| Terms |
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ribozyme
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an enzymatic RNA molecule that catalyzes reactions during RNA splicing
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kelp
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a giant brown alga, up to 100 meters long, that forms extensive undersea forests
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extreme thermophiles
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microorganisms that thrive in hot environments (often 60-80 degrees C)
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in-group
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in a cladistic study of evolutionary relationships among taxa of organisms, the group of taxa that is actually being analyzed
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radiometric dating
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a method for determining the ages of rocks and fossils on a scale of absolute time, based on the half-life of radioactive isotopes
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phylogenetic trees
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Diagrams that trace evolutionary relationships as best as they can be determined
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endosymbiosis
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a process by which the mitochondria and chloroplasts evolved from symbiosis between small prokaryotic cells living inside larger ones
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clade
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each evolutionary branch in a cladogram
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Bacteria
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One of two prokaryotic domains, the other being the Archaea
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alternation of generations
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a life cycle in which there is both a multicellular diploid form, the sporophyte, and a multicellular haploid form, the gametophyte
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diplomonad
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most ancient lineage of eukaryotes, having two nuclei and multiple flagella
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protist
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a relatively simple eukaryote
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plate tectonics
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the forces w/in the earth that cause movements of the crust
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continental drift
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the major geographic factor that spatially distributed life and evolutionary episodes such as mass extinctions
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RNA world
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a hypothetical period in the evolution of life when RNA served as rudimentary genes and the sole catalytic molecules
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macroevolution
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evolutionary change on a grand scale, including origin of new taxonomic groups, adaptive radiation, and mass extinction
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five-kingdom system
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a system of taxonomic classifications based on kingdoms Monera, Plantae, Fungi, Animalia, and Protista
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Gondwana
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The southern land mass that came from the supercontinent Pangaea in the process of continental drift
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alga
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a photosynthetic, plantlike protist
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sporophyte
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the multicellular diploid form in organisms undergoing alternation of generations that results from a union or gametes
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chemoautotroph
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an organism that needs only carbon dioxide as a carbon source but that obtains energy by oxidizing inorganic substances
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red algae
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one of a group of marine, mostly multicellular, autotrophic protists which includes the reef-building coralline algae
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pseudopodium
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a cellular extension of amoeboid cells used in moving and feeding
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proetobacteria
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includes nitrogen-fixing Rhizobium and plant tumor-inducing Agrobacterium
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gram-positive bacteria
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Bacteria less likely to cause disease, posses thick layer of peptidoglycan
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Pangaea
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the supercontinent formed near the end of the paleozoic era when plate movements brought all the land masses of earth together
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gametophyte
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the multicellular haploid form in organisms undergoing alternation of generations
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stromatolites
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rock made of banded domes of sediment in which are the most ancient forms of life: prokaryotes dating back 3.5 billion years
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heterotrophs
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an organism that obtains organic food molecules by eating other organisms or their by-products
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amoeba
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a type of protist characterized by great flexibility and the presence of pseudopodia
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extreme halophiles
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microorganisms that live in unusually highly saline environments such as the Great Salt Lake or the Dead Sea
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cladogram
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a dichotomous phylogenic tree that branches repeatedly
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membrane infolding
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the process by which a eukaryotic cell's endomembrane system evolved from the plasma membrane of a prokaryotic cell
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phylogeny
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the evolutionary history of a species or group of related species
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gram stain
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identifies bacteria as "positive" or "negative"
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pathogen
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a disease-causing organism
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analogy
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the similarity of structure between two species that are not closely related; attributable to convergent evolution
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Archaea
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one of two prokaryotic domains, the other being the Bacteria
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geologic record
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Grouped into four eras: Precambrian, Paleozoic, Meozoic, and Cenozoic
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amoebozoan
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clade of protists including amoebas, plasmodial slime molds, and cellular slime molds
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pilus
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a surface appendage in certain bacteria that functions in adherence and the transfer of DNA during conjugation
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methanogens
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microorganisms that obtain energy by using carbon dioxide to oxidize hydrogen, producing methane as a waste product
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euglenozoan
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diverse clade that includes trypanosomes and euglenas
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genus
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a taxonomic category above the species level, designated by the first word of a species' binomial Latin name
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molecular clocks
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evolutionary timing methods based on the observation that at least some regions of genomes evolve at constant rates
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domain
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a taxonomic category above the kingdom level; Archaea, Bacteria, and Eukarya
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shared primitive characters
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homologous features found in members of a lineage and also in the ancestors of the lineage; ancestral features
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plasmoidial slime mold
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a type of protist that has amoeboid cells, flagellated cells, and an amoeboid plasmodial feeding stage in its life cycle
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autotroph
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an organism that obtains organic food molecules w/out eating other organisms or substances derived from other organisms
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convergent evolution
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The independent development of similarity between species as a result of their having similar ecological roles and selection pressures
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dinoflagellate
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a unicellular photosynthetic alga w/two flagella situated in perpendicular grooves in cellulose plates covering the cell
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exaptation
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a structure that evolves and functions in one environmental context but that can perform additional functions in a new environment
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taxon
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the named taxonomic unit at any given level
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spirochetes
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helical bacteria that cause syphilis and Lyme disease
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endotoxin
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a component of the outer membranes of certain gram-negative bacteria responsible for generalized symptoms of fever and ache
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bioremediation
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the use of living organisms to detoxify and restore polluted and degraded ecosystems
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peptidoglycan
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type of polymer in bacterial cell walls consisting of modified sugars cross-linked by short polypeptides
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exotoxin
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a toxic protein secreted by a bacterial cell that produces specific symptoms even in the absence of bacterium
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cladistics
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the scientific search for clades, taxonomic groups composed of an ancestor and all its descendants
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evo-devo
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the research field wherein scientists intertwine evolutionary biology and developmental biology
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green algae
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photosynthetic protists that include unicellular, colonial, and multicellular species; closely related to true plants
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shared derived characters
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Homologous features that have changed form a primitive (ancestral) condition and that are unique to an evolutionary lineage
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diatom
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a unicellular photosynthetic alga w/a unique, glassy cell wall containing silica
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phylum
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a taxonomic category divided into classes
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photoautotroph
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an organism that harnesses light energy to drive the synthesis of organic compounds from carbon dioxide
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systematics
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the study of biological diversity in an environmental context, encompassing taxonomy and reconstruction of phylogenetic history
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binomial
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the two-part latinized name of a species, consisting of genus and specific epithet
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coccus
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a spherical prokaryotic cell
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order
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in classification, the taxonomic category above family
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photoheterotroph
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an organism that uses light to generate ATP but that must obtain carbon in organic form
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endospore
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a thick-coated, resistant cell produced w/in a bacterial cell exposed to harsh conditions
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Lyme disease
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a debilitating human disease caused by a spirochete bacterium; characterized at first by a red rash
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bacillus
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a rod-shaped prokaryotic cell
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chemoheterotroph
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an organism that must consume organic molecules for both energy and carbon
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alveolate
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clade of protists including dinoflagellates, spicomplexans, and ciliates
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monophyletic
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pertaining to a taxon derived from a single ancestral species that gave rise to no species in any other taxa
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stramenopiles
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clade of protists w/"hairy" flagellum includes water molds, diatoms, and brown algae
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brown algae
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One of a group of marine, multicellular, autotrophic protists, the most common type of seaweed
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cyanobacteria
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photosynthetic, oxygen-producing bacteria (formerly known as blue-green algae)
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family
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in classification, the taxonomic category above genus
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out-group
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a species or group of species that is closely related to the group of species being studied
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apicomplexan
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one of a group of parasitic protozoans, some of which cause human diseases
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symbiosis
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an ecological relationship between organisms of two different species that live together in direct contact
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ciliate
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a type of protozoan that moves by means of cilia
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cellular slime mold
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a type of protist that has unicellular amoeboid cells and multicellular reproductive bodies in its life cycle
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class
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in classification, the taxonomic category above order
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Laurasia
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the northern land mass that came from the supercontinent Pangaea in the process of continental drift
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parsimony
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in scientific studies, the search for the least complex explanation for an observed phenomenon
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