Biology 2 Flashcards
What is speciation?
[Speciation is] the evolution of two or more distinct species from a single ancestral species.
What is a species?
[A species is] an evolutionary independent population or group of populations. Generally, distinct from other species in appearance, behavior, habitat, ecology, genetic characteristics and so on.
What is the biological species concept?
[The biological species concept is] the definition of a species as a population or group of populations that are reproductively isolated from other groups. Members of a species have the potential to interbreed in nature to produce viable, fertile offspring but cannot interbreed successively with members of other species.
What is prezygotic isolation
[Prezygotic isolation is] reproductive isolation resulting from any of the several mechanisms that prevent individuals from two different species from mating.
What is postzygotic isolation?
[Postzygotic isolation is] reproductive isolation resulting from mechanisms that operate after the mating of two individuals from different species occurs. The most common mechanisms are the death of hybrid embryos or reduced fitness of hybrids.
What is the morphospecies concept?
[The morphospecies concept is] the definition of a species as a population or group of populations that have measurably different anatomical features from other groups.
What are polymorphic species?
[A polymorphic species is] a species that has two or more distinct phenotypes in the same interbreeding population at the same time.
What are cryptic species?
[Cryptic species are] species that cannot be easily distinguished from similar species by identifiable morphological traits.
What is the phylogenetic species concept?
[The phylogenetic species concept is] the definition of a species as the smallest monophyletic group in a phylogenetic tree.
What is a subspecies?
[A subspecies is] a population that has distinctive traits and some genetic differences relative to other populations of the same species but that is not distinct enough to be classified as a separate species.
What is allopatry?
[Allopatry is] the condition in which two or more populations live in different geographic areas.
What allopatric speciation?
[Allopatric speciation, or geographic isolation, is] the speciation that occurs when populations of the same species become geographically isolated, often because of dispersal or vicariance.
What is vicariance?
[Vicariance is] the physical splitting of a population into smaller, isolated populations by a geographic barrier.
What is biogeography?
[Biogeography is] the study of how species and populations are distributed geographically.
What is sympatry?
[Sympatry is] a condition in which two or more populations live in the same geographic area, or close enough to permit interbreeding.
What is sympatric speciation?
[Sympatric speciation is] the divergence of populations living within the same geographic area into different species as the result of their genetic, not physical, isolation.
What is polyploidy?
[Polyploidy is] the state of having more than two full sets of chromosomes, either from the same species or from different species.
What is autopolyploidy?
[Autoploidy is] the state of having more than two full sets of chromosomes because of a mutation that doubled the chromosome number.
What is allopolyploidy?
[Alloploidy is] the state of having more than two full sets of chromosomes because of hybridization between different species.
What is reinforcement?
[Reinforcement,] in evolutionary biology, is the natural selection of traits that prevent interbreeding between diverged species.
What is hybrid zone?
[A hybrid zone is] a geographic area where interbreeding occurs between two species, sometimes producing fertile offspring.
What is phylogeny?
[A phylogeny is] the evolutionary history of a species.
What is a phylogenetic tree?
[A phylogenetic tree is] a branching diagram that depicts the evolutionary relationships among species of taxa.
What is the tree of life?
[The tree of life is] the phylogenetic tree that includes all organisms.
What are branches?
[A branch is] part of a phylogenetic tree that represents populations through time.
What are nodes?
[In the phylogenetic tree, nodes are] the point where two branches diverge, representing the point in time when an ancestral group split into two or more descendant groups.
What are sister groups?
[Sister groups are] two or more lineages that share a recent common ancestor at the node where branches meet.
What are tips?
[Tips, or terminal nodes, are] the endpoint of a branch; they represent a living or extinct group of genes, species, families, phyla, or other taxa.
What are outgroups?
[An outgroup is] a taxon that is closely related to the taxa studied, but that diverge earlier; a sister taxa to the group being studied.
What is polytomy?
[Polytomy is] a node in a phylogenetic tree that depicts an ancestral branch dividing into three or more descendant branches; this usually indicates that insufficient data were available to resolve which taxa are more closely related.
What is a character?
[A character is] any genetic, morphological, physiological, developmental, or behavioral characteristic of an organism to be studied. This is also a called a trait.
What is an ancestral trait?
[An ancestral trait] is a trait found in the ancestors of a group.
What is a derived trait?
[A derived trait is] a trait that is modified form of an ancestral trait, found in a descendant.
What is the cladistic approach?
[The cladistic approach is] a method for constructing a phylogenetic tree that is based on identifying the unique traits.
What is synapomorphy?
[Synapomorphy is] a shared, derived trait found in two or more taxa that is present in their most recent common ancestor but is missing in more distant ancestors.
What is homoplasy?
[Homoplasy is] the similarity between organisms of different species because of reasons other than common ancestry, such as convergent evolution.
What is a polyphyletic group?
[A polyphyletic group is] an unnatural group based on convergent characteristics that are not present in a common ancestor.
What is a paraphyletic group?
[A paraphyletic group is] a group that includes an ancestral population and some but not all of its descendants.
What is convergent evolution?
[Convergent evolution is] the independent evolution of similar traits in different species due to adaptation to similar environmental conditions and similar ways of life.
What are paleontologists?
[Paleontologists are] scientists who study the fossil record and history of life.
What does it mean to be Precambrian?
[Precambrian refers to] the interval between the formation of the Earth, about 4.6 million years ago, and the appearance of most animal groups about 541 million years ago. Unicellular organisms were dominant for most of this era, and oxygen was virtually absent for the first two billion years.
What is the Paleozoic era?
[The Paleozoic era is] the interval of geologic time, from five hundred and forty-one million to two hundred and fifty-two million years ago, during which fungi, land plants, and most animal lineages first appeared and diversified. It began with the Cambrian explosion and ended with the extinction of almost all multicellular life-forms at the end of the Permian period.
What is the Mesozoic era?
[The Mesozoic era is] the interval of geologic time, from two hundred and fifty-two million to sixty-six million years ago during which gymnosperms were the dominant plants and dinosaurs were the dominant vertebrates. It ended with the extinction of dinosaurs.
What is the Cenozoic era?
[The Cenozoic era is] the most recent interval of geologic time, beginning sixty-six million years ago, during which mammals became the dominant vertebrates and angiosperms became the dominant plants.
What is adaptive radiation?
[Adaptive radiation is] rapid evolutionary diversification in one lineage, producing many descendant species with a wide range of adaptive forms.
What is the Cambrian explosion?
[The Cambrian explosion is] the rapid diversification of animal body types and lineages that occurred during a 50-million-year period about 541 mya at the start of the Proterozoic era.
What are fauna?
[Fauna are] all the animal species characteristics of a particular region, period, or environment.
What is mass extinction?
[Mass extinction is] the extinction of a large number of diverse organisms around the world during a short period of geologic time. This may occur because of sudden and extraordinary environmental changes.
What is background extinction?
[Background extinction is] the average rate of low-level extinction that has occurred continuously throughout evolutionary history.
What is the impact hypothesis?
[The impact hypothesis is] the hypothesis that a collision between Earth and an asteroid caused mass extinction at the K-Pg boundary, 66 million years ago.
What is Bacteria?
[Bacteria is] one of the three taxonomic domains of life, consisting of unicellular prokaryotes distinguished by cell walls composed largely of peptidoglycan, plasma membranes similar to those of eukaryotic cell, and ribosomes and RNA polymerases that differ from those of archaea of eukaryotes.
What is Archaea?
[Archaea is] one of the three taxonomic domains of the life, consisting of unicellular prokaryotes distinguished by cell walls made of certain polysaccharides not found in bacterial or eukaryotic cell walls, plasma membranes composed of unique isoprene-containing phospholipids, and ribosomes and RNA polymerase similar to those of eukaryotes.
What is Eukarya?
[Eukarya is] one of the three taxonomic domains of life, consisting of unicellular organisms (most protists, yeasts) and multicellular organisms (fungi, plants, animals) distinguished by a membrane bound cell nucleus, numerous organelles, and an extensive cytoskeleton.
What are microbes?
[Microbes are] any microscopic organism, including bacteria, archaea, and various tiny eukaryotes.
What are phyla?
[Phyla are], in Linnaeus’ system, taxonomic category above the class level and below the kingdom level. In plants, sometimes called a division.
What is microbiology?
[Microbiology is] the field of study concerned with microscopic organisms.
What are extremophiles?
[An extremophile is] an organism that thrives in an “extreme” environment (e.g., high-salt, high-temperature, low-temperature, or high-pressure).
What are pathogens?
[A pathogen is] any entity capable of causing disease, such as microbes, virus or prion.
What are Koch’s postulates?
[Koch’s postulates are] four criteria used to determine whether a suspected infectious agent causes a particular disease.
What is the germ theory of disease?
[The germ theory of disease is] the theory that that infectious diseases are caused by bacteria, viruses, and other microbes.
What are infectious diseases?
[An infectious disease is] disease caused by viruses, bacteria, fungi, or parasites that can be transmitted from one organism to another or acquired from the environment.
What are toxins?
[A toxin is] a poison produced by a living organism, such as plant, animal or microorganism.
What are endospores?
[An endospore is] a tough resistant reproductive structure formed in certain bacteria in response to poor environmental conditions.
What are antibiotics?
[Antibiotics are] any substance, such as penicillin, that can kill or inhibit the growth of bacteria.
What are biofilms?
[A biofilm is a] complex community of bacteria enmeshed in a polysaccharide-rich, extracellular matrix that allows the bacteria to attach to a surface.
What is bioremediation?
[Bioremediation is] the use of living organisms, usually bacteria or archaea, to degrade environmental pollutants.
What is enrichment culture?
[Enrichment culture is a] method of detecting and obtaining cells with specific characteristics by placing a sample, containing many types of cells, under a specific set of conditions (e.g, temperature, salt concentration, available nutrients) and isolating those cells that grow rapidly in response.
What are thermophiles?
[A thermophile is] a bacterium or archaean that thrives in very hot environments.
What is environmental sequencing?
[Environmental sequencing, metagenomics, is] the inventory of all the genes in a community of ecosystem created by sequencing, analyzing, and comparing the genomes of the component organisms. Often refers to the study of microbial communities.
What is direct sequencing?
[Direct sequencing is] a technique for identifying and studying organisms that cannot be grown in culture. Involves detecting and amplifying copies of specific genes in the microorganisms’ DNA, sequencing those genes, and then comparing the sequences with the known sequences from other organisms.
What is a microbiome?
[A microbiome is] the ecological community of microbes that share a particular space (e.g., the human gut).
What is the tree of life?
[The tree of life is] the phylogenetic tree that includes all organisms.
What is binary fission?
[Binary fission is] the process of cell division used for asexual reproduction of many prokaryotic cells. The genetic material is replicated and partitioned to opposites sides of a growing cell, which then divides in half, creating two genetically identical cells.
What is lateral gene transfer?
[Lateral gene transfer is the] transfer of DNA between two different species.
What is a monophyletic group?
[A monophyletic group is] is an evolutionary unit that includes an ancestral population and all of its descendants but no others. Also called a clade or lineage.
What is transformation?
[Transformation is the] (1) incorporation of external DNA into a cell. Occurs naturally in some bacteria; can be introduced in the laboratory. (2) Conversion of a normal mammalian cell to one that divides uncontrollably.
What is transduction?
[Transduction is] (1) the conversion of information from one mode to another. For example, the process by which a stimulus outside a cell is converted into a response by the cell. (2) The transfer of DNA from one bacterial cell to another.
What is conjugation?
[Conjugation is] the transfer of genetic material between bacterial cells by direct cell-to-cell contact by formation of a bridge-like connection structure.
What is a plasmid?
[A plasmid is] a small, usually circular, supercoiled DNA molecule independent of the cell’s main chromosome(s) in prokaryotes.
What is a Gram stain?
[A gram stain is] a dye that distinguishes the two general types of cell walls found in bacteria. Used to routinely classify bacteria as Gram-negative or Gram-positive.
What does it mean for bacteria to be Gram-positive?
[Gram-positive is] describing bacteria that look purple when treated with a Gram-stain. These bacteria have cell walls composed of a thick layer of peptidoglycan and no outer phospholipid layer.
What does it mean for bacteria to be Gram-negative?
[Gram-negative is] describing bacteria that look purple when treated with a Gram stain. These bacteria have cell walls composed of a thin layer of peptidoglycan and an outer phospholipid layer.
What are phototrophs?
[A phototroph is] an organism (most plants, algae, and some bacteria and archaea) that produces ATP through phosphorylation.
What are chemoorganotrophs?
[A chemoorganotroph is] an organism that produces ATP by oxidizing organic molecules with high potential energy such as sugars. Also called organotrophs.
What are chemolithotrophs?
[A chemolithotroph is] an organism (bacteria or archaea) that produces ATP by oxidizing inorganic molecules with high potential, such as ammonia (NH3) or methane (CH4). Also called lithotroph.
What are autotrophs?
[Autotrophs are] any organism that can synthesize reduced organic compounds from simple inorganic sources such as CO2, or CH4. Most plants and some bacteria and archaea are autotrophs
What are heterotrophs?
[Heterotrophs are] any organism that cannot synthesize reduced organic molecules from inorganic sources and that must obtain them from other organisms. Some bacteria, some archaea, and virtually all fungi and animals are heterotrophs. Also called consumer.
What is fermentation?
[Fermentation is] any of several metabolic pathways in the cytosol that regenerate oxidizing agents, such as NAD+, by transferring electrons to an electron acceptor in the absence of an electron transport chain. Allows pathways such as glycolysis to continue making ATP.
What is photophosphorylation?
[Photophosphorylation is the production of ATP molecules by ATP synthase using the proton-motive force generated either (1) as light-excited electrons flow through an electron transport chain during photosynthesis, or (2) as rhodopsin-like molecules in some bacteria or archaea absorb light to pump protons across their plasma membranes to create a chemiosmotic gradient.
What is photosynthesis?
[Photosynthesis is] the complex biological process that converts light energy to chemical energy stored in the carbohydrate G3P. Occurs in most plants, algae, and some bacteria.
What does it mean to be oxygenic?
[Oxygenic is] referring to any process or reaction that produces oxygen. Photosynthesis in plants, algae and cyanobacteria, which involves photosystem two, is oxygenic because it uses water as an electron source and produces O2 as a by-product.
What does it mean to be anoxygenic?
[Anoxygenic is] referring to any process or reaction that does not produce oxygen. Photosynthesis in purple sulfur bacteria in anoxygenic because it does not use water as an electron donor so no O2 is produced.
What are methanotrophs?
[A methanotroph is] a prokaryote that uses methane (CH4) as its primary electron donor and source of carbon.
What are methanogens?
[A methanogen is] a prokaryote that produces methane (CH4 as its primary by-product of cellular respiration.
What are cyanobacteria?
[Cyanobacteria are] a lineage if photosynthetic bacteria formerly known as blue-green algae. Likely the first life-forms to carry out oxygenic photosynthesis.
What is nitrogen fixation?
[Nitrogen fixation is] the incorporation of atmospheric nitrogen (N2) into ammonia (NH3), which can be used to make many organic compounds. Occurs in only a few lineages of prokaryotes.
What is the nitrogen cycle?
[The global nitrogen cycle is] the movement of nitrogen among terrestrial ecosystems, the oceans, and the atmosphere.
What are endosymbionts?
[An endosymbiont is] an organism that lives in a symbiotic relationship inside the body of its host.
What are fruiting bodies?
[A fruiting body is] a structure formed in some prokaryotes, fungi, and protists for spore dispersal; usually consists of a base, a stalk, and a mass of spores at the top.
What are protists?
[Protists are] any eukaryote that is not a land plant, animal, or fungus. Protists are a diverse paraphyletic group. Most are unicellular, but some are multicellular, or form aggregations called colonies.
What is malaria?
[Malaria is] a human disease caused by five species of the protist Plasmodium and passed to humans by mosquitoes.
What are primary producers?
[Primary producers are] any organism that creates its own food by photosynthesis or from reduced inorganic compounds and that is a stored food source for other species in its ecosystem.
What are plankton?
[Plankton are] drifting small or microscopic organisms that serve as a food source in aquatic environments (includes animals, plants, protists, archaea, and bacteria).
What is a food chain?
[The food chain is] a relatively simple pathway of energy flow through a few species, each at a different trophic level, in an ecosystem. Might include, for example, a primary producer, a primary consumer, a secondary consumer, and a decomposer.
What is the carbon cycle?
[The global carbon cycle is] the movement of carbon among terrestrial ecosystems, aquatic ecosystems, and the atmosphere.
What is carbon sink?
[A carbon sink is] a reservoir that stores carbon-containing compounds for an indefinite period of time.
What are sedimentary rocks?
[Sedimentary rock is] a type of rock formed by gradual accumulation of sediment, particularly sand and mud, as in riverbeds and on the ocean floor. Most fossils are found in sedimentary rock.
What is a flagellum?
[Flagella are] a long, cellular projection that undulates (in eukaryotes) or rotates (prokaryotes) to move the cell through an aqueous environment.
What is picoplankton?
[Picoplankton are] plankton cells that are between 0.2 and 2.0 microns in diameter.
What is the endosymbiosis theory?
[The endosymbiosis theory is] the theory that mitochondria and chloroplasts evolved from prokaryotes that were engulfed by host cells and took up a symbiotic existence within those cells, a process termed primary endosymbiosis. In eukaryotes, chloroplasts may have originated by secondary endosymbiosis; that is, when a cell engulfed a chloroplast-containing protist and retained its chloroplast.
What is symbiosis?
[Symbiosis is] any close and prolonged physical relationship between two individuals of different species.
What is a shell?
[A shell is] a hard, protective outer surface.
What is multicellularity?
[Multicellularity is] the state of being composed of many cells that adhere to each other and do not all express the same genes, resulting in some cells having specialized functions.
What is phagocytosis?
[Phagocytosis is the] uptake by a cell of small particles or cells by invagination and pinching off of the plasma membrane to form small, membrane-bound vesicles; one type of endocytosis.
What are pseudopodia?
[A pseudopodium is] a temporary bulge-like extension of certain protist cells used in cell crawling and ingestion of food.
What are decomposers?
[A detritivore, or decomposer, is] an organism whose diet consists mainly of dead organic matter (detritus). Various bacteria, fungi, protists, and animals are detritivores.
What is detritus?
[Detritus is] a layer of dead organic matter that accumulates at ground level or on seafloors and lake bottoms.
What is a parasite?
[A parasite is] an organism that lives on a host species (ectoparasite) or in a host species (endoparasite) and damages its host.
What is amoeboid motion?
[Amoeboid motion is] a sliding movement observed in some protists accomplished by the formation of cytoplasmic extensions of the cell called pseudopodia. One form of cell crawling.
What is a life cycle?
[A life cycle is] the sequence of developmental events and phases over the life span of an organism, from fertilization to offspring production.
What is the alternation of generations?
[An alternation of generations is] a life cycle involving alternation of a multicellular haploid stage (gametophyte) with a multicellular diploid stage (sporophyte). Occurs in most plants and some protists.
What is gametophyte?
[A gametophyte] in organisms undergoing alternation of generations, the multicellular haploid form that arises from a single haploid spore and produces gametes by mitosis and cell division.
What is a sporophyte?
[A sporophyte] in organisms undergoing alternation of generations, the multicellular diploid form that develops from mitotic divisions after fertilization produces a zygote.
What is a spore?
[A spore is] (1) in bacteria, a dormant form that generally is resistant to extreme conditions. (2) In eukaryotes, a single haploid cell produced by meiosis; it is distinct from a gamete, however, in being able to grow into a multicellular, haploid organism through mitotic division.
What is Plantae?
[Plantae is] the monophyletic group that includes red, green, and glaucophyte algae, as well as land plants.
What are fungi?
[Fungi are] a lineage of eukaryotes that typically have a filamentous body (mycelium) and obtain nutrients by absorption.
What are mutualists?
[Mutualism is] a species relationship between two organisms (mutualists) that benefits both.
What does it mean to be mycorrhizal?
[Mycorrhizal] describes a fungus that lives symbiotically with the roots of vascular plants.
What are mycorrhizae?
[Mycorrhiza are] a mutualistic association between certain fungi and the roots of most vascular plants, sometimes visible as nodules or nets in or around plants.
What are saprophytes?
[A saprophyte is] an organism that feeds primarily on dead plant material.
What is yeast?
[Yeast is] any fungus growing as a single-celled form. Also a specific lineage of Ascomycota.
What are mycelia?
[Mycelia are] a mass of underground filaments (hyphae) that form the body of a fungus. Also found in some protists and bacteria.
