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Chapter 5 Study Guide
Name: ____________________________
Date: ________________Per. __________
Lesson 1: THE PROCESS OF EVOLUTION--Charles Darwin developed a theory of how organisms with the same ancestors
Essential (3.d)
can look/behave differently.
A. Charles Darwin.
1. ______________________ is change over time. Modern scientists refer to __________________ as genetic change in a
_______________________ over time.
2. Charles Darwin was a ________________, a person who studies the natural world including ____________, _________
___________________ and ___________________.
3. At 22, Darwin signed on to serve as the ______________ on the British Naval Ship called the _______________________.
a. The __________________ sailed from England to __________ ______________ and other parts of the world to make
navigational maps. The voyage lasted almost ______ years.
4. Darwin made detailed _____________ of the ______________ and ______________ of the locations he visited. Some of
the most interesting findings were the ______________ and _________________ of the organisms he saw, especially
on the _________________ Islands, located off the coast of South America.
a. When he compared many of the ____________, __________ and lizards on the Galapagos, he found they were
similar, but not the same as the organisms he found on the ______________ ________________mainland.
b. Darwin reasoned perhaps some of the animals/plants on the Galapagos originally came from ________ __________
and over time, they ________________ to be ______________.
c. Tortoises with dome-shaped shells and short necks were found where they ate _____-_____________ plants and
those that fed on high-growing cacti had ___________-___________ shells that allowed their __________ necks to
reach the cactus pads. Darwin reasoned that the different tortoises “descended with ___________________” until the
trait for long necks evolved.
d. Darwin was impressed by the ______________ of Finches on the islands. He was fascinated by the diversity of beak
size and ___________. Beaks ranged from small to large and each was _______- _________ for eating a particular food.
5. Selective breeding - When a plant/animal is bred for certain characteristic/traits by man—does not lead to new _________.
B. Darwin’s Theory of Natural Selection
1. Darwin realized that organisms with a __________ that allowed them to survive under particular environmental conditions
produced more _________________ than organisms without the trait.
2. Traits are passed from parents to ______________. Sometimes _____________ occur in genes and new __________ are
created. If the trait is _________________, the organism might die, but if the trait is __________________ the organism is
more likely to survive and reproduce. The trait will be passed on to future generations and become common in the species.
a. Genetic variation is necessary for _______________________ to occur, survival depends on other ____________ as well.
3. One influence on Darwin’s work was Thomas Malthus’ essay which argued that if the _________________ population
continued to grow unchecked, humans would run out of space/food creating a “Struggle to _______________”.
a. Darwin too had noticed that animals often produce more _________________ than limited resources can support, so only
some ________________ survive.
b. Different habitats can put pressure on animals to survive as well, Darwin suggested that organisms _____________
prepared for living in specific _________________ would survive and be able to reproduce, and their _____________ would
also be able to _____________ in the specific __________________.
c. Darwin defined ______________ _______________ as a process by which individuals with ________ that better suit the
environment are more likely to survive longer/reproduce more ___________________ than individuals without these traits.
d. Inherited _______________ that increase an organism’s chance of surviving and reproducing in a particular environment
are called _____________________________.
e. _____________________ spread through a population in future generations if _________ _______________favors them.
f. Darwin proposed that if groups of __________________ were isolated from other organisms of the same __________,
natural selection can cause them to become different over generations, as they ______________________ to different
environmental ___________________, and this process can develop a new __________________.
g. Darwin’s theory of evolution by natural _____________ can best be explained by the following 4 requirements:
overproduction, ___________________, Inherited Variation, and Natural __________________.
h. Darwin spent ________ developing his ideas on natural selection. He developed the idea that organisms have “descended
with ________________” from common ancestors over a long period of time.
i. Considering ________________ evidence that the Earth is millions of years old, Darwin proposed there had been enough
time for organisms to change and for new species to develop from ancestral _______________.
Lesson 2: ADAPTATION AND EXTINCTION—Adaptations are traits that help an organism survive and reproduce in a
particular environment, and the inability to adapt can lead to extinction.
A. Adaptations
1. Humans are skilled at ______________ their environments to suit their needs. Other organisms have unique characteristics,
or ______________________ to live in their specific _________________, which have evolved over time.
a. ________________ are inherited traits that increase an organism’s chance of surviving and reproducing in a particular
environment.
b. The desert rabbits have blotchy ___________coats that blend in with the _________________, they also have long ears
that help them stay cool as heat is _____________ through an extensive system of ________ ___________ in the ears.
B. Types of Adaptations
1. Structural Adaptations
a. Structural adaptations are inherited ______________ traits of a __________ that make its members better suited to
their ____________________. In the desert rabbit, the ears are a structural adaptation which help rabbits stay _________.
b. Blending in to the surrounding environment is a type of structural adaptation known as _________________________.
c. Another structural adaptation is _____________, in which one species (the mimic) looks like another species (the
model) to fool or deceive a third species.
d. _______ mimicry is when a species fools its prey by looking inviting or familiar--an example of this is the ___________.
2. Behavioral adaptations are inherited _____________ that make its members better suited to the environment.
a. Scientists sometimes call these behaviors _________________or ____________ behaviors. (list example of the
clapper rail/bower bird:______________________________________________________________________________
_________________________________________________________________________________________________.
b. Grass-eating animals live in large ___________ called ______. They instinctively know that a ___________ is less likely
to be attacked by a __________________ than one animal alone.
C. Extinction—When all individuals of a particular species die off that species becomes ________________.
1. _____________ ___________ can lead to extinction if the conditions of the environment change in a way that none of
the organisms of a species can survive.
2. Climate change, ________________ and _______________ are some of the environmental factors associated with
extinction. Scientists have proposed that a large ______________ collided with Earth about 65 million years ago causing
extinction of the ______________________.
3.There are several causes of extinction, they include:
a. Loss of Habitat - habitats for plants and animals are ________________ in size as humans develop and occupy more
space. With diminishing ________________ ________________ fewer organisms can ___________________.
b. Loss of Genetic Diversity – the fewer the number of individuals left of a ___________, the less the generic variability,
with limited genetic variability it is much easier for a change in ____________________ conditions to lead to extinction.
c. Competition with Exotic Species – competition between organisms is caused by the _____________________ of a new
species to the habitat. The new species may be able to _________________________ the native species and push them to
extinction.
d. Inability to _____________ - If the climate changes suddenly, a species might not have any individuals with the genetic
_____________ that will allow them to adapt. Over time the population becomes smaller, less able to _______________
and eventually the species could become _________________.
D. Darwin’s Conclusions Today
1. Extinction does not happen at the same _____________ or in the same _____________. The environment is always
_______________________ and natural selection is always acting on organisms.
EXTRA PRACTICE
1. Give an example of a structural adaptation: _____________________________________________________________________.
2. Give an example of a behavioral adaptation: ____________________________________________________________________.
3. The four environmental factors associated with extinction are: _____________________________, volcanoes, ________________
and _______________________________________________.
4. The problem with introducing Exotic Species into a different environment is ____________________________________________
____________________________________________________________________________________________________________.
5. After many years of research and thought, Darwin published _________________________________________________.