exam1 vocab, Manson Flashcards
convergent evolution
the evolution of similar features in independent evolutionary lineages
natural selection
a process in which individuals that have certain inherited traits tend to survive and reproduce at higher rates than other individuals because of those traits
evolutionary tree
a branching diagram that reflects a hypothesis about evolutionary relationships among groups of organisms
biogeography
the scientific study of the past and present geographic distributions of species
pangea
the supercontinent that formed near the end of the Paleozoic era, when plate movement brought all the landmasses of Earth together
analogous
having characteristics that’re similar because of convergent evolution (not homologous)
adaptation
inherited characteristic of an organism that enhances its survival and reproduction in a specific environment
homology
similarity in characteristics resulting from a shared ancestry
paleontology
the scientific study of fossils
vestigial structure
a feature of an organism that is a historical remnant of a structure that served a function in the organism’s ancestors
fossils
a preserved remnant or impression of an organism that lived in the past
evolution (descent with modification, a change in the genetic composition of a population from generation to generation)
the process by which species accumulate differences from their ancestors as they adapt to different environments over time
homologous structures
structures in different species that are similar because of common ancestry
artificial selection
the selective breeding of domesticated plants and animals to encourage the occurrence of desirable traits
stratum
a rock layer formed when new layers of sediment cover older ones and compress them
vestigial organs
remnants of structures that were useful to an organism’s ancestors but are now nonfunctional or show a reduced function
balancing selection
a type of natural selection that maintains two or more phenotypic forms in a population
Hardy-Weinberg equilibrium
the state of a population in which frequencies of alleles and genotypes remain constant from generation to generation, provided that only Mendelian segregation and recombination of alleles are at work
heterozygote advantage
greater reproductive success of heterozygous individuals compared with homozygotes; tends to preserve variation in a gene pool
sexual selection
a process in which individuals with certain inherited characteristics are more likely than other individuals of the same sex to obtain mates
sexual dimorphism
differences between the secondary sex characteristics of males and females of the same species
microevolution
evolutionary change below the species level; a change in the alleles frequencies in a population over generations
intersexual selection (mate choice)
a form of natural selection in which individuals of one sex are choosy in selecting their mates from the other sex
frequency-dependent selection
selection in which the fitness of a phenotype depends on how common the phenotype is in a population
bottleneck effect
genetic drift that occurs when the size of a population is reduced by a natural disaster or human actions. usually the surviving population is no longer genetically representative of the original population
genetic drift
a process in which chance events cause unpredictable fluctuations in allele frequencies from one generation to the next. effects are most pronounced in small populations
founder effect
genetic drift that occurs when a few individuals become isolated from a larger population and form a new population whose gene pool composition isn’t reflective of that of the original population
population
a group of individuals of the same species that live in the same area and interbreed, producing fertile offspring
gene pool
the aggregate of all copies of every type of allele at all loci in every individual in a population
disruptive selection
a type of natural selection in which individuals on both extremes of a phenotypic range survive or reproduce more successfully than do individuals with intermediate phenotypes
gene flow
the transfer of alleles from one population to another, resulting from the movement of fertile individuals or their gametes
adaptive evolution
when traits that enhance survival or reproduction tend to increase in frequency over time, resulting in a better match between organisms and their environment
genetic variation
differences among individuals in the composition of their genes or other DNA sequences
intrasexual selection
a form of natural selection in which there’s direct competition among individuals of one sex for mates of the. opposite sex
stabilizing selection
a type of natural selection in which intermediate phenotypes survive or reproduce more successfully than do extreme phenotypes
neutral variation
genetic variation that doesn’t provide a selective advantage or disadvantage
relative fitness
the contribution an individual makes to the gene pool of the next generation, relative to the contributions of other individuals in the population
directional selection
a type of natural selection in which individuals at one end of the phenotypic range survive or reproduce more successfully than do other individuals
hybrid
offspring that results from the mating of individuals from 2 different species or from 2 true-breeding varieties of the same species
allopolyploid
a fertile individuals that has more than 2 chromosome sets as a result of 2 different species interbreeding and combining their chromosomes
macroevolution
evolutionary change above the species level (the broad pattern of evolution at a species level)
reproductive isolation
the existence of biological factors (barriers) that impede members of 2 species from producing viable, fertile offspring