Echinoderms and chordates Announcements There will be a

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)