Download Darwin*s Theory

Darwin’s Theory
Evolution by natural selection
Who was Charles Darwin?
• Darwin was an English naturalist that
published his observations from a five year
sea voyage aboard HMS Beagle.
• His observations provided the evidence for his
book, On the Origin of Species, his theory of
evolution through natural selection, published
in 1859.
What was Darwin’s Hypothesis?
• During his five-year voyage around the world,
Charles Darwin observed great diversity among
living things, often within the same species. He
also observed fossils that shared some, but not
all, traits with living animals. He observed
differences in plants and animals that lived in
South America and the Galápagos Islands, which
are off the coast of South America. He attributed
these differences to examples of adaptation, a
trait that increases an organism’s ability to
survive and reproduce.
What was Darwin’s Hypothesis?
• Darwin hypothesized that species gradually
change over many generations and become
better adapted to new conditions. The gradual
change in a species over time is called
evolution. Charles Darwin’s ideas are often
referred to as the theory of evolution. A
scientific theory is a well-tested concept that
explains a wide range of observations.
What is natural selection?
• Natural selection is the process by which
individuals that are better adapted to their
environment are more likely to survive and
reproduce that other members of the same
species.
How does natural selection work?
• Factors that affect the process of natural
selection are:
1. Over production of young
2. Variation within a species
3. Competition
4. Selection
What was Darwin’s Theory?
• Identify Main Idea Explain Darwin’s theory of
evolution.