Speciation
This term describes the process by which one species splits into two or more species.
What is speciation?
This significant event, occurring about 2.4 billion years ago, marked a dramatic increase in Earth's atmospheric oxygen levels, largely due to the photosynthetic activity of cyanobacteria.
What is the Oxygen Revolution (or Great Oxidation Event)?
Traits that arise due to shared ancestry are called this, distinguishing them from traits that arise due to convergent evolution.
What are homologous traits?
This 18th-century scientist developed the system of binomial nomenclature still used today.
Who is Carolus Linnaeus?
This mass extinction event, occurring at the end of the Permian period, wiped out approximately 96% of marine species and is the largest known extinction in Earth's history.
What is the Permian-Triassic extinction (The Great Dying)?
A region where members of different species meet and produce offspring is known as this.
What is a hybrid zone?
This evolutionary event, which began around 535 million years ago, saw the rapid diversification of animal phyla in the fossil record.
What is the Cambrian Explosion?
The wings of birds and the wings of bats are an example of this type of similarity due to convergent evolution.
What is analogy?
The concept that changes in the DNA sequence can be passed down to subsequent generations, and those that confer a survival advantage may lead to adaptive evolution, is fundamental to this mechanism of molecular evolution.
What is genetic mutation?
A process that occurs in a hybrid zone when the offspring of two closely related species are less fit than their parents.
What is reinforcement?
This type of reproductive barrier prevents fertilization by impeding mating attempts, preventing successful mating, or hindering fertilization.
What are prezygotic barriers?
This hypothesis suggests that evolutionary change occurs in rapid bursts followed by long periods of stasis.
What is punctuated equilibrium?
This principle assumes that the simplest explanation, requiring the fewest evolutionary changes, is the most likely.
What is maximum parsimony?
This phenomenon, common in plants, results in an organism having extra sets of chromosomes, potentially leading to speciation.
What is polyploidy?
This type of selection occurs when individuals with intermediate phenotypes have higher fitness than individuals with either extreme phenotype, resulting in a narrowing of the phenotypic distribution.
What is stabilizing selection?
According to the biological species concept, a species is defined by its ability to do this successfully.
What is interbreed and produce viable, fertile offspring?
This process occurs when a single ancestral species rapidly diversifies into multiple new species to exploit different ecological niches.
What is adaptive radiation?
This type of taxonomic grouping consists of an ancestor and some, but not all, of its descendants.
What is a paraphyletic group?
This form of speciation occurs when a population is divided by a geographical barrier, leading to genetic divergence.
What is allopatric speciation?
This phenomenon occurs when a population’s gene pool is altered by chance events, such as a natural disaster or the random death of individuals with certain traits, rather than by selection pressures or adaptation.
What is genetic drift?
When first-generation hybrids are viable and fertile, but their offspring are weak or sterile, this specific type of postzygotic barrier occurs.
What is hybrid breakdown?
This molecule, believed to have been one of the key building blocks in the origin of life, is capable of both storing genetic information and catalyzing chemical reactions, offering an alternative model to RNA's role in early evolution.
What is ribozymes?
Unlike previous classification systems, the modern three-domain system was established based on this type of data, which revealed fundamental differences between prokaryotic lineages.
What is molecular (or genetic) data?
When two species in a hybrid zone experience extensive gene flow and hybrids are as fit as the parent species, this outcome can occur, eventually leading to the merging of the two species.
What is fusion?
Unlike allopatric speciation, which occurs due to geographic separation, sympatric speciation can occur through these three main mechanisms.
What are polyploidy (chromosome number changes), disruptive selection (different ecological niches within a population), and behavioral isolation (differences in mating behaviors)?