Transcript File - Ms. D. Science CGPA

Ms. De Los Rios
6th Grade
Diversity of Life
Evolution and Classification
Essential Question:
How are Living Things alike yet Different?
How are Evolution and Classification Related?
Pgs. 602-605
Vocabulary
1. Evolution is the gradual change in a species over time.
2. Branching Tree Diagram- An illustration that shows probable
evolutionary relationships among groups of organisms and the
order in which specific characteristics may have evolved
3. shared derived characteristics, which are usually homologous
structures, or structures that have the same evolutionary origin.
4. Convergent Evolution
How Are Evolution and Classification Related? Pg. 602
In 1859, Charles Darwin published a theory
about how species could change over time.
Darwin’s theory is often referred to as the
theory of evolution.
• Evolution is the gradual change in a
species over time.
•Darwin believed that evolution took place
through the process of natural selection in
which individuals that are better adapted to
their environment are more likely to survive
and reproduce than other members of the
same species.
How Are Evolution and Classification Related? Pg. 603
The theory of evolution has changed how biologists classify
organisms.
Scientists now understand that certain organisms may be similar
because they share a common ancestor and an evolutionary history.
•The more similar the two groups are, the more recent the common
ancestor probably is.
•Today’s system of classification takes into account the history of a
species.
Species with similar evolutionary histories are classified
more closely together.
Branching Tree Diagrams pg. 603
Probable evolutionary relationships
among groups of organisms and the
order in which specific characteristics
may have evolved are illustrated using a
branching tree diagram.
The base of such a diagram shows the
common ancestor.
Organisms are grouped according to
their shared derived characteristics,
which are usually homologous structures,
or structures that have the same
evolutionary origin.
In addition to comparing the structures
of organisms, scientists can also use
information about the chemical makeup
of their cells.
Evolution and Classification fig. 1
A Branching Tree
This branching tree diagram shows how cats have evolved.
1. Put squares around the shared derived characteristics.
2. Circle the animal(s) that belong to the smallest group.
3. Cats are more closely related to (reptiles/marsupials).
Evolution and Classification
Apply IT!! Pg. 604
Note the characteristics of Figures
A, B, C, and D.
1. Which Figure is most like Figure
B?
____________________________
____________________________
____________________________
2. If these figures represent fossils
of extinct organisms, which
would be the ancestor of the
others?
____________________________
____________________________
___________________________
Figure 2
Evolution and Classification Fig. 3. pg. 605
Convergent Evolution
Birds and insects both use wings to fly,
but they are not closely related
organisms.
Unrelated organisms may have similar
characteristics or body structures
because they evolved in similar
environments.
The process by which unrelated
organisms evolve characteristics that are
similar is called convergent evolution.
When studying the chemical makeup of
organisms, scientists sometimes
discover new information that results in
reclassification.
Assess your Understanding!