Chapter 10 “Natural Selection” Section 10.1 “A Riddle: Life’s Diversity and Connections”. Objectives: Define Evolution. Describe Darwin’s contributions to science.

Introduction to Evolution 1. Charles Darwin believed that humans evolved from monkeys. 2. Darwin went to the Galapagos Islands on vacation. 3. Evolution is a gradual change over time.

Cont….. 4. If I cut off my arm 50% of my offspring (children) will have only one arm. Inferior males get all the girls.

Voyage of the Beagle Charles Darwin: contributed to our understanding of Evolution. Set sail on the Beagle (a research ship) in 1831.

Observations Studied the “natural” world. Noticed diversity in his travels. Species observed were well suited to whatever environment they inhabited. Collected fossils that resembled sp. living today.

Galapagos Islands Influenced Darwin the most. Small group of islands west of South America. Paid attention mostly to giant tortoises, marine iguanas, and finches.

Continued…. Collected specimens throughout his voyage and studied comparisons. Began asking Q’s about the different species. Fitness = the ability to survive and reproduce.

Structures Discoveries made by researchers at the time. Homologous Structures = developed from similar tissues at early stages of life. Vestigial Organs = structures that have little or no obvious purpose.

Today’s Assignment Complete Worksheet 10.1

“Darwin’s Solutions” Section 10-2 Objective: Explain what is meant by the term artificial selection. Explain Evolution by Natural Selection.

Darwin’s Findings Great adventure and turning point within the scientific community. Galapagos Island species vs. Mainland species.

The Finches (page 227, fig. 10-11) Darwin thought they were different species. Why do they have different shaped beaks? Why would each island have different variations of the same bird?

Darwin’s Book In 1844 Darwin wrote most of his ideas. In 1859 (30 years later), he published his findings in the Origin of Species.

“Origin of Species” Caused mass hysteria in the community. Supported the idea that life has changed, or evolved over time. Proposed a hypothesis to explain how evolution works.

Breeding (page 228, 10-12) Selective breeding = producing a new generation by mating individuals with desired characteristics. Artificial breeding = nature provided the variation among different organisms, and humans selected those variations they found.

Natural Selection In nature, selective pressures decide who will survive and reproduce. The “struggle for existence”selects the fittest individuals to survive in nature.