Friday, May 25, 2012

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# Friday, May 25, 2012 - PowerPoint PPT Presentation

Friday, May 25, 2012. No school Monday Tuesday = Block Schedule: 1, 3, 5, 7 Wednesday =Block Schedule: 2,4,6 Thursday = Field trip (bring bag lunch and pencil) Homework: Natural Selection Checkup on Tuesday/Wednesday.

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Friday, May 25, 2012

No school Monday

Tuesday= Block Schedule: 1, 3, 5, 7

Wednesday=Block Schedule: 2,4,6

Thursday= Field trip (bring bag lunch and pencil)

Homework:

Natural Selection Checkup on Tuesday/Wednesday

Take out notes page from Block Day- we need to finish the notes on the back…

• Describe how variation existed in the PAPER SQUARES.
• Describe how inheritance existed in the PAPER SQUARES.
• Describe how population limits existed in the PAPER SQUARES.
• Describe how environmental selection affected the PAPER SQUARES.

1. Which, if any, shades of paper squares survived better than others in the second, third, and fourth generation starting populations of paper squares?

0% color survived the best.

2. What might be the reason that predators did not select these shades as much as they did other shades?

They blended into the environment and were more difficult to find.

What effect did capturing a particular shade square have on the numbers of that shade in the following generations?

The squares that were captured decreased in number in the next generation.

4. What is the average color in generation 1? What is the average color in generation 5?

45%

35%

29%

13%

50%

No

5. Did any 50% shade squares turn into 0% squares? Any 100% squares turn into 50%?

6. If none of the squares changed into other squares, then why is the average member of the dot/square population different after 5 generations?

The 100% shaded squares were “eaten” and could not pass on traits to the next generation. 0% squares continued to survive and pass on traits to next generation.

The amount of variation has decreased in the population over time. More of the population has 0% shade.

• What affect do you think the environment (habitat and predator) has on the average characteristic and the variation of a population?

The environment determines which characteristics are favorable.

Entry 55: Evolution and Natural Selection

See attached entry:

Take out notes page from Block Day- we need to finish the notes on the back…

The environment is the selective force behind evolution
• The environment determines what characteristics are “favorable”
• Because the environment changes over time, the characteristic that is more favorable for a population changes
• Therefore, characteristics of the population change, or evolution occurs
Make an entry:Entry 56: Check up Practice

Apply the 4 factors of Natural Selection

to the Bird Population

Variation:

Bird Beak lengths range from 5cm to 15cm

Inheritance:

DNA codes for the bird’s beak length and is passed on to offspring.

Population Limits:

Food (fruit and seeds) which were influenced by the drought.

Environmental Selection:

Birds with longer beaks (15 cm) were the most successful at getting food/surviving and then reproducing.

Make a graph that shows the bird’s beaks are similar but not identical to one another

Mean (average) beak length

Beak Length (cm)

Generation 1= 6(5cm)+8(10cm)+ 7(15 cm)

/ total individuals=

Generation 4= 12 cm

7 cm

Key:

5 cm beak length

10 cm beak length

15 cm beak length

Frequency

15

45

35

30

40

20

50

10

25

5

2

3

4

1

Generations

Evolution of Peppered Moths

Dark form

Peppered form

1. Describe whattrait evolved.

2.Describe how each of the 4 conditions for natural selection exists in the moth example:

a) Variation

b) Inheritance

c) Population limits

d) Selection (Environmental Selection)

Make a graph that shows how the average color changed over several generations

The population of peppered moths became darker in color near industrial areas.
• Originally, some moths were dark, some moths were peppered (light).
• Color is determined by genes inherited from parents.
• Not all moths survive to reproduce- some are eaten by birds.
• Pollution killed lichen and made the environment darker, so darker moths were better camouflaged and not eaten as much as peppered (light) moths.
• This caused the average color of the moth population to become darker