Date: 3/30/2011

Time: 9:00 and 12:00

Essential Questions: Essential Questions:

What forces cause changes in organisms?What forces cause changes in organisms?

Today's Subject Area : Evolutionary ForcesToday’s topic: What changes over time?

Required Materials:Required Materials:Have paper and pencil/pen ready to Have paper and pencil/pen ready to

work and take noteswork and take notes..The mission of the Georgia Cyber Academy is to provide an exemplary educational experience to students in a unique and individualized setting.

WELCOME TO MRS. WELCOME TO MRS. COPE AND MRS. COPE AND MRS. MEDLEY’S CLASSMEDLEY’S CLASS

2007-2008

Evolutionary ForcesWhat changes populations?

STANDARDS S7L5

S7L5.aExplain how physical characteristics of organisms have changed over successive generations (e.g., Darwin’s finches and peppered moths of Manchester).

S7L5.bDescribe ways in which species on earth have evolved due to natural selection.

Natural selection

is a process by which organisms with traits well suited to an environment survive and reproduce at a greater rate than organisms less suited to

that environment.

A change in gene frequency within a population’s gene poolCan occur via

Natural SelectionVarious types of selection pressures

Genetic DriftRandom occurrences

Evolution is…

Forces of evolutionary change

Natural selectiontraits that improve survival

or reproduction will accumulate in the populationadaptive change

Includes predation, physiological, sexual selection & coevolution

Genetic driftfrequency of traits can change

in a population due to chance eventsrandom changeIncludes founder & bottleneck effects

Selection acts on any trait that affects survival or reproductionpredation selectionphysiological selectionsexual selection

Natural selection

Predation Selection

Predation selectionSelects for traits that affect survival act on both predator & prey

behaviorscamouflage & mimicryspeeddefenses (physical & chemical)

Physiological SelectionActing on body functions

disease resistancephysiology efficiency (using oxygen, food,

water)biochemical versatilityprotection from injury

HOT STUFF!Some fish had thevariation of producinganti-freeze protein

The Antarctic Ocean The Antarctic Ocean freezes overfreezes over

Sexual SelectionActing on reproductive success

attractiveness to potential matefertility of gametessuccessful rearing of offspring

Survival doesn’t matterif you don’t reproduce!Organisms want their genes prevail and live on!

The lion’s mane…

Females are attracted to males with larger, dark manes

Correlation with higher testosterone levelsbetter nutrition & healthmore muscle & aggressionbetter sperm count / fertility longer life

But imposes a cost to maleHOT! Is it worth it??

CoevolutionTwo or more species reciprocally

affect each other’s evolutionpredator-prey

disease & hostcompetitive speciesmutualism

pollinators & flowers

Genetic Drift Chance events changing frequency of traits in a

populationnot adaptation to environmental conditions

not selectionfounder effect

small group splinters off & starts a new colonybottleneck

some factor (disaster) reduces population to small number & then population recovers & expands again but from a limited gene pool

Founder effectWhen a new population is started

by only a small group of individuals just by chance some rare alleles may

be at high frequency; others may be missing

skew the gene pool of new populationhuman populations that

started from small group of colonists

example: colonization of New World

albino deer Seneca Army Depot

Distribution of blood typesDistribution of the O type blood allele in native

populations of the world reflects original settlement

Bottleneck effectWhen large population is drastically reduced by a

disasterfamine, natural disaster, loss of habitat… loss of variation by chance event

alleles lost from gene pool not due to fitness

narrows the gene pool

Cheetahs All cheetahs share a small number of alleles

less than 1% diversityas if all cheetahs are

identical twins2 bottlenecks

10,000 years agoIce Age

last 100 yearspoaching & loss of habitat

Which of the following can fossils reveal about an organism?

I. how the organism interacted with other organisms II. the appearance of the organism and its structures III. the growth stages of the organism IV. the microscopic features of the organismA. II and IV only

B. II and III only C. I, II, III, and IV D. II, III, and IV only

Which of the following can fossils reveal about an organism?

I. how the organism interacted with other organisms II. the appearance of the organism and its structures III. the growth stages of the organism IV. the microscopic features of the organismA. II and IV only

B. II and III only C. I, II, III, and IV D. II, III, and IV only

        Write your response here:

Favorable traits are traits that promote an organism's success in a particular environment. Organisms with favorable traits are more likely to thrive, survive, and reproduce than organisms without favorable traits.

So, over time, favorable traits are likely to _______ within a population and unfavorable traits are likely to _______ within a population.

A. decrease, increase B. increase, increase C. increase, decrease D. decrease, decrease

        Write your response here:

Favorable traits are traits that promote an organism's success in a particular environment. Organisms with favorable traits are more likely to thrive, survive, and reproduce than organisms without favorable traits.

So, over time, favorable traits are likely to _______ within a population and unfavorable traits are likely to _______ within a population.

A. decrease, increase B. increase, increase C. increase, decrease D. decrease, decrease

Peppered moths use the adaptation of camouflage as protection from predators. They may have a variety of colors or shades, but before the Industrial Revolution, they were typically white with black speckles. The Industrial Revolution in the 1880s introduced large-scale pollution into the environment. The pollution resulted in widespread, dark-colored staining of buildings and trees.

Which of the following was the most likely effect of the Industrial Revolution on peppered moths in cities?

A. Over time, the white, speckled moths were outnumbered by plain white moths.

B. The population of light-colored moths decreased and the population of dark-colored moths increased.

C. The peppered moths adapted an improved sense of sight and smell. D. The peppered moths developed a tolerance to smog and chemical waste.

Peppered moths use the adaptation of camouflage as protection from predators. They may have a variety of colors or shades, but before the Industrial Revolution, they were typically white with black speckles. The Industrial Revolution in the 1880s introduced large-scale pollution into the environment. The pollution resulted in widespread, dark-colored staining of buildings and trees.

Which of the following was the most likely effect of the Industrial Revolution on peppered moths in cities?

A. Over time, the white, speckled moths were outnumbered by plain white moths.

B. The population of light-colored moths decreased and the population of dark-colored moths increased.

C. The peppered moths adapted an improved sense of sight and smell. D. The peppered moths developed a tolerance to smog and chemical waste.

Any Questions??

3. 4. 10.

 

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Independent Practice!Independent Practice!Study Island Assignment:

Subject: Life ScienceTopic: EvolutionLesson: 3h (review – already completed!)

OLS Assignment:Subject: Adaptation and ChangeUnit: Unit 8: Lesson 1-6ADVANCE: Unit 3Lesson 1 ,2, 3, 5 and 6

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