HS 5 TRUSD Review Guide

8/3/2019 HS 5 TRUSD Review Guide

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Natural Selection Natural selection is the

process by which thoseheritable traits that

make it more likely foran organism to surviveand successfullyreproduce become more

common in a populationover successivegenerations.

It is a key mechanism of

evolution.
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-Genetic variation isessential for naturalselection.-The natural geneticvariation within apopulation of

organisms means thatsome individuals willsurvive and reproduce

more successfully than


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-Natural selection actson the phenotype, or

the observablecharacteristics of anorganism, but the

genetic (heritable)basis of any phenotypewhich gives a

reproductiveadvantage will becomemore common in apopulation.

-Over time, this


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The idea that evolution takesplace at one point in time,

followed by a long periodwithout change is ______.

From: Test bank 07-08

A gradualismB punctuated equilibriumC artificial selectionD succession


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Charles Darwin proposed histheory of evolution based onobservations of nature. Which

observation that contributed tohis theory is illustrated by thispopulation of beetles?A.Species produce more offspring

than can survive.B.Populations remain stable overtime.C. Individuals within a populationmay vary widely.D. Environmental resources are


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-Genetic drift, along with naturalselection, mutation, and migration,is one of the basic mechanisms ofevolution.

-In each generation, some individualsmay, just by chance, leave behind afew more descendents (and genes,of course!) than other individuals.

The genes of the next generationwill be the genes of the luckyindividuals, not necessarily thehealthier or better individuals.

G i d if ff h i


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Genetic drift affects the geneticmakeup of the population but,

unlike natural selection, throughan entirely random process. So

although genetic drift is a

mechanism of evolution, it doesntwork to produce adaptations.


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Bottleneck andFounder Effects

-Genetic drift cancause big losses ofgenetic variation forsmall populations.-Populationbottlenecks occurwhen a populationssize is reduced for at

least onegeneration.-A founder effectoccurs when a new

colony is started bya few members of


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Sample Question 3

A small population of chimpanzeeslives in a habitat that undergoesno changes for a long period.

How will genetic drift probablyaffect this population?

A It will accelerate the appearance of newtraits.

B It will promote the survival of chimpanzeeswith beneficial traits.

C It will increase the number of alleles forspecific traits.

D It will decrease enetic variation.


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Sample Question 4Genetic drift is a

______________ process.

A. directed

B. selection-driven

C. random

D. co-evolutionary


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-A species is oftendefined as a groupof individuals that

actually orpotentiallyinterbreed in nature.In this sense, a

species is thebiggest gene poolpossible undernatural conditions.

-Speciation is a


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Causes of Speciation

1. Geographic Isolation

2. Reduction of Gene Flow


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Kinds of Speciation

Allopatric

speciation isjust a fancy

name for

speciation bygeographic

isolation

Sympatric

speciation refersto the formationof two or moredescendantspecies from asingle ancestralspecies all

occupying the


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This diagram illustrates what kind ofspeciation?A Sympatric B Allopatric

C Geographic D Catastrophic

Rive

r


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CladogramA cladogram isa diagram

used to showancestralrelations

betweenorganisms, torepresent the

evolutionary

These are twoidentical

cladograms.
http://upload.wikimedia.org/wikipedia/commons/1/1b/Identical_cladograms.svghttp://upload.wikimedia.org/wikipedia/commons/1/1b/Identical_cladograms.svghttp://upload.wikimedia.org/wikipedia/commons/1/1b/Identical_cladograms.svg


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Analyzing a cladogram1.Which species are most closelyrelated?2.Which is the common ancestor offlies and bees?

3.Which insects share the most

1

2

3
http://upload.wikimedia.org/wikipedia/commons/3/31/Cladogram-example1.svghttp://upload.wikimedia.org/wikipedia/commons/3/31/Cladogram-example1.svghttp://upload.wikimedia.org/wikipedia/commons/3/31/Cladogram-example1.svghttp://upload.wikimedia.org/wikipedia/commons/3/31/Cladogram-example1.svg


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Heres a morecomplicated one

Whatconclusio

ns canyou drawfrom this

tree of
http://upload.wikimedia.org/wikipedia/commons/3/31/Cladogram-example1.svghttp://upload.wikimedia.org/wikipedia/commons/3/31/Cladogram-example1.svghttp://upload.wikimedia.org/wikipedia/commons/3/31/Cladogram-example1.svghttp://upload.wikimedia.org/wikipedia/commons/3/31/Cladogram-example1.svghttp://upload.wikimedia.org/wikipedia/commons/3/31/Cladogram-example1.svghttp://upload.wikimedia.org/wikipedia/commons/3/31/Cladogram-example1.svghttp://upload.wikimedia.org/wikipedia/commons/3/31/Cladogram-example1.svghttp://upload.wikimedia.org/wikipedia/commons/3/31/Cladogram-example1.svg


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According to the cladogram above, which two

species are most closely-related?A clubmosses and spikemossesB spikemosses and fernsC ferns and flowering plants
http://upload.wikimedia.org/wikipedia/commons/3/31/Cladogram-example1.svghttp://upload.wikimedia.org/wikipedia/commons/3/31/Cladogram-example1.svghttp://upload.wikimedia.org/wikipedia/commons/3/31/Cladogram-example1.svghttp://upload.wikimedia.org/wikipedia/commons/3/31/Cladogram-example1.svghttp://upload.wikimedia.org/wikipedia/commons/3/31/Cladogram-example1.svg


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Fossil RecordFossils are the preserved remains or

traces of animals, plants, and otherorganisms from the remote past. The

totality of fossils, both discoveredand undiscovered, and theirplacement in fossiliferous (fossil-

containing) rock formations andsedimentary layers (strata) is knownas the fossil record.
http://upload.wikimedia.org/wikipedia/commons/3/31/Cladogram-example1.svghttp://upload.wikimedia.org/wikipedia/commons/3/31/Cladogram-example1.svghttp://upload.wikimedia.org/wikipedia/commons/3/31/Cladogram-example1.svghttp://upload.wikimedia.org/wikipedia/commons/3/31/Cladogram-example1.svghttp://upload.wikimedia.org/wikipedia/commons/3/31/Cladogram-example1.svghttp://upload.wikimedia.org/wikipedia/commons/3/31/Cladogram-example1.svghttp://upload.wikimedia.org/wikipedia/commons/3/31/Cladogram-example1.svghttp://upload.wikimedia.org/wikipedia/commons/3/31/Cladogram-example1.svghttp://upload.wikimedia.org/wikipedia/commons/3/31/Cladogram-example1.svghttp://upload.wikimedia.org/wikipedia/commons/e/e3/Amonite_Cropped.jpghttp://upload.wikimedia.org/wikipedia/commons/e/e3/Amonite_Cropped.jpghttp://upload.wikimedia.org/wikipedia/commons/e/e3/Amonite_Cropped.jpghttp://upload.wikimedia.org/wikipedia/commons/e/e3/Amonite_Cropped.jpg


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Fossil evidenceindicates that over

time organisms ofincreasing complexityappeared on Earth.Bacteria and blue-

green bacteria are thefirst fossils that werepreserved from thePrecambrian era.

The fossil recordcontains manyexamples that couldbe interpreted to

mean that species


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Sample Question 7

In a section of the GrandCanyon, scientists have foundthe fossil remains of severaldifferent groups of organisms.

The diagram on the leftrepresents the number and ageof the fossils the scientistsfound. The width of eachshaded area in the diagrambelow indicates the relative

number of fossils found.Which of the following statements is supported bythe fossil record?A Group C is the only group that no longer exists for its nowextinct.B Group B was the most numerous organism 10 million yearsago.


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Sample Question 8Which of the following is usually

most helpful in determining theage of the fossils found in rock

strata?Athe size of the fossils

B the color of the fossils

Cthe water content of the rock layerwhere the fossils were located

Dthe depth of the rock layer where thefossils were found


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Sample Question 9Which of the following best explains

how the fossil record providesevidence that evolution hasoccurred?

A It indicates the exact cause of structuraland behavioral adaptations oforganisms.

B It shows that the form and structure of

groups of organisms have changed overtime.

C It shows how the embryos of manydifferent vertebrate species are very

similar.


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Sample Question 10

Orchids were studied to determineif the amount of humidityaffected the flowering of these

plants. Which of these was theindependent variable in thisstudy?

AThe percentage of humidity

BThe length of time required forflowering

CThe amount watered


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Remember

INDEPENDENT VARIABLE

-is themanipulatedvariable in

theexperiment.

DEPENDENT

VARIABLE-is the

variablethat ismeasured

at the end

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HS 5 TRUSD Review Guide