English - SciELO Costa Rica
... of the population determined by the reproductive potential and survival rates of each species, and population regulatory interactions (Andrewartha and Birch 1954, Hubbell 2001). The application of an index, such as the Shannon-Wiener index, results in a value of difficult interpretation that has lit ...
... of the population determined by the reproductive potential and survival rates of each species, and population regulatory interactions (Andrewartha and Birch 1954, Hubbell 2001). The application of an index, such as the Shannon-Wiener index, results in a value of difficult interpretation that has lit ...
Notes and Comments Diversity-Stability Relationships: Statistical Inevitability or Ecological Consequence?
... community is necessarily more stable than the individual species that it contains and that the magnitude of this effect increases with diversity. This effect holds for all values of z. This effect, which has guided financial investment strategies for decades, contributes to the dependence of communi ...
... community is necessarily more stable than the individual species that it contains and that the magnitude of this effect increases with diversity. This effect holds for all values of z. This effect, which has guided financial investment strategies for decades, contributes to the dependence of communi ...
Allee effects, extinctions, and chaotic transients in simple population
... Predator Saturation Perhaps the most common Allee effect occurs in species subject to predation by a generalist predator with a saturating functional response. Within such populations, an individual’s risk of predation decreases as the population’s density increases. The importance of this form of p ...
... Predator Saturation Perhaps the most common Allee effect occurs in species subject to predation by a generalist predator with a saturating functional response. Within such populations, an individual’s risk of predation decreases as the population’s density increases. The importance of this form of p ...
Diversity-stability relationships: statistical inevitability or ecological
... community is necessarily more stable than the individual species that it contains and that the magnitude of this effect increases with diversity. This effect holds for all values of z. This effect, which has guided financial investment strategies for decades, contributes to the dependence of communi ...
... community is necessarily more stable than the individual species that it contains and that the magnitude of this effect increases with diversity. This effect holds for all values of z. This effect, which has guided financial investment strategies for decades, contributes to the dependence of communi ...
Allee effects, extinctions, and chaotic transients in simple population
... Discrete time single species models with overcompensating density dependence and an Allee effect due to predator satiation and mating limitation are investigated. The models exhibit four behaviors: persistence for all initial population densities, bistability in which a population persists for inter ...
... Discrete time single species models with overcompensating density dependence and an Allee effect due to predator satiation and mating limitation are investigated. The models exhibit four behaviors: persistence for all initial population densities, bistability in which a population persists for inter ...
3.1 Measuring Biodiversity
... • Biodiversity is the number and variety of organisms found within a specific region. • There are approximately 5 to 100 million species on Earth. ...
... • Biodiversity is the number and variety of organisms found within a specific region. • There are approximately 5 to 100 million species on Earth. ...
Larsen et al (2005) Ecol Letters pdf
... Rapid rates of global biodiversity loss are intensifying the need to understand the consequences for the functioning of ecosystems (Purvis & Hector 2000). Most studies to date have focused on the relationship between species richness and function, without including other components of biodiversity ( ...
... Rapid rates of global biodiversity loss are intensifying the need to understand the consequences for the functioning of ecosystems (Purvis & Hector 2000). Most studies to date have focused on the relationship between species richness and function, without including other components of biodiversity ( ...
Worksheet - Rudds Classroom
... the ________________ state of an ecosystem is crucial to its _______________ development ...
... the ________________ state of an ecosystem is crucial to its _______________ development ...
Alternative stable states and regional community structure
... extinction dynamics to identify conditions for coexistence of species whose interactions lead to local ASE. We begin by showing that local ASE can persist regionally if each species has a refuge external to the system (a form of spatial heterogeneity). We then consider two mechanisms that may lead t ...
... extinction dynamics to identify conditions for coexistence of species whose interactions lead to local ASE. We begin by showing that local ASE can persist regionally if each species has a refuge external to the system (a form of spatial heterogeneity). We then consider two mechanisms that may lead t ...
Are the ecological impacts of alien species misrepresented? A
... food plants, while more than 40% have no known native hosts for ovipositing in urban and sub-urban environments, such that many species would likely become extirpated in urban environments if alien plants were removed (Shapiro 2002). There is even evidence to suggest that natives sometimes depredate ...
... food plants, while more than 40% have no known native hosts for ovipositing in urban and sub-urban environments, such that many species would likely become extirpated in urban environments if alien plants were removed (Shapiro 2002). There is even evidence to suggest that natives sometimes depredate ...
DengBioDiversity.pdf
... that almost every species, even in its metropolis, would increase immensely in numbers, were it not for other competing species .... — Charles Darwin, On the Origin of the Species, 1859 1. Introduction. The latitudinal gradient in species distribution is one of the oldest patterns in biogeography ([ ...
... that almost every species, even in its metropolis, would increase immensely in numbers, were it not for other competing species .... — Charles Darwin, On the Origin of the Species, 1859 1. Introduction. The latitudinal gradient in species distribution is one of the oldest patterns in biogeography ([ ...
Changes in habitat heterogeneity alter marine sessile benthic
... undergo transitions from one state to another or have different degrees of heterogeneity resulting from the interplay of different processes (Seabloom et al. 2002, Thrush et al. 2006). Transitions can result in species extinction or facilitate the establishment of invasive species. Alternatively, ma ...
... undergo transitions from one state to another or have different degrees of heterogeneity resulting from the interplay of different processes (Seabloom et al. 2002, Thrush et al. 2006). Transitions can result in species extinction or facilitate the establishment of invasive species. Alternatively, ma ...
- University of Gloucestershire
... the alien honeybee (Apis mellifera) (Gross 2001), while the introduced brushtail possum (Trichosurus vulpecula) in New Zealand is an increasingly important seed disperser for native plants that produce larger seeds due to the decline in large-gaped avian frugivores such as the New Zealand pigeon (He ...
... the alien honeybee (Apis mellifera) (Gross 2001), while the introduced brushtail possum (Trichosurus vulpecula) in New Zealand is an increasingly important seed disperser for native plants that produce larger seeds due to the decline in large-gaped avian frugivores such as the New Zealand pigeon (He ...
Saving the World`s Terrestrial Megafauna - Research
... some species show resilience by adapting to new scenarios under certain conditions (Chapron et al. 2014), livestock production, human population growth, and cumulative land-use impacts can trigger new conflicts or exacerbate existing ones, leading to additional declines. According to the Food and A ...
... some species show resilience by adapting to new scenarios under certain conditions (Chapron et al. 2014), livestock production, human population growth, and cumulative land-use impacts can trigger new conflicts or exacerbate existing ones, leading to additional declines. According to the Food and A ...
Chapter 5: Ecology and evolution: Populations, communities, and
... members will begin interbreeding and reestablish gene flow, mixing those mutations that each species accrued while it was isolated. If the populations have diverged sufficiently, however, they will not interbreed, and two species will have been formed, fated to continue on their own evolutionary pat ...
... members will begin interbreeding and reestablish gene flow, mixing those mutations that each species accrued while it was isolated. If the populations have diverged sufficiently, however, they will not interbreed, and two species will have been formed, fated to continue on their own evolutionary pat ...
Bio-What? - Lesson Corner
... answers! Over 200 years ago the biologist Linnaeus told us that there were exactly 4,236 species. Since then, biologists and other scientists have named and described approximately 1.4 million species, although we know very little about the behavior of most of these species or the role they play in ...
... answers! Over 200 years ago the biologist Linnaeus told us that there were exactly 4,236 species. Since then, biologists and other scientists have named and described approximately 1.4 million species, although we know very little about the behavior of most of these species or the role they play in ...
Explaining the global biodiversity gradient: energy, area, history and
... much the same physiognomy in Indonesia as in Amazonia cannot be fed into a dynamically sufficient model that depends on the birth and death rates of species. The privileging of latitude has to arise from the way species, not organism morphologies, are distributed. Turner and Hawkins (2004) suggest t ...
... much the same physiognomy in Indonesia as in Amazonia cannot be fed into a dynamically sufficient model that depends on the birth and death rates of species. The privileging of latitude has to arise from the way species, not organism morphologies, are distributed. Turner and Hawkins (2004) suggest t ...
Ecological Consequences of Extinction
... Extinction is a natural process, but it is occurring at an unnaturally rapid rate as a consequence of human activities. Humans have caused the extinction of between 5-20% of the species in many groups of organisms, and current rates of extinction are estimated to be 100-1,000 times greater than pre- ...
... Extinction is a natural process, but it is occurring at an unnaturally rapid rate as a consequence of human activities. Humans have caused the extinction of between 5-20% of the species in many groups of organisms, and current rates of extinction are estimated to be 100-1,000 times greater than pre- ...
Gymnesic Islands, Western Mediterranean
... for the absence of both endemics from the earliest Mallorcan archaeological sites and for the introduction of the garden dormouse, Eliomys quercinus, and the wood mouse, Apodemus sylvaticus. Combined information from direct dating of bone collagen of E. quercinus and A. sylvaticus and from cultural ...
... for the absence of both endemics from the earliest Mallorcan archaeological sites and for the introduction of the garden dormouse, Eliomys quercinus, and the wood mouse, Apodemus sylvaticus. Combined information from direct dating of bone collagen of E. quercinus and A. sylvaticus and from cultural ...
99. Woodruff, D.S. The problems of conserving genes and species
... elsewhere (U.S. Congress, Office of Technology Assessment 1987) and are applicable at four different levels. First, many species are being managed where they occur naturally. The costs of conservation programs at this level are relatively low and usually benefit more than just the target species as ...
... elsewhere (U.S. Congress, Office of Technology Assessment 1987) and are applicable at four different levels. First, many species are being managed where they occur naturally. The costs of conservation programs at this level are relatively low and usually benefit more than just the target species as ...
Saving the World`s Terrestrial Megafauna
... some species show resilience by adapting to new scenarios under certain conditions (Chapron et al. 2014), livestock production, human population growth, and cumulative land-use impacts can trigger new conflicts or exacerbate existing ones, leading to additional declines. According to the Food and A ...
... some species show resilience by adapting to new scenarios under certain conditions (Chapron et al. 2014), livestock production, human population growth, and cumulative land-use impacts can trigger new conflicts or exacerbate existing ones, leading to additional declines. According to the Food and A ...
PowerPoint Presentation - Biodiversity part 2 Global Environmental
... signed the international Convention on Biological Diversity. This has been attributed to an administration unwillingness to fund a program which would almost certainly find new species that would then be subject to protection under the Endangered Species Act. ...
... signed the international Convention on Biological Diversity. This has been attributed to an administration unwillingness to fund a program which would almost certainly find new species that would then be subject to protection under the Endangered Species Act. ...
Community stability and selective extinction during Earth`s
... inter-guild links and guild richnesses were randomized. Model I and III webs of a paleocommunity are therefore of equal S and G, but S is partitioned differently among G, yielding different patterns of interspecific interactions and functional diversity. A paleocommunity matrix was determined to be ...
... inter-guild links and guild richnesses were randomized. Model I and III webs of a paleocommunity are therefore of equal S and G, but S is partitioned differently among G, yielding different patterns of interspecific interactions and functional diversity. A paleocommunity matrix was determined to be ...
Species Redundancy and Ecosystem Reliability
... that species richness, then the species within the functional group are redundant. That is, Nj is independent of Sj. Net ecosystem flows will show a significant relationship with increasing species richness until each functional group is represented, at which point an asymptote is soon reached as mo ...
... that species richness, then the species within the functional group are redundant. That is, Nj is independent of Sj. Net ecosystem flows will show a significant relationship with increasing species richness until each functional group is represented, at which point an asymptote is soon reached as mo ...
The Central American land bridge: evolution at work
... show how important it is to know the context in which they first evolved to properly understand modern species ecology and adaptation. Shallow-water benthic communities, speciation, extinction, environmental change ...
... show how important it is to know the context in which they first evolved to properly understand modern species ecology and adaptation. Shallow-water benthic communities, speciation, extinction, environmental change ...
Extinction
In biology and ecology, extinction is the end of an organism or of a group of organisms (taxon), normally a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and recover may have been lost before this point. Because a species' potential range may be very large, determining this moment is difficult, and is usually done retrospectively. This difficulty leads to phenomena such as Lazarus taxa, where a species presumed extinct abruptly ""reappears"" (typically in the fossil record) after a period of apparent absence.The age of the Earth is about 4.54 billion years old. The earliest undisputed evidence of life on Earth dates at least from 3.5 billion years ago, during the Eoarchean Era after a geological crust started to solidify following the earlier molten Hadean Eon. There are microbial mat fossils found in 3.48 billion-year-old sandstone discovered in Western Australia. Other early physical evidence of a biogenic substance is graphite in 3.7 billion-year-old metasedimentary rocks discovered in Western Greenland. More than 99 percent of all species, amounting to over five billion species, that ever lived on Earth are estimated to be extinct. Estimates on the number of Earth's current species range from 10 million to 14 million, of which about 1.2 million have been documented and over 86 percent have not yet been described.Through evolution, species arise through the process of speciation—where new varieties of organisms arise and thrive when they are able to find and exploit an ecological niche—and species become extinct when they are no longer able to survive in changing conditions or against superior competition. The relationship between animals and their ecological niches has been firmly established. A typical species becomes extinct within 10 million years of its first appearance, although some species, called living fossils, survive with virtually no morphological change for hundreds of millions of years. Mass extinctions are relatively rare events; however, isolated extinctions are quite common. Only recently have extinctions been recorded and scientists have become alarmed at the current high rate of extinctions. Most species that become extinct are never scientifically documented. Some scientists estimate that up to half of presently existing plant and animal species may become extinct by 2100.