4.26 Natural Selection Key Ideas

Context: Consider a population of ostrilopes that live in an environment where all the thornpalms are tall (Level 8). The ostrilope population has the distribution of neck lengths shown in the histogram above. Longer necks make it easier for ostrilopes to eat taller thornpalms.

Question: According to the histogram, which traits for neck length are the most common in the starting population

• short necks (level 1-2)

• medium-short necks (level 3-5)

• medium-long necks (levels 6-7)

• long necks (levels 8-9)

Tags

green

Context: Consider a population of ostrilopes that live in an environment where all the thornpalms are tall (Level 8). The ostrilope population has the distribution of neck lengths shown in the histogram above. Longer necks make it easier for ostrilopes to eat taller thornpalms.

Question: Which traits for neck length do you predict will be the most helpful for survival in this environment

• short necks (level 1-2)

• medium-short necks (level 3-5)

• medium-long necks (levels 6-7)

• long necks (levels 8-9)

Tags

green

Context: Consider a population of ostrilopes that live in an environment where all the thornpalms are tall (Level 8). The ostrilope population has the distribution of neck lengths shown in the histogram above. Longer necks make it easier for ostrilopes to eat taller thornpalms.

Question: Which traits for neck length do you predict will become the most common over time?

• short necks (level 1-2)

• medium-short necks (level 3-5)

• medium-long necks (levels 6-7)

• long necks (levels 8-9)

Tags

NGSS.MS-LS1-5

NGSS.MS-LS2-4

NGSS.MS-LS4-4

Open the Natural Selection simulation (linked in the classkick assignment for today) and open Ostrilope Neck Length Mode.

1. Press RUN and observe the results over 25 generations

2. Press ANALYZE and compare the starting and ending histograms

Question: Did any traits completely disappear from the population? Which ones?

• 1-2

• 3-5

• 6-7

• 8-9

Tags

NGSS.MS-LS4-1

NGSS.MS-LS4-4

Still looking at the results from question 4:

Which traits became more common over time?

• 1-2

• 3-5

• 6-7

• 8-9

Tags

NGSS.MS-LS4-4

What caused this change in the distribution of the ostrilope neck length trait to occur? What made the higher neck length trait adaptive in this environment?

Tags

NGSS.MS-LS4-2

NGSS.MS-LS4-4

1. In the simulation return to BUILD mode

2. Press the Thornpalm icon, and increase the thornpalm height to tall (Level 10) by adjusting the Trait-Level slider

3. Press RUN and observe the results

4. Press ANALYZE and compare the initial and final histograms

Question: Did any traits completely disappear from the population? Which ones?

• 1-2

• 3-5

• 6-7

• 8-9

Tags

NGSS.HS-LS4-4

NGSS.HS-LS4-5

Based on your observations from that 2nd test, explain what is wrong with the following statement: "If the ostrilope population needs traits for longer necks, individuals will just get longer necks."

Tags

NGSS.MS-LS3-1

NGSS.MS-LS4-2

NGSS.MS-LS4-4

Now head back into today's classkick assignment and complete the card sort activity on page 2!

• Got it

• Aight

• Leggo

Based on your card sort of the ostrilopes with different armor traits: which armor trait is adaptive and will become more common over many generations?

• 1

• 3

• 5

• 7

• 10

Tags

NGSS.MS-LS4-4