This document discusses Charles Darwin's theory of natural selection and evolution. It defines key terms like variation, reproduction, competition, and fitness. It explains that Darwin observed variation among finches in the Galapagos Islands which led him to propose that natural selection causes evolution as organisms compete for limited resources and those with traits best suited to the environment have higher fitness and are more likely to survive and reproduce, passing on their genes. Over time this leads to evolution of species adapted to their environments.

1. NATURAL
SELECTION
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2. Contents
Standard: HS-LS4-2.
Content Objective: Students will learn
and discuss the mechanism of natural
selection as it relates to evolution.
Darwin’s theory
Terminology
Natural Selection
Variation
Reproduction
Competition
Fitness
Evolution by Natural Selection

3. Padlet Warmup
How does the environment influence the survival of an
individual?
• Use the QR code to get onto Padlet and respond to the
warmup questions.

4. Charles Darwin
• Charles Darwin was a British naturalist
proposed theory of evolution by natural
selection.
– A naturalist studies patterns within nature
and impacts of living species on each other
and the environment.
• In the 1830’s, Darwin set sail on the HMS Beagle
on an expedition around the globe.
• Galapagos Island
– Darwin observed patterns between distinct
species of finches

5. Think-Pair-
Share
Why do you believe that these
finches may look different?
• Write down your observations about
the different finches.
• Turn to your partner and share your
observation.

6. DARWIN’S FINCHES

7. Darwin’s Theory of Evolution
Use interactive guide to follow along the video.

8. Terminology
Theory of Evolution
• Species evolve over time and
all living things come from a
common ancestor.
Natural Selection
• Organisms better adapted to
their environment survive and
reproduce.
• ”Survival of the Fittest”

9. Natural
Selection
VARIATION REPRODUCTION
COMPETITION FITNESS

10. Genetic
Variation
Genetic variation is caused by:
Mutation
Random
mating
Crossing
over
Random
fertilization
Genetic differences that exist
within a population.Variations of a
gene that a phenotypically
expressed.

11. Reproduction
Organisms within a species
reproduce more offspring than
can survive.
Species that are more fit will
survive and reproduce
Reproduction leads to genetic
variation of individuals

12. Think-Pair-Share
How do variations lead to adaptions?
• In your science notebook answer the following question.
• After discuss with your partner

13. Competition
Due to increase of population resources will
be limited.
• Food
• Water
• Shelter
• Mates
Individuals within a population will compete
with other individuals for resources.
Competition can occur within and between
species

14. Fitness
Natural selection acts on an
individual’s phenotype.
Individuals with high
fitness is more likely to
survive and reproduce
The higher the fitness the more likely
the organism will survive to pass on its
genes to the next generation.

15. USING WHAT
YOU NOW
KNOW….
How does natural selection play
a role in this picture?
Use specific vocabulary to support
your claim.

16. Summary
• Charles Darwin founded theTheory of
Evolution andTheory of Natural Selection.
• Evolution is the process of organisms evolving
to their environments over a period of time
and all organisms share a common ancestor.
• Natural selection is a mechanism of evolution.
• For natural selection is possible because of
reproduction, variation, fitness, and
competition.

17. Exit Slip
How does the environment influence the
survival of an individual?
• Use the QR code to get onto Padlet and respond to the
warmup questions.
• You should use knowledge gained from the lecture to
support your claim.