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1/23/20 OTHER MECHANISMS FOR EVOLUTION€¦ · TEXT GENETIC DRIFT ACTIVITY Step 1: DO NOT Eat...
Transcript of 1/23/20 OTHER MECHANISMS FOR EVOLUTION€¦ · TEXT GENETIC DRIFT ACTIVITY Step 1: DO NOT Eat...
OTHER MECHANISMS FOR EVOLUTION
1/23/20
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DO NOW▸ Identify what is wrong with the following
statement:
▸ “Polar bears evolved to become white because they needed to be camouflaged with the white snow to ensure successful hunting”
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GENETIC DRIFT ROLES▸ In your group decide who will do what.
1. Drift Picker (This Person will without looking pick 6 M&Ms out of the cup and put them on the paper towel.
2. One Person is the Counter (count the number of colored M&Ms.
3. One Person will work with the counter and Record the Data on to the lab data chart
4. One Person will Convert the data into a Percent (%) (Equation= # of colors divided by the total # of the population, Then Multiple by 100)
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GENETIC DRIFT ACTIVITY ▸ Step 1: DO NOT Eat M&M’s It will throw off your data.
▸ Step 2: WITHOUT LOOKING Drift Picker remove 6 M&M’s and place them on the paper towel; this represents the genetic drift population.
▸ Step 3: Data Recorder will Record all the necessary information for the genetic drift population.
▸ Step 4: Only after you have recorded all the info for the genetic drift population, empty the rest of the cup and record the necessary information for the original population. The 6 M&M's you removed are included in the original population data.
▸ Step 5: Together. Enjoy your M&M’s as you answer all post lab questions!
***(% Convert Equation= # of colors divided by the total # of the population (M&Ms), Then Multiple by 100)
AGENDA
▸ Pass back work/quizzes
▸ Gene flow and genetic drift
▸ Summary
GENE FLOW & GENETIC DRIFTCORNELL NOTES TITLE (PAGE 11)
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GENES▸ Determines the trait or characteristic of an
organism (DNA)
▸ Is passed down from parent to offspring
ALLELES▸ Different forms of a gene
▸ Example: gene - fur color; alleles - light fur, tan fur, dark fur
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ALLELE FREQUENCY▸ Incidence of an allele in a population
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GENETIC DIVERSITY▸ Variation of genes within a population
▸ The more genetically diverse a population is, the higher its chances of evolving with changing environments
▸ Low genetic variation puts a population at risk for extinction or population decline
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EVOLUTION CAN OCCUR THROUGH OTHER MEANS▸ Gene Flow
▸ Genetic Drift
▸ *Natural selection is not the only way evolution can occur
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GENE FLOW
GENE FLOW▸ Movement of genes from
one population to another population
▸ Changes the allele frequency of both populations
▸ Reduces differences between populations
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GENETIC DRIFT
GENETIC DRIFT
DRIFTMoving Slow
Aimless (without direction)
GENETIC DRIFT▸ Random changes in allele frequency in a
population
▸ This process is RANDOM, not influenced by adaptation
▸ 2 cases: Founder effect & Bottleneck effect
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FOUNDER EFFECT▸ Small population breaks off from the bigger
population and moves to a new habitat
▸ These individuals will become the “founders”
▸ Leads to DECREASED genetic diversityWHY?
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BOTTLENECK EFFECT▸ Drastic decrease in population size due to a
natural disaster or widespread disease
▸ Leads to DECREASED genetic diversityWHY?
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OVERVIEW
GENETIC DRIFT
▸ https://www.youtube.com/watch?v=W0TM4LQmoZY
ILLUSTRATIVE SUMMARYPAGE 10 (UNDER DO NOW)
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ILLUSTRATIVE SUMMARY
ALL TERMS must be included
If you do a flow chart, you must explain the connections
Use at least 4 colors
Label as necessary
HOMEWORK