evolution
chapters 14-17
Terms
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- conserved
- remained unchanged
- sediment
- dust, sand, or mud deposited over time by wind or water
- spontaneous generation
- an early and now disproved hypothesis that living organisms develop from nonliving material
- assortative mating
- the selection of a mate based on similarity of characteristics
- disruptive selection
- a type of natural selection in wshich individuals with two extreme forms of a trait have an advantage
- reproductive isolation
- the inability of formerly interbreeding organisms to produce offspring
- coevolution
- the mutual evolution of two different species interacting with each other
- population genetics
- the study of evolution from a genetic point of view
- relative age
- a given fossil being compared in age to another fossil
- extinction
- the dying out of species
- population
- all the members of a species that live in the same area and make up a breeding group
- biogeography
- the study of the geographical distribution of fossils and of living organsims
- prosimian primate
- a suborder of modern primates that includes lemurs, lorises, and tarsiers
- gene pool
- all the genes for all of the traits in a population
- isotope
- one of multiple forms of a chemical element that has a different number of neutrons than other atoms of that element
- natural selection
- the process by which organisms with favorable variations reproduce at higher rates than those without such variations
- mass number
- the sum of the protons and the neutrons in an atom
- biological species concept
- the principle that defines a species as those organisms that can produce offspring together
- biogenesis
- a principle that states that all living things come from other living things
- cyanobacteria
- photosyntheic unicellular prokaryotes
- adaptation
- an inherited trait that increases an organisms chance of survival in a particular environment
- bell curve
- illustrates that most members of a population have similar values for a given, measureable trait
- archaebacteria
- a prokaryotic organism distinguished from other prokaryotes by the composition of the cell membranes and walls
- punctuated equilibrium
- theory that speciation occurs during brief periods of rapid genetic change
- geographic isolation
- the physical separation of members of a population
- pelvis
- the hipbones
- founder effect
- occurs when a new population is established by a relatively few individuals
- recent-African-origin hypothesis
- states that modern Homo sapiens originated in Africa only about 100,000 to 200,000 years ago and then, like Homo erectus before them, left Africa
- law of superposition
- a law that states that successive layers of rock or soil were deposited on top of one another and the lowest level is oldest
- australopithecine
- early hominid from the genus Australopithecuz
- analogous
- similar appearance and function but different ancestral origin
- radioactive decay
- the release of particles or radiant energy by the unstable nuclei of some isotopes
- adaptive radiation
- an evolutionary pattern in which many species evolve from a single ancestral species
- ribozyme
- the underground stem of a fern sporophyte
- microsphere
- a type of microscopic droplet enclosed by a membrane composed of organic molecules
- half-life
- the period of time in which half of a radioactive substance decays
- sexual selection
- the preferential choice of a mate based on a specific phenotypic trait
- absolute age
- the age of a fossil in years, estimated from radiological evidence
- directional selection
- individuals that display a more extreme form of a trait have greater fitness
- microevolution
- small scale modifications that occur over short periods and result in a change in gene frequency within a population
- radioactive isotope
- an isotope with an unstable nucleus
- morphology
- the study of the internal and external structure and form of an organism
- anthropoid primate
- one of a subgroup of primates that includes monkeys and apes
- Lucy
- a female fossil given the species name Australopithecus afarensis, which means "southern ape of the Afar Valley"
- vestigial
- referring to a functionless structure that was funtional in an ancestral species
- stratum
- in geology, a layer of soil or rock in a cross section of the Earth
- macroevolution
- large scale modifications that occur over long time periods and produce new species
- allele frequency
- the percentage of an allele in a gene pool
- artificial selection
- breeding of an organisms by humans for specific phenotypic characteristics
- Hardy-Weinberg principle
- the stability of gene frequencies across generations
- coacervate
- a cell-like droplet formed from dissimilar substances
- genetic equilibrium
- alternate forms of a trait have equal frequencies
- postzygotic isolation
- a barrier to successful breeding that occurs after fertilization, such as the production of nonviable or sterile offspring
- fitness
- a measurement of the ability of a species to respond to the pressures of natural selection and produce the most viable offspring
- prehensile
- grasping, as in a primate's hand, foot, or tail
- adaptive advantage
- a favorable trait an organism has
- acquired trait
- a trait not determined by genes
- phenotype frequency
- a ratio stating the number of times a specific phenotype occurs in a population in a single generation
- convergent evolution
- the process by which unrelated species become more similar as they adapt to the same kind of environment
- mass extinction
- one of the brief periods of time during which large numbers of species disappeared
- radioactive dating
- a method of determinating the age of an object by measuring the amount of a specific radioactive isotope it contains
- hominid
- a subgroup of primates that includes modern humans and their bipedal ancestors
- chemosynthesis
- the production of carbohytdrates through the use of energy from inorganic molecules instead of light
- dental formula
- the number, kind, and placement of teeth that are specific for a particular kind of organism
- divergent evolution
- the process of two or more related species becoming more and more dissimilar
- uniformitarianism
- a principle that states that the geological structure of earth resulted from cycles of observable processes and that these processes operate continuously
- endosymbiosis
- a mutually beneficial relationships between one organism and another that lives within it
- stabilizing selection
- a type of natural selection in which the average form of a trait causes an organism to have an advantage in reproduction
- genetic drift
- a shift in allele frequencies in a population due to chance
- prezygotic isolation
- a barrier to successful breeding that occurs before fertilization, such as differences in mating time or behavior
- fossil
- the remains or traces of a once-living organism
- gene flow
- the movement of genes into or out of a population
- homologous
- similar features that originated in a shared ancestor