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Mesozoic Marine Revolution

Mesozoic Marine Revolution. Geologic Time. The Mesozoic is from about 243 million years ago up until 65million years ago Contains -Cretaceous -Jurassic -Triassic . Climate.

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Mesozoic Marine Revolution

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  1. Mesozoic Marine Revolution

  2. Geologic Time • The Mesozoic is from about 243 million years ago up until 65million years ago • Contains -Cretaceous -Jurassic -Triassic

  3. Climate • The Triassic was generally dry, a trend that began in the late Carboniferous, and highly seasonal, especially in the interior of Pangaea. Low sea levels may have also raised temperature extremes. • Sea levels began to rise during the Jurassic, Temperatures continued to increase and began to stabilize. Humidity also increased with the proximity of water, and deserts retreated.

  4. Con’t • In the Cretaceous the sea levels also continued to rise and so did the temperature

  5. Focus • The Focus on the next following slides will be that of the invertebrates that were mainly dominant in the Mesozoic era. • Mulluscs • Echinodemata

  6. Invertebrates • Molluscs • pelecypods (or bivalves) • gastropods (snails) • cephalopods (ammonoids, belemnoids, squids, etc.)

  7. Mulluscs Characteristics • unsegmented soft body • most have internal or external shell • have a mantle - a fold in the body wall that secretes the hard protective shell   • muscular foot and/or tentacles • have a radula - a toothed structure used to grate food • two pairs of gills except in polmonate snails

  8. Anatomy • almost all molluscs divided into two functional regions: head-foot and the visceral lump • head-foot is most visible part, easily seen in snails and slugs • also is mostly muscular and covered in cilia to help the molluscs move around • visceral mass is the rest of the body, which is entirely non-muscular and contains the species organ (digestive, reproductive, etc) • most molluscs have a shell, a thick layer made of calcium carbonate • the mantle, the fold of tissue covers the visceral mass and shell (if present) • the mantle cavity is where the lungs and gills are housed

  9. Echinodermata • Ophiuroides (brittle stars) • Asteroidea (starfish) • Echinoidea (sea urchins) • Holothuroidea (sea cucumbers) • Crinoidea (sea lilies).

  10. Echinoderms • Are part of the phylum Echinodermata • Two main subdivisions of Echinoderms are traditionally recognized: the more familiar, motile eleutherozoa, which encompasses the Asteroidea (starfish), Ophiuroidea (brittle stars), Echinoidea (sea urchin and sand dollar) and Holothuroidea (sea cucumbers and the sessile pelmatazoa, which consist of the crinoids.

  11. Characteristics • The characteristics that distinguish Phylum Echinodermata are: radial symmetry, internal skeleton, and water-vascular system. Echinoderms appear to be quite different than other ‘advanced’ animal phyla, having radial (spokes of a wheel) symmetry as adults, rather than bilateral (worm-like) symmetry as in other triploblastic (three cell-layer) animals. Viewers of this program will observe that echinoderm radial symmetry is secondary; echinoderms begin as bilateral free-swimming larvae and become radial at the time of metamorphosis • Examples: Starfish and Crinoid

  12. Starfish Anatomy • Starfish are composed of a central disc from which arms sprout in pentaradial symmetry. Most starfish have 5 arms, but some have more or fewer. Some starfish have shown differing numbers of limbs within a single species. The mouth is located underneath the starfish, or ventral surface, is located on the top of the animal..

  13. Con’t • The spiny upper surface is called the aboral or dorsal surface. On the aboral surface there is a structure called the madreporite ,a small white spot located slightly off-center on the central disc which acts as a water filter and supplies the starfish's water vascular system with water to move

  14. Crinoids • Crinoids are also typically characterized by their pentameral radial symmetry.  • Crinoids are spilt into three parts

  15. Basic Structure of a Crinoid

  16. The Calyx: contains the vital organs of the animal. It is small when compared to the total mass, most of which is devoted to food collection. The mouth and anus are located on the upper surface of the body, and are connected by a simple gut. The Arms: composed of an articulated series of ossicles that are used in suspension feeding and respiration. The gonads are also located in the arms; fertilisation takes place in open sea water during mass spawnings. The Stem: this supports the animal and together with the roots and cirri served as a means of attachment to the sea bed or other useful substrate such as logs

  17. Works Cited http://ebiomedia.com/prod/BOechinoderms.html http://en.wikipedia.org/wiki/Mollusk http://www.amonline.net.au/invertebrates/mal/index.htm http://images.google.com/imgres?imgurl=http://www.reefs.org/ http://www.cyhaus.com/marine/Echinoderm.htm

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