Unicellular eukaryotes Protists Unicellular eukaryotes

Origin of Eukaryotes Endosymbiosis: theory that explains how eukaryotic cells evolved from the symbiotic relationship between two or more prokaryotic cells one cell engulfs a different type of cell, however the engulfed cell survives and becomes an internal part of the engulfing cell

 prokaryotes lack many internal structures, where eukaryotes are very complex with multiple membrane-bound organelles believed that the organelles used to be free-living prokaryotes 2 major organelles that provide the strongest evidence for endosymbiosis: chloroplast and mitochondria

chloroplast converts solar energy into sugar mitochondria extracts energy stored in sugar for cell to use other evidence for theory: membranes of mitochondria and chloroplasts are similar to those of living prokaryotes these organelles reproduce by binary fission within the cell they also contain a circular chromosome where many sequences match those of living prokaryotes

Multicellularity hypothesized that first multicellular organisms arose from colonies created by dividing individuals cells genes within these cells contained instructions for some cells to become specialized for different functions increased specialization made it possible for different functions to develop among different groupings of cells in multicellular organisms

Life Cycles and Reproduction prokaryotes reproduce asexually, so do unicellular eukaryotes reproduction of multicellular individuals is typically sexual reproduction

Characteristics of Protists eukaryotes not quite plants, animals or fungi can be unicellular, free-living, colonial or multicellular contain a typical eukaryotic cell with organelles some have chloroplasts  photosynthesis

Theory plants, animals and fungi evolved from protists

Movement  pseudopodia – cellular extensions of streaming cytoplasm that allow organisms to move http://www.youtube.com/watch?v=7pR7TNzJ_pA&feature=fvw cilia – hair like structures flagella – tail like structures http://www.youtube.com/watch?v=QGAm6hMysTA spores: protists who can’t move release reproductive cells that enter bodies and act as a parasite e.g. apicomplexan, plasmodium (malaria)

Reproduction binary fission  amoeba, paramecium, ciliates conjugation sexual and asexual reproduction Plasmodium reproduces asexually in humans but sexually in mosquitos

Animal-like protists (Amoebas, ciliates and flagellates) heterotrophs: capture and ingest food forms internal food vacuole and digests food some species are parasites http://www.youtube.com/watch?v=ojrkxmD6tT8&feature=related

Amoeba

Trichomonas foetus : cow disease

Trichomonas vaginalis: an STD

Paramecium

Termite Gut Bacteria

Malaria in red blood cells

Fungus-like protists (slime moulds and water moulds) heterotrophs that feed mostly on decaying organic matter some slime moulds consume other organisms some water moulds are parasites

Slime Moulds In Action https://www.youtube.com/watch?v=bkVhLJLG7ug https://www.youtube.com/watch?v=GY_uMH8Xpy0 https://www.youtube.com/watch?v=czk4xgdhdY4

Plant-like protists (euglenoids, diatoms and dinoflagellates) contain chloroplasts for photosynthesis algae: autotrophs that make their own food phytoplankton some consume other organisms when light is unavailable

Red Tide