Evolution Lesson 1: An Introduction to Charles Darwin and the Nature of Science

Evolution Project New randomized groups 4 th quarter grade: Daily class work/homework collected in a final portfolio Final Exam grade: Five “In Depth Investigations” – Graded according to a rubric/ average grade will be final grade. Ends May 28 th (We will not observe review days.) Consequences of not fulfilling individual work requirements.

“A scientist, however, gifted, can be compared with a fly crawling on the inside wall of a cathedral; if it could draw what it sees, the fly’s picture of the cathedral would be as crude as early maps of the world; if it could voice its speculations about the size, appearance, and purpose of the cathedral, the fly’s opinions would be received even more guardedly.” -- Frederick Aicken, The Nature of Science, pp.29-30

Evolution As An Idea Evolution As An Idea “ If I were to give an award for the single best idea anyone has ever had, I’d give it to Darwin, ahead of Newton and Einstein and everyone else. In a single stroke, the idea of evolution by natural selection unifies the realm of life, meaning and purpose with the realm of space and time, cause and effect, mechanism, and physical law. But it is not just a wonderful idea. It is a dangerous idea.” Daniel Dennet

Evolution as an Idea “Evolution is one of the most powerful ideas ever to emerge from science. It is the very foundation of biology and the key to understanding our own human origins. The mechanism of evolution helps determine who lives, who dies, and who gets the opportunity to pass on traits to the next generation. At the same time, evolution ranks as one of the most widely misunderstood scientific principles in America today.” Richard Hutton, Executive Producer, Evolution WGBH Jody Patton, Executive in Charge, Clear Blue Sky productions

Darwin’s Voyage of Discovery Take the Pre-Test Homework Go to the following link: Complete the directions in Lesson 2 Activity 1. This will require you to… Read the activity Print the world map Read the excerpts of Darwin’s Voyage Write a paragraph that answers the question: Who was Charles Darwin?

Darwin and the Galapagos When your group finishes answering the questions for In Depth Investigation #1, discuss the following: 1.How did the Galapagos Islands get there? 2.How did the first plants get there? 3.How did the first animals get there? 4.What is ecological succession?

Galapagos Islands

Ecological Succession process in which communities of plants and animal species in a particular area are replaced over time by a series of different and often more complex communities. Two stages – Primary succession – Secondary succession

Primary Succession succession in a bare area (no mature soil) that has never been occupied before

Secondary Succession succession in an area in which natural vegetation has been removed or destroyed but the soil remains

Ecological Succession

Darwin’s Theory of Natural Selection 1.Variations exist 2.These variations are heritable 3.Some variations are advantageous and some are disadvantageous 4.Organisms compete for limited resources 5.Organisms with advantageous variations survive and reproduce most successfully, leafing more organisms like them in the next generation 6.Over time, the population changes to become more like the organisms with advantageous variations 7.Today’s species have descended from past species 8.All organisms are related and are members of a single tree of life

Darwin’s Theory of Natural Selection Individuals in a population show differences, or variations Variations are inherited Organisms have more offspring than can survive – COMPETITION for resources Variations that increase reproductive success (organism survive and reproduce) will have a greater chance of being passed

Variation in Population

Variations are Inherited More offspring are produced than can survive

Competition for available resources

Variations that are successful are passed to the offspring English Peppered Moth

Giraffe Evolution? Long neck or short neck? The neck allows feeding from high branches, serves as a weapon in males, brings the head to elevated heights that give the giraffe a large field of view, is used as a pendulum while galloping, and so on Ultimately, those with long necks were more successful at reproducing

Darwin’s Theory of Natural Selection Individual organisms differ; variation is heritable Organisms produce more offspring than can survive; they compete for limited resources Some variations are advantageous; individuals best suited to their environment survive and reproduce successfully Species alive today descent with modification from ancestral species that lived in the past

Evidence of Evolution Fossil Record Comparative Anatomy – Homologous Structures – Vestigial Structures – Analogous Structures Comparative Embryology Comparative Biochemistry Geographic Distribution

Fossil Record

Homologous Structures

Vestigial Structures

Analogous Structures

Comparative Embryology

Comparative Biochemistry Visualization -

Geographic Distribution

Examples of Natural Selection English Peppered Moth

Darwin's Finches

Darwin’s Tree of Life

Evolutionary Classification Using Cladograms Cladogram – diagram used to show the evolutionary relationship between organisms Cladograms are constructed using derived characteristics – Derived characteristics - characteristics that appear in recent parts of the lineage but not in older members; new characteristics that evolve over time – Each branch or junction shows the appearance of a new trait – Cladograms demonstrate when characteristics first appeared

Cladogram of vertebrates

Evolution Review Why is evolution considered a theory? Give a simple definition evolution. How is variation important for natural selection? Briefly describe “survival of the fittest”. Explain why the environment is considered the “selector” in natural selection? Compare and contrast homologous structures and analogous structures. How can the study of embryos show evidence of evolution? How do the following terms relate to natural selection: competition, adaptation, descent with modification? How does genetic mutation influence natural selection? Why is it useful for scientists to be skeptical? Explain how plants and animals could colonize islands from the mainland. Can evolution occur in individuals? Why or why not? What are vestigial structures? Why are they considered evidence of evolution? What does a cladogram illustrate? Explain Darwin’s role on the HMS Beagle. Give an example of evolution.

Evolution Review Why is evolution considered a theory? Briefly describe “survival of the fittest”. Give a simple definition evolution. How is variation important for natural selection? Explain why the environment is considered the “selector” in natural selection? Compare and contrast homologous structures and analogous structures. How can the study of embryos show evidence of evolution? How do the following terms relate to natural selection: competition, adaptation, descent with modification? How does genetic mutation influence natural selection? Why is it useful for scientists to be skeptical? Explain how plants and animals could colonize islands from the mainland. Can evolution occur in individuals? Why/why not? What are vestigial structures? Why are they considered evidence of evolution? What does a cladogram illustrate? Explain Darwin’s role on the HMS Beagle. Give an example of evolution.

Primate Evolution st-primates.html st-primates.html