2. SB3C. Examine the evolutionary basis of modern classification systems.
History or the Theory (15.1)
State Standard
SB3C. Examine the evolutionary basis of modern classification systems.

3. Revered Greek philosopher & scientist
Chapter 15
Evolution
15.1 Darwin’s Theory of Natural Selection
Before Darwin
Aristotle – BC
Revered Greek philosopher & scientist
Believed organisms were created in a permanent form that could not change over time
His ideas were highly influential for centuries

4. Jean Baptiste de LaMarck – 1800s French naturalist
Chapter 15
Evolution
15.1 Darwin’s Theory of Natural Selection
Before Darwin
Jean Baptiste de LaMarck – 1800s
French naturalist
Believed inheritance of acquired traits were the driving force of evolution.
Believed traits were acquired through use and disuse.
Ex: A giraffe had to stretch its neck in order to reach food – so the neck got longer during the giraffe’s lifetime and was passed to the next generation.

5. Chapter 15
Evolution
15.1 Darwin’s Theory of Natural Selection
Before Darwin
Geologists were discovering ancient bones, shells, & fossilized plants in England in the 1800s.
These items were being found in hillsides & riverbeds & gave new clues about diversity of organisms.

6. James Hutton & Charles Lyell – Gradualism
Chapter 15
Evolution
15.1 Darwin’s Theory of Natural Selection
Other Names Who Influenced Darwin
James Hutton & Charles Lyell – Gradualism
Earth had changed over very long periods of time.
Thomas Malthus – Struggle for survival
Populations outgrew resources & had to compete.

7. In 1831, Darwin set sail on the HMS Beagle
Chapter 15
Evolution
15.1 Darwin’s Theory of Natural Selection
Darwin’s Voyage
In 1831, Darwin set sail on the HMS Beagle
Darwin’s role on the ship was as naturalist and companion to the captain.
His job was to collect biological and geological specimens during the ship’s travel.

8. Off the west coast of South America
Chapter 15
Evolution
15.1 Darwin’s Theory of Natural Selection
The Galápagos Islands
Off the west coast of South America
Each island had a unique climate & geographical features.
Darwin began to collect mockingbirds, finches, and other animals on the four islands.
He noticed that the different islands seemed to have their own, slightly different varieties of animals.

9. Populations from the mainland changed after reaching the Galápagos.
Chapter 15
Evolution
15.1 Darwin’s Theory of Natural Selection
The Galapagos Islands – cont’d
Darwin theorized that the island populations came from the same ancestral populations on the mainland.
Populations from the mainland changed after reaching the Galápagos.

10. Chapter 15
Evolution
15.1 Darwin’s Theory of Natural Selection
Concepts That Emerged from Darwin’s Work…
ADAPTATIONS – inherited traits that may give an individual survival & reproductive advantages over other individuals.
Darwin hypothesized that new species could appear gradually through small changes in ancestral species.
Darwin inferred that if humans could change species by artificial selection, then perhaps the same process could work in nature (natural selection).

11. Chapter 15
Evolution
15.1 Darwin’s Theory of Natural Selection
Concepts That Emerged from Darwin’s Work…
cont’d
REPRODUCTIVE ISOLATION – populations that get geographically separated may give rise to adaptations specifically suited to each environment.

12. Principles of Natural Selection
Chapter 15
Evolution
15.1 Darwin’s Theory of Natural Selection
Principles of Natural Selection
Individuals in a population show variations.
Variations can be inherited.
Organisms have more offspring than can survive on available resources (overproduction).
Variations that increase reproductive success will have a greater chance of being passed on.

13. Natural Selection was a means of explaining how evolution works.
Chapter 15
Evolution
15.1 Darwin’s Theory of Natural Selection
Darwin & Wallace
Darwin published On the Origin of Species by Means of Natural Selection in 1859.
Natural Selection was a means of explaining how evolution works.
Wallace also studied & wrote about evolution, emphasizing competition of resources, while Darwin focused on reproductive success.
Darwin’s amount of data & thorough explanations caused his theories to be become dominant.

15. Which is not a principle of Darwin’s theory about
Chapter 15
Evolution
Chapter Diagnostic Questions
Which is not a principle of Darwin’s theory about
the origin of species?
Individuals show variations.
Variations can be inherited.
Organisms have more offspring than available resources will support.
Offspring always inherit the best traits. A B C D
CDQ 1

16. Which was Charles Darwin’s only qualification
Chapter 15
Evolution
15.1 Formative Questions
Which was Charles Darwin’s only qualification
for his position as naturalist on the Beagle?
a degree in theology
an interest in science
a knowledge of biology
an understanding of geology A B C D
FQ 1

17. What was Darwin’s term for selective breeding?
Chapter 15
Evolution
15.1 Formative Questions
What was Darwin’s term for selective breeding?
evolution
speciation
artificial selection
natural selection A B C D
FQ 2

18. What did Darwin infer from his observations of artificial selection?
Chapter 15
Evolution
15.1 Formative Questions
What did Darwin infer from his observations of
artificial selection?
Animal breeders could create new species.
A similar process could work in nature.
Reproductive success could be increased.
Variation in a species could be produced. A B C D
FQ 3

19. What is the relationship between the terms
Chapter 15
Evolution
15.1 Formative Questions
What is the relationship between the terms
natural selection and evolution?
They mean the same thing.
Evolution works against natural selection.
Evolution explains how natural selection works.
Natural selection explains how evolution works. A B C D
FQ 4

20. Which explains why the tortoises on the different
Chapter 15
Evolution
Standardized Test Practice
Which explains why the tortoises on the different
islands of the Galápagos had slightly different
variations in their shells?
The different tortoises were different species.
The environment on each island was different.
Each type of tortoise could survive only on its own island.
They arrived on the islands from different continents. A B C D
STP 1