Tag Archives: evolution

The lives and times of prosimian primates

Prosimian primates—lemurs, lorises and galagos—form a sister group to the other nonhuman primates: apes, Old World monkeys and New World monkeys. Many prosimian species are endangered in the wild and can be very difficult to observe and monitor, limiting our knowledge of their life histories. Lab Anim. (NY) 43, 302 (2014). view full text (loginContinueContinue reading “The lives and times of prosimian primates”

The evolution of breathing

When birds breathe, air flows through their lungs in a unidirectional pattern, once thought to be a unique adaptation to meet the high oxygen demands of flight. But when similar unidirectional flow patterns were discovered in the lungs of crocodilians, paleobiologists began to consider that this trait may have developed in an ancestor common toContinueContinue reading “The evolution of breathing”

Exploring the molecular underpinnings of convergent evolution

Similar phenotypic traits such as anatomical structures and physiological functions often evolve independently in different organisms. Nonetheless, the evolutionary paths leading to these convergent phenotypes were typically thought to be quite different. Many such phenotypes are quite complex, requiring coordination among many different genes, suggesting that their development likewise involved multiple evolutionary twists and turns.ContinueContinue reading “Exploring the molecular underpinnings of convergent evolution”

Reptiles at heart

To support the high rates of oxygen consumption associated with being warm-blooded, the hearts of birds and mammals must pump rapidly and frequently. These high heart rates are made possible by a network of conductive tissue that spreads across the heart, controlling its contraction. The evolutionary origin of this conductive tissue has long been aContinueContinue reading “Reptiles at heart”

Human Y chromosome isn’t wasting away

Some time ago, the future of the human Y chromosome was called into question. After all, other species, such as mole voles and spiny rats, have lost their Y chromosomes, and sex-determination responsibilities have fallen to other chromosomes. In fact, the human Y did not start off as a sex-determining chromosome either. Human X andContinueContinue reading “Human Y chromosome isn’t wasting away”

How low can worms go?

Bacteria-eating worms dwell in treasure caves deep below the earth’s surface, where only single-celled organisms were thought to exist. Although it may sound like the premise of a sci-fi masterpiece, this scenario is the major finding of a recent report in Nature. The report describes the discovery of four species of nematodes, or roundworms, in theContinueContinue reading “How low can worms go?”

The secret to primate success

In a changing environment, fitness of a population might be expected to fluctuate, as environmental variables influence that population’s fertility and survival rates. In a recent analysis of long-term fitness of seven primate populations, however, changes in adult survival rates were relatively small (Am. Nat. doi:10.1086/657443; published online 30 November 2010). Lab Anim. (NY) 40,ContinueContinue reading “The secret to primate success”

The basics of being animal

The oldest surviving multicellular animals (or metazoans)—sponges—are simple organisms. Though they lack organs and muscles, they possess valuable genetic information that explains how cells first came to cooperate and behave as a collective. Understanding the mechanisms underlying the development of multicellularity can help us to define what it really means to be an animal. LabContinueContinue reading “The basics of being animal”