Echinoderms and chordates
Announcements
*There will be a quiz next lab period
*Assignment for this lab include pages 95, 96, 97, 98, 99
100, 101.
Group project
-Choose your group (usually 4)
-Start to out-line (Project proposal-worth 5 points)
1-Hypothesis or question you want to ask with some
back groud informations and justification
2-How you are going to test this hypothesis or solve this
question (number of samples, type of data)
3-What kind of statistical analysis you will perform
4-The oral presentation must be in powerpoint format
This lab
•Why they are grouped together
•Different Echinoderms
•Different Chordates
•Dissecting two distantly related chordates
Echinoderms and chordates
* They are grouped together b/c
1- they are metazoans
2-deuterostome mode of development
3-enterocoelom
out-pocketing of the gut into mesoderm layer
Echinoderms
1-exclusively marine
2-internal skeleton (calcareous with protruding spines on
the surface…spiny skin)
3-coelomic cavity forms a water-vascular system
4-tube feet (extension of coelomic canals with suction
pads)
5-radial symmetry
6-male & female
7-gas exchange through body wall or tube feet.
8-ciliated larvae
Echinoderms
1-Crinoidea (feather star)
-primitive
-filter feeders
-feathery arms
2-Asteroidea(sea stars)
- 5 arms or more
-carnivores
3-Ophiuroidea(brittle star)
-long arms (snake stars)
-more mobile by crawling
Echinoderms
4-Echinoidea(sea urchins)
-covered with spines
-no arms
-solid skeletal encasement
-scraping teeth (feed on algae)
5-Holothuroidea(sea cucumbers)
-no arms
-few calcareous plates
-no spines
-body elongated
Chordates
1- gills slits
2-notochord
3-dorsal hollow nerve tube
4-post-anal tail
4-metamerism (segmentally arranged blocks of muscles)
5-bilateral symmetry
The world is numerically dominated by
invertebrates and microorganisms
Chordates
1-Urochordata or tunicates(sea squirts)
-show the derived character
only during larval stage
-notochord& metamerism are in the tail
2-Cephalochordata(amphioxus)
-adults show the derived characters
-notochord extend to the head
3-Vertebrata
a-Fish… paraphyletic group contain 5 classes
b-class Amphibians(frogs)
-tetrapod
-lungs
Chordates
C- class Reptilia… paraphyletic group of 5
differentiated based on the presence or absence of
openings in the temporal bone
D-class Aves
E-class Mammalia
-mammary gland
-4 chambered heart
-synapsid skull
-variable teeth
-complete diaphragm
-endothermy
-large brain
P.s. the ancestor of the last 3 classes share
1-shelled eggs or viviparity
2-amniotic egg
Class Mammalia
1-order Carnivora (cat)
2-order Perissodactyla (horse)
3-order Artiodactyla (cow)
4-order Cetacea (dolphins)
5-order Rodentia (rat and mice)
6-order primates (human)
Anatomy of the fore-limb in
horse and human
1-Scapula
2-Humerus
3-Radius and Ulna
4-Carpus
5-Metacarpus
6-Phalanges
What should I do now
1- dissect frog and/or rat
2-demo
3-answer the questions
4-ask if there is uncertainty