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Review for Review for CH. 15.1 POP QUIZCH. 15.1 POP QUIZ

If everyone is reviewing when the bell rings, I will give you an additional 5 minutes to study,

otherwise, we will take the quiz when the bell rings

PASS IT ON!PASS IT ON!

W a r m- u pW a r m- u pTurn-in Natural Selection Lab and Super Organism for Late gradeTurn-in Natural Selection Lab and Super Organism for Late grade..

Get out Evolution Notes & Picture the Vocab.Get out Evolution Notes & Picture the Vocab.Pick up handoutsPick up handouts

Write on your warm-up pageWrite on your warm-up page

1.1. What is a gene?What is a gene?2.2. What is a mutation?What is a mutation?3.3. What does isolation mean?What does isolation mean?4.4. What does Equilibrium mean?What does Equilibrium mean?

Turn in for extra points on your Labs. Due 2 minutes after bellTurn in for extra points on your Labs. Due 2 minutes after bell

W a r m- u pW a r m- u pTurn-in Super Organism for a grade, if you did not last Turn-in Super Organism for a grade, if you did not last

period.period.

Turn-in Bird Beak Lab for a late grade.Turn-in Bird Beak Lab for a late grade.Get out Evolution Notes & Picture the Vocab.Get out Evolution Notes & Picture the Vocab.

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Compare and Contrast adaptation and mutationCompare and Contrast adaptation and mutation

Ch. 15.2 NotesCh. 15.2 Notes“Mechanisms of Evolution”“Mechanisms of Evolution”

I. Who Evolves??I. Who Evolves??

• Individuals DO NOT evolve…Populations evolve

• Within a population genes and their frequencies will change over time

A. VocabularyA. Vocabulary

• 1. Population Genetics

• 2. Gene pool

• 3. Frequency

• 1. Population Genetics – the way genes act in plant and animal populations

Population GeneticsPopulation Genetics

**Based on the idea that evolution happens

when the genes in a population change

over a long period of time**

• 2. Gene pool – all the alleles of a population’s genes

• 3. Frequency – how often something occurs –allelic frequency-how often an allele is seen in a population

Vocabulary (cont.)Vocabulary (cont.)

• 4. Genetic equilibrium – allelic frequency remains the same over generations (evolution is not occurring) – The Hardy-Weinburg Principle states that for The Hardy-Weinburg Principle states that for

a population to remain stable, four things a population to remain stable, four things must happen:must happen:

No natural selection__No natural selection__

Random mating_____Random mating_____

No migration____No migration____No mutation________No mutation________

HowHow do do

populations populations evolve?evolve?

• **A disruption in a population’s equilibrium will result in evolution.**

• Ex: 1. Genetic drift - the alteration of allelic sequences by chance events

-greatly affects small populations-natural disasters such as forest fires

-Galapagos Islands, -Lancaster Pennsylvania Amish community

(population 12,000)*allele frequency originally 1 in 30*now (due to small population) 1 in

14 rather than 1 in 1000 like U.S.

Genetic DriftGenetic Drift

• 2. Mutation - any change or random error in the DNA sequence

-Can occur by chance; radiation, some chemicals

-Can be lethal or useful-if useful will be passed on to

next generation

• II. Evolution of Species

A.A. SpeciationSpeciation – evolution of a – evolution of a new speciesnew species

-occurs when -occurs when members of similar members of similar populations no longer populations no longer interbreed to produce interbreed to produce offspringoffspring

Possible AncestralLasan finch

Amakihi Extinct mamo

Crestedhoneycreeper

Akialoa

Akepa

Akiapolaau LiwiMaui parrotbill

Apapane

Ou

Grosbeak finch

PalilaAkikiki

Niihau

Kauai

Oahu

Lanai

Molokai

Maui

KahoolaweHawaii

Diversity in new environmentsDiversity in new environments

• 1. Geographic isolation1. Geographic isolation – physical barrier divides a population; rivers, volcanic eruptions, earthquakes

-population can no longer interbreed; two new populations form

Geographic isolationGeographic isolation

• 2. Reproductive isolation2. Reproductive isolation – formerly interbreeding organisms can no longer mate and produce fertile offspring

-genetic makeup too different or behavioral reasons such as mating seasons

B. How fast does speciation occur?B. How fast does speciation occur?

Scientists once believed that evolution occurs at a slow,

steady rate, with small adaptive changes gradually accumulating over time in

populations.

• 1. Gradualism1. Gradualism

– the idea that species

originate through a gradual

change of adaptations.

• 2. Punctuated equilibrium2. Punctuated equilibrium – hypothesis that argues that evolution occurs quickly in rapid bursts with long periods of genetic equilibrium in between

III. Patterns of Evolution

1. Divergent evolution1. Divergent evolution – species that were once similar to an ancestral species diverge, or become increasingly distinct

–a. Adaptive radiation – ancestral species evolves into an array of species to fit a number of diverse habitats

-Darwin’s finches (pg.412)

2. 2. Convergent evolutionConvergent evolution – a pattern of evolution in which distantly related organisms evolve similar traits

-occurs when unrelated species occupy similar environments