Evolution definition, any process of formation or growth. Natural selection, inbreeding, hybridization, or mutation could bring about evolution. Evolution occurs by the natural selection of those who, by the fortune of spontaneous random changes mutations, happen to be best suited to their contemporary environment, to survive and reproduce. From the humboldt universitys department of biology we thank. Morphology and evolution of spider book lungs institut fur biologie. Scorpion book lungs are formed near the bilateral sites of earlier limb buds. Morphology and evolution of spider book lungs araneae. Evolutionary definition of evolutionary by medical. However, they were limited by their inability to inhabit drylands. Evolution definition and examples biology online dictionary. Why the evidence of evolution reveals a universe withou. The landmark paper for the field in the late 20th century is futuyma and moreno 1988 also see the historical overview in berenbaum 1996. The theory that all living organisms have developed in complexity, from a simple life form. The selfish gene by richard dawkins, the blind watchmaker.
Molluscs and arthropods use tracheae, book lungs, skin, or gills for gas exchange. Bmc evolutionary biology volume 18, article number. The ultrastructure of book lung development in the bark scorpion. Book lung development in the embryo, postembryo and first instar of. However, evolutionary biology is an intellectually and technologically dynamic discipline that includes some of the most exciting contemporary discoveries in the biological sciences. Shown herein are typical examples of lamellar formation in.
Pairs of book lungs bl and their stigmata st are formed on o4o7, and. In biology, evolution is the change in the inherited traits of a population from generation to generation. Evolutionist definition, a person who believes in or supports a theory of evolution, especially in biology. Results support the hypotheses for book gillbook lung homology and spider. Evolutionary biology definition of evolutionary biology. The study of specialization was growing rapidly in the 1980s, and condensing around a set of core hypotheses e. Each of these organs is found inside an open ventral abdominal, airfilled cavity atrium and connects with the surroundings through a small opening for the purpose of respiration. An additional abiogenic theory posits that falling sea levels and the. Book lungs definition and examples biology online dictionary. Book lungs are unique to five extant arachnid orders scorpiones. Evolutionary biology is the subfield of biology that studies the evolutionary processes natural selection, common descent, speciation that produced the diversity of life on earth. One of the longrunning controversies in arachnid evolution is whether the book lung evolved from book gills just once in a. Book lungs are an iconic character for arachnids, yet previous accounts of their morphology in spiders arachnida.
Homeosis in a scorpion supports a telopodal origin of pectines and. A book lung is a type of respiration organ used for atmospheric gas exchange that is found in many arachnids, such as scorpions and spiders. The morphological and functional evolution of appendages has played a. Evolutionary biology definition is a discipline of biology concerned with the processes and patterns of biological evolution especially in relation to the diversity of organisms and how they change over time.
1136 995 432 976 1322 1191 560 499 362 1467 1454 948 582 119 937 1156 1368 799 303 67 1405 1531 368 151 996 1548 1190 1468 1508 859 278 522 871 1089 1268 698 618 1122 846 382 157 682 164 1373 1337