Download Chapter 5: Changes Over Time

Chapter 5: Changes Over Time
What is Evolution?
-___________________ is the change in the hereditary
features of a species over time.
*A ____________ is a group of similar organisms
that can mate with each other and produce fertile
offspring. Today, we have identified more than
________________________.
*How do _____________________________?
Theories on Evolution
-_________________________________ (1809)
*Proposed the ____________________________________
which states that species change over time by __________
__________ that their _______________________ during
their lifetime.
*This ___________________________ once we
understood _________________.
-_____________________________ (1859)
*Proposed the ____________________________
*This theory states that organisms with ________________
____________________________ are more likely to
_____________ and therefore ________________ these
favorable traits.
*Darwin was a naturalist on the ______________________
*In Dec. 1831, he began a 5 year voyage to ____________
___________________________ from all over the world.
*One stop on the voyage was the _____________________
(a group of 19 small islands off the coast of ____________).
*Much of Darwin’s Theories were developed after studying
the _______________________of the Galapagos Islands.
*Darwin spent over _______________ collecting his
thoughts and writing a book.
*He presented his book, ____________________________
_____________________, in 1859
Four Basic Points of Natural Selection
-___________________--organisms produce more offspring than
can possibly survive.
-___________________--many differences are found among
individuals of a species due to meiosis and genetic inheritance.
-__________________--some variations allow members of a
population to survive and reproduce better than others.
-__________________--over time, offspring of individuals with
helpful variations make up more and more of the population.
Variations and Adaptations
-A _________________ is any difference between individuals of
the same species.
-An ________________ is any trait that helps an organism survive
and reproduce.
*Examples: _______________________________________
-If enough ________________ occur in a _________________
over time, a _________________________________.
-The movement of individuals ____________________________
helps to bring about more variations.
What Brings About Evolutionary Change?
-____________________________________________________
can bring about evolutionary change by ____________________
one variation over another.
*Example: _________________________________
Eventually, a new species could form if the environmental
change is drastic enough.
-______________________________ can also bring about
evolutionary change. Example: __________________________
These two kinds of squirrels have been isolated from one another
for a long time. Eventually, this isolation may result in two
different species.
Evidence for Evolution
-_______________________________________
*All vertebrate embryos __________________________
early in development. These similarities show an
_________________________ among all vertebrates.
-___________________________--similar structures that related
species have inherited from a _____________________.
*Example: the bones in a _________ flipper, a ______ wing,
and a ________ leg.
-__________________________--body parts that are __________
_______________ and do not appear to have a function.
*Examples: human ______________, _______________ in
whales and snakes.
*Scientists believe these once functioned in an ___________
-______________________________--organisms that are close
relatives have ____________________.
*Example: The DNA of humans and chimps differs by
__________________. This supports the idea that primates
All evolved from a ____________________.
-_____________________________________--organisms that
have genes that make them resistant to a particular chemical will
be the only ones to survive in the presence of that chemical to
pass on their traits.
*Examples: ________________ resistant bacteria
________________resistant insects
-_____________________
*A _____________ is the preserved remains of an organism
that ______________________.
*Fossils show that many organisms from the past are
____________________than organisms alive today.
*Types of fossils:
1. ________________________________
2. ________________________________
3. ________________________________
4. ________________________________
*Most fossils form when organisms that die become buried in
_________________.
*Two methods for dating fossils:
1. ______________________--fossils are dated
according to the layer of rock in which they are
found. This is just an estimate.
2. _____________________--fossils are dated by
measuring the amount of radioactive material
present. This is more accurate.
Fossil Record and Geologic Time Scale
-____________________________--a calendar of Earth’s history.
*Using the ___________________ (all the fossils scientists
have collected) and _______________________________,
scientists have developed the Geologic Time Scale (pg. 160)
Combining Evidence
-DNA evidence is a newer source of evidence.
-In most cases, evidence from DNA and protein structure
___________________ conclusions based on fossils, embryos,
and body structure.
-In some cases, scientists have ____________________________
-Scientists can use the combined evidence of species relationships
to draw ________________________--diagrams that show how
different groups of organisms are related.
How Fast Does Evolution Occur? Two Theories
-_______________________--very slow change from one species
to another.
*Involves _______________________
*Supported by some _________________ (like the horse)
-_____________________________--more rapid evolution of a
species brought about by the mutation of just a few genes.
*Supported by some fossil records and __________________
-Today, scientists think both probably occurred.
Extinction and Evolution
-__________________ is the dying out of a species.
*______________________ because the environment is
always changing. Through natural selection, ____________
which are ____________________________ to a changing
world ____________________.
*Earth’s history shows at least _______________________
followed by rapid explosion of new species.
-______________________________ and ___________________
are contributing to the rapid extinction of thousands of species.
*This led to the passage of the ________________________.
As a result, many captive breeding programs were
established. They are expensive and for some species, they
may be too late.