Download LEFT- Tortoises

5.1 Natural Selection
Vocabulary
• Evolution is change over time.
• The naturalist Charles Darwin was the first
person to write a thorough collection of
evidence supporting evolution.
• Species a group of organisms that share
traits AND can reproduce a fertile
offspring.
5.1 Natural Selection
Darwin’s Claims
• Darwin made observations about the
diversity and uniqueness of organisms.
• He then made CLAIMS about the process
responsible for this diversity.
• Darwin used all his years of observations as
EVIDENCE to support these claims.
Left - Voyage of the Beagle
• Look at Figure 2 on pg 211.
• Where did the HMS Beagle stop before
reaching the Galapagos Islands?
• Multiple locations on South America
5.1 Natural Selection
Voyage of the Beagle
5.1 Natural Selection
Tortoises
• Darwin found giant tortoises on all the
Galapagos Islands, but nowhere else.
• He wondered why they were so different
even though they lived on islands only
about 50 miles apart.
• He reasoned that each new population
changed slightly, or evolved, to fit its
unique environment on the island.
5.1 Natural Selection
LEFT- Tortoises
• Read the first two paragraphs on pg 212.
What is unique about these tortoises?
Dome-shaped
Saddle-shaped
5.1 Natural Selection
LEFT- Tortoises
• Read the first two paragraphs on pg 212.
What is unique about these tortoises?
Dome-shaped
Saddle-shaped
Short necks
Long necks
Eat low growing plants
High growing catus.
5.1 Natural Selection
LEFT- Tortoises
• Why might one tortoise population evolve
long necks?
• Share with your partner.
RIGHT - Species
– Western spotted skunk,
– mountain lions
– great white sharks
– With your partner think of five other
species, and write them down.
5.1 Natural Selection
Vocabulary
• Selective breeding is breeding plants
and animals to get offspring with
desired characteristics based on
HUMAN needs only.
Not a Species
– A mule is the offspring of a male donkey
and a female horse. Horses and
donkeys are different species, with
different numbers of chromosomes.
– A liger is the offspring of a male lion and
a female tiger.
These are both examples of selective
breeding, even if accidental.
Liger in
action
LEFT - Not a Species
•Summarize what you learned about ligers!
•Now summarize what you learned today.