Charles darwin
This process, famously described by Charles Darwin, explains how organisms with traits better suited to their environment are more likely to survive and reproduce.
natural selection
These preserved remains or traces of ancient organisms provide a chronological record of how species have changed over millions of years.
fossils
This is a heritable trait that increases an organism's chances of surviving and reproducing in its specific environment.
adaptation
This is the estimated age of planet Earth, give or take a few hundred million years.
4.5 billion years old
He is the British naturalist who famously traveled aboard the HMS Beagle and wrote On the Origin of Species.
charles darwin
This term refers to a random change in the DNA sequence of an organism, which serves as the ultimate source of all new genetic variation.
mutation
Structures in different species that share a similar physical framework because they were inherited from a common ancestor, such as a human arm and a bat wing.
hologous structure
This evolutionary process results in the formation of a new, distinct species from an existing one.
Speciation
This term describes an event in Earth's history where a vast majority of all living species disappear in a relatively short geological time frame.
mass extinction
This French naturalist proposed an early theory of evolution involving the "inheritance of acquired characteristics," mistakenly believing giraffes stretched their necks and passed that exact trait to offspring.
Jean-Baptiste Lamarck
This mechanism of evolution occurs when allele frequencies change across generations due to purely random chance events, impacting small populations most severely.
generic drift
Modern organisms often carry these remnants of structures—like the human appendix or pelvic bones in whales—that had important functions in their ancestors but are now largely useless.
vestigial structures
This type of speciation occurs when a physical barrier, such as a mountain range or a river, geographically isolates a population into two or more groups.
allopatric speciation
Taking place roughly 540 million years ago, this sudden evolutionary event marked the rapid appearance of most major animal phyla in the fossil record.
cambrian explotion
This British naturalist independently conceived the theory of evolution through natural selection, prompting Darwin to finally publish his own work.
alferd Russel walace
Also known as gene flow, this is the transfer of genetic material from one population to another through the movement of individuals.
migration
Scientists use this modern molecule to compare the genetic codes of different species; the fewer differences found, the more closely related they are.
DNA
This pattern of evolution occurs when two unrelated species develop similar traits because they occupy similar environments, such as the streamlined bodies of sharks and dolphins.
convergent evolution
This widely accepted scientific theory explains that eukaryotic cells evolved when one prokaryotic cell engulfed another, forming a symbiotic relationship.
endosymbiosis
This diagram, often resembling a tree, is used by scientists to show the evolutionary relationships and shared ancestry among various species.
phylogenetic tree
This specific type of genetic drift occurs when a small group of individuals splits off from a larger population to establish a new colony, resulting in reduced genetic diversity.
founder effect
This field of study looks at the geographic distribution of plants and animals around the world, showing how isolation leads to the evolution of unique species, like marsupials in Australia.
biogeography
The rapid evolution of many diversely adapted species from a common ancestor when new ecological niches open up, famously seen in Darwin's finches.
adaptive radiation
Occurring roughly 252 million years ago, this catastrophic event is known as "The Great Dying" and is the most severe mass extinction in Earth's history.
permian extinction
This model of evolution suggests that species remain relatively stable for long periods of time, interrupted by brief, rapid bursts of significant change.
punctuated equilibrium