Gen Bio 104 Ch. 22-25
Terms in this set (101)
The medium formed by the slow accumulation of organic molecules in the early oceans over a long period of time prior to the existence of life.
The term used to describe the first nonliving structures that evolved into living cells
Droplets that form spontaneously from the association of charged polymers such as proteins, carbohydrates, or nucleic acids surrounded by water.
A vesicle surrounded by a lipid bilayer.
A biological catalyst that is an RNA molecule.
Occurs when a chemical within a mixture has special properties or advantages that cause it to increase in amount. May have played a key role in the formation of an RNA world.
A hypothetical period on primitive Earth when both the information needed for life and the enzymatic activity of living cells were contained solely in RNA molecules.
Recognizable preserved remains of past life on Earth
A scientist who studies fossils
A common way to estimate the age of a fossil by analyzing the elemental isotopes within the accompanying rock.
1. In the case of organic molecules in a cell, refers to the time it takes for 50% of the molecules to be broken down and recycled. 2. In the case of radioisotopes, the time it takes for 50% of the molecules to decay and emit radiation.
A time line of the Earth's history from its origin about 4.55 bya to the present
The end of the existence of a species or a group of species.
he process by which, over the course of billions of years, the major landmasses, known as the continents, have shifted their positions, changed their shapes, and, in some cases, have become separated from each other.
When many species become extinct at the same time.
Organisms that cannot produce their own organic molecules and thus must obtain organic food from other organisms.
An organism that has metabolic pathways that use energy from either inorganic molecules or light to make organic molecules.
A layered calcium carbonate structure in an aquatic environment generally produced by cyanobacteria.
Describes a relationship in which one organism lives inside the other.
An event during the Cambrian period (543-490 mya) in which there was an abrupt increase (on a geological scale) in the diversity of animal species.
A member of a group of primates that includes gibbons, orangutans, gorillas, chimpanzees, and humans
Thought that relies on observation to form an idea or hypothesis, rather than trying to understand life from a nonphysical or spiritual point of view.
inheritance of acquired characteristics
Jean-Baptiste Lamarck's incorrect hypothesis that species change over the course of many generations by adapting to new environments.
The process that eliminates those individuals that are less likely to survive and reproduce in a particular environment, while allowing other individuals with traits that confer greater reproductive success to increase in numbers.
An organism that provides a link between earlier and later forms in evolution
The study of the geographic distribution of extinct and modern species.
The term to describe organisms that are naturally found only in a particular location
The process whereby two different species from different lineages show similar characteristics because they occupy similar environments.
A structure that is the result of convergent evolution. Such structures have arisen independently, two or more times, because species have occupied similar types of environments on Earth
Programs and procedures designed to modify traits in domesticated species
A variant form of a gene
A fundamental similarity that occurs due to descent from a common ancestor
Structures that are similar to each other because they are derived from the same ancestral structure
An anatomical feature that has no apparent function but resembles a structure of a presumed ancestor
Similarities at the molecular level that indicate that living species evolved from a common ancestor or interrelated group of common ancestors.
Genes derived from the same ancestral gene that have accumulated random mutations that make their sequences slightly different.
A homologous gene in different species
Homologous genes within a single species
A group of homologous genes within a single species
A form of mutation in which exons and their flanking introns are inserted into genes and thereby create proteins with additional functional domains
A process in which species evolve from pre-existing species by the accumulation of mutations.
horizontal gene transfer
A process in which an organism incorporates genetic material from another organism without being the offspring of that organism.
All of the genes in a population
The phenomenon that many traits or genes may display variation within a population
A gene that commonly exists as two or more alleles in a population.
A gene that exists predominantly as a single allele in a population.
single-nucleotide polymorphism (SNP)
A type of genetic variation in a population in which a particular gene sequence varies at a single nucleotide.
A medical practice in which information about a patient's genotype is used to individualize their medical care.
The number of copies of a particular allele in a population divided by the total number of alleles in that population.
In a population, the number of individuals with a given genotype divided by the total number of individuals.
An equation (p2 + 2pq + q2 = 1) that relates allele and genotype frequencies; the equation predicts an equilibrium if no new mutations are formed, no natural selection occurs, the population size is very large, the population does not migrate, and mating is random.
Changes in a population's gene pool from generation to generation.
The processes and structures by which organisms adjust to changes in their environment.
The likelihood of contributing fertile offspring to the next generation.
The relative likelihood that a genotype will contribute to the gene pool of the next generation as compared with other genotypes.
mean fitness of the population
The average reproductive success of members of a population.
A pattern of natural selection that favors individuals at one extreme of a phenotypic distribution.
A pattern of natural selection that favors the survival of individuals with intermediate phenotypes
A pattern of natural selection that favors the survival of two or more different genotypes that produce different phenotypes.
A type of natural selection that maintains genetic diversity in a population.
The phenomenon in which two or more alleles are kept in balance and maintained in a population over the course of many generations.
A phenomenon in which a heterozygote has a higher Darwinian fitness than either corresponding homozygote.
negative frequency-dependent selection
A pattern of natural selection in which the fitness of a genotype decreases when its frequency becomes higher; the result is a balanced polymorphism.
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 mating.
A pronounced difference in the morphologies of the two sexes within a species
Sexual selection between members of the same sex.
Sexual selection between members of the opposite sex.
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.
A situation in which a population size is dramatically reduced and then rebounds. While the population is small, genetic drift may rapidly reduce the genetic diversity of the population.
Genetic drift that occurs when a small group of individuals separates from a larger population and establishes a colony in a new location.
Genetic variation in which natural selection does not favor any particular genotype.
The idea that much of the modern variation in gene sequences is explained by neutral variation rather than adaptive variation.
Occurs when individuals migrate between different populations and results in changes in the genetic composition of the resulting populations.
The phenomenon that individuals choose their mates based on their genotypes or phenotypes.
Mating among genetically related relatives.
The phenomenon whereby inbreeding produces homozygotes that are less fit, thereby decreasing the reproductive success of a population.
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.
Genetically distinct populations adapted to their local environments.
Refers to the concept that a species cannot successfully interbreed with other species.
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.
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
A progression of changes in a series of ancestors.
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.
general lineage concept
A widely accepted approach used to distinguish species; states that each species is a population of an independently evolving lineage.
reproductive isolating mechanisms
Mechanisms that prevent interbreeding between different species.
prezygotic isolating mechanisms
A mechanism that stops interbreeding by preventing the formation of a zygote.
postzygotic isolating mechanisms
A mechanism that prevents interbreeding by blocking the development of a viable and fertile individual after fertilization has taken place.
The offspring resulting from the mating of two different species.
A pattern of speciation in which a species is divided into two or more species.
A form of speciation that occurs when a population becomes geographically isolated from other populations and evolves into one or more new species.
The process whereby a single ancestral species evolves into a wide array of descendant species that differ greatly in their habitat, form, or behavior.
An area where two populations can interbreed.
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.
In an organism, the state of having three or more sets of chromosomes.
An organism having at least one set of chromosomes from two or more different species.
A concept suggesting that species evolve continuously over long spans of time.
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.
evolutionary developmental biology
(evo-devo) - A field of biology that compares the development of different organisms in an attempt to understand ancestral relationships between organisms and the developmental mechanisms that bring about evolutionary change.
The process that gives rise to a plant or animal with a particular body structure.
Evolutionary changes in the rate or timing of developmental events.
The retention of juvenile traits in an adult organism.