A4.1: Evolution and Speciation

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The first half of the page is very concise notes for cramming, and the latter half is more in detail

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A4.1.1 – Evolution & Natural Selection

🔹 Evolution: The change in heritable characteristics of a population over time.

🔹 Lamarckism vs. Darwinism:

Lamarckism	Darwinism
Traits acquired during life are inherited.	Variation exists, and natural selection favors the best traits.
Example: Giraffes stretch necks, pass to offspring.	Example: Giraffes with longer necks survive, reproduce.

🔹 Natural Selection as a Paradigm Shift:

Before: Fixity of species (unchanging organisms).
After: Evolution by natural selection explained biodiversity and adaptation.

🔹 DNA, RNA & amino acid sequences show evolutionary relationships.

🔹 Sequence Data as Evidence:

🔹 Time & Evolutionary Relationships:

More mutations = more time since species diverged.
Closely related species have fewer differences in nitrogen bases or amino acids.

🔹 Artificial Selection: Human-driven breeding of organisms for desirable traits.