Pereskia s.l. was found to be separated into the same clades in a 2011 study that used fewer genes but more species, although it was unable to resolve the members of the “core cacti” clade. The relationships depicted above were agreed to be “the most substantial to date.” [33]
Leuenbergeria species (Pereskia s.l. Clade A) consistently lack two essential stem characteristics that are present in the majority of the remaining “caulocacti”: first, like most non-cacti, their stems start to develop bark early in the plants’ lives; second, they lack stomatastructures that regulate air intake into a plant and, consequently, regulate photosynthesis. Contrarily, caulocacti, such as the surviving species of Pereskia s.s. and several Rhodocactus species, generally delay the formation of bark and have stomata on their stems, allowing the stem the ability to play a significant role in photosynthesis. (The two extremely specialized Maihuenia species make an exception.) [34] [36]
The original cacti are believed to have been tiny trees or shrubs with photosynthesis occurring in their leaves. They were residents of tropical regions that occasionally experienced drought. If Leuenbergeria is a suitable representation of these early cacti, then despite having superficial similarities to adjacent trees, they had already developed water-saving techniques (some of which are present in members of other families in the order Caryophyllales). These included the ability to react quickly to periods of rain and minimizing transpiration by making excellent use of water during photosynthesis. The latter was accomplished by closely regulating the stomata’s opening. Early relatives of Pereskia species may have had the ability to change from the typical C3 mechanism, in which carbon dioxide is continuously used in photosynthesis, to CAM cycling, in which carbon dioxide produced during respiration is stored for use during photosynthesis when the stomata are closed. [10]
The evolutionarily significant shift toward stems serving as photosynthetic organs can be seen in the group that includes Rhodocactus and Pereskia s.s. Stomata are present in stems, and bark develops later than it does in typical trees. The “core cacti” exhibit multiple leaf losses that are more-or-less total in the Cactoideae and a continuous rise in stem succulence and photosynthesis. Whether the transition to full CAM photosynthesis in stems occurred separately in Opuntioideae and Cactoideae, in which case it never developed in Maihuenia, or whether it occurred once in the core cacti, in which case it has been lost in Maihuenia. [10]
This article’s “Phylogeny”-related sections need to be updated. Please contribute to updating this article with new information or recent events. (May 2021)
Evolutionary history
Cacti have no fossilized remains that could shed light on how they evolved. [40] Cacti’s global range, however, provides some proof. Cacti are plants native to South America and primarily the southern areas of North America, with the exception of Rhipsalis baccifera, which has only recently expanded to parts of the Old World. This indicates that the family must have originated following the division of the once-common continent Gondwana into South America and Africa during the Early Cretaceous, some 145 to 101 million years ago. [41] It’s less known exactly when cacti evolved after this divide. Older data point to an early origin that occurred in the Late Cretaceous period 9066 million years ago. The origin may have occurred considerably more recently, maybe in the very Late Eocene to Early Oligocene periods, about 3530 million years ago, according to more recent molecular analyses. [40] [42] According to the cacti’s phylogeny, the Leuenbergeria cactus may have originated in Central America and northern South America, but the caulocacti, which have stems that are more or less succulent, evolved later in the southern region of South America before migrating north. [34] It is thought that core cacti, which have firmly succulent stems, first appeared about 25 million years ago. [40] Uplifting in the central Andes, around 2520 million years ago, which was connected to rising and fluctuating aridity, may have served as a catalyst for their evolution. [34] Other succulent plants, such as the Aizoaceae in South Africa, the Didiereaceae in Madagascar, and the genus Agave in the Americas, appear to have diversified at the same time, which coincided with a global expansion of arid environments. However, the current species diversity of cacti is thought to have arisen only in the last 105 million years (from the late Miocene into the Pliocene). [40]
What was the cactus’ ancestor?
Cactus by Dan Torre (Reaktion Books, 2017), which is essentially a social history of cacti, is the most recent book I’ve finished reading. Unfortunately,
at the rear. I decided to do more research because it piqued my attention.
About 1750 plant species make up the New World genus known as the cactus family.
The four subfamilies that make up the cactoids (including the common stem cacti, and
the opuntioids (the prickly pears, which make up around 75% of the species), the Pereskia (17 species, separated into two groups), and the Maihuenia (two species). In order to further understand the classification of cactus, a group was formed in 2012.
DNA analysis of the cacti’s traditional morphological classification scheme
taxonomists. Early findings indicate that more than half of the examined species do not
the other species in the same subfamily share common ancestors, hence there will be significant
Cacti share a number of physical and physiological characteristics that define them as cacti.
Most people think of cacti as having thorns and living in a desert, although not all species do.
Where orchids flourish, there are many cactus and plants with thorns. Like any substantial, intricate
They are particularly interesting because there are so many variations on the theme of family.
Since cactus fossils are unknown, determining their timing and location requires some
guesswork. Africa does not contain any cactus, so they must have developed after the
Gondwana broke split approximately 120 million years ago. new genetic research
Research on population radiation also indicate that the family has only recently appeared.
emerging for the first time between 30 and 35 million years ago, most likely in southern South America.
The cactus family is said to have descended from scrubby trees from a
It’s likely that the rate was accelerated by the continent’s uplift as the Andes started to emerge.
of species development within cacti. Previously, the Amazon River discharged into the Pacific Ocean,
nonetheless, the Andean uplift reversed that flow with an immense force around 15 million years ago.
Much of Amazonia is developing freshwater lakes. the river channel that exists today
Approximately 10 million years ago, the inland lake vanished. The climate dropped.
Further north, Central America was working to span the North Atlantic.
as well as South America. the shifting of tectonic jigsaw pieces that
represents the limited regions of Central America, the Caribbean, and Mexico.
only the final merging of the continents over a period of 100 million years
The geographical mass that is now Panama formed roughly five million years ago.
Cactus migration into North America has therefore been fairly quick. that 5 million people
types of prickly pair have spread across the entire country of the United States and into
regions of Canada. Specifically because they don’t exhibit the freeze, the cactoid group
In the arid southwest, opuntioids’ tolerance has trailed behind, although they do
Several more million years will likely pass before they stop radiating out into
Many gardeners express a strong dislike for cacti, especially the spiky ones.
they are resilient and fascinating plants. Learning a little bit more about them
Even the most adamant cactus hater might grow to like them a little bit more.
When did succulents begin to change?
Between 5 and 10 million years ago, the Earth’s topography underwent a significant alteration. Cacti appeared on the planet at around the same geologic time as other succulent plants and tropical grasses, according to biologists at Brown University and their colleagues. The catalyst was a worldwide cooling and aridification episode, possibly accompanied by a decrease in atmospheric carbon dioxide levels. The Proceedings of the National Academy of Sciences publishes their research.
PROVIDENCE [Brown University], Rhode Island
The cactus, a desert stalwart, has a fascinating tale to tell about the development of plant communities found all across the world.
Researchers from Brown University and their colleagues found that the rapid speciation of cacti took place between 5 and 10 million years ago and coincided with species explosions by other succulent plant groups all over the world. Their findings were published in a paper that was made available online by the Proceedings of the National Academy of Sciences. The researchers hypothesize that a protracted dry period and probably lower atmospheric carbon dioxide levels during that period, known as the late Miocene, created environment that supported the emergence of these plants and a significant change in the Earth’s vegetation.
“Although the cacti as a whole have been there for a while, Monica Arakaki, a postdoctoral researcher at Brown University and the paper’s primary author, claimed that the majority of the species diversity we see today was created only recently.
The primary goal of the Brown team’s research, along with those of associates from Oberlin College and the University of Zurich in Switzerland, was to determine when the cacti first appeared (scientific name Cactaceae). A phylogeny, or evolutionary tree, for angiosperms, the genealogical line of flowering plants that accounts for about 90% of all plants in the world, was constructed by the team by sequencing the chloroplast genomes (the organelles inside plant leaves that engineer photosynthesis) of a dozen cacti and their relatives. The scientists came to the conclusion that Cactaceae and its relatives in the angiosperm family first diverged approximately 35 million years ago, but that rapid speciation did not occur for at least another 25 million years.
“According to Erika Edwards, an assistant professor of biology in the Department of Ecology and Evolutionary Biology at Brown University and a corresponding author on the paper, cacti were actually present on the landscape for millions of years looking like cacti and behaving like cacti before they started their major diversification.
The crew then read up on the time of diversification in other succulents from different geographical areas. Aloes, North American agaves, South African ice plants, and other varieties are examples of succulents. Their natural habitat is in water-scarce environments, and they have developed physical adaptations to survive there, including shallow root systems, specialized water-storing tissue, and gas exchange at night when it is cooler and less humid, resulting in reduced water loss. The researchers were surprised to find that all succulent lineages underwent dramatic diversification between 5 and 10 million years ago, nearly at the same time as the cactus. This occurred across habitats and continents.
The tropical grasses known as C4 grasses, which currently make up up to 20% of our planet’s vegetative cover, also emerged during this same time period.
The researchers reasoned that this must be more than just a coincidence. “It shouldn’t come as a huge surprise that the majority of the standing cactus diversity is quite young. But when you consider all the other changes in plant communities that were occurring at the same time, all around the world, these species radiations beg the question of a worldwide environmental cause, according to Edwards.
The experts believed that a drying up of the globe and a decline in atmospheric carbon dioxide levels were the most likely explanations. Numerous studies using oxygen isotopes from a deep-sea organism revealed the Earth’s temperature dropped, which the experts believe caused worldwide rainfall to decline and aridity to rise.
The carbon dioxide connection is more complex and debatable. The authors draw attention to a study that suggested that atmospheric CO2 levels began to fall downward around 15 million years ago. When coupled with the global cooling, “According to the authors, a decrease in CO2 concentration would consequently rapidly increase the ecological space in which drought-tolerant succulent plants would be competitive due to their high photosynthetic water consumption efficiency.
We propose that the global diversification of plant lineages with a preadapted succulent condition during the late Miocene was mostly driven by a rapid expansion of suitable habitat (rather than any specific new ‘key’ innovation), the researchers write.
A dramatic CO2 reduction is a likely cause of the simultaneous spread of C4 grasslands, the clustering of new C4 origins, and the diversification of succulent lineages against a background of growing worldwide aridity.
Other authors who have contributed include Michael Moore from Oberlin, Reto Nyffeler and Anita Lendel from the University of Zurich, Urs Eggli from the Succulent Plant Collection in Zurich, graduate student R. Matthew Ogburn, and undergraduate student Elizabeth Spriggs, all from Brown.
Note to Editors:
Editors: For domestic and international live and recorded interviews, Brown University has a fiber link television studio available. For radio interviews, the university maintains an ISDN connection. You can reach us at (401) 863-2476 for further details.
How old are cacti on the planet?
The majority of plants from the New World are cacti. This indicates that only North America, South America, and the West Indies are home to them. Rhipsalis baccifera, a species with a pantropical distribution that can be found in tropical America as well as Old World tropical Africa, Madagascar, and Sri Lanka, is the sole exception. This plant is believed to have only recently colonized the Old World (within the last few thousand years). Its seeds were likely transported there by migratory birds. After being introduced by humans to comparable habitats in other regions of the world, many additional cacti have naturalized there.
It is thought that cacti have just been around for the past 30–40 million years. The Americas were once connected to the other continents, but continental drift caused them to separate. The New World’s distinctive species must have evolved after the continents split apart. Only in the last 50 million years have the continents moved significantly apart. The fact that the continents had already separated when cactus developed may help to explain why they are so uncommon in Africa. Many succulent plants, both in the Old and New Worlds, resemble cacti greatly and are frequently referred to as “cactus” in everyday speech. However, none of these are closely linked to the Cactaceae and this is because of parallel evolution.
In order to create a cochineal dye industry and serve as a natural agricultural fence, prickly pears (genus Opuntia) were brought to Australia in the 19th century. However, they soon spread like wildfire and became a major weed. For local herbivores, this invasive species is toxic, and it has rendered 40,000 km2 of arable ground unusable.