PATTERNS OF EVOLUTIONChapter 16 & 17

http://www.baystatereplicas.com/images/repro_dino_pecksrex3.jpg

_______________ traits are controlled by two or more genes.

POLYGENIC

A bell shaped curve is typical of polygenic traits

Graph from BIOLOGY by Miller and Levine; Prentice Hall Publshing©2006

The ___________ of individuals near each other will not be very different, but fitness may vary from one end of curve to the other.

FITNESS

Graph from BIOLOGY by Miller and Levine; Prentice Hall Publshing©2006

Where fitness varies, ________________ can act!

NATURAL SELECTION

Natural selection can affect thedistribution of phenotypes in 3 ways:

______________________

______________________

______________________

DIRECTIONAL selection

STABILIZING selection

DISRUPTIVE selection

• DIRECTIONAL SELECTION

Graph from BIOLOGY by Miller and Levine; Prentice Hall Publshing©2006

Individuals at _____________ of the curve have higher fitness than individuals in middle or at other end.

Graph shifts as some individuals fail to survive at one end and succeed and reproduce at other

ONE END

Low mortality, high fitness

High mortality, low fitness

KEY

Food becomes scarce.

Beak size varies in a population

Birds with bigger beaks can feed more easily on harder, thicker shelled seeds.

Suppose a food shortage causessmall and medium size seeds to run low.

Birds with bigger beaks would be selected for and increase in numbers in population.

EXAMPLE OF DIRECTIONAL SELECTION

http://www.animalbehavior.org/ABS/Stars/ONI/Podos_-_finch_graphic.jpg

• STABILIZING SELECTIONGraph from BIOLOGY by Miller and Levine; Prentice Hall Publshing©2006

Individuals in _____________ of the curve have higher fitness than individuals at either end

Graph stays in same place but narrows as more organisms in middle are produced.

CENTER

Key

Per

cen

tag

e o

f P

op

ula

tio

n

Brightness of

Feather Color

Selection against both

extremes keep curve narrow and in same

place.

Section 16-2

Low mortality, high fitness

High mortality, low fitness

Stabilizing SelectionMale birds use their plumage to attract mates. Male birds in the population with less brilliant and showy plumage are less likely to attract a mate, while male birds with showy plumage are more likely to attract a mate.

Male birds withshowier, brightly-colored plumagealso attractpredators, and areless likely to livelong enough tofind a mate.The mostfit, then, is the malebird in the middle--showy, but not tooshowy.

STABILIZING SELECTION

Graph from BIOLOGY by Miller and Levine; Prentice Hall Publshing©2006

Human babies born with low birth weight are less likely to survive.

Babies born too large have difficultybeing born.

Average size babies are selected for.

EXAMPLE OF STABILIZING SELECTION

http://www.animalbehavior.org/ABS/Stars/ONI/Podos_-_finch_graphic.jpg

• DISRUPTIVE SELECTIONGraph from BIOLOGY by Miller and Levine; Prentice Hall Publshing©2006

Individuals at _____________ of the curve have higher fitness than individuals in middle.

Can cause graph to split into two. Selection creates __________________PHENOTYPES

EXTREMES

TWO DISTINCT

Suppose bird population lives in area where climate change causes medium size seeds become scarce while large and small seeds are still plentiful.

Birds with bigger or smaller beaks would have greater fitness and thepopulation may split into TWO GROUPS. One that eats small seeds and one that eats large seeds.

EXAMPLE OF DISRUPTIVE SELECTION

http://www.animalbehavior.org/ABS/Stars/ONI/Podos_-_finch_graphic.jpg

Large scale evolutionary patterns and processes that occur over long periods of time = ________________________

1. _______________________2. ________________________3. ________________________4. ________________________5. ________________________

Macroevolution

Mass extinctionAdaptive radiation (Divergent evolution)Convergent evolutionCoevolutionPunctuated equilibrium

Mass ExtinctionsAt several times in Earth’s history large numbers

of species became extinct at the same time

Caused by several factors:• erupting volcanoes• Plate tectonics (continents were moving)• Changing sea levels• Asteroids hitting the Earth• Global climate change

Example:At the end of the _________________more than HALF of all plants and animals were wiped out… including the dinosaurs

http://www.changbi.com/file_img/webzine/dinosaur02_02.jpg

MESOZOIC Era-

Effects of mass extinctions:_____________ and provides opportunitiesfor ______________species

After mass extinctions there is often a ___________________ that produces many __________________EX: Cenozoic era that followed = “_______________”Mammals species increased dramatically

Image from: BIOLOGY by Miller and Levine; Prentice Hall Publishing©2006

Opens habitats

remaining

burst of evolutionnew species

Age of Mammals

When a single species or small group of species has evolved through ___________________ into diverse forms that live in different ways =____________________________________

http://www.pbs.org/wgbh/evolution/library/01/6/image_pop/l_016_02.html

natural selection

adaptive radiation OR divergent evolution

Ex: Galápagos finches

More than a dozen species evolved from one species

Sometimes different organisms evolution in different places or at different times but in _________________________ environments…and end up looking very similar.

Process by which unrelated organisms come to resemble each other = _______________________

ecologically similar

convergent evolution

Example:

Sharks, penguins, dolphins have all developed ________________ and appendages to move through water.

streamlined bodies

The process by which twospecies evolve in response to changes in each other over time

= __________________

http://biology.clc.uc.edu/courses/bio303/coevolution.htm

coevolution

http://www.painetworks.com/photos/ii/ii1971.JPG

How fast does evolution operate?

http://animals.timduru.org/dirlist/dino/FlyingDinosaurus-Pterodon-fossil.jpg

If biological change is at a slow pace, it is called _____________.gradualism

Darwin believed evolution happened slowly over a long time

Fossil record shows evolution happens more in _____.

Pattern of a long stable period interrupted by a briefperiod of more rapid change

=____________Punctuated Equilibrium

bursts

Rapid evolution after long periods of equilibrium can occur for several reasons:1) Happens when a small population is

____________ from the main population OR2) A small group ________________to a new

environment (like Galápagos finches)

http://tolweb.org/tree/ToLimages/blank_map.250a.gifhttp://www.pbs.org/wgbh/evolution/library/01/6/image_pop/l_016_02.html

ISOLATEDMIGRATES

ARE THERE ANY CONDITIONS IN WHICH EVOLUTION WILL NOT OCCUR?

IS THERE A WAY TO TELL IF THIS IS HAPPENING?

__________________________HARDY-WEINBERG PRINCIPLE

Graph from BIOLOGY by Miller and Levine; Prentice Hall Publshing©2006

Hardy & WeinbergWho?

Godfrey Hardy1877-1947

Wilhelm Weinberg1862-1937

They developed an equation that predicted the relative frequency of alleles in a population based on the frequency

of the phenotypes in a population.

Gene Frequency & theHardy-Weinberg Equation

p2 + 2pq + q2 = 1The Hardy-Weinberg Equation

p2 = the frequency of homozygous dominant genotype

2pq = the frequency of heterozygous genotype

q2 = the frequency of homozygous recessive genotype

HARDY-WEINBERG PRINCIPLE = allele frequency in a population will remain __________ unless one or more ________ cause the frequency to __________.

In a situation in which allele frequencies remain constant

( = _________________ ) populations will NOT EVOLVE!

constant

Genetic equilibrium

factors

change

5 CONDITIONS REQUIRED TO MAINTAIN GENETIC EQUILIBRIUM FROM GENERATION TO GENERATION 1. _________________________ 2. _________________________ 3. _________________________ 4. _________________________

5. _________________________

Random mating

Large population

No movement in or out

No mutations

No natural selection

RANDOM MATING = ____________of the population musthave an equal opportunity to produceoffspring

If some organisms are more likely toreproduce than others, the alleles in thepopulation change.

ALL members

http://ideiasemdesalinho.blogs.sapo.pt/arquivo/Peacock%20with%20its%20tail%20fanned%20out_Tony%20Ruta.jpghttp://www.wasatchcomputers.net/gallery/elk_fight.jpg

LARGE POPULATIONS

In small populations, changes can happen due to _________ instead ofnatural selection.

chance

http://evolution.berkeley.edu/evosite/evo101/IIIDGeneticdrift.shtml

NO MOVEMENT IN OR OUT

Organisms take their alleles with themwhere ever they go.

http://evolution.berkeley.edu/evosite/evo101/IIIC4Geneflow.shtml

NO MUTATION

Mutations add new alleles to gene pool.

http://evolution.berkeley.edu/evosite/evo101/VADefiningSpecies.shtml

NO NATURAL SELECTION

If some organisms are more likely tosurvive than others, the alleles in thepopulation change.

Evolution vs. Genetic EquilibriumIn some populations, these conditionsmay be met or nearly met over longperiods of time, and little or no________ occurs.

BUT in most populations it is _______for ____ conditions of Hardy-Weinbergto be met.

difficult

evolution

ALL

In MOST populations . . .EVOLUTION happens !

LATEST DISCOVERIES IN SCIENCE:

WAS LAMARCK RIGHT AFTER ALL? Can ACQUIRED TRAITS be inherited?

http://www.educa.rcanaria.es/fundoro/00.corsi.htm

?http://www.geocities.com/arnold_schwarzenegger_pictures

Both missing same piece of chromosome #15 Prader- Willi- paternal piece missing Angelman – maternal piece missing Difference is due to genomic imprinting

http://www.angelman.org/angel/

REMEMBER: EPIGENETICS

Prader-Willi syndrome- Born floppy and pale; Mildly retarded;Obesity;Tiny hands and feet; Short statureUnderdeveloped sex organs, Spectacular temper tantrums especially if refused food

Angelman syndrome -spontaneous laughter, jerky movements, severe retardation; and other motor and mental symptoms.

GENOMIC IMPRINTINGAddition or removal or “methyl tags” may beinfluenced by environment

•Twins start with same methyl tags but become more different with age

•Agouti rats – changing diet of pregnant mom can change expression of genes

http://www.precisionnutrition.com/wordpress/wp-content/uploads/2009/12/Figure-3-Agouti-mice.jpg

VIDEO

SO WHAT?•If things you do can change the way your genes are expressed , then …..

maybe you can inherit some acquired traits!

•Can your choices affect your kids’ and grandkids’ epigenome?

http://www.naturepedic.com/blog/wp-content/uploads/2010/11/BPA_free_logo.jpghttp://www.knowabouthealth.com/wp-content/uploads/2010/06/mcdonalds_.jpghttp://emilyscarenhealth.wordpress.com/2011/10/04/attention-a-must-read-for-smokers/

Chapter 16 – Evolution of Populations:

The students will be able to:•Explain Darwin’s observations of population variation•Compare contributions of scientists to our understanding of a changing population • (9-12.S.1.2)•Predict the results of complex inheritance patterns involving multiple alleles and genes (9-12.L.2.1A)•Predict inheritance patterns using a single allele (9-12.L.2.1) •Evaluate changes in gene frequencies in populations to determine if Hardy-Weinberg equilibrium exists or evolution has occurred (9-12.L.2.1A.)•Describe how genetic recombination, mutations, and natural selection lead to adaptations, evolution, extinction, or emergence of new species (9-12.L.2.2)• (Directional, stabilizing, disruptive selection, Genetic drift, Founder effect)•Use comparative anatomy to support evolutionary relationships (9-12.L.2.2) (homologous structures, embryology)•Predict the impact of genetic changes in populations (9-12.L.2.2) (mutation, natural selection, artificial selection, gene shuffling) •Predict the results of complex inheritance patterns involving multiple alleles and genes (9-12.L.2.2) (SYNTHESIS)

• 9-12.L.2.2. Students are able to describe how genetic recombination, mutations, and natural selection lead to adaptations, evolution, extinction, or the emergence of new species.

• Examples: • behavioral adaptations, environmental pressures, allele

variations, bio-diversity

• Use comparative anatomy to support evolutionary relationships.

LIFE SCIENCE:Indicator 2: Analyze various patterns and products of natural and induced biological change

• 9-12.L.3.1. Students are able to identify factors that can cause changes in stability of populations, communities, and ecosystems.

• Predict the results of biotic and abiotic interactions.• Examples:

Tolerances (temperature, weather, climate)MigrationFluctuation in available resources (water, food, shelter)Cooperation and competition in ecosystems

LIFE SCIENCE:

Indicator 3: Analyze how organisms are linked to one another and the environment.

Indicator 2: Analyze various patterns and products of natural and induced biological change.

•9-12.L.2.1A. Students are able to predict the results of complex inheritance patterns involving multiple alleles and genes.

•Examples: human skin color, polygenic inheritance•Relate crossing over to genetic variation.•Evaluate changes in gene frequencies in populations to see if Hardy- Weinberg equilibrium exists or evolution has occurred.

SOUTH DAKOTA ADVANCED STANDARDS

LIFE SCIENCE

SOUTH DAKOTA CORE SCIENCE STANDARDS

9-12.L.2.2. Students are able to describe how genetic recombination, mutations, and natural selection lead to adaptations, evolution, extinction, or the emergence of new species.

(SYNTHESIS)

LIFE SCIENCE:Indicator 2: Analyze various patterns and products of natural and induced biological change.

Core High School Life SciencePerformance Descriptors

High school students performing at the

ADVANCED level:

predict how traits are transmitted from parents to offspring;

High school students performing at the

PROFICIENT level:

predict the impact of genetic changes in populations (mutation, natural selection and artificial selection, adaptation/extinction);predict how life systems respond to changes in the environment;;

High school students performing at the

BASIC level

identify DNA as the structure that carries the genetic code;

identify that genetic traits can be transmitted from parents to offspring;