Ancestor Quote by David M. Raup
![“In the beginning, there were bacteria… [A] nearly universal assumption is that all subsequent life descended from the original life form through a continuous chain of ancestor-descendant pairs. This assumption looks good because all living organisms share biochemical traits. It is conceivable, of…” quote by David M. Raup](https://sms4smile.com/quotes/img-quotes/d27/david-m-raup-33751_ancestor_in-the-beginning-there-were-bacteria-a-n_1413265.jpg)
“In the beginning, there were bacteria… [A] nearly universal assumption is that all subsequent life descended from the original life form through a continuous chain of ancestor-descendant pairs. This assumption looks good because all living organisms share biochemical traits. It is conceivable, of course, that life originated more than once on the early earth but that all except one life form died out early, leaving a single lineage as the ancestor of life as we know it. If this did happen, it was the first important species extinction.”
About This Quote
Source Book: Extinction: The Facts and the Theories, 1991
Life likely began once, with a single lineage surviving after early extinctions, shaping all modern biodiversity.
In simple terms: All modern life may trace back to one surviving ancestor.
Key Takeaway
Consider the impact of early extinctions on current life.
Themes
evolution
extinction
origin of life
biology
phylogeny
Mood
curious
thoughtful
Type
scientific
educational
When to use this quote
- research on early Earth conditions
- educational curricula
- public science communication
Key Concepts
common descent
bottleneck events
survival of lineages
Questions to Reflect On
- How would multiple origins change our view of evolution?
- What evidence could support a second surviving lineage?
A Different Perspective
Alternative hypotheses suggest multiple origins, but evidence favors a single surviving line.
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