Looking Back at Bio 115 The Organism as a Unit of Life Cellular Structure (cell = unit of life)…one or many! Metabolism = Homeostasis (PSN, Resp, N 2 fix, ferment, etc.) Growth = irreversible change in size Reproduction…failure = extinction Acclimatization-short term responses = behavior Adaptation-long term responses = evolution
Shifting Kingdoms Bacteria Archaebacteria Archezoans Euglenoids Chrysophytes Green Algae Brown Algae Red algae Slime Molds True Fungi Bryophytes Tracheophytes Protozoans Myxozoans Multicellular Animals Lumpers Splitters PlantaeProtista
How Many Kingdoms? Multicellular Animals MyxozoansProtozoans Tracheophytes Bryophytes True Fungi Slime Molds Red algae Brown Algae Green Algae Chrysophytes Euglenoids Archezoans Archaebacteria Bacteria Original Cell Extant Extinct Long Time with Prokaryotes only
Euglenozoa Flagellated protists which can be photosynthetic Odd features Protein pellicle instead of cell wall Odd mitochondria (discoid cristae) Chromosomes condensed during interphase 400 species (many more likely unknown parasites!) Two sub-phyla: 1.Kinetoplasta (Trypanosoma gambiense) sleeping sickness 2.Euglenoida (Euglena) photosynthetic, chlorophyll a,b, paramylum
Trypanosoma gambiense Blood-borne parasite Flagellated undulating cell Chemical agent causes African sleeping sickness Vectored by Tsetse fly between alternate hosts Nucleus Flagellum
Euglena gracilis Nucleus Eyespot Anterior invagination With internal short flagellum Long flagellum rooted here also (not shown) Paramylon grain Chloroplasts Protein pellicle (striations) Posterior extension Contractile vacuole Pyrenoid Mitochondrion
How Many Kingdoms? Multicellular Animals MyxozoansProtozoans Tracheophytes Bryophytes True Fungi Slime Molds Red algae Brown Algae Green Algae Chrysophytes EuglenoidsArchezoans Archaebacteria Bacteria Original Cell Extant Extinct Cyanobacterium endosymbiosis Eukaryotes ARE Chimeras! Eubacterium endosymbiosis Though sketched here as single events, these endosymbioses were very likely multiple events! Chlorophyte algal endosymbiosis For euglenoids, the chloroplast is a secondary endosymbiosis. Euglenoid mitochondria are unique!
Pseudopodia Contractile vacuole Nucleus Food vacuoles Mitochondria Amoeba proteus A freshwater amoeboid protist Engulfing a Staurastrum green alga epeast01/logs/sep24/media/Foram_600.jpg The pseudopodia assist in locomotion and phagocytosis, but they also secrete proteolytic enzymes to digest particles outside the cell. Marine relatives, the foraminifera, secrete calcareous shells, contributing to reefs and sands.
Freshwater amoeboid protist Chitinous test Hyaline connections to the cell Food vacuoles obvious Some have two or more nuclei Pseudopodia protrude from the test Feeding here upon green algae Arcella gibbosa
A living foraminiferan demonstrates its many and delicate pseudopodia In addition to capturing food items, the foram also receives nutrients from its endosymbionts Orbulina universa, or Globigerina bulloides
Actinosphaerium eichhorni It is related to many radiolarians which are known only from their tests fossilized in silicate deposits. This organism is an actinopod. Its axipods are stiff projections rather than delicate pseudopodia. The axipods are stiffened primarily by silicates taken from the water.