USGS Paleontology glossary Acritarch microscopic organic structure from any of a number of organisms; common during the Proterozoic. Adaptive radiation, evolutionary radiation the rapid expansion and diversification of a group of organisms as they fill unoccupied ecological niches , evolving into new species.
Age of Mammals term found in popular books on evolutionary systematics for the Cenozoic era, beginning with the Paleocene Epoch when following the K—T end Cretaceous mass extinction , mammals underwent a huge evolutionary radiation and thus replaced reptiles as the dominant life on Earth.
The Age of Mammals has in turn been replaced by the Anthropocene or Age of Man, Holocene when humans dominate every conceivable environment and most other life forms apart from weedy species are suffering a mass extinction Yes, I know humans are also mammals, so technically speaking this is still the Age of Mammals, but I tend to think of the Age of Mammals as a period of flourishing biodiversity.
MAK Age of Reptiles term found in popular books on evolutionary systematics for the Permian through to Cretaceous periods but obviously originating with Victorian discoveries of "antediluvian monsters" , when reptiles first mammal-like reptiles , then archosaurs and marine reptiles were the dominant life on Earth. Paleontologist Edwin Colbert wrote a popular intelligent layperson book with the same title. The Age of Reptiles was followed by the Age of Mammals. The fresco sits in the Yale Peabody Museum in New Haven, Connecticut, and was completed in after three years of work.
The Age of Reptiles was at one time the largest painting in the world, and depicts a span of nearly million years in Earth's history. Painted in the Renaissance fresco secco technique, The Age of Reptiles was an important cultural influence during the s—60s, images of which are often found in earlier books on paleontology, and was also the model for dinosaur toys. Despite its somewhat outdated view of dinosaurs presenting them as slow, sluggish creatures , The Age of Reptiles is still notable for its historical and artistic merit and as the largest natural history painting in the world.
It has been an inspiration to many visitors including both Robert Bakker and Peter Dodson , who credit it with influencing them to become paleontologists. Dodson was nearly moved to tears upon first seeing it as a college senior. In my own case MAK , a photo of this mural in a book I no longer remember which one when I was still a young child maybe 10 or so exerted a huge influence on me, like a revelation, and for the first time gave me a visual appreciation of deep time in terms of succession and transformation of various forms of plant and animal life.
To this day, this mural, along with a spindle diagram of vertebrate evolution in G. Well's Science of Life, have been the two central influences that determined the way I think about deep time and the evolution of life on Earth. I think of Palaeos as in many ways simply an extension, update in keeping with more recent discoveries and commentary on this magnificent work.
MAK Wikipedia Agnatha name given to what was previously considered a class of jawless fish, including both Paleozoic ostracoderms and extant lampreys and hagfish. With the cladistic revolution , the term has been replaced by more phylogenetically accurate terms such as " basal vertebrate ". Armoured agnathans are called ostracoderms.
USGS Paleontology glossary Algae generic term for photosynthetic , almost exclusively aquatic, non-vascular plants; Precambrian to recent. Algorithm In mathematics and computer science, an effective method a procedure that reduces the solution of some class of problems to a series of rote steps that give a specific and correct answer expressed as a finite list of well-defined instructions for calculating a function.
Algorithms are used for calculation, data processing, and automated reasoning. Amino acid The molecular building blocks of proteins. The properties of a protein are determined by its particular amino acid sequence.
There are 20 amino acids in the proteins of life on Earth. Ammonite A coiled, chambered fossil shell of a cephalopod mollusc of the extinct subclass Ammonoidea.
Amoeba A microscopic, single celled protozoan consisting of a naked mass of protoplasm. Once considered the simplest form of animal life, they are now known to consist of several distinct and unrelated groups of protists. Morphologically and ecologically diverse during the late Paleozoic era, including aquatic, semi-aquatic, and terrestrial newt, snake, crocodile, and frog analogues.
The traditional term "amphibian" is disliked by cladists because it does not constitute a natural clade and so is considered phylogenetically meaningless. Hence instead terms like basal tetrapod or the names of individual clades and taxa temnospondyls, lepidospondyls, Lissamphibia , etc , are used.
Nevertheless, "amphibian" can still be used in a generic sense to refer to any non-amniotic tetrapod. MAK, Perseus Digital Library Amniote major tetrapod lade that reproduce by means of an external or internal egg in which the embryo or fetus is protected and nourished by several extensive membranes.
Include reptiles , birds , and mammals. Middle Carboniferous to recent. Anagenesis the evolutionary transformation of one species over time into another, resulting in the emergence of a new character or attribute which in this case a new species from an older one. Compare with cladogenesis and budding.
Ancestor in this context, an organism, or more correctly a population , lineage , or species , that through evolution gives rise to one or more descendants that generally belong to a distinct species or lineage. See also common ancestor.
A secular form of intelligent design. Generally does not try to explain where the rest of life or the aliens themselves, for that matter!
A more recent iteration can be found in Ridley Scott's movie Prometheus. Palaeobiology and Biodiversity Research Group: Late Cretaceous Climate Change: Glossary Ankylosaur herbivourous armoured mostly Cretaceous "bird hipped" dinosaurs with rows of bony plates protecting the sides and back, and armed with either spikes along the sides or a bony club at the end of the trail Anthropocene informal geochronological term that serves to mark the evidence and extent of human activities that have had a significant global impact on the Earth's ecosystems.
Compare Ascent , Creationism , Teleology. Apomorphy In cladistics , a unique derived character trait found in a particular taxon, which is also possessed by a common ancestor. Aptian geologic age of the Early Cretaceous , spanning the time between and million years ago.
USGS Paleontology glossary Archaea one of the three domains of life in the molecular phylogeny described by Carl Woese originally Archaeobacteria, renamed Archaea by Woese et al , prokaryotes that are metabolically and morphologically distinct from Eubacteria ; includes many types of extremophiles , remnants from the earlier history of the earth.
Since each presents strong arguments, we defer trying to decide which paradigm is correct. MAK Archean the second of the four eons of the geological timescale , characterised by a reducing non-oxygen atmosphere and the earliest prokaryote life. It lasted from about 3. Archaeopteryx the earliest and most primitive known bird , most of whose fossil remains were recovered in the 19th century, from the Jurassic Solnhofen limestone in Bavaria.
Perfectly intermediate between reptile or more correctly, theropod dinosaur and modern bird, its discovery was powerful evidence for Darwinian evolution. Dominated terrestrial ecosystems for the entirety of the Mesozoic. An important component in marine and terrestrial ecosystems.
Perseus Digital Library Ascent The premise that evolution directional , moving from primitive and less perfect to more complex and perfect forms, the whole constituting a sort of hierarchical gradation , usually with man at the top. Criticised by popular science writers like Stephen Jay Gould , but remains a very influential meme. Some popular thinkers, such as Teilhard de Chardin , have argued for an anthropocentric cosmology, culminating in a future omega point.
Assemblage zone An aggregation of fossils in a body of sedimentary rock. Mostly smaller than a modern human, walked erect, with a human-like body but ape-like skull, showing that brain size evolved late in evolution, rather than early, as the Piltdown forgery led early 20th century scientists to believe.
The famous early hominid fossil " Lucy " is an example of an Australopithecine. Perseus Digital Library , Wiktionary Astrobiology, also Exobiology is the study of the origin, evolution , distribution, and future of life in the universe.
This interdisciplinary field uses physics, chemistry, astronomy, biology, molecular biology, ecology, planetary science, geography, and geology to investigate the possibility of life on other worlds and help recognize biosphere s that might be different from the biosphere on Earth. It includes the search for habitable environments in our Solar System and habitable planets outside our Solar System, the search for evidence of prebiotic chemistry, laboratory and field research into the origins and early evolution of life on Earth, and studies of the potential for life to adapt to challenges on Earth and in outer space.
Astrobiology addresses the question of whether life exists beyond Earth, and how humans can detect it if it does. The term exobiology is similar but more specific — it covers the search for life beyond Earth, and the effects of extraterrestrial environments on living things. I have here used these two terms as synonyms.
Wikipedia , MAK Autotroph an organism which makes its own food from inorganic materials, using sunlight or chemical reactions for energy. B Bakker, Robert T. Bacteria microscopic single-celled organism ; the commonest and most ubiquitous form of life on Earth. Woese et al restrict the term "Bacteria" to Eubacteria only, and this practice has since been widely adopted, but in order to avoid confusing with the more general definition we have avoided following this course.
MAK Barremian geologic age of the Early Cretaceous , spanning the time between and million years ago. USGS Paleontology glossary Basal Preferred cladistic substitute for "primitive", as it is felt the latter may carry false connotations of inferiority or a lack of complexity.
Basal node the node or base of the cladogram , representing the hypothetical common ancestor of the entire clade Basal taxon general term in phylogenetic systematics for any terminal taxa that lie at the base of a cladogram , i.
Equivalent to primitive or ancestral these terms not being used in cladistics. Belemnite a Mesozoic to early Tertiary cephalopod mollusc with an internal cone-, bullet-, or cigar-shaped shell. In life a squid-like animal, along with their cousins the ammonites they were important members of the Mesozoic marine ecosystem. Benthic Used to describe aquatic organisms that are bottom dwelling.
British paleontologist, professor of vertebrate palaeontology in the Department of Earth Sciences at the University of Bristol and author of many papers and several popular science books, as well as the palaeontology textbook Vertebrate Palaeontology. Berriasian geologic age of the earliest Cretaceous , spanning the time between and million years ago. Raup in a paper published in Ordovician—Silurian extinction event Late Devonian extinction event.
Triassic—Jurassic extinction event apparently two, the End-Carnian and the End-Triassic, not as large as the others. Cretaceous—Tertiary K—T extinction event. Big History history not just on the human scale, but also Earth and cosmic history. In a sense, the Palaeos website is concerned with Big History.
Compare Deep Time , Universe Story.