bio unit 4 vocab Flashcards
theory about the process of heritable change over time; all living things on Earth have their origin in other preexisting types and the differences are due to modifications in successive generations
Evolutionary Theory
a natural process that results in the survival and reproductive success of individuals or groups best adjusted to their environment and that leads to the perpetuation of genetic qualities best suited to that particular environment
Natural selection
trait that helps an organism be more suitable to its surrounding environment
Adaptation
remnants of a structure with no apparent function ex. appendix in humans
Vestigial structure
same function , different structure Ex. wing of a bird and wing of a butterfly
Analogous structure
same structure, different function ex. arms, wings, flippers
Homologous structure
process by which two new species are formed due to reproductive isolation mechanisms
Speciation
when populations are reproductively isolated by courtship rituals
Behavioral Isolation
species isolated by different times of reproduction
Temporal Isolation
2 populations reproductively isolated by a body of water, or a mountain
Geographic Isolation
Genetic drift that occurs when a few individuals become isolated from a larger population and form a new population whose gene pool composition is not reflective of that of the original population.
Founder Effect
variation in the relative frequency of different genotypes in a small population, owing to the chance disappearance of particular genes as individuals die or do not reproduce
Genetic drift
the total of the genes of every reproducing individual in a population
Gene pool
proposed the theory of evolution by natural selection in his book “ On Origin of Species”
Charles Darwin
explained long necks of Giraffe by Law of use and disuse
Lamarck
evolutionary history of a species
Phylogeny
Species evolve by adapting to surrounding environment from one common ancestor species
Adaptive radiation
Unrelated organisms are similar due to their evolution in similar environments. Show analogous structures
Convergent Evolution
Genetic drift resulting from the reduction of a population, typically by a natural disaster, such that the surviving population is no longer genetically representative of the original population.
Bottleneck effect
Also known as adaptive radiation
Divergent evolution
Analysis of evolutionary relationships based on the order of the derived characteristics
Cladistic Analysis
Characteristics that appear in later organisms as an “innovation” in a cladogram
Derived characteristics
Heritable differences that exist in natural populations due to gene shuffling and mutations; the differences in characteristics between organisms of the same population
Variation
natural selection in which both extremes of the phenotype have a higher fitness than individuals near the middle of the curve; a single curve splits into two; may lead to speciation over time
diversifying selection
occurs when natural selection favors one of the extreme variations of a trait; form of natural selection in which the entire curve moves; occurs when individuals at one end of a distribution curve have higher fitness than individuals in the middle or at the other end of the curve
directional selection
Natural selection that favors intermediate variants by acting against extreme phenotypes; form of natural selection in which individuals near the center of a distribution curve have higher fitness than individuals at either end of the curve
stabilizing selection
the history of life as documented by fossils; the remains or imprints of organisms from earlier geological periods preserved in sedimentary rock
Fossil record
similar DNA (amino acid sequences) among different species from a common ancestor; the similarity that two organisms share at the genetic level for a particular molecule
molecular homology
a principle in evolutionary theory that explains the long periods of geologic time over which species evolve slowly and continuously
gradualism
Similarities in structures among species that exist because of descent from a common ancestor.
anatomical homologies
when a species is not undergoing any reactive evolutionary change over a long period of time
Stasis
Number of times that an allele occurs in a gene pool
Allele frequency
a group of interbreeding organisms of the same species within an environment
population
the transfer or exchange of genetic material (alleles) from one population to another through interbreeding, migration, or dispersal
Gene flow
the exchange of genetic material between chromosomes ; the product of the crossing over of chromosomes during meiosis, producing novel combinations of alleles in the gametes that did not exist in the parent
Genetic recombination
a change to a gene’s DNA sequence
mutation
Process by which unrelated organisms independently evolve similarities when adapting to similar environments - such analogous structures of wings in a butterfly and a bird
convergent evolution
