Macroevolution
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Macroevolution usually means the
evolution Evolution is change in the heritable characteristics of biological populations over successive generations. These characteristics are the expressions of genes, which are passed on from parent to offspring during reproduction. Variation ...
of large-scale structures and traits that go significantly beyond the intraspecific variation found in
microevolution Microevolution is the change in allele frequencies that occurs over time within a population. This change is due to four different processes: mutation, selection (natural and artificial), gene flow and genetic drift. This change happens over a r ...
(including
speciation Speciation is the evolutionary process by which populations evolve to become distinct species. The biologist Orator F. Cook coined the term in 1906 for cladogenesis, the splitting of lineages, as opposed to anagenesis, phyletic evolution within ...
). In other words, macroevolution is the
evolution Evolution is change in the heritable characteristics of biological populations over successive generations. These characteristics are the expressions of genes, which are passed on from parent to offspring during reproduction. Variation ...
of
taxa In biology, a taxon (back-formation from ''taxonomy''; plural taxa) is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit. Although neither is required, a taxon is usually known by a particular nam ...
above the
species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...
level (
genera Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nomenclat ...
,
families Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Ideal ...
,
orders Order, ORDER or Orders may refer to: * Categorization, the process in which ideas and objects are recognized, differentiated, and understood * Heterarchy, a system of organization wherein the elements have the potential to be ranked a number of d ...
, etc.). Macroevolution is often thought to require the evolution of completely new structures such as entirely new
organs In biology, an organ is a collection of tissues joined in a structural unit to serve a common function. In the hierarchy of life, an organ lies between tissue and an organ system. Tissues are formed from same type cells to act together in a f ...
. However, fundamentally novel structures are not necessary for dramatic evolutionary change. For instance, the evolution of
mammal Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur or ...
diversity in the past 100 million years has not required any major innovation. All of this diversity can be explained by modification of existing organs. In most cases, macroevolution cannot be observed directly because numerous mutations are required for large-scale changes. Hence specific methods are required to study and prove it. However, in rare cases single mutations can cause dramatic change and thus serve as models for macro-evolutionary processes.


Origin and changing meaning of the term

Philiptschenko distinguished between microevolution and macroevolution because he rejected natural selection in the sense of Darwin as an explanation for larger evolutionary transitions that give rise to taxa above the species level in the
Linnean taxonomy Linnaean taxonomy can mean either of two related concepts: # The particular form of biological classification (taxonomy) set up by Carl Linnaeus, as set forth in his ''Systema Naturae'' (1735) and subsequent works. In the taxonomy of Linnaeus t ...
. Accordingly, he restricted Darwinian "
microevolution Microevolution is the change in allele frequencies that occurs over time within a population. This change is due to four different processes: mutation, selection (natural and artificial), gene flow and genetic drift. This change happens over a r ...
" to evolutionary changes within the boundary of given species that may lead to different races or subspecies at the most. By contrast, he referred "macroevolution" to major evolutionary changes that correspond to taxonomic differences above the species level, which in his opinion would require evolutionary processes different from natural selection. An explanatory model for macroevolution in this sense was the "hopeful monster" concept of geneticist
Richard Goldschmidt Richard Benedict Goldschmidt (April 12, 1878 – April 24, 1958) was a German-born American geneticist. He is considered the first to attempt to integrate genetics, development, and evolution. He pioneered understanding of reaction norms, gen ...
, who suggested saltational evolutionary changes either due to mutations that affect the rates of developmental processes or due to alterations in the chromosomal pattern. Particularly the latter idea was widely rejected by the
modern synthesis Modern synthesis or modern evolutionary synthesis refers to several perspectives on evolutionary biology, namely: * Modern synthesis (20th century), the term coined by Julian Huxley in 1942 to denote the synthesis between Mendelian genetics and s ...
, but the hopeful monster concept based on evo-devo explanations found a moderate revival in recent times. Occasionally such dramatic changes can lead to novel features that survive. As an alternative to saltational evolution,
Dobzhansky Theodosius Grigorievich Dobzhansky (russian: Феодо́сий Григо́рьевич Добржа́нский; uk, Теодо́сій Григо́рович Добржа́нський; January 25, 1900 – December 18, 1975) was a prominent ...
suggested that the difference between macroevolution and microevolution reflects essentially a difference in time-scales, and that macroevolutionary changes were simply the sum of microevolutionary changes over geologic time. This view became broadly accepted, and accordingly, the term macroevolution has been used widely as a neutral label for the study of evolutionary changes that take place over a very large time-scale. However, the tenet that large-scale evolutionary patterns were ultimately reducible to microevolution has been challenged by the concept of species selection, which suggests that selection among species is a major evolutionary factor that is independent from and complementary to selection among organisms. Accordingly, the level of selection (or, more generally, of sorting) has become the conceptual basis of a third definition, which defines macroevolution as evolution through selection among interspecific variation.


Macroevolutionary processes


Species selection

"Species selection operates on variation provided by the largely random process of speciation and favors species that speciate at high rates or survive for long periods and therefore tend to leave many daughter species." Species selection comprises (a) effect-macroevolution, where organism-level traits (aggregate traits) affect speciation and extinction rates (Stanley's original concept), and (b) strict-sense species selection, where species-level traits (e.g. geographical range) affect speciation and extinction rates. It has been argued that effect macroevolution is reducible to microevolution because both operate through selection on organismic traits, but Grantham demonstrated that effect macroevolution can oppose selection at the organismic level and is therefore not reducible microevolution. Cases in which selection on the same trait has opposing effects at the organismic and the species level have been made in the context of sexual selection, which increases individual fitness but may also increase the extinction risk of the species.


Evolution of new organs and tissues

One of the main questions in evolutionary biology is how fundamentally new structures evolve, such as new
organs In biology, an organ is a collection of tissues joined in a structural unit to serve a common function. In the hierarchy of life, an organ lies between tissue and an organ system. Tissues are formed from same type cells to act together in a f ...
. As can be seen in
vertebrate evolution Vertebrates () comprise all animal taxa within the subphylum Vertebrata () ( chordates with backbones), including all mammals, birds, reptiles, amphibians, and fish. Vertebrates represent the overwhelming majority of the phylum Chordata, ...
, most "new" organs are actually not new—they are still modifications of previously existing organs. Examples are
wings A wing is a type of fin that produces lift while moving through air or some other fluid. Accordingly, wings have streamlined cross-sections that are subject to aerodynamic forces and act as airfoils. A wing's aerodynamic efficiency is expresse ...
(modified limbs),
feather Feathers are epidermal growths that form a distinctive outer covering, or plumage, on both avian (bird) and some non-avian dinosaurs and other archosaurs. They are the most complex integumentary structures found in vertebrates and a premier ...
s (modified
reptile scale Reptile skin is covered with scutes or scales which, along with many other characteristics, distinguish reptiles from animals of other classes. They are made of alpha and beta-keratin and are formed from the epidermis (contrary to fish, in which t ...
s),
lung The lungs are the primary organs of the respiratory system in humans and most other animals, including some snails and a small number of fish. In mammals and most other vertebrates, two lungs are located near the backbone on either side of t ...
s (modified
swim bladder The swim bladder, gas bladder, fish maw, or air bladder is an internal gas-filled Organ (anatomy), organ that contributes to the ability of many bony fish (but not cartilaginous fish) to control their buoyancy, and thus to stay at their curren ...
s, e.g. found in
fish Fish are aquatic, craniate, gill-bearing animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Approximately 95% of li ...
), or even the
heart The heart is a muscular organ in most animals. This organ pumps blood through the blood vessels of the circulatory system. The pumped blood carries oxygen and nutrients to the body, while carrying metabolic waste such as carbon dioxide t ...
(a muscularized segment of a
vein Veins are blood vessels in humans and most other animals that carry blood towards the heart. Most veins carry deoxygenated blood from the tissues back to the heart; exceptions are the pulmonary and umbilical veins, both of which carry oxygenated b ...
). The same concept applies to the evolution of "novel" tissues. Even fundamental tissues such as
bone A bone is a Stiffness, rigid Organ (biology), organ that constitutes part of the skeleton in most vertebrate animals. Bones protect the various other organs of the body, produce red blood cell, red and white blood cells, store minerals, provid ...
can evolve from combining existing
protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, respo ...
s (
collagen Collagen () is the main structural protein in the extracellular matrix found in the body's various connective tissues. As the main component of connective tissue, it is the most abundant protein in mammals, making up from 25% to 35% of the whole ...
) with calcium phosphate (specifically, hydroxy-apatite). This probably happened when certain cells that make collagen also accumulated calcium phosphate to get a proto-bone cell.


Molecular macroevolution

Microevolution is facilitated by
mutation In biology, a mutation is an alteration in the nucleic acid sequence of the genome of an organism, virus, or extrachromosomal DNA. Viral genomes contain either DNA or RNA. Mutations result from errors during DNA or viral replication, mi ...
s, the vast majority of which have no or very small effects on gene or protein function. For instance, the activity of an
enzyme Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products. A ...
may be slightly changed or the stability of a protein slightly altered. However, occasionally mutations can dramatically change the structure and functions of protein. This may be called "molecular macroevolution". Protein function. There are countless cases in which protein function is dramatically altered by mutations. For instance, a mutation in
acetaldehyde dehydrogenase Acetaldehyde dehydrogenases () are dehydrogenase enzymes which catalyze the conversion of acetaldehyde into acetic acid. The oxidation of acetaldehyde to acetate can be summarized as follows: Acetaldehyde + NAD+ + Coenzyme A ↔ Acetyl-CoA + NA ...
(EC:1.2.1.10) can change it to a 4-hydroxy-2-oxopentanoate pyruvate lyase (EC:4.1.3.39), i.e., a mutation that changes an enzyme from one to another EC class. Another example is the conversion of a
yeast Yeasts are eukaryotic, single-celled microorganisms classified as members of the fungus kingdom. The first yeast originated hundreds of millions of years ago, and at least 1,500 species are currently recognized. They are estimated to constitut ...
galactokinase Galactokinase is an enzyme (phosphotransferase) that facilitates the phosphorylation of α-D-galactose to galactose 1-phosphate at the expense of one molecule of ATP. Galactokinase catalyzes the second step of the Leloir pathway, a metabolic ...
(Gal1) to a
transcription factor In molecular biology, a transcription factor (TF) (or sequence-specific DNA-binding factor) is a protein that controls the rate of transcription of genetic information from DNA to messenger RNA, by binding to a specific DNA sequence. The fu ...
(Gal3) which can be achieved by an insertion of only two amino acids. While some mutations may not change the molecular function of a protein significantly, their biological function may be dramatically changed. For instance, most brain receptors recognize specific neurotransmitters, but that specificity can easily be changed by mutations. This has been shown by
acetylcholine receptor An acetylcholine receptor (abbreviated AChR) is an integral membrane protein that responds to the binding of acetylcholine, a neurotransmitter. Classification Like other transmembrane receptors, acetylcholine receptors are classified according ...
s that can be changed to
serotonin Serotonin () or 5-hydroxytryptamine (5-HT) is a monoamine neurotransmitter. Its biological function is complex and multifaceted, modulating mood, cognition, reward, learning, memory, and numerous physiological processes such as vomiting and vas ...
or
glycine receptor The glycine receptor (abbreviated as GlyR or GLR) is the receptor of the amino acid neurotransmitter glycine. GlyR is an ionotropic receptor that produces its effects through chloride current. It is one of the most widely distributed inhibitory ...
s which actually have very different functions. Their similar gene structure also indicates that they must have arisen from
gene duplication Gene duplication (or chromosomal duplication or gene amplification) is a major mechanism through which new genetic material is generated during molecular evolution. It can be defined as any duplication of a region of DNA that contains a gene. ...
s. Protein structure. Although protein structures are highly conserved, sometimes one or a few mutations can dramatically change a protein. For instance, an IgG-binding, 4\beta+\alpha fold can be transformed into an
albumin Albumin is a family of globular proteins, the most common of which are the serum albumins. All the proteins of the albumin family are water-soluble, moderately soluble in concentrated salt solutions, and experience heat denaturation. Albumins ...
-binding, 3-α fold via a single amino-acid mutation. This example also shows that such a transition can happen with neither function nor native structure being completely lost. In other words, even when multiple mutations are required to convert one protein or structure into another, the structure and function is at least partially retained in the intermediary sequences.


Examples


Stanley's rule

Macroevolution is driven by differences between species in origination and extinction rates. Remarkably, these two factors are generally positively correlated: taxa that have typically high diversification rates have also high extinction rates. This observation has been described first by
Steven Stanley Steven J. C. Stanley (born July 11, 1958), is a Jamaican audio engineer, record producer and keyboardist who has worked in the reggae, dub and rock music genres since 1975, most notably with Talking Heads, Tom Tom Club and Black Uhuru. Stanle ...
, who attributed it to a variety of ecological factors. Yet, a positive correlation of origination and extinction rates is also a prediction of the
Red Queen hypothesis The Red Queen hypothesis is a hypothesis in evolutionary biology proposed in 1973, that species must constantly adapt, evolve, and proliferate in order to survive while pitted against ever-evolving opposing species. The hypothesis was intended ...
, which postulates that evolutionary progress (increase in fitness) of any given species causes a decrease in fitness of other species, ultimately driving to extinction those species that do not adapt rapidly enough. High rates of origination must therefore correlate with high rates of extinction. Stanley's rule, which applies to almost all taxa and geologic ages, is therefore a strong indication for a dominant role of biotic interactions in macroevolution.


"Macromutations": Single mutations leading to dramatic change

While the vast majority of mutations are inconsequential, some can have a dramatic effect on morphology or other features of an organism. One of the best studied cases of a single mutation that leads to massive structural change is the
Ultrabithorax Ultrabithorax (Ubx) is a homeobox gene found in insects, and is used in the regulation of patterning in morphogenesis. There are many possible products of this gene, which function as transcription factors. Ubx is used in the specification of s ...
mutation in fruit flies. The mutation duplicates the wings of a fly to make it look like a
dragonfly A dragonfly is a flying insect belonging to the infraorder Anisoptera below the order Odonata. About 3,000 extant species of true dragonfly are known. Most are tropical, with fewer species in temperate regions. Loss of wetland habitat threate ...
which represents a different order of insect.


Evolution of multicellularity

The evolution of multicellular organisms is one of the major breakthroughs in evolution. The first step of converting a unicellular organism into a metazoan (a multicellular organism) is to allow cells to attach to each other. This can be achieved by one or a few mutations. In fact, many
bacteria Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were among ...
form multicellular assemblies, e.g.
cyanobacteria Cyanobacteria (), also known as Cyanophyta, are a phylum of gram-negative bacteria that obtain energy via photosynthesis. The name ''cyanobacteria'' refers to their color (), which similarly forms the basis of cyanobacteria's common name, blu ...
or
myxobacteria The myxobacteria ("slime bacteria") are a group of bacteria that predominantly live in the soil and feed on insoluble organic substances. The myxobacteria have very large genomes relative to other bacteria, e.g. 9–10 million nucleotides except ...
. Another species of bacteria, ''Jeongeupia sacculi'', form well-ordered sheets of cells, which ultimately develop into a bulbous structure. Similarly, unicellular yeast cells can become multicellular by a single mutation in the ACE2 gene, which causes the cells to form a branched multicellular form.


Evolution of bat wings

The wings of
bat Bats are mammals of the order Chiroptera.''cheir'', "hand" and πτερόν''pteron'', "wing". With their forelimbs adapted as wings, they are the only mammals capable of true and sustained flight. Bats are more agile in flight than most ...
s have the same structural elements (bones) as any other five-fingered mammal (see periodicity in limb development). However, the finger bones in bats are dramatically elongated, so the question is how these bones became so long. It has been shown that certain growth factors such as bone morphogenetic proteins (specifically Bmp2) is over expressed so that it stimulates an elongation of certain bones. Genetic changes in the bat genome identified the changes that lead to this phenotype and it has been recapitulated in mice: when specific bat DNA is inserted in the mouse genome, recapitulating these mutations, the bones of mice grow longer.


Limbloss in lizards and snakes

Snake Snakes are elongated, Limbless vertebrate, limbless, carnivore, carnivorous reptiles of the suborder Serpentes . Like all other Squamata, squamates, snakes are ectothermic, amniote vertebrates covered in overlapping Scale (zoology), scales. Ma ...
s evolved from
lizard Lizards are a widespread group of squamate reptiles, with over 7,000 species, ranging across all continents except Antarctica, as well as most oceanic island chains. The group is paraphyletic since it excludes the snakes and Amphisbaenia alt ...
s.
Phylogenetic In biology, phylogenetics (; from Greek φυλή/ φῦλον [] "tribe, clan, race", and wikt:γενετικός, γενετικός [] "origin, source, birth") is the study of the evolutionary history and relationships among or within groups o ...
analysis shows that snakes are actually nested within the
phylogenetic tree A phylogenetic tree (also phylogeny or evolutionary tree Felsenstein J. (2004). ''Inferring Phylogenies'' Sinauer Associates: Sunderland, MA.) is a branching diagram or a tree showing the evolutionary relationships among various biological spec ...
of lizards, demonstrating that they have a common ancestor. This split happened about 180 million years ago and several intermediary fossils are known to document the origin. In fact, limbs have been lost in numerous clades of reptiles, and there are cases of recent limb loss. For instance, the skink genus Lerista has lost limbs in multiple cases, with all possible intermediary steps, that is, there are species which have fully developed limbs, shorter limbs with 5, 4, 3, 2, 1 or no toes at all.


Human evolution

While human evolution from their primate ancestors did not require massive morphological changes, our brain has sufficiently changed to allow human consciousness and intelligence. While the latter involves relatively minor morphological changes it did result in dramatic changes to
brain function A brain is an organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals. It is located in the head, usually close to the sensory organs for senses such as vision. It is the most complex organ in a ver ...
. Thus, macroevolution does not have to be morphological, it can also be functional.


Evolution of viviparity in lizards

Most lizards are egg-laying and thus need an environment that is warm enough to incubate their eggs. However, some species have evolved
viviparity Among animals, viviparity is development of the embryo inside the body of the parent. This is opposed to oviparity which is a reproductive mode in which females lay developing eggs that complete their development and hatch externally from the m ...
, that is, they give birth to live young, as almost all
mammal Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur or ...
s do. In several clades of lizards, egg-laying (oviparous) species have evolved into live-bearing ones, apparently with very little genetic change. For instance, a European common lizard, ''Zootoca vivipara'', is vivparous throughout most of its range, but oviparous in the extreme southwest portion. That is, within a single species, a radical change in reproductive behavior has happened. Similar cases are known from South American lizards of the genus ''
Liolaemus ''Liolaemus'' is a genus of iguanian lizards, containing many species, all of which are endemic to South America. Description Members of the genus ''Liolaemus'' form a dominant part of the lizard fauna of the southern part of the continent of ...
'' which have egg-laying species at lower altitudes, but closely related viviparous species at higher altitudes, suggesting that the switch from oviparous to viviparous reproduction does not require many genetic changes.


Criticism

Evolution Evolution is change in the heritable characteristics of biological populations over successive generations. These characteristics are the expressions of genes, which are passed on from parent to offspring during reproduction. Variation ...
as a biological process is now broadly accepted by the scientific community, but also by circles who were formerly opposed to it, such as the
Catholic church The Catholic Church, also known as the Roman Catholic Church, is the largest Christian church, with 1.3 billion baptized Catholics worldwide . It is among the world's oldest and largest international institutions, and has played a ...
. Below are some common misrepresentations of macroevolution. Lack of observation and missing links. While microevolution can be observed and measured in living organisms (e.g. as
genetic variation Genetic variation is the difference in DNA among individuals or the differences between populations. The multiple sources of genetic variation include mutation and genetic recombination. Mutations are the ultimate sources of genetic variation, ...
or selection within
population Population typically refers to the number of people in a single area, whether it be a city or town, region, country, continent, or the world. Governments typically quantify the size of the resident population within their jurisdiction using a ...
s), critics argue that macroevolution cannot be observed, given that it occurs over millions of years. Long-term changes as "observed" through the
fossil record A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved in ...
are usually spotty so that links between different species are often missing. This argument has been refuted by the fact that many transitional forms have indeed been found (e.g. '' Archaeopteryx'' and living examples above). More importantly, transitions have been meticulously documented in the
genome In the fields of molecular biology and genetics, a genome is all the genetic information of an organism. It consists of nucleotide sequences of DNA (or RNA in RNA viruses). The nuclear genome includes protein-coding genes and non-coding ge ...
s of organisms (e.g. all mutations are known that happened in
human evolution Human evolution is the evolutionary process within the history of primates that led to the emergence of ''Homo sapiens'' as a distinct species of the hominid family, which includes the great apes. This process involved the gradual development of ...
since our lineage split from that leading to
chimpanzee The chimpanzee (''Pan troglodytes''), also known as simply the chimp, is a species of great ape native to the forest and savannah of tropical Africa. It has four confirmed subspecies and a fifth proposed subspecies. When its close relative th ...
s). Finally, historical processes can be recapitulated in the laboratory and thus observed using experiments (e.g., see evolution of bat wings, above).
Irreducible complexity Irreducible complexity (IC) is the argument that certain biological systems with multiple interacting parts would not function if one of the parts was removed, so supposedly could not have evolved by successive small modifications from earlier l ...
. Large transitions in evolution are said to be impossible because many structures in biology are "irreducibly complex". The most cited example is the
bacterial flagellum A flagellum (; ) is a hairlike appendage that protrudes from certain plant and animal sperm cells, and from a wide range of microorganisms to provide motility. Many protists with flagella are termed as flagellates. A microorganism may have f ...
, a multiprotein complex that, allegedly, cannot evolve from simpler structures because any simpler ancestor would be non-functional. However, this claim has been debunked numerous times: many proteins of the flagellar apparatus can be deleted without loss of function, hence the structure is certainly not "irreducibly complex". In addition, there is convincing evidence that flagella have evolved from much simpler structures similar to type III secretion systems.


Research topics

Subjects studied within macroevolution include:Grinin, L., Markov, A. V., Korotayev, A. Aromorphoses in Biological and Social Evolution: Some General Rules for Biological and Social Forms of Macroevolution / Social evolution & History, vol.8, num. 2, 200

/ref> *
Adaptive radiation In evolutionary biology, adaptive radiation is a process in which organisms diversify rapidly from an ancestral species into a multitude of new forms, particularly when a change in the environment makes new resources available, alters biotic int ...
s such as the
Cambrian Explosion The Cambrian explosion, Cambrian radiation, Cambrian diversification, or the Biological Big Bang refers to an interval of time approximately in the Cambrian Period when practically all major animal phyla started appearing in the fossil recor ...
. * Changes in
biodiversity Biodiversity or biological diversity is the variety and variability of life on Earth. Biodiversity is a measure of variation at the genetic (''genetic variability''), species (''species diversity''), and ecosystem (''ecosystem diversity'') l ...
through time. *
Genome evolution Genome evolution is the process by which a genome changes in structure (sequence) or size over time. The study of genome evolution involves multiple fields such as structural analysis of the genome, the study of genomic parasites, gene and ancient ...
, like
horizontal gene transfer Horizontal gene transfer (HGT) or lateral gene transfer (LGT) is the movement of genetic material between Unicellular organism, unicellular and/or multicellular organisms other than by the ("vertical") transmission of DNA from parent to offsprin ...
, genome fusions in endosymbioses, and adaptive changes in genome size. *
Mass extinctions An extinction event (also known as a mass extinction or biotic crisis) is a widespread and rapid decrease in the biodiversity on Earth. Such an event is identified by a sharp change in the diversity and abundance of multicellular organisms. It ...
. * Estimating
diversification rates Diversification rates are the rates at which new species form (the Speciation rate, λ) and living species go extinct (the extinction rate, μ). Diversification rates can be estimated from fossils, data on the species diversity of clades and their ...
, including rates of
speciation Speciation is the evolutionary process by which populations evolve to become distinct species. The biologist Orator F. Cook coined the term in 1906 for cladogenesis, the splitting of lineages, as opposed to anagenesis, phyletic evolution within ...
and
extinction Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...
. * The debate between
punctuated equilibrium In evolutionary biology, punctuated equilibrium (also called punctuated equilibria) is a Scientific theory, theory that proposes that once a species appears in the fossil record, the population will become stable, showing little evolution, evol ...
and gradualism. * The role of development in shaping evolution, particularly such topics as
heterochrony In evolutionary developmental biology, heterochrony is any genetically controlled difference in the timing, rate, or duration of a developmental process in an organism compared to its ancestors or other organisms. This leads to changes in the ...
and
phenotypic plasticity Phenotypic plasticity refers to some of the changes in an organism's behavior, morphology and physiology in response to a unique environment. Fundamental to the way in which organisms cope with environmental variation, phenotypic plasticity encompa ...
.


See also

*
Extinction event An extinction event (also known as a mass extinction or biotic crisis) is a widespread and rapid decrease in the biodiversity on Earth. Such an event is identified by a sharp change in the diversity and abundance of multicellular organisms. I ...
*
Interspecific competition Interspecific competition, in ecology, is a form of competition in which individuals of ''different'' species compete for the same resources in an ecosystem (e.g. food or living space). This can be contrasted with mutualism, a type of symbiosis. ...
*
Microevolution Microevolution is the change in allele frequencies that occurs over time within a population. This change is due to four different processes: mutation, selection (natural and artificial), gene flow and genetic drift. This change happens over a r ...
*
Molecular evolution Molecular evolution is the process of change in the sequence composition of cellular molecules such as DNA, RNA, and proteins across generations. The field of molecular evolution uses principles of evolutionary biology and population genetics ...
*
Punctuated equilibrium In evolutionary biology, punctuated equilibrium (also called punctuated equilibria) is a Scientific theory, theory that proposes that once a species appears in the fossil record, the population will become stable, showing little evolution, evol ...
*
Red Queen hypothesis The Red Queen hypothesis is a hypothesis in evolutionary biology proposed in 1973, that species must constantly adapt, evolve, and proliferate in order to survive while pitted against ever-evolving opposing species. The hypothesis was intended ...
*
Speciation Speciation is the evolutionary process by which populations evolve to become distinct species. The biologist Orator F. Cook coined the term in 1906 for cladogenesis, the splitting of lineages, as opposed to anagenesis, phyletic evolution within ...
*
Unit of selection A unit of selection is a biological entity within the hierarchy of biological organization (for example, an entity such as: a self-replicating molecule, a gene, a cell, an organism, a group, or a species) that is subject to natural selection. ...


References


Further reading

*What is marcroevolution? (pdf) https://onlinelibrary.wiley.com/doi/full/10.1111/pala.12465 * * * * *


External links


Introduction to macroevolution

Macroevolution as the common descent of all life


Macroevolution as an independent discipline.

{{evolution Evolutionary biology