Despite slang terms that imply otherwise, the human penis contains no bones. The same cannot be said for many of our closest evolutionary relatives: Chimpanzees and bonobos both have penis bones (a macaque one is pictured, left), also known as bacula.
To find out why some primates have the feature whereas others don’t, researchers traced the bone’s evolutionary history through time. The baculum first evolved between 145 million and 95 million years ago, as reported in the Proceedings of the Royal Society B. That means it was present in the most recent common ancestor of all primates and carnivores. Why some descendants, like humans, lost their bacula appears to be due to differences in mating practices: In primates, the presence of a penis[ ... ]
The photo shown below was taken at a market in Shanghai, China.
Can you guess what they are?
If you guessed, water caltrop 菱, you're right!
Water caltrops (Trapa natans) are the seeds of a floating annual aquatic plant that's native to warm temperate parts of Eurasia and Africa. The plant grows in slow-moving water up to 5 m deep, and bear an ornately shaped fruit that resembles the head of a bull or the silhouette of a flying bat. Each fruit contains a single very large, starchy seed. T. natans and T. bicornis have been cultivated in China and the Indian subcontinent for at least 3,000 years for the edible seeds that are used in pastries, served steamed or boiled from street vendors, and even as a remedy for inebriation.
Opals (shown above) are is a hydrated amorphous form of silica (SiO2·nH2O); its water content may range from 3 to 21% by weight, but is usually between 6 and 10%. Because of its amorphous character, it is classed as a mineraloid, unlike crystalline forms of silica, which are classed as minerals. It is deposited at a relatively low temperature and may occur in the fissures of almost any kind of rock, being most commonly found with limonite, sandstone, rhyolite, marl, and basalt. Opal is the national gemstone of Australia.
The internal structure of precious opal makes it diffract light. Depending on the conditions in which it formed, it can take on many colors. The one pictured on the left is called the "Virgin Rainbow" opal, being the finest [ ... ]
It doesn't take a genius to recognize the vast number of contributions the people of Jewish ancestry have made in modern history. According to a 2005 scientific paper, "Natural History of Jewish Intelligence", Jews as a group inherit higher verbal and mathematical intelligence than other ethnic groups, on the basis of inherited diseases and the peculiar economic situation of Jews in the Middle Ages. Specifically, the Ashkenazi Jews - those who originated in Eastern Europe, such as Albert Einstein (left) and Carl Sagan (right) - tend to have higher intelligence than other ethnic groups; in fact, about 80% of modern Jews have Ashkenazi ancestry.
One observational basis for inferring that Jews have high intelligence is their prevalence in occup [ ... ]
Early birds and night owls have radically different daily habits. But a new study suggests they both share one trait: As the clock ticks, their decisions get dicey. Neuroscientists examined the quality of moves in more than 1 million games of chess in an online database. They charted the decisions of 99 prolific players by gauging the time they took for each move and its usefulness in leading to a victory - factors that impact games like high-speed tiebreakers in the World Chess Championships.
As expected, early risers played more games in the morning, whereas night owls were active at dusk and beyond. But both sets of players took longer for each move and made better game choices early in the day and soon after they woke up. Come evening, [ ... ]
Christmas Island is a unique natural habitat located in the Indian Ocean with many endemic species. The national park covers two-thirds of the island, which has been referred to as the Galapagos of the Indian Ocean.
Many people are aware of the red crabs whose mass migration to the sea has been described as one of the wonders of the natural world. Christmas Island has many other species of crabs, including the impressive robber crabs (Gecarcoidea natalis). These may be the largest land-dwelling arthropod on Earth.
Together these abundant land crabs clear the forests of leaf litter and maintain burrows that prevent soil becoming compacted, creating an open and diverse forest.
This thriving natural system, however, was disrupted by an invasive [ ... ]
Biology Forums - Master Your Courses is the leading provider of online homework help for college and high school students. Get homework help and answers to your toughest questions in biology, chemistry, physics, math, calculus, engineering, accounting, English, writing help, business, humanities, and more. Master your assignments with step-by-step solutions to countless homework questions asked and answered by our members. If we don't have your question, don’t worry. You can ask any homework question and get expert homework help in as little as two hours.
Our extensive online study community is made up of college and high school students, teachers, professors, parents and subject enthusiasts who contribute to our vast collection of study resources: textbook solutions, study guides, practice tests, practice problems, lecture notes, equation sheets and more. With our help, your homework will never be the same!