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phylum : the category in the taxonomic classification system that falls within kingdom and includes classes
https://openstax.org/books/concepts-biology/pages/12-key-terms
rooted : describing a phylogenetic tree with a single ancestral lineage to which all organisms represented in the diagram relate
https://openstax.org/books/concepts-biology/pages/12-key-terms
shared ancestral character : a character on a phylogenetic branch that is shared by a particular clade
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shared derived character : a character on a phylogenetic tree that is shared only by a certain clade of organisms
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sister taxa : two lineages that diverged from the same branch point
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species : the most specific category of classification
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systematics : the science of determining the evolutionary relationships of organisms
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taxon : a single level in the taxonomic classification system
https://openstax.org/books/concepts-biology/pages/12-key-terms
taxonomy : the science of classifying organisms
https://openstax.org/books/concepts-biology/pages/12-key-terms
Prokaryotes existed for billions of years before plants and animals appeared. Microbial mats are thought to represent the earliest forms of life on Earth, and there is fossil evidence, called stromatolites, of their presence about 3.5 billion years ago. During the first 2 billion years, the atmosphere was anoxic and on...
https://openstax.org/books/concepts-biology/pages/13-chapter-summary
Prokaryotes (domains Archaea and Bacteria) are single-celled organisms lacking a nucleus. They have a single piece of circular DNA in the nucleoid area of the cell. Most prokaryotes have cell wall outside the plasma membrane. Bacteria and Archaea differ in the compositions of their cell membranes and the characteristic...
https://openstax.org/books/concepts-biology/pages/13-chapter-summary
Bacterial cell walls contain peptidoglycan. Archaean cell walls do not have peptidoglycan. Bacteria can be divided into two major groups: Gram-positive and Gram-negative. Gram-positive organisms have a thick cell wall. Gram-negative organisms have a thin cell wall and an outer membrane. Prokaryotes use diverse sources ...
https://openstax.org/books/concepts-biology/pages/13-chapter-summary
Infectious diseases caused by bacteria remain among the leading causes of death worldwide. The excessive use of antibiotics to control bacterial infections has resulted in resistant forms of bacteria being selected. Foodborne diseases result from the consumption of contaminated food, pathogenic bacteria, viruses, or pa...
https://openstax.org/books/concepts-biology/pages/13-chapter-summary
The first eukaryotes evolved from ancestral prokaryotes by a process that involved membrane proliferation, the loss of a cell wall, the evolution of a cytoskeleton, and the acquisition and evolution of organelles. Nuclear eukaryotic genes appear to have had an origin in the Archaea, whereas the energy machinery of euka...
https://openstax.org/books/concepts-biology/pages/13-chapter-summary
Protists are extremely diverse in terms of biological and ecological characteristics due in large part to the fact that they are an artificial assemblage of phylogenetically unrelated groups. Protists display highly varied cell structures, several types of reproductive strategies, virtually every possible type of nutri...
https://openstax.org/books/concepts-biology/pages/13-chapter-summary
The process of classifying protists into meaningful groups is ongoing, but genetic data in the past 20 years have clarified many relationships that were previously unclear or mistaken. The majority view at present is to order all eukaryotes into six supergroups. The goal of this classification scheme is to create clust...
https://openstax.org/books/concepts-biology/pages/13-chapter-summary
Fungi are eukaryotic organisms that appeared on land over 450 million years ago. They are heterotrophs and contain neither photosynthetic pigments such as chlorophylls nor organelles such as chloroplasts. Because they feed on decaying and dead matter, they are saprobes. Fungi are important decomposers and release essen...
https://openstax.org/books/concepts-biology/pages/13-chapter-summary
The divisions of fungi are the Chytridiomycota, Zygomycota, Ascomycota, Basidiomycota, and Glomeromycota.
https://openstax.org/books/concepts-biology/pages/13-chapter-summary
Fungi establish parasitic relationships with plants and animals. Fungal diseases can decimate crops and spoil food during storage. Compounds produced by fungi can be toxic to humans and other animals. Mycoses are infections caused by fungi. Superficial mycoses affect the skin, whereas systemic mycoses spread through th...
https://openstax.org/books/concepts-biology/pages/13-chapter-summary
Fungi have colonized all environments on Earth but are most often found in cool, dark, moist places with a supply of decaying material. Fungi are important decomposers because they are saprobes. Many successful mutualistic relationships involve a fungus and another organism. They establish complex mycorrhizal associati...
https://openstax.org/books/concepts-biology/pages/13-chapter-summary
Fungi are important to everyday human life. Fungi are important decomposers in most ecosystems. Mycorrhizal fungi are essential for the growth of most plants. Fungi, as food, play a role in human nutrition in the form of mushrooms and as agents of fermentation in the production of bread, cheeses, alcoholic beverages, a...
https://openstax.org/books/concepts-biology/pages/13-chapter-summary
Amoebozoa : the eukaryotic supergroup that contains the amoebas and slime molds
https://openstax.org/books/concepts-biology/pages/13-key-terms
anaerobic : refers to organisms that grow without oxygen
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anoxic : without oxygen
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Archaeplastida : the eukaryotic supergroup that contains land plants, green algae, and red algae
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Ascomycota : (sac fungi) a division of fungi that store spores in a sac called ascus
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basidiomycota : (club fungi) a division of fungi that produce club shaped structures, basidia, which contain spores
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biofilm : a microbial community that is held together by a gummy-textured matrix
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bioremediation : the use of microbial metabolism to remove pollutants
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Black Death : a devastating pandemic that is believed to have been an outbreak of bubonic plague caused by the bacteriumYersinia pestis
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botulism : a disease produce by the toxin of the anaerobic bacteriumClostridium botulinum
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capsule : an external structure that enables a prokaryote to attach to surfaces and protects it from dehydration
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Chromalveolata : the eukaryotic supergroup that contains the dinoflagellates, ciliates, the brown algae, diatoms, and water molds
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Chytridiomycota : (chytrids) a primitive division of fungi that live in water and produce gametes with flagella
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commensalism : a symbiotic relationship in which one member benefits while the other member is not affected
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conjugation : the process by which prokaryotes move DNA from one individual to another using a pilus
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cyanobacteria : bacteria that evolved from early phototrophs and oxygenated the atmosphere; also known as blue-green algae
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endosymbiosis : the engulfment of one cell by another such that the engulfed cell survives and both cells benefit; the process responsible for the evolution of mitochondria and chloroplasts in eukaryotes
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epidemic : a disease that occurs in an unusually high number of individuals in a population at the same time
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Excavata : the eukaryotic supergroup that contains flagellated single-celled organisms with a feeding groove
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extremophile : an organism that grows under extreme or harsh conditions
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foodborne disease : any illness resulting from the consumption of contaminated food, or of the pathogenic bacteria, viruses, or other parasites that contaminate food
https://openstax.org/books/concepts-biology/pages/13-key-terms
Glomeromycota : a group of fungi that form symbiotic relationships with the roots of trees
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Gram-negative : describes a bacterium whose cell wall contains little peptidoglycan but has an outer membrane
https://openstax.org/books/concepts-biology/pages/13-key-terms
Gram-positive : describes a bacterium that contains mainly peptidoglycan in its cell walls
https://openstax.org/books/concepts-biology/pages/13-key-terms
hydrothermal vent : a fissure in Earth’s surface that releases geothermally heated water
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hypha : a fungal filament composed of one or more cells
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lichen : the close association of a fungus with a photosynthetic alga or bacterium that benefits both partners
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microbial mat : a multi-layered sheet of prokaryotes that may include bacteria and archaea
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mold : a tangle of visible mycelia with a fuzzy appearance
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MRSA : (methicillin-resistantStaphylococcus aureus) a very dangerousStaphylococcusaureusstrain resistant to antibiotics
https://openstax.org/books/concepts-biology/pages/13-key-terms
mycelium : a mass of fungal hyphae
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mycorrhiza : a mutualistic association between fungi and vascular plant roots
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mycosis : a fungal infection
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Opisthokonta : the eukaryotic supergroup that contains the fungi, animals, and choanoflagellates
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pandemic : a widespread, usually worldwide, epidemic disease
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parasite : an organism that lives on or in another organism and feeds on it, often without killing it
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pathogen : an organism, or infectious agent, that causes a disease
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pellicle : an outer cell covering composed of interlocking protein strips that function like a flexible coat of armor, preventing cells from being torn or pierced without compromising their range of motion
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peptidoglycan : a material composed of polysaccharide chains cross-linked to unusual peptides
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phototroph : an organism that uses energy from sunlight
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plastid : one of a group of related organelles in plant cells that are involved in the storage of starches, fats, proteins, and pigments
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polyphyletic group : group of organisms that is of mixed evolutionary origin
https://openstax.org/books/concepts-biology/pages/13-key-terms
pseudopeptidoglycan : a component of some cell walls of Archaea
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Rhizaria : the eukaryotic supergroup that contains organisms that move by amoeboid movement
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saprobe : an organism that feeds on dead organic material
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septum : the cell wall division between hyphae
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stromatolite : a layered sedimentary structure formed by precipitation of minerals by prokaryotes in microbial mats
https://openstax.org/books/concepts-biology/pages/13-key-terms
thallus : a vegetative body of a fungus
https://openstax.org/books/concepts-biology/pages/13-key-terms
transduction : the process by which a bacteriophage moves DNA from one prokaryote to another
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transformation : a mechanism of genetic change in prokaryotes in which DNA present in the environment is taken into the cell and incorporated into the genome
https://openstax.org/books/concepts-biology/pages/13-key-terms
yeast : a general term used to describe unicellular fungi
https://openstax.org/books/concepts-biology/pages/13-key-terms
Zygomycota : (conjugated fungi) the division of fungi that form a zygote contained in a zygospore
https://openstax.org/books/concepts-biology/pages/13-key-terms
Land plants evolved traits that made it possible to colonize land and survive out of water. Adaptations to life on land include vascular tissues, roots, leaves, waxy cuticles, and a tough outer layer that protects the spores. Land plants include nonvascular plants and vascular plants. Vascular plants, which include see...
https://openstax.org/books/concepts-biology/pages/14-chapter-summary
Seedless nonvascular plants are small. The dominant stage of the life cycle is the gametophyte. Without a vascular system and roots, they absorb water and nutrients through all of their exposed surfaces. There are three main groups: the liverworts, the hornworts, and the mosses. They are collectively known as bryophyte...
https://openstax.org/books/concepts-biology/pages/14-chapter-summary
Vascular systems consist of xylem tissue, which transports water and minerals, and phloem tissue, which transports sugars and proteins. With the vascular system, there appeared leaves—large photosynthetic organs—and roots to absorb water from the ground. The seedless vascular plants include club mosses, which are t...
https://openstax.org/books/concepts-biology/pages/14-chapter-summary
Gymnosperms are heterosporous seed plants that produce naked seeds. They appeared in the Carboniferous period (359–299 million years ago) and were the dominant plant life during the Mesozoic era (251–65.5 million years ago). Modern-day gymnosperms belong to four divisions. The division Coniferophyta—the conifersâ...
https://openstax.org/books/concepts-biology/pages/14-chapter-summary
Angiosperms are the dominant form of plant life in most terrestrial ecosystems, comprising about 90 percent of all plant species. Most crop and ornamental plants are angiosperms. Their success results, in part, from two innovative structures: the flower and the fruit. Flowers are derived evolutionarily from modified le...
https://openstax.org/books/concepts-biology/pages/14-chapter-summary
Angiosperms’ life cycles are dominated by the sporophyte stage. Double fertilization is an event unique to angiosperms. The flowering plants are divided into two main groups—the monocots and eudicots—according to the number of cotyledons in the seedlings. Basal angiosperms belong to a lineage older than monocots ...
https://openstax.org/books/concepts-biology/pages/14-chapter-summary
anther : a sac-like structure at the tip of the stamen in which pollen grains are produced
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Anthophyta : the division to which angiosperms belong
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apical meristem : the growing point in a vascular plant at the tip of a shoot or root where cell division occurs
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basal angiosperms : a group of plants that probably branched off before the separation of monocots and eudicots
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calyx : the whorl of sepals
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carpel : the female reproductive part of a flower consisting of the stigma, style, and ovary
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club moss : the earliest group of seedless vascular plants
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cone : the ovulate strobilus on gymnosperms that contains ovules
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conifer : the dominant division of gymnosperms with the most variety of species
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corolla : the collection of petals
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cotyledon : the one (monocot) or two (dicot) primitive leaves present in a seed
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cycad : a division of gymnosperms that grow in tropical climates and resemble palm trees
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dicot : a group of angiosperms whose embryos possess two cotyledons; also known as eudicot
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diplontic : describes a life cycle in which the diploid stage is the dominant stage
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eudicots : a group of angiosperms whose embryos possess two cotyledons; also known as dicot
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fern : a seedless vascular plant that produces large fronds; the most advanced group of seedless vascular plants
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filament : the thin stalk that links the anther to the base of the flower
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gametangium : (plural: gametangia) the structure within which gametes are produced
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gametophyte : the haploid plant that produces gametes
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gingkophyte : a division of gymnosperm with one living species, theGingko biloba, a tree with fan-shaped leaves
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gnetophyte : a division of gymnosperms with varied morphological features that produce vessel elements in their woody tissues
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