30 JAN 2015 by ideonexus
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 ...16 SEP 2011 by ideonexus
Big History: A Summary of Evolution of Life on Earth
The first organisms, simple photosynthetic bacteria, appear in sediments
about 3.5 billion years old, only about a billion years after the
planet was formed. These single cells were all that occupied the Earth
for the next two billion years, after which we see the first simple “eukaryotes”:
organisms having true cells with nuclei and chromosomes. Then,
around 600 million years ago, a whole gamut of relatively simple but
multicelled organisms arise, including worms, jellyfish, and sponges....Folksonomies: evolution big history
Folksonomies: evolution big history
A good summary of the origin of life on Earth evolving all the way up to human beings.