Evolution and Classification Essential Question: 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 Evolution is the gradual change in a species over time. Branching Tree Diagram- An illustration that shows probable evolutionary relationships among groups of organisms and the order in which specific characteristics may have evolved shared derived characteristics, which are usually homologous structures, or structures that have the same evolutionary origin. 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.

This branching tree diagram shows how cats have evolved. Evolution and Classification fig. 1 A Branching Tree This branching tree diagram shows how cats have evolved. Put squares around the shared derived characteristics. Circle the animal(s) that belong to the smallest group. 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. Which Figure is most like Figure B? ____________________________________________________________________________________ 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!