Sentences with phrase «small population size»

The researchers found that the species that died out had lower genetic diversity than the ones that survived — a hallmark of small population size.

Low - carbohydrate advocates are masters of documenting the efficacy of their philosophy using studies with small population sizes conducted over short time periods — often over weeks or months.

In large organisms with relatively small population sizes, such as humans, only in the order of 1 % of the genomic information is shaped by the environment via natural selection.

The comparison gives researchers the rare opportunity to see what happens to the genome as a population declines, and supports existing theories of genome deterioration stemming from small population sizes.

«Based on census data there are probably only a thousand individuals, which is a very small population size,» he says.

Many climate relicts are threatened by small population size, ongoing environmental change in already stressful environments, invasions from species in adjacent non-relict communities, and human encroachment.

The increased risk of extinction occurred because at small population sizes, as the flies spent more time being vigilant and less time eating, populations that declined could not quickly rebound.

But the fact that passenger pigeons persisted at relatively small population sizes gives fresh hope to efforts to bring them back — so - called de-extinction.

The scientists estimate that these gene variations were able to persist in Neanderthals because Neanderthals had a much smaller population size than humans.

They explained the trend as a correlate of smaller population size in the more advanced species.

Despite small population sizes and limited geographic distribution, island foxes have generated and maintained mitochondrial diversity, even with population reductions to only 15 individuals on some islands during the 1990s [11].

Regarding ideal small population size.

Biologists report that a population of 240 panthers requires between 8,000 and 12,000 square miles of habitat and sufficient genetic diversity in order to avoid inbreeding as a result of small population size.

Lead author Dr Orly Razgour, of the University of Southampton, explained: «Long - lived, slow - reproducing species with smaller population sizes are not likely to be able to adapt to future climate change fast enough through the spread of new mutations arising in the population.

Small population sizes.

TURIANA HAMEL - SMITH: I think it's silly that they chose such a small population size and then said like: «This is it.

Subica and his colleague, Li - Tzy Wu, a professor at Duke University Medical Center, took on the project in part because national estimates of Pacific Islander, American Indian, and multiracial adolescent substance use and suicidality are scarce, presumably due to their small population sizes.

In 2012, research by FFI and partners led to the species being formally designated as critically endangered due to its small population size and threats from hunting and habitat loss.

But an analysis of their DNA suggests that the largest lemurs were more prone to extinction than smaller - bodied species because of their smaller population sizes, according to this team of American and Malagasy researchers.

Altogether, decline in pup survival seems to be the most acute threat to the Saimaa ringed seal posed by climate change and the seal's adaptation to climate change is hindered by its small population size and additional human - induced mortality.

Other forms of rarity, like a limited range and a small population size for species that once were common, are not sustainable and could lead to extinction.

The small population size explains why genetic diversity is so low and inbreeding so extensive.

First discovered in 1932 and believed to be nearing extinction due to its small population size and unregulated hunting, this species has perplexed scientists for decades because of its elusive nature.

Those animals are especially vulnerable because they tend to have smaller population sizes and longer times between generations, Ripple says.

A rare plant is threatened due to its small population size and restricted range.

«Small population sizes and habitat fragmentation are well known threats to animals with limited mobility, but the impacts of these factors are hard to observe in wild populations,» said Forero - Medina, Species and Science Director for WCS's Colombia Program and a study co-author.

The failure of these early glimmerings of art and sophisticated weaponry to spread and become permanent fixtures of the Middle Paleolithic and the Middle Stone Age seems to have been the result of small population sizes and local extinctions of these populations and their traditions.

Species with smaller population size can more easily escape the harsh scrutiny of natural selection.

«Population genetics theory tells us that means a small population size» for those archaic humans, said Montgomery Slatkin, a biologist at the University of California, Berkeley, who was not convinced of Rogers» results.

The Glen of Imaal Terrier's small population size and its limited gene pool, along with the adult onset of disease — often after an animal has been bred multiple times — have resulted in widespread distribution of crd3 within the breed, and many Glens in the general population are likely to be carrying at least one copy of the disease mutation.

The density of females on Sea Lion Island was quite low (about 110 females per km of the coastline suitable for breeding) compared to densities recorded in other sub-Antarctic populations: this low level of crowding of females probably depends on the small population size and the abundance of sandy beaches with a gentle slope, which are the preferred breeding habitat for elephant seal.

The skunk's small population size can be attributed to several factors.

Barney Long, WWF's Asian Species Expert, commented that «These dolphins are at high risk of extinction by their small population size alone... with the added threats of gill net entanglement and high calf mortality, we are seriously concerned about their future.»

The factors identified in this study as predisposing species to high extinction risk due to climate change suggest that conservation actions should focus on species that occupy a small or declining area, have small population size, or have synchronized population fluctuations.