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51 Cards in this Set
- Front
- Back
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Evolution
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The change, over time, in the heritable characteristics of organisms, resulting in the alteration of the structure and function, and leading to the diversity of living forms present today.
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Adaptation
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Features of structure and function which suit and organism to its environment.
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Natural Selection
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Charles Darwin recognized that individuals with adaptations suiting them to their environ. are more likely to survive and produce offspring. Advantageous traits passed to their progeny are preserved. Individuals with less favourable traits do not survive or produce fewer offspring and these characteristics disappear from the population as a whole.
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Descent with Modification
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Changes arising through natural selection could lead to alteration of a population, and eventually to the emergence of new species. All organisms have arisen through descent from some common ancestor. As descendants of that early ancestor dispersed into new habitats over millions of years they accumulated diverse adaptations fitting them to varying ways of life.
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Taxonomy
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Branch of science concerned with naming, describing and classifying organisms. Putting organisms into categories based on specific characteristics.
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Taxonomic Hierarchy (Levels)
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Begins with Domain followed by Kingdom, Phylum, Class, Order, Family, Genus and Species Level.
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Taxon
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A NAMED level of classification in the taxonomic hierarchy. Eg. Kingdom is a level of classification but Animalia is a taxon; phylum is a level of classification but Chordata is a taxon.
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Domain
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Another level of the taxonomic hierarchy which is now the level that has the greatest diversity of organisms. The organisms assigned to it are classified into a variety of kingdoms. Eg. A leopard is in the kingdom Animalia which is in the domain Eukarya.
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Binomial System of Nomenclature
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Ea. Species is assigned a unique two part name. The first name is the genus name to which the species belongs. The second is a specific term which can only be used once in that genus. Both names are Latin. The genus name is alway capitalized while the species name is not. Both names must be underlined when hand written and italicized when typed.
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Dichotomous Key
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How the classification system, based on selected characteristics, can be organized into a tool to identify organisms. It is a series of paired choices in a specific sequence.
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Artificial Classification System
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Sole purpose is to act as an aid to find, identify and describe the organisms with the best criteria in groups to allow easy identification.
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Natural Classification System
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The members of a given taxon must share a more recent ancestor with eachother, and all of the descendants of that ancestor should be included in the group.
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Phylogeny
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The evolutionary history of a species or group of related species.
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Systematics
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A scientific discipline focused on classifying organisms and determining their evolutionary relationships. Provides the categories used to construct the phylogenetic tree.
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Clades
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Relative to the taxon (named level of classification in the taxonomic hierarchy). Taxon may be called a clade IF all the members included in the taxon have descended from a single ancestor and if all descendants of that ancestor are present in the group.
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Phylogenetic Tree
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A branching diagram that represents a hypothesis about the evolutionary history of a group of organisms.
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Domain Bacteria
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Cell Type: Prokaryotic. Number of Cells: unicellular or colonial. Mode of Nutrition: heterotrophic or autotrophic.
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Domain Archaea
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Cell Type: Prokaryotic. Number of Cells: unicellular or colonial. Mode of Nutrition: heterotrophic or autotrophic.
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Domain Eukarya: The Protists (includes several kingdoms)
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Cell Type: Eukaryotic. Number of Cells: Animal-like protists-All unicellular; Plant-like protists-unicellular and colonial phytoplankton, multicellular seaweeds; Fungus-like protists- unicellular and multicellular stages. Mode of nutrition: heterotrophic or autotrophic.
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Domain Eukarya: Kingdom Animalia
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Cell Type: Eukaryotic. Number of Cells: Multicellular. Mode of Nutrition: heterotrophic by ingestion.
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Domain Eukarya: Kingdom Fungi
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Cell Type: Eukaryotic. Number of Cells: Multicellular. Mode of Nutrition: Heterotrophic by absorption.
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Domain Eukarya: Kingdom Plantae
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Cell Type: Eukaryotic. Number of Cells: Multicellular. Mode of Nutrition: Autotrophic by photosynthesis.
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Bacteria (Characteristics/Criteria)
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Cell Configuration: Prokaryotic. Distribution in Ecosystems: Ubiquitous. Nuclear Membrane: Absent. Number of Molecules of Hereditary Material: 1. Chromosome Shape: Circular. Membrane-bound organelles: Absent. Cytoplasmic Streaming: Negative. Live in Absence of Oxygen: Some. Cell Membrane Lipids: Unbranched. Protein Synthesis starts with: N-formyl methionine. Sensitive to penicillin: Yes. Live in extreme environments: Few. Peptidoglycan in cell wall: Yes.
Protein synthesis inhibited by streptomycin and chloramphenicol antibiotics: Yes. |
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Archaea (Characteristics/Criteria)
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Cell Configuration: Prokaryotic. Distribution in Ecosystems: Ubiquitous. Nuclear Membrane: Absent. Number of molecules of Hereditary Material: 1. Chromosome Shape: Circular. Membrane-bound organelles: Absent. Cytoplasmic streaming: Yes. Live in absence of Oxygen: Some. Cell membrane lipids: Branched. Protein synthesis: methionine. Sensitive to penicillin: No. Live in extreme environments: Many. Peptidoglycan in Cell Wall: No. Protein synthesis inhibited by streptomycin and chloramphenicol antibiotics: No.
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Eukarya (Characterisics/Criteria)
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Cell Configuration: Eukaryotic. Distribution in ecosystems: limited. Nuclear membrane: present. Number of molecules of hereditary material: >1. Chromosome shape: Linear. Membrane-bound organelles: present. Cytoplasmic streaming: Yes. Live in absence of oxygen: No. Cell membrane lipids: Unbranched. Protein synthesis starts with: methionine. Sensitive to penicillin: No. Live in extreme environments: No. Peptidoglycan in cell wall: No. Protein synthesis inhibited by streptomycin and chloramphenicol antibiotics.
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Distinguishing Characteristics of the Protists
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Eukaryotic Organisms. Most unicellular or colonial, multicellular group (seaweeds). Found in water. Many types of protists without a common ancestor- therefore cannot by classified in a single taxon.
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Plankton
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Communities of organisms, mostly microscopic, that drift passively or swim weakly near the water surface.
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Phytoplankton
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Includes the unicellular, plant-like protists, and forms the base for all marine, and freshwater foor chains.
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Zooplankton
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Includes the animal-like protists, that are microscopic organisms which feed on the phytoplankton and/or other members of the zooplankton. Makes up a large portion of the food source for larger, multicellular, heterotrophic organisms Ie. Filter feeders.
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Animal-like (protozoan) Protists
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Unicellular organisms that are heterotrophic and feed by ingestion. Including free-living species that eat bacteria, other unicellular eucaryotes, and/or dead organic material. As well as species that live in symbiotic(mutualistic or parasitic) associations with other organisms. Eg. Paramecium.
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Fungus-like Protists
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Heterotrophic, have a cell wall at some point in their life (although the wall is NOT made of chitin- therefore not true fungi). This category includes Slime Molds and Water Molds.
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Cellular Slime Molds
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Alternate between unicellular and multicellular stages. They feed as individual, single celled amoeba until a lack of food (bacteria) causes either a group of cells or a single cell to secrete a chemical called acrasis, to attract surrounding amoebas. They move to a central point and aggregate to form a multicellular organism. A tip forms on the mass of cells and the cells undergo differentiation. Some cells form a rigid, internal stalk while the remainder become spores on top of the top of the stalk. In Dictyostelium, there is a single spherical mass of spores at the tip of a mature fruiting body. In Polyphondylium there are whorls of small fruiting bodies in addition to an apical spore mass on the central stalk. The spores become dispersed and germinate to release more individual amoebae.
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Plasmodial Slime Molds
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Usually bright yellow or orange and alternate between uninucleate and multinucleate stages. Pairs of single-celled amoeba join and undergo nuclear division without cytoplasmic division- producing a single, large mass of cytoplasm with many nuclei.
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Plant-like Protists (algae)
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All protists in this category are photo-autotrophic, including several groups of algae: green algae, red algae, brown algae golden algae as well as diatoms, dinoflagellates etc. Algae includes unicellular photoautotrophs (phytoplankton).
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Brown Seaweeds (Kelp)
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More complex structured, multi-cellular, plant-like protists. Including a root-like 'holdfast' that anchors the algae to rocks, a stem-like 'stipe' and leaf-like blades. Despite this complex body form, they have little cellular specialization. Ie. not specialized cells or tissues for transport of water, minerals or organic nutrients throughout the multicellular body. Therefore, the structures are not considered to be 'true' roots, stems and leaves.
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Members of Kingdom Fungi
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Molds, mushrooms, yeasts--and also lichens, organisms composed of a fungus and an algae growing in close association.
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Distinguishing Characteristics of Fungi
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Multicellular, heterotrophic organisms by absorption. Characteristics 1. Multicellular body of hyphae. 2. Heterotrophic with absorptive nutrition. 3. Reproduction by spores. 4 cell wall containing chitin.
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Multicellular Body of Hyphae
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The fungal body is a network of tiny filaments. Tightly packed they form the mycelium. The filaments infiltrate their food sourse.
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Mycelium
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Tightly packed hyphae.
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Yeasts
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Unicellular fungi that evolved from multicellular ancestors related to the present-day mushrooms such as truffles and morels.
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Heterotrophic with Absorptive Nutrition.
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The body form of the fungus maximizes the surface area to volume ratio between the fungal cells and the food source. The cells secrete hydrolytic enzymes into the surrounding environment to digest the large, complex molecules to smaller, organic molecules. The hyphae arrangement allow each cell to be close to it's food. The smaller molecules can then be absorbed directly by each cell. Fungi vary on the basis of their nutrient source: Saprotrophic (saprobic) fungi, Parasitic fungi, and Mutualistic Fungi.
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Saprotrophic (saprobic) Fungi
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Digest and absorb organic molecules from dead matter. Fungi which digest fallen logs, animal waste, dead plant and animal tissues, garbage etc. Eg. Mushrooms and bread mold.
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Parasitic Fungi
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Digest and absorb organic molecules from a live host. Eg. those responsible for the following human infections: Athlete's foot, some lung infections, ringworm etc.
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Mutualistic Fungi
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Obtain organic molecules from another organism with which it shares a mutually beneficial symbiosis. Eg. Lichen and mycorrhizae.
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Reproduction by Spores
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Single cells which are released from the parent body, dispersed by wind or water and under appropriate conditions germinate to produce a new mycelium. Eg. Mushroom.
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Cell Wall Structure
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The cell wall surrounding the cells of the hyphae contains chitin- NOT cellulose as found in plant cell walls.
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Chitin
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A hard material which is also deposited in the exoskeleton of insects and other arthropods for additional strength.- Found in the cell walls of fungi as opposed to cellulose found in the cell walls of plants.
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Mutualism
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An ecological relationship involving two different species living in close association wither each other- BOTH benefiting from the association.
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Lichens
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Classic example of mutualism. One species is a fungus, and the other is photosynthetic algae (Either a green algae-(protist) or a cyanobacterium (domain bacteria)) The algeal cells sit inside the protective layers of fungal hyphae. In most, the fungus is a species that cannot live without the algae from which it absorbs sugars and other nutrients. The algae receive water, mineral and protection from the fungi.
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Major Human Uses for Fungi
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-Production of antibiotics. -Leavening baked goods (bakers yeast). -Production of wine, beer, sake and other alcoholic beverages (relative of baker's yeast). -Flavoring cheeses and other food products. -Food
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Decomposer
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A saprotrophic organism whose actions on dead matter result in the release of inorganic nutrients. In inorganic nutrients (eg. carbon dioxide and ammonia) are then available for use by other organisms (eg. plants).
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