78 terms

Biology Evolution Test

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Evolution
Change in a kind of organism over time; process by which modern organisms have descended from ancient organisms.
Species
A group of similar organisms that can breed and produce fertile offspring.
Fossil
A trace of an ancient organism that has been preserved in rock.
Catastrophism
A principle that states that geologic change occurs suddenly
Gradualism
Principle that states that the changes in landforms result from slow changes over a long period of time
Uniformitarianism
Theory that states that the geologic processes that shape Earth are uniform through time
Variation
Differences in physical traits of an individual from the group in which it belongs
Adaptation
Inherited trait that is selected for over time because it allows organisms to better survive in their environment
Artificial selection
Process by which humans modify a species by breeding it for certain traits
Heritability
Ability of a trait to be passed from one generation to the next
Natural selection
Mechanism by which individuals that have inherited beneficial adaptations produce more offspring on average than do other individuals
Population
All of the individuals of a species that live in the same area
Fitness
Measure of an organism's ability to survive and produce offspring relative to other members of a population
Biogeography
Study of the distribution of organisms around the world
Homologous structure
Body part that is similar in structure on different organisms but performs different functions
Analogous structure
Body part that is similar in function as a body part of another organism but is structurally different
Vestigial structure
Remnants of an organ or structure that functioned in an earlier ancestor
Gene pool
Collection of alleles (genes) found in all of the individuals of a population
Allele frequency
Proportion of one allele, compared with all the alleles for that trait, in the gene pool
Normal distribution
Distribution in a population in which allele frequency is highest near the mean range value and decreases progressively toward each extreme end
Microevolution
Observable change in the allele frequencies of a population over a few generations
Directional selection
Pathway of natural selection in which one uncommon phenotype is selected over a more common phenotype
Stabilizing selection
Pathway of natural selection in which intermediate phenotypes are selected over phenotypes at both extremes
Disruptive selection
Pathway of natural selection in which two opposite, but equally uncommon, phenotypes are selected over the most common phenotype
Gene flow
Physical movement of alleles from one population to another
Genetic drift
Change in allele frequencies due to chance alone, occurring most commonly in small populations
Bottleneck effect
Genetic drift that results from an event that drastically reduces the size of a population
Founder effect
Genetic drift that occurs after a small number of individuals colonize a new area
Sexual selection
Selection in which certain traits enhance mating success; traits are, therefore passed on to offspring
Hardy-Weinberg equilibrium
Condition in which a population's allele frequencies for a given trait do not change from generation to generation
Reproductive isolation
Final stage in speciation, in which members of isolated populations are either no longer able to mate or no longer able to produce viable offspring
Speciation
Evolution of two or more species from one ancestral species
Behavioral isolation
Isolation between populations due to differences in courtship or mating behavior
Geographic isolation
Isolation between populations due to physical barriers
Temporal isolation
Isolation between populations due to barriers related to time, such as differences in mating periods or differences in the time of day that individuals are most active
Convergent evolution
Evolution toward similar characteristics in unrelated species, resulting from adaptations to similar environmental conditions
Divergent evolution
Evolution of one or more closely related species into different species; resulting from adaptations to different environmental conditions
Coevolution
Process in which two or more species evolve in response to changes in each other
Extinction
Elimination of a species from Earth
Punctuated equilibrium
Theory that states taht speciation occurs suddenly and rapidly followed by long periods of little evolutionary change
Adaptive radiation
Process by which one species evolves and gives rise to many descendant species that occupy different ecological niches
Relative dating
Estimate of the age of a fossil based on the location of fossils in strata
Radiometric dating
Technique that measures the natural decay rate of isotopes to calculate the age of material
Isotope
Form of an element that has the same number of protons but a different number of neutrons as another elements
Half-life
Amount of time it takes for half of the isotope in a sample to decay into its product isotope
Index fossil
Fossil of an organism that existed during only specific spans of geological time across large geographic areas
Geologic time scale
Time scale representing the history of Earth
Era
Second largest unit of geological time, lasting tens to hundreds of millions of years and consisting of two or more periods
Period
Unit of geologic time that lasts tens of millions of years and is associated with a particular type of rock system. (the 3rd largest)
Epoch
Smallest unit of geological time, lasting several million years
Nebula
Rotating cloud of gas and dust
Ribozyme
RNA molecule that can catalyze specific chemical reactions
Cyanobacteria
Bacteria that can carry out photosynthesis
Endosymbiosis
Ecological relationship in which one organism lives within the body of another
Paleozoic
Era of geological time (from 544 to 248 million years ago) during which members of every major animal group alive today evolved
Cambrian explosion
Earliest part of the Paleozoic era, when a huge diversity of animal species evolved
Mesozoic
Era during which dinosaurs roamed Earth (from 248 million years ago to 65 million years ago)
Cenozoic
Geological time period that began 65 million years ago and continues today
Bya
Billion years ago
Mya
Million years ago
Precambrian
Name for the time in earth's early history that accounts for ninety percent of earth's time, but only cellular organisms lived.
Comparative embryology
Embryos of vertebrates share many anatomical homologies. (Supports the concept of evolution)
Molecular comparisons (DNA and proteins)
Universal genetic code and the conserved sequences of amino acids in proteins and nucleotides in DNA
Oparin-Haldane hypothesis
Inorganic molecules used energy from sun to become organic
Miller-Urey experiment
Found that organic molecules can form in a strongly reducing atmosphere
Meteorite hypothesis
Organic molecules may have arrived on Earth through meteorite or asteroid impacts
Iron-sulfide hypothesis
Hydrothermal vents produce sulfur that mixes with ocean water to make compartments of rock. Walls containing these compartments could have served as the first cell membranes.
Lipid-membrane hypothesis
Lipid molecules spontaneously form membrane-enclosed spaces called liposomes.
What is the first genetic material?
RNA
First organisms to live on earth?
Bacteria (Prokaryotes)
Theory of endosymbiosis
This theory states that cell organelles, like mitochondria, were once tiny, free-living prokaryotic organisms that took up permanent residence inside larger prokaryotic organisms.
Allopatric Speciation
The formation of a new species as a result of an ancestral population's becoming isolated by a geographic barrier.
Sympatric Speciation
The formation of a new species as a result of a genetic change that produces a reproductive barrier between the changed population (mutants) and the parent population. No geographic barrier is present.
Hardy- Weinberg principle
Principle that allele frequencies in a population will remain constant unless one or more factors cause the frequencies to change
Five factors that lead to evolution
Genetic drift, gene flow, mutation, sexual selection, natural selection
List the conditions that need to be met in order it maintain Hardy-Weinberg equilibrium?
The population must be very large in size.
It must be isolated from other populations. (no gene flow)
No mutations.
Random mating.
No natural selection.
Two Hardy-Weinberg equations to calculate genotype and allele frequencies
p2 + 2pq + q2 = 1

p + q = 1
Eon
The largest period of geological time