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Paleontology Laboratory

Paleontology Laboratory. PROTISTA, EUBACTERIA, ARCHEOCYATHIDS , PORIFERA & CONULARIDS. Fossil organisms within the Kingdom Protista represent the earliest life forms known. These organisms are characterized by a single-celled body plan

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Paleontology Laboratory

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  1. Paleontology Laboratory PROTISTA, EUBACTERIA, ARCHEOCYATHIDS, PORIFERA & CONULARIDS

  2. Fossil organisms within the Kingdom Protista represent the earliest life forms known. • These organisms are characterized by a single-celled body plan • Kingdom Eubacteria (green and blue-green algae) have no nucleus. • The protist phyla Foraminifera and Diatoms have mineralized skeletons and an extensive fossil record. • Because of their wide-spread distribution and rapid evolutionary rates, many of the protists are excellent index fossils used in biostratigraphic studies.

  3. FORAMINIFERA • Foraminifera are the most common and geologically most important of the fossil protozoans. • Today, nearly all forams live in marine environments and are either bottom dwellers (benthic) or float in the water column (planktic). • Forams are characterized by multi-chambered tests which are built by addition of new chambers during life. Chambers are separated by partitions called septa (singular = septum), whose exterior expressions are termed sutures. • Composition of the tests are either calcite (CaCO3) or agglutinated (cemented foreign particles, e.g., sand or silt grains). • The classification of Foraminifera is based on • (i) test microstructure, • (ii) test symmetry, and • (iii) aperture type.

  4. BENTHIC FORAM PLANKTIC FORAM

  5. FUSILINID NUMMULITES

  6. Radiolarians and Diatoms • Radiolarians are heterotroph protozoans which thrive in the upper layers of the seas. • The protoplasm of radiolarians is surrounded by a test commonly composed of an intricate lattice work of opaline silica • The tests of radiolarians exhibit great morphologic diversity, but they are typically characterized by radial or spherical symmetry. • Diatoms are a kind of microscopic golden-brown algae that secrete siliceous tests (sometimes called frustules) consisting of two overlapping halves or valves that fit together. • The walls of the tests are ornamented by pores, grooves, and ridges.

  7. RADIOLARIAN DIATOM

  8. EUBACTERIA • Stromatolites are organically produced sedimentary structures and are amongst the oldest fossils known on Earth • They are made by cyanobacteria (often erroneously called “blue-green algae”, however, because the cells are prokaryotic, they should not be confused with true algae which are eukaryotes. • Stomatolites are without skeletons (they are layers of sediment), and differ from some similar-looking sponges that have a mineralized skelton.

  9. Archeocyathids • Archeocyathids have been assigned by paleontologists to many different animal groups, primarily the corals and Pleosponges. • Many researchers even referred to them to a distinct, separate Phylum, Archeocyatha. • Recent investigations have proved pretty conclusively that archeocyathids were an early experiment in the Phylum Porifera--they are now generally considered an extinct type of calcareous sponge.

  10. Archaeocyathids • Archaeocyathids were sessile, marine organisms of shallow, tropical and subtropical waters that lived during the early Cambrian period about 550 million years ago. T • hey were widespread in Cambrian seas throughout the world and were the first major reef-builders before the true corals

  11. PHYLUM PORIFERA (sponges) • Porifera means "pore-bearing". Exterior covered by tiny pores. Globular, cylindrical, conical or irregular shape. • Interior may be hollow or filled with branching canals. • Solitary or colonial. • Skeletal elements are called spicules, and they may be separate or joined. • Composition may be calcareous, siliceous or organic material called spongin. • Geologic range: Cambrian to Recent. • Mode of life: Attached to the sea floor. Most are marine.

  12. SPONGES • Sponges have an asymmetric body with no true tissues, or organs. • They have two layers of cells. • Flattened cells cover the exterior. Collar cells line the interior chambers. Collar cells move large volumes of water through body pores by their beating flagella. • They also trap suspended food particles in their microvilli collars. • Between the two layers of cells there is a semifluid matrix with needlelike structures for support. • Sponges reproduce sexually and have a free-living larval stage. They also reproduce asexually by fragmentation or gemmules.

  13. PORIFERA

  14. SPONGE SPICULES

  15. GLASS SPONGE

  16. DEVONIAN GLASS SPONGE

  17. CONULARIDS • CONULARIDS- Although there is some controversy in regards to the systematic position of the conularids, most workers today place them with the scyphozoan cnidarians. • The exoskeleton of conularids is composed of chitin and in outline is pyramidal with four sides. • The exterior surfaces of conularids normally have finely spaced longitudinal ribs. • The interior of conularids may have thickenings or septa developed. • In life, conularids lived attached apical end down to the substrate.

  18. Conularid

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