The GED science test might include questions related to Evolution.
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Video Transcription
Let’s explore evolution and natural selection, two fundamental concepts that have profoundly shaped our understanding of life on Earth.
Evolution: The Story of Life’s Changes
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Evolution refers to the process through which species of organisms change over time through successive generations. It is not about individuals evolving during their lifetime but rather how populations of a species adapt and change.
Real-Life Example: The Galápagos Finches
Charles Darwin observed the finches on the Galápagos Islands. These birds have evolved different beak shapes and sizes to adapt to varied food sources, demonstrating evolution in action.
Natural Selection: Nature’s Way of Shaping Life
Natural selection is the mechanism by which organisms better adapted to their environment are more likely to survive and reproduce. Over time, advantageous traits become more common in the population.
Real-Life Example: Antibiotic Resistance in Bacteria
Some bacteria develop mutations that make them resistant to antibiotics. These bacteria survive antibiotic treatments, reproduce, and pass on their resistant traits, becoming more common in the bacterial population.
The Role of Genetic Variation
Genetic variation is crucial for natural selection. Variations within a population mean that some individuals have traits better suited to the environment, increasing their chances of survival and reproduction.
Real-Life Example: Cichlid Fishes of East African Lakes
Cichlid fishes have evolved various jaw structures to exploit different food sources in East African lakes, thanks to genetic variations that provide survival advantages in specific niches.
Adaptation: The Outcome of Evolution
Adaptation is the process where organisms become better suited to their habitat. This results from natural selection, where beneficial traits become more common over generations.
Real-Life Example: Polar Bears
Polar bears have evolved features like white fur, thick blubber, and large paws for swimming, which help them survive in Arctic conditions.
Homologous Structures: Evidence of Evolution
Homologous structures are physical features in different species that share a common ancestral origin, even though they may serve different functions today. These structures provide strong evidence for evolution, showing how species are connected through common ancestry.
Real-Life Example: The Forelimbs of Vertebrates
The forelimbs of humans, bats, whales, and cats are homologous structures. While they serve different purposes—such as grasping, flying, swimming, or walking—they share a similar bone structure, indicating they evolved from a common ancestor.
Why Homologous Structures Matter
Homologous structures highlight how different species have adapted to their environments over time while retaining evidence of their evolutionary relationships. They are an essential part of understanding evolution and are frequently mentioned on the GED science test.
Now that you are familiar with this topic take our quiz to see how GED® test writers might frame questions related to it.
Last Updated on January 15, 2026.