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Mass extinctions are characterized by the loss of at least 75% of species within a geologically short period of time (i.e., less than 2 million years). [18] [51] The Holocene extinction is also known as the "sixth extinction", as it is possibly the sixth mass extinction event, after the Ordovician–Silurian extinction events, the Late Devonian extinction, the Permian–Triassic extinction ...
The origins and evolutionary relationships between the three main groups of amphibians (apodans, urodeles and anurans) is a matter of debate.A 2005 molecular phylogeny, based on rDNA analysis, suggested that the first divergence between these three groups took place soon after they had branched from the lobe-finned fish in the Devonian (around 360 million years ago), and before the breakup of ...
While human activities are causing a loss of much of the world's biodiversity, amphibians appear to be suffering much greater effects than other classes of organism. Because amphibians generally have a two-staged life cycle consisting of both aquatic ( larvae ) and terrestrial ( adult ) phases, they are sensitive to both terrestrial and aquatic ...
Anthropogenic biomes, also known as anthromes, human biomes or intensive land-use biome, describe the terrestrial biosphere in its contemporary, human-altered form using global ecosystem units defined by global patterns of sustained direct human interaction with ecosystems.
The rapid expansion of the global human population is increasing the world's food requirement substantially. Simple logic dictates that more people will require more food. In fact, as the world's population increases dramatically, agricultural output will need to increase by at least 50%, over the next 30 years. [56]
Insects make up the vast majority of animal species. [14]Chapman, 2005 and 2009 [9] has attempted to compile perhaps the most comprehensive recent statistics on numbers of extant species, drawing on a range of published and unpublished sources, and has come up with a figure of approximately 1.9 million estimated described taxa, as against possibly a total of between 11 and 12 million ...
At the time, third grade teacher, Lynn K. Burgess, and her 1997-1998 class were studying about South Carolina when they found that the state did not have an official state amphibian and decided to ...
Lissamphibia (extant amphibians) retain many features of early amphibians but they have only four digits (caecilians have none). 330-300 Ma Hylonomus. From amphibians came the first amniotes: Hylonomus, a primitive reptile, is the earliest amniote known.