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Classification of Living Things

Classification of Living Things. Classification System. Domain Kingdom Phylum Class Order Family Genus Species. Cell type. Prokaryotes: no membrane bound nucleus, DNA is free floating in the cell. Eukaryotes: have a membrane bound nucleus and complex organelles. Prokaryotes.

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Classification of Living Things

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  1. Classification of Living Things

  2. Classification System • Domain • Kingdom • Phylum • Class • Order • Family • Genus • Species

  3. Cell type • Prokaryotes: no membrane bound nucleus, DNA is free floating in the cell. • Eukaryotes: have a membrane bound nucleus and complex organelles.

  4. Prokaryotes • Smallest and structurally simplest living organisms. • Oldest forms of life on earth • Microscopic • Lack a membrane bound nucleus and most other organelles • Circular shaped DNA molecules • Shapes: rod, spherical or spiral • Two Domains: Bacteria and Archae

  5. Metabolism • Autotrophic -photosynthetic -chemosynthetic • Heterotrophic -aerobic respiration (with oxygen) -anaerobic respiration (with out oxygen) ex: use SO4-2 instead of oxygen Anoxic: environment without oxygen

  6. Domain Bacteria • Unicellular; some form colonies. • Cell wall of peptidoglycan • Essential role in nutrient cycles • Major groups: Cyanobacteria, decay bacteria, nitrifying bacteria, pathogenic bacteria

  7. Decay Bacteria • Break down waste products and detritus • Detritus: dead organic matter • Release nutrients into the environment • Importance: recycling of essential nutrients

  8. Cyanobacteria • Also known as blue-green algae • Photosynthetic • Photosynthetic Pigments -Contains chlorophyll a (pigment in plants) -Phycocyanin: bluish pigment -Phycoerythrin: reddish pigment -Dominant pigment determines color

  9. Cyanobacteria • Stromatolites: Thought to have an important role in the accumulation of oxygen in earth’s atmosphere • Prochlorococcus: thought to be most abundant photosynthetic organism in the ocean • Red tides: bloom of cyanobacteria with red pigment (can cause skin rashes)

  10. Prochlorococcus

  11. Oscillatoria

  12. Spirulina and Oscillatoria

  13. Anabaena

  14. Nitrifying Bacteria • Carry out nitrogen fixation -converting nitrogen gas into ammonium which is then converted into nitrates.

  15. Domain Archae • Used to be classified with Bacteria but are now thought to be closer related to eukaryotes. • Extremophiles: found in extreme environments (acid pools, hot springs, hydrothermal vents, etc…) • Methanopyrus: methanogen living near hydrothermal vents • Common throughout the ocean not just extreme environments

  16. Unicellular Protista Kingdom ProtistaPart 1

  17. Kingdom Protista • Domain Eukarya • Eukaryotic cells: have a membrane bound nucleus • Most diverse kingdom • Algae: plant-like protists. • Protozoans: animal-like protists.

  18. Unicellular Algae • Single cell • Mostly photosynthetic, contain chloroplast. • Referred to as phytoplankton

  19. Phylum Bascillariophyta (a.k.a. Diatoms) • “golden algae”: carotenoid pigments (such as xanthophyll = yellow pigment) and chlorophyll a and c • Classified according to shape -Centricae: round -Pennatae: pen-shaped Some have spines; spines help with prevention of sinking by decreasing density • Oil droplet(lipids): helps with bouyancy; need to float near the surface to absorb sunlight

  20. Cell Structure • Contain nucleus, cytoplasm, plasma (cell)membrane, cell wall, chloroplast, endoplasmic reticulum, ribsomes, mitochondria, vacuole, lysosomes, golgi apparatus. • Cell wall: made of silica (main ingredient of glass). Has tiny pores to allow for exchange of materials. Also called frustule.

  21. Diatoms

  22. Reproduction • Asexual: fission; two frustules separate and each half secretes a new frustule to complete the formation of the new diatom. • Sexual: diatom develops into a male or female. Male releases sperm and enter the female diatom where it unites with an egg. The fertilized egg develops into a mature diatom.

  23. Blooms • Occur in favorable conditions such as adequate nutrition and light • Normally spring and fall due to overturn (upwellings) • Some contain a toxin called domoic acid that can build up in plankton eating organisms

  24. Diatomaceous Earth • Dead diatom frustules fall to ocean floor • Form a thick deposit of siliceous material • Biogenous sediment: a.k.a. diatomaceous ooze • Used in many industries; good for filtering (swimming pools, drinking water, clarifying beer) and a good mild abrasive (toothpaste and polishers)

  25. Ecological Importance • Basis of the food chain in both marine and freshwater environments • Consumed by tiny invertebrates called copepods who are eaten by fish • Shellfish consume diatoms by filtering them out of the water

  26. Phylum Dinophyta (a.k.a. dinoflagellates) • Unicellular • Planktonic • Two flagella • Cell wall made of plates of cellulose • Autotrophic and heterotrophic • Eyespot: detect light

  27. Flagella • Used in locomotion • One trails free • One wrapped around a groove along the middle of the cell

  28. Reproduction and Blooms • Almost exclusively asexual (fission) • Red Tide: caused by Gymnodinium (contains a red pigment) • Gonyaulax: produces a neurotoxin that causes paralytic shellfish poisoning that can lead to illness and death in fish and humans.

  29. Red Tide (Gymnodinium)

  30. Gymnodinium

  31. Some are bioluminescent :produces light (Pyrodinium) • Zooxanthellae: round, golden brown dinoflagellates that live in close association with a variety of animals -sponges -corals -sea anemones -giant clams

  32. Bioluminescent Dinoflagellate

  33. Protozoans • Animal-like • Structurally simple and very diverse • Most are unicellular • Heterotrophs • Some are also photosynthetic • Marine and freshwater as well as inside other organisms

  34. Phylum Granuloreticulsa (aka Foraminiferans) • Called forams • Marine • Have tests (shells) of calcium carbonate (CaCO3) • Pseudopodia: extension of cytoplasm that protrude through pores; trap food • Benthic or planktonic

  35. Foraminiferan Ooze • Calcareous ooze • Create limestone and chalk beds • Biogenous ooze

  36. Phylum Polycystina (aka Radiolarians) • Planktonic, marine • Delicate shells of glass with radiating spines • Needle-like pseudopodia that capture food • Radiolarian ooze

  37. Phylum Ciliophora (aka ciliates) • Protozoans with cilia • Cilia: hair-like and used in locomotion and feeding • Planktonic or benthic • Live on the gills of clams, intestines of sea urchins or on the skin of fish • Paramecium: most common freshwater forms

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