My notes and thoughts from Biology 111, for Wednesday, August 20, 2008. The entire series can be found here.
Great introductory bio lecture this morning. Living vs. nonliving stuff, hierarchies, stressing on evidence, that sort of thing.
One thing Doc really spent some time on was the difficulty in defining life, and how any definition of life has to encompass so much.
Over the thin skin of the earth, the only place we know for sure that life exists, we’ve documented and cataloged:
over 350,000 species of plants, over a million species of animals (BEETLES!!!), and thousands upon thousands of fungi, protists, bacteria. Given that we have documented about 1.8 million species of life, here’s some context:
That’s life on earth now.
(More Below the fold)
Water covers 70+% of the surface area and 99% of the volume of the known biosphere. We’ve explored perhaps 5% of that.
Over 95%, and perhaps as much as 99% of all species ever are now extinct.
Earth is a dust mote in the context of the cosmos
Any definition of life would have to cover the species we know, the species that are extinct, the species that live in the vast majority of the Earth we haven’t even been to, and then still cover any life we might find elsewhere.
Holy crap, that really is overwhelming in that context.
He also mentioned Justice Potter Stewart’s famous quote about pornography from the 1964 Jacobellis v. Ohio case, “I know it when I see it”. It was an interesting aside.
Another interesting note from today’s lecture:
Discussing the definition of Science, our working definition is ‘an evidence-based way of learning about the natural world’.
and allow me this little quote on the subject of evidence, from my prof:
“…not just because it’s written in a book somewhere.”
Dogs and cats came up in the context of heredity, and I imagine that it wasn’t accidental. Sort of the wind up for the pitch to follow later, I think.
I’m loving my Biology class, in case anyone couldn’t tell.
From whence came the art:
That image is of our textbook, Biology, Eighth Edition, by Campbell & Reese et al.