Chapter 13 / 32. The Theory of Evolution by Natural Selection Charles Darwin Before Darwin: Strong religious power 1800s Lamarck (scientists) believed.

Chapter 13 / 32

The Theory of Evolution by Natural Selection

Charles Darwin

Before Darwin:Strong religious power1800s Lamarck (scientists)

believed that organisms change based on needs

What was Thought.. Later Proved Wrong

Topic 1: Darwin’s Mechanism for Evolution

• 1859 Charles Darwin developed theory of evolution– Decades of science observations & experiments– Struggled in life: parents, school, religion– Interest in natural science conflicted his parents

values• 1831 HMS BeagleHMS Beagle voyage to S. America (5

years)– Found evidence that species change over timeFound evidence that species change over time

• Fossils• Influenced by Malthus (increase in human population Vs

food)• Charles Lyell (earth geology is changing)

The HMS Beagle

• Galapagos Islands (off

coast of Ecuador)

• Species there were similar to mainland but not the same– “descent with

modifications”

– OR evolution!!

Studied many organismsTurtles, Iguanas, Finches

most popular

Evolution by Natural Selection

• Darwin’s association with Malthus:

–““Natural Selection”Natural Selection”–Favorable traits are Favorable traits are selectedselected for for

byby

NATURENATURE NOT THE ANIMAL!! NOT THE ANIMAL!!

• This “selection” or favorable VS favorable VS unfavorableunfavorable CAUSES changing in a population

(EVOLUTION)– Organisms differ from place to place Organisms differ from place to place

because their because their habitats change from habitats change from place to placeplace to place

– Form ADAPTATIONS (selective advantage)

Evolution by Natural Selection

examples

Animal Mimicry!

Open Notes Pop Quiz!

1. Name a scientists that influenced Darwin’s theory of evolution? What did that scientist do?

2. What was the name of the most famous island Darwin traveled to during his voyage?

3. The favorable traits are selected by___________ for natural selection.

4. What is an adaptation?Finished?

Make 4 Post-its about the notes we took today!

Darwin’s Theory of Evolution

• Published in The Origin of Species– SERIOUSLY controversial (humans

evolved from apes)

• 4 Major points to Evolution

4 major points to Theory of Evolution

1. Variation exists within the genes of every population or species (random mutation)

4 major points to Theory of Evolution

2. In a particular environment, somesome individuals of a population or species are better suited to survivebetter suited to survive and have offspring

3. Over time, the traitstraits that make certain individuals of a population able to surviveable to survive and reproduce tend to spread in that populationspread in that population

4 major points to Theory of Evolution

4. There is overwhelming evidenceoverwhelming evidence from fossils and many other sources that living species evolved from species evolved from organisms that are extinctorganisms that are extinct (EVOLUTION)

4 major points to Theory of Evolution

Tempo of Evolution

• Gradual change over long periods of time– GradualismGradualism

• Rapid change separated by periods of little or no change– Punctuated Punctuated

equilibriumequilibrium

Anatomy and Development

• Vestigial Vestigial StructuresStructures: evidence of evolution, not used today

• Homologous Homologous structures:structures: share common ancestor because of structure NOT FUNCTION

Notes Quiz1. What are the 4 points to Darwin’s

Theory of Evolution? Give an Give an example of eachexample of each

2. What are the 2 tempos of evolution? Give an example of eachGive an example of each

3. What is the difference between a homologous trait and a vestigial trait?

Do Now:

• List any examples of evolution found in the following species

–Tigers–Whales–Turkeys– Insects–Humans

Examples of Evolution

• NATURE selects the favorable traits!

– 4 Factors that drive natural selection

Topic 2: 4 factors of Natural Selection

1. All populations have genetic variation

4 factors of Natural Selection

2. The environment presents challenges to successful reproduction

4 factors of Natural Selection

3. Individuals tend to produce more offspring than the environment can support (COMPETETION)

4 factors of Natural Selection4. Individuals that are better able to

cope with environmental challenges tend to leave more offspring than those less suited to their environment

Examples of Evolution • Antibiotic Resistance

in Bacteria– Tuberculosis 1980s,

new strains– Original drugs

Isoniazid and Rifampin don’t work anymore

Pesticide Resistance in Insects

EID Emerging Infections Diseases!!

Re-Emerging Infectious Diseases

Topic 3: Examples of Evolution

• Darwin’s Finches– 31 specimens– 9 with

similarities except for beaks• Determined by

availability of food supply

-Damp YearSmall narrow

-Dry Year Big thick

Formation of New Species

• Occurs in stages to best “fit” environment– Divergence- differences between groups– Leads to formation of new species (speciation)

• Formation of Sub-species– Different habitats different needs

difference in species

• Maintaining New Species– Reproductive barriers

• Timing, geography, physical traits

ReviewWrite this down

1. What are the reproductive barriers when maintaining a new species?

1. Geography, timing, physical traits

2. What are the 4 factors of Natural Selection1. Adapt or die, competition, nature’s challenges,

variation

3. Example of a vestigial trait? 1. Whale hip-bone

4. Example of homologous trait? 1. Bat wing, human arm

The Evolution of ManThe Evolution of Man32.3 (731-738)32.3 (731-738)

Darwin theorized that humans evolved from primates (prosimians, monkeys, apes) because of certain traits

1. Grasping Hands cling to mothers, branches, food

2. Forward Eyes judge distance, depth perception

First primates evolved ~50 million yrs ago (MYA)

Non-Human Primates

Monkeys & Apes ~36 MYA– DiurnalDiurnal (sleep at night, active

during day)• Detect predators & food

• Monkeys– First primates with opposable opposable

thumbsthumbs• Apes

– No tail, larger brains– DNA of chimpanzee is 95%

identical to human DNA

Human Primates (Hominids)

• Primates that walk upright on 2 legs = hominid species– 5-7 MYA– Early hominids walked on all fours…

why change?– “Lucy” is an Australopithecine afarensis

• 3 MYA• Increased brain size• Walked upright• ~40lbs and 3.5 ft tall

Homo habilis, erectus, sapienHomo habilis, erectus, sapien

• Homo habilis = “Handy man” 2MYA

– Tools & speech

• Homo erectus = “Upright man” 1.5MYA

– Evolved in Africa and migrated to Asia

• Homo sapien = “Wise man” ~200,000 yrs

– Only surviving of the hominids– Modern day human species and

genus

VIDEO!!!!!

• https://www.youtube.com/watch?v=ad0ELPLANWM&feature=related