Evolution!

Vocab

Population- group of organisms of the SAME species that occupies certain area

Species- organisms that can INTERBREED and produce FERTILE offspring

Ex) Sauerman Woods Crown Point -whitetail rabbits -deer

-sparrows -squirrels

Liger (lion and tiger)-infertile

Cama (camel and llama)-infertile

Tigon (tiger and lion)--infertile

Can we capture all the whitetail rabbits in Sauerman Woods?

Population Sampling- technique uses part of population to represent whole population

Capture 100 random rabbits – These rabbits are a representation of all the

rabbits in the area.– We can study many things within this group…

Genetics of the Population…Gene Pool- all of the genes of every individual in population sampleFrequency- how often something occursPopulation genetics involves studying the frequency with which certain alleles occur in a population’s gene pool.

In 50 years, will the allele frequencies be the same?

Hardy-Weinberg Equilibrium Principle – “Under certain conditions, the frequencies of

thedominant and recessive alleles will remain the

samegeneration after generation.”

HARDY WEINBERG 5 CONDITIONS

To keep H-W equilibrium there must be:No mutationsLarge population Population size remains same (no migration)Random matingNo “survival of fittest” (evolution)

***These conditions are NEVER all met, so populations are always changing and NOT in H-W equilibrium.

History of Evolutionary ThoughtBefore 1850, most people believed…– Earth formed by supernatural events and never changed.– Earth only a few thousand years old.– Each species was made to fit its environment.– Species never changed and did not go extinct.

History of Evolutionary Thought

Jean Baptiste LamarckProposed that species DO evolve ***PROPOSED EVOLUTION OCCURRED BY INHERITANCE OF ACQUIRED CHARACTERISTICS

LamarckLamarck’s Hypothesis:1. Desire causes change Ex.) ancestors of birds had a desire to fly, so they did.2. Use and Disuse Ex.) If species used its arms to swim over and over, it would develop flippers. If not, flippers would disappear.3. Traits acquired during life can be passed on Ex.) Tiger Woods’ children will be great golfers.

WRONG!!!!

History of Evolutionary ThoughtAlfred Wallace

English teacher who collected plants and insects.Observed variations in organismsProposed that species DO evolve

similar to Darwin’sSent idea to Darwin

Charles DarwinAt 22, sailed on the “HMS Beagle” to the Galapagos Islands.Was going to school to be a minister-believed God created each species to match its habitat and they never changed.Thought Earth was about 6,000 years old and didn’t change.

Charles Darwin cont.

During journey, he made observations and recorded them in a journal.Darwin began to doubt that species remained “constant.”

Charles Darwin cont.

In 1859, Darwin published The Origin of Species.His book stirred up controversy.Proposed **EVOLUTION OCCURRED BY NATURAL SELECTION

Major points of Darwin’s book:Organisms have more offspring than can survive.Certain individuals are more likely to survive than others (survival of the fittest.)Species DO change over time.Gradual changes may cause members of one species to eventually evolve into new species.African apes are close genetic relatives of modern humans.

Darwin Video

What We Know Now

Evolution is a Scientific Theory

Not a hypothesis, or an educated guess, or a “theory” in layman’s terms.Unending amount of evidence to support it

Evolution is called “the unifying principle of Biology”Isn't Evolution JUST a Theory?

Types of EvolutionEvolution - genetic change of a population of organisms over time- descent with modification

Microevolution: Small genetic changes of a populationShorter amount of time Bengal tiger simulation was microevolution

Types of EvolutionMACROevolution:– When new species are

formed over long periods of time.

– Due to tremendous amounts of accumulated genetic changes in a population

– Speciation- formation of new species due to accumulated microevolution and mutations.

SpeciationGeographical isolation- members of a population are separated geographically– Major step that leads to speciation.– Due to volcanoes, earthquakes, flooding, etc.– Can lead to divergence and then speciation.

How does macroevolution work?dibosirdsaur

GEOGRAPHIC ISOLATIONdibosirdsaur dibosirdsaur

10 million years of accumulated mutations diosirdsaur ibosirdsaur

10 million years of accumulated mutationsdiosirdsaur iboirdsaur

10 million years of accumulated mutationsdinoirdsaur boirdsaur

10 million years of accumulated mutationsdinordsaur boirdsur

10 million years of accumulated mutationsdinodsaur boirdsu

10 million years of accumulated mutationsdinodsaurs boirds

10 million years of accumulated mutationsDINOSAURS BIRDS

Darwin and the Finches

When Darwin traveled to the Galapagos he took interest in the finches.He noticed the finch species on the islands were different, but all resembled one from S. America.Darwin thought some migrated and new species evolved. This is what he proposed:

Darwin’s Finches

Finches migrated from South America to the islands– Populations on different

islands adapted to different environments and food sources they found.

Darwin’s Finches

Different mutations accumulated in the different populations on the different islands and they became more and more different from each other.Divergence- the accumulation of differences between species or populations.

Darwin’s FinchesOver time the populations on the islands became so different they no longer mated->speciationSeveral new finch species evolved from a common ancestor from S. AmericaThis is an example of macroevolution

Recent finch research

Darwin’s Natural Selection is the Driving Force Behind Evolution

Natural selection- organisms best suited to their environment survive and reproduce.

– Darwin’s proposed mechanism of evolution – Survival depends on the particular environmental

conditions a species finds itself in—nature!– If the environment changes, so do the populations

that live there.Adaptation- using inherited genetic characteristics to increase chance of survival in new environment.Natural Selection and Salamanders

Whose idea for evolution is this?

Natural SelectionThree conditions necessary for natural selection to

occur:1. Genetic variation: Individuals within a population must be

genetically different. This is due to mutation.****Random mutations are the raw material for evolution to

occur!!!!!!!2. Overproduction of offspring: More organisms are born than

can survive.3. Differential reproduction: Certain traits enable individuals to

survive and have more offspring than others.—SURVIVAL OF THE FITTEST

Natural Selection

Result of Natural Selection: - Genes that help a species survive stay in the

gene pool. - “Unfavorable” genes gradually decrease. - This causes changes in the genetics of

populations EVOLUTION!!!!!- Over a long time, the new populations no longer

can mate with the original they started as. New species have formed.

Natural Selection ExampleThe industrial revolution– In England in the early 1800’s industry boomed– Factories, trains, smoke and smog– Peppered moths were dark or light colored, and

the dark ones that were once rare became more common.

– Hypothesis?

The Peppered Moth– Kettlewell tested this hypothesis

Released equal numbers of moths in polluted AND clean forests.In industrialized areas, dark gray moth was better camouflaged.They survived, had more offspring

– The population *as a whole* evolved to be better suited to the environment more gray and camouflagedADAPTATION!

– This is an example of microevolution

The Peppered Moth

Peppered Moth Simulation

EVOLUTIONby natural selection

MACROevolutionMicroevolution

Changes in gene frequencies

in a population

Shorter timesExamples:

Peppered moth and Bengal tiger

Accumulated microevolution and mutations to form whole new species

Longer timesExamples:

Darwin’s finches and geographical isolation

Artificial SelectionArtificial selection- human intervention in animal or plant reproduction to ensure that certain desirable traits are passed on.Instead of NATURE selecting which traits are favorable, HUMANS selectively breed those animals with favorable traits.

Ex. dogs or racehorses