Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Advent of The Eukaryotes Chapter 14 Copyright © McGraw-Hill Companies Permission required for reproduction or display

Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Outline Endosymbiosis Evolution of Sex General Biology of Protists Protist Reproduction Classifying Protists - Five General Categories

Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Endosymbiosis Most biologists believe mitochondria originated as symbiotic, aerobic eubacteria (endosymbiosis).  Bacteria thought to have been engulfed by ancestral eukaryotic cells early in the history of eukaryotes.

Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Endosymbiosis Mitochondria  Bound by two membranes (Outer smooth, inner- folded) and divide by simple fusion. - Each still has own circle of closed DNA containing genes encoding for essential proteins of oxidative metabolism. Chloroplasts  Bacteria-like organelles apparently derived from symbiotic photosynthetic bacteria.

Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Endosymbiosis

Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Evolution of Sex During sexual reproduction, two different parents contribute gametes to form offspring. Asexual Reproduction forms offspring identical to the parents.  Parthenogenesis - Development of an adult from an unfertilized egg. - Common among insects.  Self-Fertilization - One individual provides both gametes.

Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Evolution of Sex Sexual Reproduction provides a powerful means of shuffling genes, and rapidly generating genetic diversity. Sexual Life Cycles  Zygotic Meiosis - Zygote formed by fusion of gametes is the only diploid cell.  Gametic Meiosis - Gametes are the only haploid cells.  Sporic Meiosis - Alteration of generations

Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies General Biology of Protists Protists are eukaryotes united on the basis that they are not fungi, plants, or animals.  All have cell walls.  Movement accomplished by various means. - Flagella - Lobopodia - Filopodia - Axopodia

Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies General Biology of Protists Cysts - Dormant form with resistant outer covering. Nutrition  Phototrops (photosynthesis)  Phagotrophs (ingest visible food particles) - Holozoic feeders  Osmotrophs (ingest food in soluble form) - Saprozoic feeders Food Vacuoles (phagosomes)

Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Protist Reproduction Multicellularity - Composed of many permanently associated cells with integrated activities. Allows for specialization. Occurs only in eukaryotes - Colonies - Permanent association, but no integration of cell activities. - Aggregates - Transient collection of cells.

Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Protist Reproduction Multicellular Organisms - Individuals composed of many cells that interact and coordinate their activities.

Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Classifying Protists Most diverse of four kingdoms in the domain.  Artificial group formed for convenience. - Five general groups according to major shared characteristics.  Presence or absence of cilia / flagella  Presence and kind of pigment  Type of mitosis  Kinds of cristae in mitochondria

Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Classifying Protists  Molecular genetics of ribosomal s subunit.  Kinds of inclusions  Overall body form  Outer shell or armor  Modes of nutrition and movement

Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Heterotrophs Lacking Permanent Locomotor Apparatus Largest of the five groups.  Amoebas - Lack flagella and cell walls, and move with pseudopodia.  Forams - Possess rigid shells and move by cytoplasmic streaming (podias). - Marine with pore-studded shells (tests).  Radiolarians - Phylum Actinopoda - Glassy skeletons with many needlelike pseudopods.

Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Heterotrophs With Flagella Zoomastigotes  Ancestor of all animals appears to have been a member of this group. - All have at least one flagellum. Copyright © McGraw-Hill Companies Permission required for reproduction or display

Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Heterotrophs With Flagella Ciliates  Possess large number of cilia, fixed cell shape, and two nuclei per cell.  Reproduction usually by fission.  Move by beating cilia.

Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Nonmotile Spore-Formers Sporozoans are nonmotile, spore-forming, unicellular parasites.  Responsible for many diseases. - Sporozoans of genus Plasmodium are spread among humans by mosquitoes of genus Anopheles.  Malaria

Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Sporozoan Life Cycle

Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Photosynthetic Protists Dinoflagellates  Photosynthetic unicellular protists, most with two flagella of unequal lengths. - One flagella beats in a groove circling body, while the other beats in a groove perpendicular to it. Copyright © McGraw-Hill Companies Permission required for reproduction or display

Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Photosynthetic Protists Euglenoids  Freshwater protists with two flagella. - One-third are photosynthetic, while others are heterotrophic.  Reproduction by mitotic cell division. Copyright © McGraw-Hill Companies Permission required for reproduction or display

Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Photosynthetic Protists Diatoms  Photosynthetic unicellular protists with unique double shell of silica. Golden Algae  Named for yellow and brown accessory pigments in chloroplasts. Copyright © McGraw-Hill Companies Permission required for reproduction or display

Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Photosynthetic Protists Green Algae  Ancestor of true plants is a member of this group. - Contain chlorophyll a and b. - Most are microscopic and unicellular. Copyright © McGraw-Hill Companies Permission required for reproduction or display

Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Photosynthetic Protists Red Algae  Contain red pigments (phycobilins). - Almost all multicellular and live at sea. Brown Algae  Life cycle employs alteration of generations. (Kelp) Copyright © McGraw-Hill Companies Permission required for reproduction or display

Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Heterotrophs With Restricted Mobility Cellular Slime Molds  More closely related to ameobas.

Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Heterotrophs With Restricted Mobility Plasmodial Slime Molds  Stream along as a non-walled multinucleate mass of cytoplasm (plasmodium). - Extend pseudopodia as they move. Water Molds  Downy mildews often seen in moist environments. - All either parasitize living organisms or feed on dead organic material.

Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Review Endosymbiosis Evolution of Sex General Biology of Protists Protist Reproduction Classifying Protists - Five General Categories

Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies Copyright © McGraw-Hill Companies Permission required for reproduction or display