Sentences with phrase «skewed sex ratio»

Demographic studies since the 1980s have suggested son preference and sex - selective abortions of girls were the main causes of the skewed sex ratio in these countries.

Evolutionary biologists say male mortality, which is overall higher than that of females, explains the male bias in sex ratio: A slightly skewed sex ratio at birth that favors males ensures that there are roughly an equal number of males and females of reproductive age.

Besides skewing the sex ratio, the hormone could be disrupting the animals» reproduction, a concern because American crocodiles are already listed as vulnerable, and this part of Costa Rica is a stronghold for the species.

FEELING THE HEAT Climate change may skew the sex ratios of sea turtles (loggerhead shown), but that could be a small worry compared with the dangers of overheated nests.

To find out if global warming might skew the sex ratio of hatchlings, Rory Telemeco and his colleagues at Iowa State University in Ames developed a mathematical model to predict the sex ratio of eggs laid at different temperatures.

Owing to a quirk of ant reproductive biology, the female workers are three times more closely related to the queen's female offspring than they are to the males, so, in theory, the female workers should skew the sex ratio in favor of females.

It remains unclear what evolutionary purpose is served by such skewed sex ratios.

Some sea lamprey populations have skewed sex ratios, but the reasons why have remained a biological mystery for decades.

They stress that inclusive fitness ideas have helped yield insights into many biological phenomena, such as why social insects have skewed sex ratios.

In laboratory tests, just a few tens of nanograms of these compounds per litre can skew sex ratios and decrease fertility in fish.

These skewed sex ratios cripple the species» reproductive capacity for each breeding season.

Stranger still, parasitologist Jaroslav Flegr of Charles University in Prague thinks T. gondii could also be skewing our sex ratios.

What is known from global studies is that exposure to biologically active compounds, even at ng / L concentrations, can impact endocrine systems in nature and manifest as negative impacts like altered gene regulation, the presence of mixed reproductive tissues (intersex) and skewed sex ratios.

Not exact matches

For example, according to the Shettles method, having sex as close to the moment of ovulation as possible is supposed to skew the ratio towards boys: the Y chromosome is smaller, so the reasoning is that Y - carrying sperm swim faster and are first to reach the egg.

Surveys have shown that paleo is evenly split between men and women — eating real food isn't a male or female thing — but an even sex ratio is still heavily male relative to most other dietary approaches, which tend to skew female.

Dating and mating behavior is influenced by prevailing sex ratios, when there are plenty of marriageable men, dating culture emphasizes courtship and romance, but when gender ratios skew toward women the whole dating culture becomes more sexualized.