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 perform4-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/c1- they are metazoans2-deuterostome mode of development 3-enterocoelomout-pocketing of the gut into mesoderm layer

Echinoderms

1-exclusively marine2-internal skeleton (calcareous with protruding spines on the surface…spiny skin)3-coelomic cavity forms a water-vascular system4-tube feet (extension of coelomic canals with suction pads)5-radial symmetry6-male & female7-gas exchange through body wall or tube feet.8-ciliated larvae

Echinoderms1-Crinoidea (feather star) -primitive -filter feeders -feathery arms2-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 slits2-notochord3-dorsal hollow nerve tube4-post-anal tail4-metamerism (segmentally arranged blocks of muscles)5-bilateral symmetry

The world is numerically dominated by invertebrates and microorganisms

Chordates1-Urochordata or tunicates(sea squirts) -show the derived character only during larval stage -notochord& metamerism are in the tail2-Cephalochordata(amphioxus) -adults show the derived characters -notochord extend to the head3-Vertebrata a-Fish… paraphyletic group contain 5 classes b-class Amphibians(frogs) -tetrapod -lungs

ChordatesC- class Reptilia… paraphyletic group of 5 differentiated based on the presence or absence of openings in the temporal bone D-class AvesE-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 share1-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-Scapula2-Humerus3-Radius and Ulna4-Carpus5-Metacarpus6-Phalanges

What should I do now

1- dissect frog and/or rat2-demo3-answer the questions4-ask if there is uncertainty