Chapter 5:
Expert Question Answers
1. What are the five pieces of evidence for evolution?
Describe how each one proves evolution.
1. Fossils - shows how some species have changed over time.
2. Homologous Structures - Body parts are similar in related
animals so there must be a common ancestor.
3. Vestigial Structures - There are structures present in modern
day organisms but are not even used, so they may have been
used by a common ancestor.
4. Molecular Biology - Similar species of organisms have more
common DNA than do organisms that are more different!
5. Fetal Similarities - The unborn offspring of many species
resemble each other, suggesting a common ancestor.
2. Who is Charles Darwin? Describe why he
traveled to the Galapagos Islands?
• Charles Darwin is a scientist who
developed “The Theory of Natural
Selection”.
• He went to the Galapagos Islands
to study many diverse plants and
animals and learn how they were
successful in the environment that
they inhabited.
3. List and explain the 4 steps of natural selection.
1. Overproduction and Variation – There are many offspring and
they are all different.
2. Competition - A natural environment does not have enough
resources (food, water, shelter, space, and mates) to keep all
offspring alive. Only the organism with a variation that makes
them better adapted to the environment will survive.
3. Survival of the Fittest – the offspring best suited to the
environment will survive.
4. Successful Reproduction- Individuals who adapt to their
environment are more likely to survive and reproduce and pass
on the successful traits to offspring.
4. Using the four steps of natural selection,
describe how sharks have sharp teeth.
1. Overproduction and variation – lots of baby sharks are born.
Some have sharp teeth, some have dull.
2. Competition - The sharks with dull teeth can’t attack pray and eat
as well as sharks with sharp teeth and will die.
3. Survival of the fittest - The sharks with sharp teeth will survive.
4. Successful Reproduction – the sharks that survive pass their sharp
teeth on to their offspring.
5. What is speciation?
•
When over time, 2 populations become so
different that they can no longer interbreed.
6. Describe the three steps of speciation.
1. Separation - portion of the population becomes isolated.
2. Adaptation- as the environment changes, so may the
population living there change and evolve separately to
form separate species.
3. Division- over hundreds to thousands of generations, the
2 groups became so different that they were no longer
the same species and could no longer interbreed.
7. What are 4 things that could cause speciation?
1. Canyon Forms
3. Volcano
2. Mountain Range
4. Tsunami
8. What are 4 things that species compete
for? 3. Shelter
1. Food
2. Water
4. Mates
9. Describe what would happen to lizards where they could only eat
bugs. How would these new conditions affect the species?
They may develop the following:
• New digestive system
• Smaller heads with quick reflexes
• Softer bite
• Long and skinny tongue
Darwin’s Theory of Natural
Selection would come into play.
1. Overproduction and variation – lots of baby lizards are born.
Some inherit the traits above & some don’t.
2. Competition – there isn’t enough food to go around.
3. Survival of the fittest- Lizards that do not inherit the traits above
will die.
4. Successful Reproduction - The lizards with the traits above will
survive, reproduce, and pass their sharp teeth on to their offspring.
Describe what would happen to lizards that could only eat plants.
How would these new conditions affect the species?
They may develop the following:
• New digestive system
• Larger heads
• Harder bite
• Short and thick tongue
Darwin’s Theory of Natural Selection would come into play.
1. Overproduction and variation– lots of baby lizards are born.
Some inherit the traits above & some don’t.
2. Competition – There isn’t enough food for everyone.
3. SOTF - Lizards that do not inherit the traits above will die.
4. Successful Reproduction - The lizards with the traits above will
survive, reproduce, and pass their sharp teeth on to their offspring.