Evidence of Evolution
Structures that have similar anatomy but different functions, like a whale flipper and bat wing, are called these.
homologous structures
Slow, steady change in species over long periods of time is called this.
gradualism
Traits that help an organism survive and reproduce are called this.
adaptations
A random change in DNA is called this.
mutation
The formation of a new species is called this.
speciation
The study of where organisms live and how they are distributed around the world is called this.
biogeography
Long periods of little or no evolutionary change in the fossil record are called this.
stasis
Natural selection acts on this level of organization.
population
Movement of individuals into or out of a population that changes allele frequencies is called this.
gene flow
When populations become separated by a physical barrier like a river or mountain, this type of speciation may occur.
geographic isolation
Similar DNA sequences between humans and chimpanzees provide this type of evidence for evolution.
molecular homology
A species appears suddenly in the fossil record, remains unchanged for long periods, then disappears. This pattern supports this theory.
punctuated equilibrium
A population of insects develops resistance to pesticides over generations. This is an example of natural selection because the resistant insects do this
survive and reproduce more successfully
A natural disaster randomly kills many individuals in a population, leaving only a few survivors. This is an example of this mechanism.
genetic drift
If two populations of the same species can no longer interbreed to produce fertile offspring, they are considered this.
gametic / reproductive isolation
Embryos of fish, birds, and mammals share similar early developmental stages. This provides this type of evolutionary evidence.
embryology
A scientist finds fossils showing small changes in shell size across many layers of rock over millions of years. This most strongly supports this model of evolution.
gradualism
In a population of rabbits, some are faster than others. Predators catch the slower rabbits more often. Over time, the population of rabbits become faster because this occurs.
natural selection
During reproduction, chromosomes exchange genetic material, creating new combinations of alleles. This mechanism is called this.
genetic recombination
A small group of birds migrates to a new island and develops different traits over many generations due to limited genetic diversity. This is an example of this effect.
founder effect
Scientists discover fossils of similar organisms on continents that are now far apart. This most strongly supports the idea that these continents were once this.
biogeography
A fossil record shows long periods with no change followed by rapid appearance of new species after a major environmental event. This pattern best supports which explanation for evolutionary change?
punctuated equilibrium
A drought reduces available food in a population of finches. Birds with stronger beaks survive and reproduce more than birds with weaker beaks. Over several generations, most birds have stronger beaks. This demonstrates that natural selection causes change in this.
population
A population becomes resistant to disease after a mutation introduces a new allele. This mechanism changes the gene pool by adding this.
genetic variation
Two populations of frogs live in the same area but breed at different times of the year. Over time, they become separate species. This type of reproductive isolation is called this.
temporal isolation