Biology 112 Study Flashcards
(167 cards)
1
Q
FITNESS
A
The relative likelihood that a genotype will contribute to the gene pool of the next generation as compared with other genotypes.
2
Q
Mean fitness of the population
A
The average reproductive success of members of a population.
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Q
Directional Selection
A
A pattern of natural selection that favors individuals at one extreme of a phenotypic distribution.
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Q
Stabilizing Selection
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A pattern of natural selection that favors the survival of individuals with intermediate phenotypes.
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Q
Diversifying Selection (aka Disruptive Selection)
A
A pattern of natural selection that favors the survival of two or more different genotypes that produce different phenotypes.
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Balancing Selection
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A type of natural selection that maintains genetic diversity in a population.
7
Q
Balanced Polymorphism
A
The phenomenon in which two or more alleles are kept in balance and maintained in a population over the course of many generations.
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Q
Heterozygote Advantage
A
A phenomenon in which a heterozygote has a higher fitness than either corresponding homozygote.
9
Q
Negative frequency- dependent selection
A
A pattern of natural selection in which the fitness of a genotype decreases when its frequency becomes higher; the result is balanced polymorphism.
10
Q
Sexual Selection
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A type of natural selection that is directed at certain traits of sexually reproducing species that make it more likely for individuals to find or choose a mate and/or engage in successful reproduction.
11
Q
Sexual Dimorphism
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A pronounced difference in the morphologies of the two sexes within a species.
12
Q
Sexual Dimorphism
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A pronounced difference in the morphologies of the two sexes within a species.
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Q
Intrasexual Selection
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Sexual selection that occurs via competition between members of the same sex for the opportunity to mate with individuals of the opposite sex.
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Intersexual Selection
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Sexual selection between members of the opposite sex.
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Genetic Drift
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The random change in a population’s allele frequencies from one generation to the next that is attributable to chance. It occurs more quickly in small populations.
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Bottleneck Effect
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A change in allele frequencies due to genetic drift in a population that has been dramatically reduced in size; this effect can reduce the genetic diversity of the population.
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Bottleneck Effect
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A change in allele frequencies due to genetic drift in a population that has been dramatically reduced in size; this effect can reduce the genetic diversity of the population.
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Q
Founder Effect
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Genetic drift that occurs when a small group of individuals separates from a larger population and establishes a colony in a new location.
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Q
Neutral Variation
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Changes in genes and proteins that result from genetic drift and do not have an effect on reproductive success.
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Neutral Variation
A
Changes in genes and proteins that result from genetic drift and do not have an effect on reproductive success.
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Q
non-Darwinian Evolution
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The idea that much of the modern variation in gene sequences is explained by neutral variation rather than adaptive variation.
22
Q
Gene Flow
A
A transfer of alleles into or out of a population that occurs when fertile individuals migrate between populations having different allele frequencies.
23
Q
Gene Flow
A
A transfer of alleles into or out of a population that occurs when fertile individuals migrate between populations having different allele frequencies.
24
Q
Nonrandom Mating
A
The phenomenon that occurs when individuals choose their mates based on their genotypes or phenotypes.
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Nonrandom Mating
The phenomenon that occurs when individuals choose their mates based on their genotypes or phenotypes.
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Inbreeding
Mating between genetically related individuals.
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Inbreeding Depression
The phenomenon whereby inbreeding produces homozygotes that are less fit, thereby decreasing the reproductive success of a population.
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Macroevolution
Evolutionary changes that produce new species and groups of species.
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Speciation
The formation of new species.
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Subspecies
A subdivision of a species; this designation is used when two or more geographically restricted groups of the same species differ, but not enough to warrant their placement into separate species.
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Ecotypes
Genetically distinct populations adapted to their local environments.
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Morphological Traits
Changes to the outward appearance of an animal as well as the form and structure of internal parts, like bones and organs.
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Reproductive Isolation
A criterion for identifying a species; the circumstances and mechanisms that collectively prevent a species from interbreeding with other species.
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Biological Species Concept
An approach used to distinguish species, which states that a species is a group of individuals whose members have the potential to interbreed with one another in nature to produce viable, fertile offspring but cannot successfully interbreed with members of other species.
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Evolutionary Lineage Concept
An approach used to distinguish species; states that a species is derived from a single distinct lineage and has its own evolutionary tendencies and historical fate.
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Lineage
A series of species that forms a line of descent.
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Ecological Species Concept
An approach used to distinguish species; considers a species within its native environment and states that each species occupies its own ecological niche.
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General Lineage Concept
A widely accepted approach used to distinguish species; states that each species is a population of an independently evolving lineage.
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Reproductive Isolating Mechanisms
Mechanisms that prevent interbreeding between different species.
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Prezygotic Isolating Mechanisms
A mechanism that blocks interbreeding by preventing the formation of a zygote.
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Postzygotic Isolating Mechanisms
A mechanism that prevents interbreeding by blocking the development of a viable and fertile individual after fertilization has taken place.
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Interspecies Hybrid
The offspring resulting from the interbreeding of members of two different species.
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Habitat Isolation
Species occupy different habitats, so they never come in contact with each other
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Temporal Isolation
Species have different mating or flowering seasons or times of day or become sexually mature at different times of the year
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Behavioral Isolation
Sexual attraction between males and females of different animal species is limited due to differences in behavior or physiology
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Mechanical Isolation
Morphological features such as size and incompatible genitalia prevent 2 members of different species from interbreeding
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Gametic Isolation
Gametic transfer takes place, but the gametes fail to unite with each other. This can occur because the male and female gametes fail to attract, because they are unable to fuse, or because the male gametes are inviable in the female reproductive tract of another species. In plants, the pollen of one species usually cannot generate a pollen tube to fertilize the egg cells of another species.
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Hybrid Inviability
The egg of one species is fertilized by the sperm from another species, but the fertilized egg fails to develop past the early embryonic stages.
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Hybrid Sterility
An interspecies hybrid survives, but it is sterile. For example, the mule, which is sterile, is produced from a cross between a male donkey (Equus asinus) and a female horse (Equus ferus caballus)
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Hybrid Breakdown
The F1 interspecies hybrid is viable and fertile, but succeeding generations (F2, and so on) become increasingly inviable. This is usually due to the formation of less-fit genotypes by genetic recombination.
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Cladogenesis
The splitting or diverging of one species into two or more species.
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Allopatric Speciation
A form of speciation that occurs when a population becomes geographically isolated from other populations and evolves into one or more new species.
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Adaptive Radiation
The process whereby a single ancestral species evolves into a wide array of descendant species that differ greatly in their habitat, form, or behavior.
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Hybrid Zones
An area where two populations can interbreed.
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Sympatric Speciation
A form of speciation that occurs when members of a species that initially occupy the same habitat within the same range diverge into two or more different species even though there are no physical barriers to interbreeding.
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Polyploidy
The condition in which a cell or organism has three or more sets of chromosomes.
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Alloploid
An organism having at least one set of chromosomes from two or more different species.
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Gradualism
A concept suggesting that species evolve continuously over long spans of time.
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Punctuated Equilibrium
A concept that suggests that the tempo of evolution is more sporadic than gradual. Species rapidly evolve into new species followed by long periods of equilibrium with little evolutionary change.
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Evolutionary Developmental Biology (Evo-Devo)
The field of biology that compares the development of different organisms in an attempt to understand relationships between organisms and the mechanisms that bring about evolutionary change; referred to as evo-devo.
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Pattern Formation
The process that gives rise to a plant or animal with a particular body structure.
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Heterochrony
Differences among species in the rate or timing of developmental events.
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Taxonomy
The field of biology that is concerned with the theory, practice, and rules of classifying living and extinct species and also viruses.
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Extant
Refers to a species that is still in existence.
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Extinct
Refers to a species that existed in the past, but has died out.
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Systematics
The study of biological diversity and evolutionary relationships among species, both extant and extinct.
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Taxon
A group of species that are evolutionarily related to each other. In taxonomy, each species is placed into several taxons that form a hierarchy from large (domain) to small (genus).
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Kingdom
A taxonomic group; the second largest division after domain.
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Domain
1. A defined region of a protein with a distinct structure and function. 2. One of the three major categories of life: Bacteria, Archaea, and Eukarya.
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Phyla (singular, Phylum)
In taxonomy, a subdivision of a kingdom.
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Class
In taxonomy, a subdivision of a phylum.
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Orders
In taxonomy, a subdivision of a class.
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Families
n taxonomy, a subdivision of a order.
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Genera (singular, Genus)
n taxonomy, a subdivision of a family.
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Species
In taxonomy, a subdivision of a genus. Each species is a group of related organisms that share a distinctive set of attributes in nature and (for sexually reproducing species) are capable of interbreeding.
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Species
In taxonomy, a subdivision of a genus. Each species is a group of related organisms that share a distinctive set of attributes in nature and (for sexually reproducing species) are capable of interbreeding.
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Binomial Nomenclature
The standard format for scientific naming of species. Each species has a genus name and a specific epithet.
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Binomial Nomenclature
The standard format for scientific naming of species. Each species has a genus name and a specific epithet.
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Phylogeny
The evolutionary history of a species or group of species.
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Phylogenetic Tree
A diagram that describes the evolutionary relationships among various species, based on the information available to and gathered by systematists.
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Anagensis
The pattern of speciation in which a single species is transformed into a different species over the course of many generations.
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Cladogensis
The splitting or diverging of one species into two or more species.
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Node
1. The region of a plant stem from which one or more leaves, branches, or buds emerge. 2. The branch points in a phylogenetic tree.
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Clade
A group of species consisting of a common ancestral species and all of its descendant species.
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Clade
A group of species consisting of a common ancestral species and all of its descendant species.
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Monophyletic Group
A group of species, a taxon, that is a clade.
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Paraphyletic Group
A group of species that contains a common ancestor and some, but not all, of its descendants.
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Polyphyletic Group
A group of species that consists of members of several evolutionary lines and does not include the most recent common ancestor of the included lineages.
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Homolgy
A similarity that occurs due to descent from a common ancestor.
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Molecular Systematics
A field of study that involves the analysis of genetic data, such as DNA and amino acid sequences, to identify and study genetic homologies and construct phylogenetic trees.
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Cladistics
The classification of species based on evolutionary relationships.
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Cladistic Approach
An approach used to construct a phylogenetic tree by comparing shared primitive and shared derived characters among different species.
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Shared Primitive Character (Symplesiomorphy)
A character that is shared by two or more different taxa and inherited from ancestors older than their last common ancestor.
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Shared derived Character (Synapomorphy)
A character that is shared by two or more species or taxa and originated in their most recent common ancestor.
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Principle of Parsimony
The concept that the preferred hypothesis is the one that is the simplest.
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Neutral Theory of Evolution
Theory proposing that most genetic variation in a population is due to the accumulation of neutral mutations that have attained high frequencies in the population via genetic drift.
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Biological Diversity (Biodiversity)
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Archaea
One of the three domains of life; the other two are Bacteria and Eukarya.
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Bacteria
One of the three domains of life; the other two are Archaea and Eukarya.
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Extremophiles
An organism that occurs primarily in extreme habitats.
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Perthermophiles
An organism that thrives in extremely hot temperatures.
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Horizontal gene transfer
A process in which an organism incorporates genetic material from another organism without being the offspring of that organism.
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Vertical Evolution
A type of evolution in which genetic changes occur in a series of related species that form a lineage; species evolve from pre-existing species by the accumulation of mutations.
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Biofilms
An aggregation of microorganisms that secrete adhesive mucilage, thereby gluing themselves to surfaces.
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Quorum Sensing
A mechanism by which prokaryotic cells are able to communicate by chemical means when they reach a critical population size.
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Pepidoglycan
A polymer composed of carbohydrates crosslinked with peptides that is an important component of the cell walls of most bacteria.
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Lipopolysaccharides
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Motility
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Binary Fission
The process of cell division in bacteria and archaea in which one cell divides into two cells.
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Akinetes
A thick-walled, food-filled cell produced by certain bacteria or protists that enables them to survive unfavorable conditions in a dormant state.
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Endospores
A structure with a tough coat that is produced inside of certain bacteria and then released when the enclosing bacterial cell dies and breaks down.
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Autotrophs
An organism that has metabolic pathways that use energy from either inorganic molecules or light to make organic molecules.
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Photoautotrophs
An organism that uses the energy from light to make organic molecules from inorganic sources.
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Chemoautotrophs
An organism able to use energy obtained by chemical modifications of inorganic compounds to synthesize organic compounds.
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Heterotrophs
Organisms that cannot produce their own organic molecules by using energy from inorganic sources or light; they must obtain one or more organic compounds from their environment.
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Photoheterotrophs
An organism that is able to use light energy to generate ATP but must take in organic compounds from the environment as a source of carbon.
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Chemoheterotroph
An organism that must obtain organic molecules both for energy and as a carbon source.
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Obligate Aerobes
Organisms that require oxygen for survival.
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Aerotolerant Anaerobe
A microorganism that does not use oxygen but is not poisoned by it either.
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Facultative Anaerobe
A microorganism that can use oxygen in aerobic respiration, obtain energy via anaerobic fermentation, or use inorganic chemical reactions to obtain energy.
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Nitrogen Fixation
A specialized metabolic process in which certain prokaryotes use the enzyme nitrogenase to convert inert atmospheric nitrogen gas (N2) into ammonia (NH3); also, the industrial process by which humans produce NH3 fertilizer from N2.
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Methanogens
Several groups of anaerobic archaea that convert CO2, methyl groups, or acetate to methane, and release it from their cells.
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Methanotrophs
An aerobic bacterium that consumes methane.
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Producers
An organism that synthesizes the organic compounds used by other organisms for food.
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Decomposer
An organism that gets its energy from the remains and waste products of other organisms.
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Symbiosis
An intimate association between two or more organisms of different species.
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Mutualism
A symbiotic interaction in which both species benefit.
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Pathogens
A virus or microorganism that causes disease symptoms in its host.
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Koch's Postulates
A series of steps used to determine whether a particular organism causes a specific disease.
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Bioremediation
The use of living organisms, usually microbes or plants, to detoxify polluted habitats such as dump sites or oil spills.
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Algae
A term that applies to about 10 phyla of protists, including mostly photosynthetic and some nonphotosynthetic species; often also includes cyanobacteria.
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Protozoa
A term commonly used to describe diverse heterotrophic protists.
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Fungus-like protists
Heterotrophic protists that often resemble true fungi in having threadlike, filamentous bodies and absorbing nutrients from their environment.
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Phytoplankton
Microscopic photosynthetic protists that float in water or actively move through it.
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Periphyton
Communities of microorganisms that are attached by mucilage to underwater surfaces such as rocks, sand, and plants.
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Macroalgae (seaweeds)
Photosynthetic protists that can be seen with the unaided eye; also known as seaweeds. (Usually grow attached to underwater surfaces such as rocks, sand, docks, ship bulls, or offshore oil platforms.)
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Flaggellates
Photosynthetic protists that can be seen with the unaided eye; also known as seaweeds.
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Ciliates
A protist that moves by means of cilia, which are tiny hairlike extensions that occur on the outside of cells and have the same internal structure as flagella.
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Amoebae
A protist that moves by pseudopodia, which involves extending cytoplasm into filaments or lobes.
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Phagocytosis
A type of endocytosis that involves the formation of a membrane vesicle, called a phagosome, or phagocytic vacuole, which engulfs a particle such as a bacterium.
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Endosymbiosis
A symbiotic relationship in which the smaller species (the symbiont) lives inside the larger species (the host).
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Phagotrophs
An organism that specializes in phagotrophy (particle feeding) by means of phagocytosis as a mechanism of nutrition.
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Osmotrophs
An organism that relies on osmotrophy (uptake of small organic molecules) as a mechanism of nutrition.
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Photoautotrophs
An organism that uses the energy from light to make organic molecules from inorganic sources.
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Mixotrophs
An organism that is able to use photoautotrophy as well as phagotrophy or osmotrophy to obtain organic nutrients.
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Cysts
A unicellular or multicellular structure that often has a thick, protective wall and can remain dormant through periods of unfavorable climate or low food availability.
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Streptophytes
Land pants (embryophytes) and their close relatives among the green algae.
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Streptophyte Algae
The green algae that are closely related to land plants (embryophytes).
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Alternation of Generations
The phenomenon that occurs in plants and some protists in which the life cycle alternates between multicellular diploid organisms, called sporophytes, and multicellular haploid organisms, called gametophytes.
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Sporophyte
The diploid generation of plants or multicellular protists that have a sporic life cycle; this generation produces haploid spores by the process of meiosis.
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Gametophyte
In plants and many multicellular protists, the haploid stage that produces gametes by mitosis.
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Spores
A haploid, typically single-celled reproductive structure of fungi and plants. A spore is able to grow into a new fungal mycelium or plant gametophyte in a suitable location.
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Vascular plants
A broad category of plants distinguished by internal water and nutrient-conducting (vascular) tissues that also provide structural support.
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Bryophytes
Liverworts, mosses, and hornworts, the modern nonvascular land plants.
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Tracheid
A type of dead, lignified plant cell in xylem that conducts water, along with dissolved minerals and hormones; also provides structural support.
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Spermatophytes
All of the living and extinct phyla of seed-producing plants.
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Gymnosperm
A plant that produces seeds that are exposed rather than seeds enclosed in fruits.
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Gametangia
Specialized structures produced by some fungi and many land plants in which developing gametes are protected by a jacket of tissue.
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Archegonia
Flask-shaped gametangia that each enclose a single egg cell in plants.
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Antheridia
Spherical or elongate gametangia that produce sperm in plants.
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Matrotrophy
In plants, the phenomenon in which zygotes remain enclosed within gametophyte tissues, where they are sheltered and fed.
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Progymnosperms
An extinct group of plants having wood but not seeds, which evolved before the gymnosperms.
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Eustele
In plants, a ring of vascular tissue arranged around a central pith of nonvascular tissue; typical of progymnosperms, gymnosperms, and angiosperms.
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Coevolution
The process by which two or more species of organisms influence each other’s evolutionary pathway.
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Pollination Syndromes
The pattern of coevolved traits between particular types of flowers and their specific pollinators.
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Domestication
A process that involves artificial selection of plants or animals for traits desirable to humans.
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Shattering
The process by which ears of wild grain crops break apart and disperse seeds.
