer 7

Longitudinal flexible rod located between digestive tract and nerve cord in embryo providing skeletal support in chordates

Question 8

what is the second chord found in chordates?

Answer 8

dorsal hollow nerve chord

Question 9

how do chordata feed?

Answer 9

through pharyngeal slits by filter feeding

Question 10

what is a difference between chordata and protostomes?

Answer 10

chordata don’t usually end in an anus they have a muscular post anal tail

Question 11

what is the function of the WVS in echinodermata?

Answer 11

branch into extensions called tube feet which function in locomotion, feeding and gas exchange

Question 12

how do starfish class asteroidea feed and on what?

Answer 12

preys on molluscs, uses arms to pry open shell, everts stomach

Question 13

what is a feature of brittle stars Class Ophiuroidea?

Answer 13

distinct central disc, long highly mobile arms

Question 14

how do sea urchins Class Echinoidea move?

Answer 14

no arms they have rows of tube feet that move slowly

Question 15

how do sea lilies Class Crinoidea feed?

Answer 15

long flexible arms used in suspension feeding

Question 16

describe the structure of sea cucumbers Class Holothuroidea

Answer 16

they lack spines and have reduced endoskeleton - tube feet adapted as tentacles for feeding

Question 17

describe the adult and larvae stages of sea squirts

Answer 17

adult - sessile filter feeder

larvae - free living with chordate characteristics

Question 18

what are features of the Subphylum Cephalochordata (lancelets)

Answer 18

• no real head, brain, sensory organs, heart or jaws

- mouth surrounded by oral hood with cirri that strain and direct food to mouth.

Question 19

describe segementation in chordates

Answer 19

muscle segments develop from blocks of mesoderm called somites arranged along the notochord

Question 20

what are segmented muscle blocks called

Answer 20

Segmented muscle blocks are called myotomes

Question 21

what is the simplest explanation for how segmentation evolved?

Answer 21

occurred 3 times separately in 3 groups

Question 22

how is it thought vertebrates evolved?

Answer 22

from the larval form of a sessile ancestor by paedogenesis (sexual maturity in the larva), because of the similarity of cephalochordates to urochordate larval form

Question 23

what are the 4 main characteristics of the subphylum verterbrata?

Answer 23

1) neural crest cells from embryonic ectoderm layer give rise to branches teeth and nervous system
2) cephalisation and brain derived from end of nerve chord
3) vertebral column (backbone) forming main body axis
4) closed circulatory system with chambered heart