Evolutionary radiation

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Evolutionary radiation

An evolutionary radiation is an increase in taxonomic

Taxonomy

Taxonomy is the practice and science of classification. The word comes from the Greek language ', taxis and ', nomos .Taxonomies, or taxonomic schemes, are composed of taxonomic units known as taxa , or kinds of things that are arranged frequently in a hierarchical structure....
diversity or morphological

Morphology (biology)

The term morphology in biology refers to form, structure and configuration of an organism. This includes aspects of the outward appearance as well as the form and structure of the internal parts like bones and organs....
disparity, due to adaptive

Adaptation

Adaptation is the process, which takes place under natural selection, whereby an organism becomes better suited to its habitat. Also, the term may refer to some characteristic which stands out as being especially significant in the organism's survival....
change or the opening of ecospace. Radiations may affect one clade

Clade

A clade is a term used in modern alpha taxonomy, the scientific classification of living and fossil organisms, to describe a monophyletic group, defined as a group consisting of a single common ancestor and all its descendants.The term "monophyletic group" is used in this article in the conventional sense of "an a...
or many, and be rapid or gradual; where they are rapid, and driven by a single lineage's adaptation to their environment, they are termed adaptive radiations.

aps the most familiar example of an evolutionary radiation is that of placental mammals

Eutheria

Eutheria are a group of mammals consisting of placental mammals plus all extinct mammals that are more closely related to living placentals than to living marsupials ....
immediately after the extinction

Extinction

In biology and ecology, extinction is the death of every member of a species or group of taxon. The moment of extinction is generally considered to be the death of the last individual of that species ....
of the dinosaur

Dinosaur

Dinosaurs were the dominant vertebrate animals of Landform ecosystems for over 160 million years, from the late Triassic Period until the end of the Cretaceous Period , when most of them became extinct in the Cretaceous?Tertiary extinction event....
s at the end of the Cretaceous

Cretaceous

The Cretaceous , usually abbreviated K for its German translation Kreide, is a geologic period from circa to million years ago . In the geologic timescale, the Cretaceous follows on the Jurassic period and is followed by the Paleogene period....
, about 65 million years ago.

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Encyclopedia

An evolutionary radiation is an increase in taxonomic

Taxonomy

Morphology (biology)

Adaptation

Clade

Examples of evolutionary radiation

Perhaps the most familiar example of an evolutionary radiation is that of placental mammals

Eutheria

Extinction

Dinosaur

Cretaceous

Shrew

Shrews are small, superficially mouse-like mammals of the Family Soricidae. Although their external appearance is generally that of a long-nosed mouse, the shrews are not rodents and not closely related: the shrew family is part of the order Soricomorpha....
s. By the Eocene

Eocene

The Eocene Geologic time scale is a major division of the geologic timescale and the second epoch of the Palaeogene period in the Cenozoic era....
(58-37 million years ago), they had evolved into such diverse forms as bat

Bat

Bats are mammals in the order Chiroptera. The forelimbs of all bats are developed as wings, making them the only mammals naturally capable of sustained flight ....
s, whale

Whale

Whales are marine mammals of order Cetacea which are neither dolphinsmembers, in other words, of the families Oceanic dolphin or River dolphinnor porpoises....
s, and horse

Horse

The horse is a hoofed mammal, a subspecies of one of seven extant species of the family Equidae. The horse has evolution of the horse over the past 45 to 55 million years from a small multi-toed creature into the large, odd-toed ungulate animal of today....
s.

Other familiar radiations include the Cambrian explosion

Cambrian explosion

The Cambrian explosion or Cambrian radiation was the seemingly rapid appearance of most major groups of complex animals around , as evidenced by the fossil record....
, the radiation of land plants after their colonisation of land

Evolutionary history of plants

Plants have evolution through increasing Evolutionary grade, from the earliest algal mats, through bryophytes, lycopods, ferns and gymnosperms to the complex angiosperms of today....
, the Cretaceous radiation of angiosperms

Evolutionary history of plants

Devonian

The Devonian is a geologic period of the Paleozoic era spanning from . It is named after Devon, England, where rocks from this period were first studied....
, .

Types of radiation

Radiations may be discordant, with either diversity or disparity increasing almost independently of the other, or concordant, where both increase at a similar rate.

Evolutionary radiation in the fossil record

Much of the work carried out by palaeontologists studying evolutionary radiations has been using marine invertebrate

Invertebrate

An invertebrate is an animal lacking a vertebral column. The group includes 98% of all animal species ? all animals except those in the Chordate subphylum vertebrate ....
fossil

Fossil

Fossils are the preserved remains or trace fossil of animals, plants, and other organisms from the remote past. The totality of fossils, both discovered and undiscovered, and their placement in fossiliferous Rock formations and sedimentary rock layers is known as the fossil record....
s simply because these tend to be much more numerous and easy to collect in quantity than large land vertebrate

Vertebrate

Vertebrates are members of the subphylum Vertebrata, chordates with Vertebras or Vertebral columns. The grouping sometimes includes the hagfish, which have no vertebrae, but are genetically quite closely related to lampreys, which do have vertebrae....
s such as mammal

Mammal

Mammals are a class of vertebrate animals whose name is derived from their distinctive feature, mammary glands, with which they feed their young....
s or dinosaur

Dinosaur

Brachiopod

Brachiopods are a small Phylum of benthic invertebrates. Also known as lamp shells , "brachs" or Brachiopoda, they are Sessility , two-valved, Marine animals with an external morphology superficially resembling Bivalvias to which they are not closely related....
s, for example, underwent major bursts of evolutionary radiation in the Early Cambrian

Cambrian

The Cambrian is a geologic period that began about Mya at the end of the Proterozoic eon and ended about Ma with the beginning of the Ordovician period ....
, Early Ordovician

Ordovician

The Ordovician is a geologic period, the second of six of the Paleozoic era , and covers the time between 488.3?1.7 to 443.7?1.5 million years ago ....
, to a lesser degree throughout the Silurian

Silurian

The Silurian is a geologic period that extends from the end of the Ordovician period, about 443.7 ? 1.5 annum , to the beginning of the Devonian period, about 416.0 ? 2.8 Mya ....
and Devonian

Devonian

The Devonian is a geologic period of the Paleozoic era spanning from . It is named after Devon, England, where rocks from this period were first studied....
, and then again during the Carboniferous

Carboniferous

The Carboniferous is a geologic period that extends from the end of the Devonian period, about 359.2 ? 2.5 annum , to the beginning of the Permian period, about 299.0 ? 0.8 Ma ...
. During these periods, different species

Species

In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring....
of brachiopods independently assumed a similar morphology, and presumably mode of life, to species that had lived millions of years before. This phenomenon, known as homeomorphy is explained by convergent evolution

Convergent evolution

Convergent evolution describes the acquisition of the same biological trait in unrelated lineages.The wing is a classic example of convergent evolution in action....
: when subjected to similar selective pressures, organisms will often evolve similar adaptations. . Further examples of rapid evolutionary radiation can be observed among ammonite

Ammonite

Ammonites are an Extinction group of marine animals of the Subclass Ammonoidea in the class Cephalopoda, phylum Mollusca. They are excellent index fossils, and it is often possible to link the rock layer in which they are found to specific Geologic time scale....
s, which suffered a series of extinctions from which they repeatedly re-diversified; and trilobite

Trilobite

Trilobites are extinction marine arthropods that form the class Trilobita. They appeared in the Early Cambrian period and flourished throughout the lower Paleozoic era before beginning a drawn-out decline to extinction when, during the Late Devonian extinction, all trilobite orders, with the sole exception of Proetida, died out....
s which, during the Cambrian, rapidly evolved into a variety of forms occupying many of the niche

Ecological niche

In ecology, a niche is a term describing the relational position of a species or population in its ecosystem to each other; e.g. a dolphin will be in another ecological niche to one that travels in a different school.....
s exploited by crustacean

Crustacean

Crustaceans are a large group of arthropods, comprising almost 52,000 described species , and are usually treated as a subphylum . They include various familiar animals, such as crabs, lobsters, crayfish, shrimp, krill and barnacles....
s today , ,

Recent evolutionary radiations

A number of groups have undergone evolutionary radiation in relatively recent times. The cichlids in particular have been much studied by biologists

Biology

Biology is a branch of the natural sciences concerned with the study of living organisms and their interaction with each other and their environment ....
. In places such as Lake Malawi

Lake Malawi

Lake Malawi , is the most southerly lake in the East African Rift valley system. The lake, third largest in Africa and List of lakes by area, is situated between Malawi, Mozambique, and Tanzania....
they have evolved into a very wide variety of forms, including species that are filter feeders, snail eaters, brood parasites, algal grazers, and fish-eaters. Grass

Grass

Grass is the common word that generally describes monocotyledonous green plants. The family Poaceae are the "true grasses" and include most plants grown as grains, for pasture, and for lawns ....
es have been another success, evolving in parallel with grazing

Grazing

Grazing generally describes a type of predation in which a herbivore feeds on plants , or more broadly on a multicellular autotrophs . Grazing differs from true predation because the organism being eaten is not death, and it differs from parasitism as the two organisms do not symbiosis, nor is the grazer necessarily so limited in what it can...
herbivore

Herbivore

Herbivory is a form of predation in which an organism, known as an herbivore, heterotrophs principally autotrophs such as plants, algae and photosynthesizing bacteria....
s such as horses and antelope

Antelope

Antelope are ruminant hoofed mammals of the family Bovidae in the order of even-toed ungulates. These animals are spread relatively evenly throughout the various subfamily of Bovidae and many are more closely related to cows or goats than to each other....
.