patterns of evolution chapter 16 & 17
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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;
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