BIOLOGY 1424

Objectives: Chapters 16, 17, 18, 19  Exam 3

CHAPTER 16: PLANT NAMES AND CLASSIFICATION

1. Early man classified plants based upon their use to man or its impact upon man.  Later people grouped organisms based upon characteristics such as herbs, shrubs and trees.

2. Carolus Linnaeus was the great classifier. He designed the system of binomial nomenclature where each unique type of organism is given a unique two word name, the genus and specific epitaph (species).  He also designed a system for grouping and naming flowering plants.  This system was based on the number, structure and arrangement of floral parts.  Considerable weight is still given to floral parts in the grouping and naming of flowering plants.

3. A natural classification system is based on the evolutionary background and genetic relationships that exist between organisms.   The natural systems attempts to arrange organisms based upon their phylogeny.   Artificial systems of taxonomy are based on other factors that facilitate identification or are groupings of unknown lineage, thus they do not reflect the phylogeny of the organisms.

4. Lumpers group organisms upon a few relatively broad characteristics while splitters often group organisms based upon many narrowly defined variations.  Lumpers will recognize fewer species and taxa where splitters will have more species and taxa in their system.

5. Systematics is the study of phylogeny, taxonomy and classification.  Phylogeny is the evolutionary history of an organism. Classification is the grouping of organisms and taxonomy is the naming of the groups. A taxon is any taxonomic group or level.

6. The hierarchy of classification in order is:
Kingdom, Phylum (Division), Class, Order, Family, Genus, species

7.  Phenetics - System of classification based upon similarities and dissimilarities. Does not attempt to reconstruct evolutionary relationships and may be both a monophyletic and polyphyletic classification.

9. The five kingdoms used in today's taxonomic system and their characteristics are: 

• KINGDOM MONERA - Composed of unicellular prokaryotic organisms.  Prokaryotic cells do not have a defined nucleus or membrane bound organelles such as mitochondria or chloroplast. Ex. bacteria, blue green algae
• KINGDOM PROTISTA - Mostly unicellular organisms, some simple multicells, eukaryotic. Eukaryotic cells have a nucleus and membrane bound organelles.
• KINGDOM FUNGI - Multicellular, eukaryotic, heterotrophic organisms that carry on absorptive heterotrophic nutrition.
• KINGDOM PLANTAE - Multicellular, eukaryotic autotrophic organisms, plants.
• KINGDOM ANIMALIA - Multicellular, eukaryotic, heterotrophic organisms that carry on ingestive nutrition.

CHAPTER 17: KINGDOM MONERA

1. Review the general characteristics of the kingdom Monera.

• 3.5 billion years, oldest fossils found in Northwest Australia
• 3800 species
• Considerable range of habitat, nutrition and respiration.
• Can tolerate temperatures from far below 0^o to 360^o C near oceanic vents
• Can remain dormant for up to 10,000 years
• Prokaryotic
• Cell division by binary fission

2. The classification of Monerians is partially based upon shape and the arrangement of cells. Coccus bacteria are spherical, bacillus are rod or stick-like and spirillum are curved of coiled. Diplococcus and diplobacillus are aggregations of two cells; "strep" is a chain of cells and "staphlo" is an irregular cluster of cells. Additionally metabolism, cell wall structure, differential stains and other characteristics are considered in the classification of bacteria. Most bacteria are 0.2 to 2 micrometers in diameter.

3. Characteristics of the Subkingdom Archaebacteria. Archaebacteria have NO peptidoglycans in their cell walls but contain complex protein/lipid complexes. They are little understood because their metabolism is very different from that of true bacteria.  As a result many of them will not grow on commonly used nutrient agars used in the laboratory to grow bacteria.  Many of them grow in what we consider to be very harsh environments.   Examples:

• Thermoacidophiles - High temperature (70-75^o C) and low pH (.9)
• Methanogens - produce methane from the reduction of carbon dioxide.  Cow gut, ocean bottom, volcanic vents, produce 2 billion tons of methane yearly.
• Strict Halophiles - High salinity and 11.5 pH.

4. How do humans use Archaebacteria?

5. Characteristics of the Subkingdom Eubacteria.   Eubacteria are the true bacteria and are the familiar bacteria that we and most other organisms interact with the most.  The following is a list of characteristics and cell structures common to eubacteria.

• Typical shapes are Coccus, bacillus, spirillum.
• Most have cell walls that contain peptidoglycans which are composed of complex polysaccharides cross linked by polypeptides.
• Gram-positive - mostly peptidoglycans - stain blue or violet.
• Gram negative - contains peptidoglycans but also contains additional lipopolysaccharides and lipid proteins as wall material, has an outer membrane and a capsule or slime layer - stain red.
• Pili - involved in sexual reproduction and adhesion to surfaces
• Flagella - For locomotion.
• Nucleoid - region of the cell where the genetic material is located
• Some contain magnetite in their cytoplasm.
• DNA - loop, no histones, no mitosis

6. Bacterial nutrition and respiration

Heterotrophs

• Chemoheterotrophs - secure organic compounds (carbon source) from the environment, Types -parasites, saprobes, mutualistic symbionts

• Photoheterotrophs - use light as a source of energy (to synthesize ATP) but use C compounds from other organisms as a carbon source.

Autotrophs

• Photoautotrophs -

• Cyanobacteria - Photosynthesis like eukaryotes, produce 0₂ and contain chlorophyll "a"

• Photosynthetic bacteria - Bacteriochlorophyll - no 0₂ produced,   produce S₂ and use H₂S as a H₂ source.

Purple sulfur bacteria.
Green sulfur bacteria

• Chemoautotrophs

• Nitrifiers- oxidize nitrite or ammonia to nitrate.

• Others oxidize H₂, H₂S, S₂, Fe compounds and other substances.

7.    7. Recognize that bacteria are responsible for many animal diseases and to a lesser extent affect plants. Fungi are the primary pathogens that affect plants.

8.  8. True bacteria are useful to humans in the processing of foods, the production of various medicines, for environmental cleanup, genetic engineering and many other processes.

9.  9. Characteristics of the class Cyanobacteria (Blue-green algae).

• 1700 species, many are nitrogen fixers.
• Cell wall of peptidoglycans with muramic acid and diaminopimelic acids.
• Cell wall often covered by a slime layer
• Can exist in extreme environments
• Contain chlorophyll a, thus carry on photosynthesis as higher plants liberating oxygen from the hydrolysis of water.
• Heterocyst - enlarged cells involved in nitrogen fixation, contain the enzyme nitrogenase, do not contain photosynthetic pigments.
• Contain unique accessory pigments, phycobiliproteins organized into phycobilosomes.

10. Review the characteristics of Anabaena, Nostoc and Oscillatoria in your Unit 10 Lab unit.

11. Cyanobacteria are significant photosynthesizers, live in many rather hostile environments, are major nitrogen fixers, are autotrophic symbionts in many symbiotic associations and their ancestors were among the first photosynthetic organisms.

12. Recognize that virus are not cellular organisms, that they are minimally composed of a nucleic acid core and an outer shell of protein.

13. Virus are responsible for some plant diseases.

CHAPTER 18: KINGDOM PROTISTA, PART I

1. Characteristics of the Kingdom Protista.

• Unicellular to colonial to multicellular forms as large as the giant seaweeds, but in these multicellular forms tissue development is limited resulting in a relatively simple body plan. All are eukaryotic, but show considerable variation in nuclear membrane structure. Those with flagella and cilia have a 9+2 arrangement of microtubules.
• Most carry on Mitosis and Meiosis, but there is considerable variation in the process within this kingdom.
• Habitat Diversity: Many live in fresh water or the oceans as members of the floating plankton, others are bottom dwellers that attach to rocks or move about between the particles of sediment. Still others exist as filamentous photosynthetic algae or as multicellular forms that either grow attached to the substrate or are free floating. Other varieties are important members of the terrestrial community, mostly in the soil. Many other forms live in a variety of symbiotic relationships in marine, aquatic and terrestrial environments.
• Most are Aerobic, but some are anaerobic either living in anaerobic environment or have symbiotic aerobic bacteria in their cytoplasm.
• Nutrition is the most diverse of all kingdoms except the Monera. Nutrition ranges from autotrophic, to heterotrophic to mixotrophic, those that carry on both autotrophic and heterotrophic nutrition in the same cell depending upon the environment.
• Protistan diversity is based on how they feed and move.

3. Characteristics of the Division Bacillariophyta (Chrysophyta in the text).

• Most members of this group are unicellular and have overlapping cell walls of silica and an organic matrix.
• Centric - disk shaped, Pennate - elongate or cigar shaped.
• Many of these organisms store food as oils which assist them in floating since many are members of the marine and freshwater plankton.
• These organisms are responsible for a major portion of the photosynthetic out put of both marine and freshwater environments.
• Photosynthetic and accessory pigments are chlorophyll a and c, yellow and brown carotenoids and xanthrophylls.
• Most move by a peculiar gliding movement caused by chemical secretions.
• Reproduction is usually asexual, sexual reproduction is rare.

4. Characteristics of the Division Dinoflagellata.

• Most are unicellular with some being colonial. Several species are symbionts of reef building coral.
• Most are marine and are major photosynthetic food producers in the oceans.
• The cell wall is composed of overlapping cellulose plates.
• Two Flagella extend from a transverse and longitudinal groove in cell wall. The lashing of the flagella results in a whirling motion.
• Photosynthetic pigments are Chlorophyll a and c with a mixture of carotenoids, including peridinin which is unique to this phylum. Often have brownish chloroplast. A few are not photosynthetic.
• Cell division is unique with all division of the chromosomes occurring inside the nuclear envelope.
• Large populations of some species may be toxic, i.e. Red Tide.

5. Characteristics of the Division Euglenophyta.

• Photosynthetic pigments are Chlorophyll a and b, carotenoids and xanthrophyll. Some have no chloroplast and are heterotrophic, while others are heterotrophic in the absence of light.
• No true cell wall, but the cell surface is supported by flexible internal protein plates, the pellicle.
• Usually have from 1 to 3 apical flagella.
• Ex. Euglena sp.

6. Characteristics of the Division Chlorophyta; Green Algae.

• Members of this phylum range from unicellular to colonial to multicellular.
• Most are fresh water inhabitants, but some live in marine environments, some are terrestrial and others symbiotic.
• Chlorophyll a and b are the primary photosynthetic pigments as in land plants. Secondary pigments are also like those of terrestrial plants and it is thought that the green algae are the ancestors of terrestrial plants.
• Some enter into symbiotic associations with fungi forming lichens.
• Many have complex life cycles involving both sexual and asexual stages.
• Asexual reproduction includes mitotic cell division, fragmentation and zoospore production.
• Sexual reproduction is varied with gamete morphology being the distinguishing factor.

7. Review the characteristics of Chlamydomonas, Spirogyra, Volvox, Oedogonium and Ulva in Lab Unit 10.

8. Characteristics of the Division Phaeophyta; Brown Algae.

• Largest, Most Complex Protists
• All Multicellular
• Almost all are marine
• Photosynthetic pigments are chlorophyll a and c, with the brown carotenoid fucoxanthin.
• Cell walls contain cellulose and the commercially valuable compound algin.
• Most show an alternation of generations with either isomorphic or heteromorphic alternations of generations.

9. Characteristics of the Division Rhodophyta; Red Algae.

• Mostly found in tropical marine environments and most are multicellular
• Chlorophyll a, carotenoids, phycobillins and chlorophyll d in some
• Cell walls contain cellulose, agar and carageenan.
• Several species are calcareous, meaning that they deposit calcium carbonate and are important reef builders.
• Appear to have evolved from a symbiotic relationship between cyanobacteia and another prokaryote.
• Algae seem to have evolved along at least three different lines and chloroplast seem to have evolved at least three different times. These lines are the red line, the brown line and the green line.

10. Human and ecological relevance of the algae. Algae are used as food for man and livestock as well as providing numerous compounds used in processed foods, cosmetics and other commercial applications.  Algae are the plants of both fresh water and marine environments, thus they are the primary photosynthetic organisms in these environments.

CHAPTER 19:  KINGDOM PROTISTA, PART 2;
KINGDOM FUNGI AND LICHENS

1. Review the characteristics of the Kingdoms Protista and Fungi to distinguish the two.

2. Characteristics of the following fungus-like divisions from the Kingdom Protista.

A. Division Myxomycota - Plasmodial Slime Molds

• 500 species
• Body called a plasmodium which is a multinucleate mass of cytoplasm.
• Produce resistant bodies called sclerotia
• Most produce upright sporangia, meiosis produces haploid spores, spores fuse to form a diploid zygote. The zygote develops into a diploid plasmodium.

B. Division Acrasiomycota - Cellular Slime Molds

• Exist most of the time as amoeba-like unicells.
• 35 species.
• Saprophytic.
• Most are non-flagellated.
• During adverse conditions, under the influence of cAMP thousands of cells aggregate to form a multicellular pseudoplasmodium. A fruiting body develops which releases haploid spores.
• These spores become individual amoeba-like cells.

C. Division Oomycota - Water Molds

• More complex water molds.
• Saprophytic to parasitic.
• Coenocytic thallus with few septa.
• Diploid vegetative mycelium.
• Asexual reproduction by diploid zoospores.
• Sexual reproduction is oogamous involving an oogonium and antheridial hypha.
• Saprolegnia parasitica - Commonly attacks fish and fish eggs.
• Phytophthora infestans - Causative organism of late blight of potato and tomato.

4. List the characteristics of the Kingdom Fungi.

• Absorptive heterotrophic nutrition.
• Parasitic, saprophytic or mutualistic.
• Chitin cell walls.
• Do not produce flagellated cells.
• Sexual reproduction by conjugation.
• Hyphae (hypha sing.) - filaments from which the body of the fungus is composed.
• Mycelium - The total mass of hyphae or the total body of the fungus.
• Haustoria - Hyphae that are specialized for the penetration of host cells.
• Rhizoids - Hyphae that are specialized as root-like structures which anchor the fungus to the substrate.
• Stolons - Hyphae that spread over the surface of the substrate.
• Septate (divided by cross walls)and non septate (not divided by cross walls) hyphae.
• Vegetative thallus haploid.

5. Define sporangium and sporangiophore.

6. Characteristics of the Division Zygomycota.

• Coenocytic thallus with nonseptate hyphae.
• Important in the formation of endomycorrhizal associations with thousands of vascular plants.
• Asexual reproduction by an upright sporangiophore with a sac-like sporangium at the tip.
• Sexual reproduction by conjugation and zygospore formation, no fleshy fruiting bodies.
• Produce upright sporangiophores.
• Black bread mold - Rhizopus stolonifera

7. Review the characteristics of the Division Ascomycota.

• 30,000 species.
• Sac or cup fungi.
• Hemiascomycetes - unicellular, yeast.
• Euascomycetes - produce multicellular fruiting bodies.
• Perforated cross walls or septa.
• Produce dikaryotic hyphae during the life cycle.
• Sexual reproduction involves the formation of an ascocarp with elongate cells (asci, ascus singular)that produce ascospores.
• Three types of ascocarps are produced.

8. Review the characteristics of the Division Basidiomycota.

• 25,000 species.
• Some have very complex life cycles. i.e. rust, smuts
• Basidium - Club shaped terminal cell that produces sexual spores.
• Basidiospores - Sexual spores.
• Asexual spores are not conidia.
• Many have dolipore septa. These are septa with a pore that allows nuclei and other organelles to pass through. Unique to the Basidiomycota.
• Produce dikaryotic cells during the life cycle.
• Mushrooms, bracket and shelf fungi, smuts and rust, polyporous fungi.

In the sexual phase of the life cycle, basidiomycetes produce short lived haploid hyphae of the plus aand minus mating types. These hyphae soon undergo plasmogamy producing a dikaryotic mycelium that soon over grows the parental haploid mycelia. The haploid mycelium is long lived in some, such as mushrooms, and produces fruiting bodies year after year. When the environment is appropriate the dikaryotic mycelium forms a compact mass and swells producing the fruiting body. Terminal cells in the hypha of the fruiting body undergo karyogamy producing a diploid basidium.  Meiosis occurs producing four haploid nuclei. Each haploid nucleus buds from the surface of the basidium producing four haploid basidiospores, two plus and two minus.

9.   Review the characteristics of the Division Deuteromycota.

• 22,000 species.
• Saprophytic, parasitic and predatory.
• Many produce conidia and appear to be ascomycetes, but no sexual phase exist or has been identified in the life cycle.
• Fusarium wilt of tomato, potato and cotton.
• Athletes foot, ring worm

10. Ecological relevance of fungi.

• Fungi are saprophytic or parasitic. They play a major role in the recycling of nutrients in the ecosystem. (decomposers)
• Many are pathogenic, particularly on plants.
• All carry on absorptive nutrition.
• All except the Deuteromycota carry on sexual reproduction.
• All produce asexual spores.

11. List the characteristics of lichens and their ecological importance. Lichens are mutualistic symbiotic associations between a fungus (usually an ascomycete) and an alga (usually a green or a blue green).

• Very important as pioneer plants in very hostile habitats.
• 13,000 "species".
• Fungus provides structure, shelter, moisture and nutrients for the algal partner.
• The alga carries on photosynthesis thus producing food for itself and the fungus.
• Lichens are very sensitive to environmental pollution.
• Three types: