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Home Q & A Board Biology-Related Homework Help Zoology and Botany (Moderator: ehd123)
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firepain firepain
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11 years ago
This doesn't need to be too long of an answer.  Just a couple of sentences will suffice. Thank you
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#1
11 years ago
If you look at the evolutionary tree in detail, you will see that there are no milestones.  The transitions are smooth.

However, here are a few important events:

The emergence of the first self-synthesizing chemical compound (probably RNA)
The emergence of the first cell
Photosynthesis
Development of bacteria that could use the otherwise toxic oxygen from photosynthesis
Development of sexual reproduction
Development of multicellular organisms
wrote...
#2
11 years ago
I usually refer to 5:  photoautrophy, which allowed life to leave the sea; the amniotic egg that allowed animals to have a terrestrial habitat; homeothermy, which allowed animals to inhabit  colder climates; placental/marsupial mammals that kept their young with them for longer times; and plant vascular tissue so that plants could grow taller.  Evolution of flowers is important, too.

Of course, this is just an opinion.
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