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AP Biology
Chapter 15 – Mechanisms of Evolution
15.1 Evolution is Both Factual and the Basis of Broader Theory
15.1 #1 Why is evolution the unifying
principle in biology?
• Things change all the time
• These changes drive the origin of species
• These changes drive the extinction of species
• These changes drive the diversity of life
15.1 #2 What was the significance of
Lamarck’s ideas?
• His ideas led to the field of epigenetics – which is the
study, in the field of genetics, of phenotypic trait variations that are
caused by external or environmental factors that switch genes on and
off and affect how cells read genes instead of being caused by
changes in the DNA sequence
15.1 #3 What was the mechanism Lamarck
proposed?
• is the idea that an organism can pass on
characteristics that it acquired during its lifetime to
its offspring (also known as heritability of acquired
characteristics)
15.1 #4 How does the present knowledge of
molecular biology and genetics refute his
mecahnism.?
• Traits are passed down by genes and DNA, and
changes in DNA (mutations) not by acquired
characteristics
15.1 #5 Summarize Darwin’s theory of
evolution by natural selection
1. Species change over time
2. Divergent (different) species share a common
ancestor
3. What produces change in species is natural selection
– the differential survival and reproduction of
individuals in a population based on variation in
their traits
15.1 #6 What was the significance of Darwin’s
theory of evolution by natural selection?
• It provided the first, and only explanation of the existence of
adaptations in nature.
• It got proven and accepted after Mendel’s statistical analysis of
genetic traits.