Evolution Study Guide

Evolution

-Process by which modern organisms descend from ancient organisms

Charles Darwin

• Theology became naturalistic

• Took a trip around the world in 1831 at age 21

• Made observations & formed his own beliefs

Galapagos Islands

• Located in South America (West), Equator: Varied Climate

• Observed: Finches (Beaks), Tortoises (Necks/Shells), Blue Footed Booby (Mating Rituals)

• Diversity & Adapting to Environment

• Could these organisms be related?

Evolutionary Roadblocks (Incorrect beliefs at the time)

1. Earth was only approximately. 2000 years old

2. Earth/Organisms were immutable (unchanging)

3. Natural Disasters were infrequent miracles

People That Influenced Darwin

1. James Hutton

   • Proved Earth is millions of years old through rock layering

2. Charles Lyell

   • Wrote Principles of Geology

   • Supported Hutton

3. Jean Baptiste Lamarck

   • Giraffes

   • Organisms change over time

   • “I think I can, I think I can”

     A) Tendency Towards Perfection

     B) Use & Disuse (if something goes unused, it will vanish eventually)

     C) Inheritance of Acquired Traits (Tattoos passing down to offspring)

4. Thomas Malthus

   • Economist, population

   • More are being born than dying

   • War, famine, and disease regulate population

   • Organisms must compete

Evidence of Evolution

1. Fossil evidence

   • Provides age of planet/organisms & common ancestors

2. Homologous Structure

   • Same structure, different function

   • Ex) Human arm, whale fin cat leg, bird wing

3. Analogous Structures

   • Same function, different structure

   • Ex) Dolphin, shark, penguin’s fin; fly wing vs bird wing

4. Vestigial Structure

   • Organ you no longer need

   • Ex) Wisdom teeth, tailbone, appendix, whale legs

5. Comparative Embryology

   • At embryo stage, organisms have many similarities

   • Ex) Gills, structure

6. Biochemical Evidence

   • DNA similarities

Darwin’s Theory of Evolution

1. Varitation

   • Variation in traits

2. Overpopulation

   • Not enough resources

3. Competition & Struggle

   • Compete to survive

4. Survival of the Fittest

   • Natural Selection

   • Only the “strong” will survive

5. Species Change Over Time

   • Slow Process

Darwin vs Lamarck

• Giraffes

Sources of Variations

1. Mutations

2. Gene Shuffling

3. Crossing Over

Adaptive Radiation

• Organisms adapt to environment & spread out

• Ex) Finches

Evolutionary Patterns

1. Convergent

   • Species become more similar

   • Analogous

   • Ex) Shark & Dolphin

2. Divergent

   • Species become more different

   • Homologous

   • Ex) Finches

Genetic Drift, Founder Effect, Bottlenecks

• How recessive traits become more prominent

Isolating Mechanisms

1. Behavioral

   • Mating hibernation

   • Ex) Blue Footed Boobie

2. Temporal

   • Timing

   • Ex) Frogs

3. Geographical

   • Geographical obstacles

   • Ex) Mountain

Evolutionary Paths

1. Gradualism

   • Small changes over time

2. Punctuated Equilibrium

   • Big changes over time

Five Fingers of Evolution