News tagged with population size
Big-mouthed babies drove the evolution of giant island snakes
Some populations of tiger snakes stranded for thousands of years on tiny islands surrounding Australia have evolved to be giants, growing to nearly twice the size of their mainland cousins. Now, new research ...
May 15, 2012 |
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Whale population size, dynamics determined based on ancient DNA
Estimates of whale population size based on genetics versus historical records diverge greatly, making it difficult to fully understand the ecological implications of the large-scale commercial whaling of the 19th and early ...
May 09, 2012 |
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Cod has a key role in the whole Baltic Sea
A new investigation put in evidence the key role of cod as regulator of the whole Baltic Sea ecosystem. The study shows that when the cod population in the central Baltic increases, it spreads into larger ...
Apr 18, 2012 |
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Ticks can adapt to the Spain's climatic diversity
Carnivores in the Iberian Peninsula, such as the Iberian lynx, are under an increasingly serious threat: ticks that can adapt to changing climatic conditions and that can even survive in extremely arid environments. ...
Mar 29, 2012 |
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Kazakhstan sounds alarm over dying Caspian seals
The Kazakhstan government and environmentalists Tuesday sounded the alarm over the declining numbers of endangered Caspian seals after 35 animals were found dead over the weekend.
Mar 27, 2012 |
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Researchers create first large-scale model of human mobility that incorporates human nature
For more than half a century, many social scientists and urban geographers interested in modeling the movement of people and goods between cities, states or countries have relied on a statistical formula called ...
Feb 27, 2012 |
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Bird populations near Fukushima are more diminished than expected
(PhysOrg.com) -- Low-level radiation in Fukushima Prefecture appears to have had immediate effects on bird populations, and to a greater degree than was expected from a related analysis of Chernobyl, an international ...
Feb 09, 2012 |
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New fluorescent imaging sorts microbiome in human mouth
New fluorescent labeling technology that distinguishes in a single image the population size and spatial distribution of 15 different taxa has uncovered new taxon pairings that indicate unsuspected cooperation -- and standoffishness ...
Dec 07, 2011 |
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Powerful mathematical model greatly improves predictions for species facing climate change
UCLA life scientists and colleagues have produced the most comprehensive mathematical model ever devised to track the health of populations exposed to environmental change.
Dec 03, 2011 |
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Study of wolves will help scientists predict climate effects on endangered animals
Scientists studying populations of gray wolves in the USA's Yellowstone National Park have developed a way to predict how changes in the environment will impact on the animals' number, body size and genetics, amongst other ...
Dec 01, 2011 |
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How does a plant survive with few mates or pollinators? A European herb has figured out its own way
In plants that rely on animals for pollination, the number of seeds they produce, or their relative fitness, is influenced by pollinator visits and the successful deposition of pollen. The number of visits ...
Nov 10, 2011 |
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Between geometry and biology: How and why does the number of species depend on area
There are few universal rules in ecology, but arguably one is the relationship between the area of a study plot and the number of species counted within that plot, the so called species-area relationship. Larger study plots ...
Nov 10, 2011 |
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Atlantic herring population trends linked to egg predation by haddock
(PhysOrg.com) -- NOAA scientists have developed a population model for Atlantic herring that links herring population trends to the size of the haddock population. The model also provides evidence that egg predation by haddock ...
Aug 09, 2011 |
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There's no magic number for saving endangered species
A new study offers hope for species such as the Siberian Tiger that might be considered 'too rare to save', so long as conservation efforts can target key threats.
May 16, 2011 |
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Bats keep separate households
(PhysOrg.com) -- The use of different resources by males and females exacerbates the estimation of population sizes. However, the monitoring of population sizes, particularly for rare and threatened species, ...
Mar 24, 2011 |
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Population size
In population genetics and population ecology, population size (usually denoted N) is the number of individual organisms in a population.
The effective population size (Ne) is defined as "the number of breeding individuals in an idealized population that would show the same amount of dispersion of allele frequencies under random genetic drift or the same amount of inbreeding as the population under consideration." Ne is usually less than N (the absolute population size) and this has important applications in conservation genetics.
Small population size results in increased genetic drift. Population bottlenecks are when population size reduces for a short period of time.
Overpopulation may indicate any case in which the population of any species of animal may exceed the carrying capacity of its ecological niche.
For more information about Population size, read the full article at
Wikipedia.
This text uses material from Wikipedia and is available under the GNU Free Documentation License.
