Section 1: Darwin’s Theory What important observations did Darwin make on his voyage? How did Darwin account for the diversity of species and the differences between similar species? How does natural selection lead to evolution?

Darwin’s Voyage Charles Darwin sailed on the HMS Beagle, from England to the Galápagos Islands and back, for 5 years starting in 1831.

Galápagos Islands Located 525 miles west of Ecuador. Was visited by Darwin in 1835.

Galápagos Finches Darwin noticed that on each island, the finches had adapted to the local environment. Adaptation: a trait that helps an organism survive and reproduce in its environment

Galápagos Finches

Overproduction and Variation Natural selection is the process by which individuals who are better adapted to their environment are more likely to survive and reproduce than other members of the same species.

Competition and Selection Variations among turtles make some of them better able to survive. Turtles that survive to become adults will be able to reproduce.

Competition and Selection Variations among turtles make some of them better able to survive. Turtles that survive to become adults will be able to reproduce.

Factors that Affect Natural Selection Overproduction Animals (including humans), plants, and other organisms tend to produce too many offspring, and there may not be enough food, water, or shelter to protect them all.

Factors that Affect Natural Selection Variation Members of the same species differ from one another in many of their traits Example: You may be faster than your sibling, but your sibling may be taller, or have a better immune system, or have better reflexes.

Factors that Affect Natural Selection Competition All living things struggle to survive. Sometimes they compete for more food, or running away from a predator, or fighting off a disease.

Factors that Affect Natural Selection Overproduction + Variation + Competition = Natural Selection The environment “selects” which members of a species lives long enough to have offspring. Some members have lots of offspring, others have few, and some have no offspring. Over time, helpful traits (like speed, camouflage, and disease-resistance) will show up more often in a species. Eventually, most members will have this trait.

Adaptation: a trait that can help an organism survive Things to Remember Species: a group of similar organisms that can mate with each other and produce offspring Overproduction: species creating more offspring than can possibly survive Adaptation: a trait that can help an organism survive

Section 2: Evidence of Evolution What evidence supports the theory of evolution? How do fossils form? What do scientists learn from fossils?

Homologous Structures The structure of the bones in a dolphin’s flipper, a bird’s wing, and a dog’s leg is similar. Homologous bones are shown in the same color.

Similarities in Early Development

Similarities in DNA and Protein

How Do Fossils Form? Most fossils form when organisms that die become buried in sediments.

Types of Fossils Molds and Casts: Most common fossil; organism dies and gets buried in sediment, creating a mold; more sediment later fills in this mold to create a cast

Types of Fossils Petrified: rock minerals replace parts of the organism, turning the fossil into a hard, rock-like state

Types of Fossils Trace: evidence of activity, such as footprints or cave paintings

Types of Fossils Preserved Remains: organism trapped in amber, tar or ice; produces the best fossils

Section 3: Evolution of Species What factors have contributed to the diversity of species? How do new species form? How do scientists infer evolutionary relationships among species? What causes the extinction of species?

Evolution in Progress There are over 150 major breeds of dogs and hundreds of other cross-breeds. All of these dog breeds (and wolves) came from the same ancestral animal

Kaibab and Abert’s Squirrels These two kinds of squirrels have been isolated from one another for a long time. Eventually this isolation may result in two different species. Kaibab Squirrel Abert’s Squirrel

A Branching Tree This branching tree shows how scientists now think that raccoons, lesser pandas, giant pandas, and bears are related.

Extinction of Species Extinction is caused by a change in species' environment. The members of a species may not have adaptations that allow them to survive and reproduce in the changed environment. ccc Woolly Mammoth Baiji River Dolphin Thylacine

Things to Remember Extinct: no more members of a particular species exist; occurs when a species does not have the right adaptations to survive and reproduce

End of Section: Evolution of Species

Section 4: Classifying Organisms Why do biologists organize living things into groups? What do the levels of classification indicate about the relationship between organisms? What characteristics are used to classify organisms into domains and kingdoms?

Classification through Names Kingdom: Animalia Animalia Phylum: Chordata Chordata Class: Mammalia Mammalia Order: Primates Carnivora Family: Hominidae Felidae Genus: Homo Felis Species: H. sapiens F. domesticus

Classification through Names Kingdom: Animalia Animalia Phylum: Chordata Chordata Class: Mammalia Mammalia Order: Carnivora Carnivora Family: Felidae Felidae Genus: Felis Felis Species: F. domesticus F. chaus

Three Domains of Life In the three-domain system of classifications, all known organisms belong to one of three domains–Bacteria, Archaea, or Eukarya. Bacteria Archaea Eukarya Protists Fungi Plants Animals

Levels of Classification As you move down the levels of classification, the number of organisms decreases. The organisms at lower levels share more characteristics with each other.

End of Section: Classifying Organisms

Section 5: Branching Trees How does a branching tree diagram show evolutionary relationships?

A Branching Tree Branching trees such as this show relationships between groups of organisms. It also shows the order in which specific characteristics may have evolved.

Shared Derived Characteristics A branching tree diagram shows evolutionary relationships by grouping organisms according to shared derived characteristics. Reptiles Amphibians Fishes Egg with shell Invertebrates Four limbs Backbone Ancestor of animals

End of Section: Branching Trees