The evolution of a new feature may let a group diversify because it makes possible new ways of living. A most striking example is the cleidoic egg, which developed in early amniotes, and permitted vertebrates to invade the land. The cleidoic egg must have been developed in the latest Devonian or early Carboniferous. Amphibians, who branched off before this event, still lay their eggs in water, and so are limited in the extent to which they can exploit land environments.
An example of a more modest innovation is the evolution of a fourth cusp in the mammalian tooth. This trait permits a vast increase in the range of foodstuffs which can be fed on. Evolution of this character has thus increased the number of ecological niches available to mammals. The trait arose a number of times in different groups during the Cenozoic, and in each instance was immediately followed by an adaptive radiation. With birds, the evolution of flight opened new possibilities, and at least two huge adaptive radiations occurred (one before and one after the K/T extinction event). Even more striking was the evolution of insect flight, which led to huge radiation in the Mesozoic era. Then, these insect groups developed ways of feeding on flowering plants. They now outnumber all other forms of animal life by quite a margin.
Adaptive radiations often happen when organisms enter environments with unoccupied niches, such as a newly formed lake or an isolated island chain. The colonizing population(s) may diversify rapidly and take advantage of all possible niches. Opportunities occur when land bridges form between areas which were previously separate, and whenever species get to new place in the world.
In Lake Victoria, an isolated lake which formed recently in the African rift valley, over 300 species of cichlid fish radiated from one parent species in just 15,000 years.
In about , the Hawaiian Islands have the most diverse collection of drosophilid flies in the world, living from rainforests to mountain meadows. About 800 Hawaiian drosophilid species are known.
Studies show a clear "flow" of species from older to newer islands. There are also cases of colonization back to older islands, and skipping of islands, but these are much less frequent. By potassium/argon radioactive dating, the present islands date from 0.4 million years ago (mya) (Mauna Kea) to 10mya (Necker). The oldest member of the Hawaiian archipelago still above the sea is Kure Atoll, which can be dated to 30 mya. The archipelago itself, produced by the Pacific plate moving over a hot spot, has existed for far longer, at least into the Cretaceous. The Hawaiian islands plus former islands which are now beneath the sea make up the Hawaiian–Emperor seamount chain; and many of the underwater mountains are guyots.
All of the native drosophilid species in Hawaii have apparently descended from "a single ancestral species" that colonized the islands, about 20 million years ago. The subsequent adaptive radiation was spurred by a lack of competition and a wide variety of vacant niches. Although it would be possible for a single pregnant female to colonise an island, it is more likely to have been a group from the same species.
There are other animals and plants on the Hawaiian archipelago which have undergone similar, if less spectacular, adaptive radiations.
Adaptive radiations commonly follow mass extinctions. After an extinction event, many niches are left vacant. A classic example of this is the replacement of the non-avian dinosaurs at the end of the Cretaceous with mammals in the Palaeocene.
Ajda Pekkan
Ajda Pekkan (born February 12, 1946 in Istanbul, Turkey) is a Turkish singer and actress. She is one of the most successful Turkish singers with the sales of over 30 million copies worldwide. She is called ""Superstar"". She has released more than 20 albums. Most famous ones are "Superstar", "Superstar II", "Superstar III" (also known as Superstar 83), "Ajda '90", "Ajda '93", "The Best of Ajda", "Diva", "Cool Kadın" and "Farkın Bu". Also he recorded singles in French and English.
Ajda was born to Rıdvan Pekkan, an officer in the Turkish Navy, and Nevin Dobruca, a housewife. She spent her childhood at the Gölcük Naval Base in Kocaeli Province. Ajda graduated from the Çamlıca Kız Lisesi.
She won a Cover Star contest in 1963 and she began her professional career. She started her career as an actress. She was a popular actress in 60s. She released her very first recording, "Göz Göz Değdi Bana" as a B-Side in 1964. Following year, she released her first single, "Her Yerde Kar Var" in 1965. In April 1977, she released an album called "Superstar". It was a great success. Album sold over millions of copies and became a classic. Her next album, "Superstar II", released in May 1979. It was more successful than Superstar. Songs from album, Bambaşka Biri (It was a Turkish cover of I Will Survive and it became a signature song of Ajda Pekkan), Dile Kolay, Ya Sonra, Haykıracak Nefesim Kalmasa Bile, Yeniden Başlasın, Bir Köşede Yalnız were successful hits. She gave concerts in Tehran, Paris and Tokyo in the 70s. She represented Turkey with the famous entry "Petr' oil" at the 1980 Eurovision Song Contest in the Hague, the Netherlands.
She released her first album on CD, "Ajda '90" in 1990. She recorded her "Ajda '93" album in the USA and Switzerland. Her complation albums containing the new recordings of his hit songs, "The Best of Ajda" and "Diva" were very successful albums. Her latest album, "Farkın Bu", which released in July 2011 became the most selling album of 2011 in Turkey.
The Fabulous Moolah
Mary Lillian Ellison (born July 22, 1923 in Kershaw County, South Carolina – died November 2, 2007 in Columbia, South Carolina), better known by her ring name The Fabulous Moolah, was an American female professional wrestler. She wrestled for WWE. She was a 4 time WWF Women's Champion. She was champion for almost thirty years. That made her champion longer than anyone else in the sport. She was inducted into the 1995 WWE Hall of Fame. She was the first woman to join the WWE Hall of Fame. She is also the oldest WWE Women's Champion ever to win the title against Ivory at No Mercy in 1999. She was best friends with fellow wrestler "Mae Young". The Fabulous Moolah also has a book about her life titled, "The Fabulous Moolah: First Goddess of the Squared Circle".
Moolah died on November 2, 2007 in Columbia, South Carolina of a heart attack.
Percentile
A percentile (or a centile) is a measure in statistics. It shows the value below which a given percentage of observations falls.
For example, the 20th percentile is the value (or score) below which 20% of the observations may be found. The 35th percentile is the value below which 35% of the data may be found. In general, the "i"-th percentile, written as formula_1, is the value below which "i" percents of data may be found.
In statistics, a large set of numerical data is sometimes divided into 100 groups, each with 1% of the data. The data are arranged in ascending order. Each of the 99 dividing points is called a percentile of the data set.
Some of the percentiles have special names. For example. the 25th, 50th and 75th percentiles are called the first, second and third quartile, respectively. The 50th percentile is also called the median.
Grand Coulee
The Grand Coulee used to be a river in the U.S. state of Washington. This dry river stretches for sixty miles from the Grand Coulee Dam to Soap Lake. A feature known as Dry Falls divides the Coulee into two parts. Dry Falls is thought to be the remains of the largest waterfall ever, two or three times higher than Niagara Falls.