“Evolution demands that all species solve the equation of converting energy from the world around them into the next generation. Living things, from bacteria to blue whales, solve this equation in different and often ingenious ways based on their biology, environmental pressures, the care required for offspring to reach maturity, and even social structure. For example, some organisms reproduce asexually, some deposit unfertilized eggs that will hopefully get fertilized, and some have very long gestations, like an elephant, which carries its calf -- which will ultimately weigh approximately 110kg (243kg) at birth -- for twenty two months.”