Mitochondria and Chloroplasts

Margulis believes that mitochondria were originally parasites (or predators - the distinction is not important at this level) which attacked the larger bacteria that were destined to provide the shell of the eucaryotic cell. There are still some bacterial parasites that do a similar trick, burrowing through the prey's cell wall, then, when safely inside, sealing up the wall and eating the cell from within. The mitochondrial ancestors, according to the theory, evolved from parasites that kill ...

 Think Bottom-Up

One of the most general shorthand abstractions that, if adopted, would improve the cognitive toolkit of humanity is to think bottom up, not top down. Almost everything important that happens in both nature and society happens from the bottom up, not the top down. Water is a bottom-up, self-organized emergent property of hydrogen and oxygen. Life is a bottom-up, self-organized emergent property of organic molecules that coalesced into protein chains through nothing more than the input of energ...

 How Plants and Animals Survive in Their Environment

Plants and animals are separated by about 1.5 billion years of evolutionary history. They have evolved their multicellular organization independently but using the same initial tool kit the set of genes inherited from their common unicellular eucaryotic ancestor. Most of the contrasts in their developmental strategies spring from two basic peculiarities of plants. First, they get their energy from sunlight, not by ingesting other organisms. This dictates a body plan different from that of ani...

 Why Plants Evolved to be Green

why is green the dominant color of terrerestrial plants? That's easy. Chlorophyll molecules absorb light at the red and blue ends of the spectrum. It is the middle of the spectrum (the green part) that is reflected and gives plants their characteristic color. A more efficient photosynthetic pigment would be black, absorbing all colors, soaking up all the energy of sunlight, reflecting nothing. The reflected green light of plants is wasted energy. So perhaps the real question is. Why isn't gra...