ChordatesLEC32 Flashcards
1
Q
class Ophiuriodea
A
- brittle stars
- have a distinct central disk & long, flexible arms
2
Q
class Echinoidea
A
- Sea urchins and sand dollars
- have no arms, but have five rows of tube feet & teeth
3
Q
class Crinoidea
A
-Sea lilies(sessile) & Feather Stars(free-living)
4
Q
class holothuroidea
A
- Sea cucumbers
- lack spines, and their endoskeleton is much reduced
- defend by shooting their intestines
5
Q
phylum Chordata
A
humans
6
Q
all chordates share what characters?
A
- nerve cord
- Notochord
- muscle segments
- gill slits (develop into parts of neck in terrestrial vertebrates)
- TAIL
7
Q
Marine Tunicates
A
- Sea Squirts (our closest relative?)
- earliest branch of chordates
- resemble other chordates during their “tadpole” larval stage
- adult tunicate is a filter feeder
8
Q
subphylum Cephalochordata
A
- Lancelets
- named for their bladelike shape
9
Q
Craniates
A
-chordates with a skull, cephalization
10
Q
T or F, Cephalization opened up a new way of feeding for chordates
A
true
11
Q
what is earliest craniate fossils called?
A
- Haikouella
- 3-cm-long
- Discovered in China in 1999
12
Q
most primitive surviving craniate
A
hagfish
13
Q
characteristics of hagfish
A
- jawless with a cartilage skull
- no vertebrae
- defend with slime
- scavengers, feed on dead animals
14
Q
Vertebrates
A
- craniates with a backbone
- during the Cambrian period some craniates evolved into vertebrates
15
Q
how many species of vertebrates are there?
A
- 52,000, which include the largest animals ever to live on Earth, whales
- discover new ones all the time
