Evolve

In the history of life on earth, sex may be the ultimate survival skill, because the bottom line is reproduce or die. This episode looks at sex in its many forms, from sharks--among the first vertebrates to have intercourse--to dinosaurs that had to figure out how to join their giant bodies together to mate; from the stick insect (that mates nonstop for 10 straight weeks) to the panda (just three days a year)... and finally to humans, this diving force of life comes in many forms. How will sex evolve in the future? Are we in fact evolving beyond sex? Is a time coming when we will be able to seize control of our own evolution... not via sex at all, but genetic engineering?

It's one of the most important developments in the history of life. An adaptation that lets animals kill, butcher, and devour. There is perhaps no instrument more important to survival than a strong set of jaws. From the shark's rows of razor-sharp serrated teeth, the crocodile's overwhelmingly swift-snapping-trap, to the lion's shredding canines--all have evolved in response to the never-ending struggle between predator and prey. But just how did these ultimate killing weapons develop in the first place?

It makes up 16% of your body weight, is the largest organ in the human body, allows birds to fly, mammals to nurse their young, and provides a lifelong defense against predators and parasites alike. What is it? Skin. From the delicate membranes that encased the earliest animals to the leathery hides that protected the dinosaurs, this episode looks at how skin has changed and adapted to virtually any challenge it has faced throughout history.

Life has evolved into a multitude of sizes. Over the course of 3 billion years, life has taken on many forms- from an .02 micrometer long bacteria to the 110 foot long blue whale. Scientists are learning how the struggle for survival has led some animals to become small and others to get huge. Understanding the evolution of size tells us why giant dinosaurs went extinct while the first tiny mammals thrived; give us answers to why mammoths evolved into pygmies when restricted to islands; and why carnivorous mammals have never grown to weigh over a ton. Whether it's the speed of movement or population numbers, the biological world revolves - and 'Evolves' - around size.

Humans have always been fascinated with the one part of the world that we could not conquer- the sky. How did the earth's first flying creatures come to be? In this episode of Evolve we will examine the first vertebrate flyer, the pterosaur, which took to the air over 220 million years ago and eventually evolved to be the size of small airplanes. Scientists have long pondered how they, the largest flying creatures ever, were able to achieve such an astonishing feat. Scientists examine the fossil record and living birds to try and unlock how some species evolved to have the remarkable trait of flight.

The deadliest natural weapon employed in the animal kingdom, venom has independently evolved in creatures as diverse as jellyfish, insects, snakes, and even mammals. Scientists from around the globe show how evolution adapted venom to fit the needs of the animals who wield it. Injecting venom into samples of his blood, Australia's Bryan Fry demonstrates how the world's deadliest snake, the inland taipan, has converted the building blocks of its body into lethal toxins. Toto Olivera will introduce us to the cone snail, pound-for-pound the most toxic creature in the world, able to continually update its chemical cocktails with the help of the world's fastest-evolving genes, guaranteeing the creatures stay one step ahead of their prey.