Nearly blind mammals retain numerous genetic remnants of sighted past

Animals that live underground inhabit a lightless environment. Some aspects of vision in this context might not be useful, particularly those that facilitate vision in bright light. Indeed, numerous subterranean mammals have eyes that have regressed at multiple levels, including disorganized retinas and abnormal lenses. Some species even lack eyelids, so their eyes remain beneath …

Continue reading Nearly blind mammals retain numerous genetic remnants of sighted past

Fetal baleen whales develop with remnants of toothy past

Baleen whales include the world's largest mammals, such as humpback, bowhead and blue whales. Despite their immense size, which necessitates consuming an enormous amount of food, they completely lack teeth. Instead, they possess rows of a broom-like protein called baleen, which they use to filter clouds of tiny organisms (plankton) from the water column. Despite …

Continue reading Fetal baleen whales develop with remnants of toothy past

Developmental biology: When embryos point to evolution

While scientists find evidence of evolution in fossils, DNA, broken genes, and where organisms live, few people realize that sometimes developing embryos can point to an organism's evolutionary past. This concept was popularized by scientist Ernst Haeckel (1834-1919), who suggested that humans, and other animals, would resemble different stages of their evolutionary history during development. …

Continue reading Developmental biology: When embryos point to evolution

Toothless, baleen whales have remnants of tooth genes

Blue, gray and humpback whales, are among the largest animals ever to have existed on earth. To reach and maintain such an immense size, they need to consume copious amounts of prey. Yet, unlike most vertebrates, they completely lack teeth. Instead they have a plates of protein known as baleen. Baleen acts as a sieve …

Continue reading Toothless, baleen whales have remnants of tooth genes