EVOLUTIONChapter 15

Florida State Standards Associated With Evolution SC.912.L.15.1- Explain how the scientific theory of

evolution is supported by the fossil record, comparative anatomy, embryology, biogeography, molecular biology, and observed evolutionary change (Assessed on Biology EOC)

SC.912.L.15.10- Identify basic trends in hominid evolution from early ancestors six million years ago to modern humans, including brain size, jaw size, language, and manufacture of tools (Assessed on 15.1)

SC.912.L.15.13- Describe the conditions required for natural selection, including: overproduction of offspring, inherited variation, and the struggle to survive, which result in differential reproductive success (Assessed on Biology EOC).

SC.912.L.15.14- Discuss mechanisms of evolutionary change other than natural selection such as genetic drift and gene flow (Assessed on 15.13).

Chapter 15- Section : Darwin’s Theory of Evolution by Natural Selection (p.418-p.422)

Interesting Facts about Charles Robert Darwin

He was born in 1809 in England. He was one of 6 children. He went to medical school and didn’t like it

so he did poorly. During the time he was spending not doing

medical school things, he was gaining interest in taxidermy, natural history, etc.

His dad sent him to become a parson (like a priest) instead.

There he focused on providing arguments for the existence of God through reason and ordinary experience in nature.

Darwin’s Voyage on the HMS Beagle

Darwin was invited to be a companion and collector for a trip on the

HMS Beagle. His father didn’t want him to go because

he thought it was a waste of time. For 5 years Darwin was on the voyage

investigating geology and making natural history collections (rocks, fossils, plants, animals).

The Galapagos Islands Galapagos Islands are off the Coast of South America Collected mockingbirds, finches and other animals. Noticed each island seemed to have theirown slightly different varieties of animals.

Tortoises on different islands

Finches on different islands

The Galapagos Islands Darwin suspected populations from the

mainland (South America) began to change after reaching the Galapagos.

Darwin hypothesized that new species could appear gradually through small changes in ancestral species.

He tried to figure this out by observing artificial selection (or selective breeding; dogs, pigeons, etc)

Natural Selection Thought about the struggle for

existence and how some individuals would be better equipped to survive than others. Those less equipped would die. This is the process of natural selection.

The Four Principles of Natural Selection Individuals in a population show variations (or

differences) (VARIATION- ex. Students in classroom look different)

Variations can be inherited (passed down from parent to offspring) (HERITABILITY-ex. You look similar to your biological parents)

Organisms have more offspring than can survive on available resources. (OVERPRODUCTION- ex. Average cardinal lays 9 eggs- more than can survive)

Variations that increase reproductive success have a greater chance of being passed on than those that do not (REPRODUCTIVE ADVANTAGE- moth gray color helps it blend in to tree branch)

Peppered Moth Example

Peppered moths - the peppered moths of northern England. Originally they were light colored and blended in with the light bark of trees. However, due to the Industrial Revolution soot and particulate matter covered trees making them darker, and so the light colored moths stood out like sore thumbs. They became easy pickings for predators. Darker colored moths were able to avoid predation and so passed on their genes to subsequent generations because they were able to hang around long enough to breed. Dark colored moths therefore survived. The whole process was completely reversed when cleaner air returned, allowing the trees to revert back to their pale color; the lighter moths thrived once more.

Natural Selection Given enough time, natural selection

could modify a population enough to produce a new species.

Assignment Answer Questions 1-5 from page 445.

Answers 1. Natural selection is a mechanism for evolution. 2. Artificial selection was used to produce purebred

Chihuahuas and cocker spaniels. 3. Natural selection is a mechanism for a theory developed

by Charles Darwin. 4. Which best describes the prevailing view about the age of

the Earth and evolution before Darwin’s voyage on the HMS Beagle? A. Earth and life are recent and have remained unchanged.

5. Which statement about the tortoise above would be part of an explanation for tortoise evolution based on natural selection? B. Tortoises with domed shells have more young than tortoises

with flat shells.