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Course: Big History Project > Unit 5
Lesson 1: What Is Life? |5.0- ACTIVITY: DQ Notebook 5.0
- WATCH: Unit 5 Overview - Life
- ACTIVITY: Vocab Tracking
- WATCH: A Big History of Everything - H2
- ACTIVITY: How Closely Related Are We?
- ACTIVITY: Threshold Card — Threshold 5 Life
- WATCH: The Origin of Life
- READ: Life and Purpose
- READ: Gallery — What is Life?
- ACTIVITY: Claim Testing – What Is Life?
- Quiz: What Is Life?
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WATCH: The Origin of Life
How did life on Earth begin? Learn about the conditions on Earth that made life possible and the theories about how life might have started, from simple molecules to complex organisms as you embark on a fascinating journey through time and biology. Created by Big History Project.
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@6:50JG says the prokaryotes floated up from thermal vents and started to use the sun to make energy through photo synthesis, but this seems like a leap. Where did they get chloraphile from? or the ability to produce, or use it? These seem like some pretty major developments that were just skipped all together, but is none of that important to the process? Thanks, T.S.(10 votes)
Great question--they are indeed skipping many steps! Talking about the origins of life and the earliest life on Earth almost always involves making some leaps, some of them huge, since so little is known about exactly what happened and how. The evolution of chlorophyll biosynthesis (the process by which cells build chlorophyll molecules) and of photosynthesis itself are no exception. It's not that the details aren't important, it's just that (at least as far as I know; I admittedly haven't followed all the details of the debate) no one really knows. As a 2010 journal article states: "We know very little about the earliest origins of photosynthesis. There have been numerous suggestions as to where and how the process originated, but there is no direct evidence to support any of the possible origins." http://www.plantphysiol.org/content/154/2/434.full
Stanley, what you described is "endosymbiont" theory, which could definitely explain the origins of chloroplasts, but not chlorophyll itself.(11 votes)
At1:00JG says that we have to know the current theories about the origin of life, presumably in order to advance the frontiers of knowledge on this matter.
Can't knowledge of current theories be as much of a hindrance as a help to further progress? Similar to the Einstellung effect, in which people get caught up in one idea and can't see past it, can knowledge of current theories serve to calcify thought making any further progress dependent on amateurs, hobbyists, or scientific renegades? I'm not just talking about this particular problem, but problems in all of the sciences and fields of mathematics?
The Einstullung effect discussed here: http://en.wikipedia.org/wiki/Einstellung_effect(5 votes)- Hold on, wouldn't a strand of RNA that could code and self-replicate be uber successful and still be around today? Correct me if I'm wrong.(4 votes)
Definitely, because then it wouldn't need to find a mate(2 votes)
how come this is yet not on their youtube site but on here?(2 votes)
Hi hoimook. I'm not sure why they are not all on the Crash Course site yet, but if you follow this link (https://www.youtube.com/playlist?list=PL4e9AQVlcJTQdxGeeApugAEomCc02lchm) you can find all of the crash course videos in one place on YouTube. Thanks!(3 votes)
- If life was somehow transported to the earth from another place, would not any life be burned up entering the atmosphere? Or would maybe not because there was so little oxygen at the time?(2 votes)
life did not come to earth like that it spawned on earth over time(2 votes)
- how close are we to chimps and how do u know(2 votes)
I dunno how close we r but probably u compare ur dna with chimp dna(3 votes)
- Also @8:50JG asks how a prokaryote would emerge. Also @9:15JG mentions many different historical theories are seeking evidence. Are any scientists working on creating a prokaryote from organic and non-organic chemicals?(2 votes)
6:50