It is not always the magnitude of the differences observed between species that must determine specific distinctions, but the constant preservation of those differences in reproduction.
Interpretation
The importance of how differences between species are maintained through reproduction is more significant than their size.
Jean-Baptiste Lamarck emphasizes that while observable differences between species can vary greatly, it is the consistency in how these differences are passed on through reproduction that truly defines the uniqueness of each species. This highlights the role of heredity and reproduction in evolutionary biology, suggesting that the stability of traits is fundamental to the identification of species rather than just the extent of their differences.
In practice
In a biology class discussing evolution, this quote could be used to explain how traits are inherited.
Now this circumscribed power, which we have scarcely examined, scarcely studied, this power to whose actions we nearly always attribute an intention and a goal, this power, finally, that always does necessarily the same things in the same circumstances and nevertheless does so many and such admirable ones, is what we call 'nature' .
All knowledge that is not the real product of observation, or of consequences deduced from observation, is entirely groundless and illusory.
It is not enough to discover and prove a useful truth previously unknown, but that it is necessary also to be able to propagate it and get it recognized.
If you set out in a spaceship to find the one planet in the galaxy that has life, the odds against your finding it would be so great that the task would be indistinguishable, in practice, from impossible.
Since we proposed punctuated equilibria to explain trends, it is infuriating to be quoted again and again by creationists-whether through design or stupidity, I do not know-as admitting that the fossil record includes no transitional forms. Transitional forms are generally lacking at the species level, but they are abundant between larger groups.
As Darwin himself was at pains to point out, natural selection is all about differential survival within species, not between them.
Here we were, the only seven humans in space, repairing a telescope whose only purpose is to enrich the minds of people on planet Earth and increase our understanding of the workings of the universe. I can think of no better peaceful use of space for all humankind.
We will first understand how simple the universe is when we recognize how strange it is.
There must be enormous numbers of planets around the stars in the many galaxies in our observable universe. We may be sure that wonderful things are happening on these planets that the human race never will observe.
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