Evolution in Action
Understand evolution in action through the natural selection of poison levels in newt populations for Grade 8 science. Students learn that high-poison genes were repeatedly passed down while low-poison genes were lost, producing today's extremely toxic population through accumulated selection across hundreds of years.
Key Concepts
Over many generations, the "high poison" genes were passed down repeatedly, while "low poison" genes were lost.
Today, the population is extremely poisonous not because individual newts decided to change, but because Natural Selection removed the less poisonous individuals over hundreds of years.
Common Questions
How did natural selection produce extremely poisonous newts over time?
Natural selection removed low-poison newts from the breeding population generation after generation. Only high-poison newts survived to reproduce and pass their genes. Over hundreds of years of this consistent selection, high-poison genes accumulated and low-poison genes virtually disappeared.
Did individual newts become more poisonous during their lifetime?
No—individual organisms cannot change their genetic traits. The poison level of today's population increased because natural selection changed who survived and reproduced each generation. Individual newts still had fixed poison levels; what changed was which individuals' genes carried forward.
What is evolution in action and why is the newt example a good illustration?
Evolution in action refers to observable natural selection producing measurable population change. The newt population shifted from mildly toxic to extremely poisonous through a documented pressure (garter snake predation) and a measurable outcome (poison level distribution). This makes it a clear, concrete example of the mechanism.