Educational worksheet on Darwin's Natural Selection featuring scenarios about nocturnal vs. diurnal worms and polar bears with different coat thicknesses.
Worksheet titled "Darwin's Natural Selection" with two scenarios involving worms and polar bears, each with questions about natural selection.
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Step-by-step solution for: Darwins Natural Selection worksheet
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Show Answer Key & Explanations
Step-by-step solution for: Darwins Natural Selection worksheet
Let's solve each question step by step, based on Darwin’s four points of natural selection:
1. Variation: Individuals in a population vary in their traits.
2. Overproduction: Populations produce more offspring than can survive.
3. Struggle for Existence: There is competition for limited resources (e.g., food, space, mates).
4. Survival of the Fittest / Descent with Modification: Organisms with advantageous traits are more likely to survive and reproduce, passing those traits to the next generation.
---
## Question 1: Worms – Nocturnal vs Diurnal
- Two types of worms: nocturnal (eat at night) and diurnal (eat during the day).
- Birds eat during the day and only eat diurnal worms.
- Nocturnal worms stay in burrows during the day → protected from birds.
- Each spring, worms produce ~500 babies, but only ~100 live long enough to reproduce.
---
- AGAINST: Diurnal worms — they are eaten by birds during the day.
- FOR: Nocturnal worms — they avoid predation by being active at night.
> ✔ Answer:
> AGAINST: Diurnal worms
> FOR: Nocturnal worms
---
#### i. How does the population have variation?
- The worms vary in their feeding behavior: some are active at night (nocturnal), others during the day (diurnal). This is a behavioral trait variation.
> ✔ Answer: The worms show variation in their activity time — nocturnal vs diurnal.
#### ii. Which variation is an adaptation (beneficial)?
- The nocturnal behavior is beneficial because it avoids bird predators that hunt during the day.
> ✔ Answer: Nocturnal behavior is an adaptation.
#### iii. How is the population overproducing?
- Each worm produces about 500 babies, but only 100 survive to reproduce. This means many offspring die before reproducing — indicating overproduction.
> ✔ Answer: The worms produce far more offspring (500) than can survive (only 100 reach reproductive age).
#### iv. Which population will descend with modification?
- The nocturnal worms are more likely to survive and reproduce. Over time, their traits (night activity) will become more common in the population.
> ✔ Answer: The nocturnal worm population will descend with modification.
---
## Question 2: Polar Bears – Thick, Thin, and Medium Coats
- Three types of polar bears: thick coat, thin coat, medium coat.
- It's fall, temperatures dropping fast; bears need warmth to survive.
- Many mothers had 2 cubs, but due to cold, many now have only one cub left.
---
- AGAINST: Bears with thin coats — they cannot retain heat and are more likely to freeze.
- FOR: Bears with thick coats — better insulation, more likely to survive cold.
> ✔ Answer:
> AGAINST: Bears with thin coats
> FOR: Bears with thick coats
---
#### i. How does the population have variation?
- The bears vary in coat thickness: thick, medium, and thin coats.
> ✔ Answer: The population varies in fur thickness — thick, medium, and thin coats.
#### ii. Which variation is an adaptation (beneficial)?
- In cold weather, thick coats help retain body heat → survival advantage.
> ✔ Answer: Thick coats are an adaptation.
#### iii. How is the population overproducing?
- Each mother has 2 cubs, but due to extreme cold, many only have one cub left. So, more offspring are born than can survive.
> ✔ Answer: Bears produce more offspring (2 cubs per mother) than can survive the harsh conditions.
#### iv. Which population will descend with modification?
- The thick-coated bears are more likely to survive and pass on genes for thick fur. Over generations, the population will evolve toward thicker coats.
> ✔ Answer: The thick-coated bear population will descend with modification.
---
## ✔ Final Answers Summary
---
a.
- AGAINST: Diurnal worms
- FOR: Nocturnal worms
b.
i. Variation: Worms differ in feeding time — nocturnal vs diurnal.
ii. Adaptation: Nocturnal behavior (avoids birds).
iii. Overproduction: 500 babies produced, only 100 survive to reproduce.
iv. Descend with modification: Nocturnal worms.
---
a.
- AGAINST: Bears with thin coats
- FOR: Bears with thick coats
b.
i. Variation: Bears have different coat thicknesses (thick, medium, thin).
ii. Adaptation: Thick coats (better insulation in cold).
iii. Overproduction: Mothers give birth to 2 cubs, but many lose one due to cold.
iv. Descend with modification: Thick-coated bears.
---
This worksheet illustrates how natural selection acts on variation in populations, favoring traits that improve survival and reproduction in a given environment.
Darwin’s 4 Points of Natural Selection:
1. Variation: Individuals in a population vary in their traits.
2. Overproduction: Populations produce more offspring than can survive.
3. Struggle for Existence: There is competition for limited resources (e.g., food, space, mates).
4. Survival of the Fittest / Descent with Modification: Organisms with advantageous traits are more likely to survive and reproduce, passing those traits to the next generation.
---
## Question 1: Worms – Nocturnal vs Diurnal
Scenario Summary:
- Two types of worms: nocturnal (eat at night) and diurnal (eat during the day).
- Birds eat during the day and only eat diurnal worms.
- Nocturnal worms stay in burrows during the day → protected from birds.
- Each spring, worms produce ~500 babies, but only ~100 live long enough to reproduce.
---
a. Which worm has natural selection selected AGAINST? FOR?
- AGAINST: Diurnal worms — they are eaten by birds during the day.
- FOR: Nocturnal worms — they avoid predation by being active at night.
> ✔ Answer:
> AGAINST: Diurnal worms
> FOR: Nocturnal worms
---
b. Identify Darwin’s 4 points:
#### i. How does the population have variation?
- The worms vary in their feeding behavior: some are active at night (nocturnal), others during the day (diurnal). This is a behavioral trait variation.
> ✔ Answer: The worms show variation in their activity time — nocturnal vs diurnal.
#### ii. Which variation is an adaptation (beneficial)?
- The nocturnal behavior is beneficial because it avoids bird predators that hunt during the day.
> ✔ Answer: Nocturnal behavior is an adaptation.
#### iii. How is the population overproducing?
- Each worm produces about 500 babies, but only 100 survive to reproduce. This means many offspring die before reproducing — indicating overproduction.
> ✔ Answer: The worms produce far more offspring (500) than can survive (only 100 reach reproductive age).
#### iv. Which population will descend with modification?
- The nocturnal worms are more likely to survive and reproduce. Over time, their traits (night activity) will become more common in the population.
> ✔ Answer: The nocturnal worm population will descend with modification.
---
## Question 2: Polar Bears – Thick, Thin, and Medium Coats
Scenario Summary:
- Three types of polar bears: thick coat, thin coat, medium coat.
- It's fall, temperatures dropping fast; bears need warmth to survive.
- Many mothers had 2 cubs, but due to cold, many now have only one cub left.
---
a. Which bear will natural selection select AGAINST? FOR?
- AGAINST: Bears with thin coats — they cannot retain heat and are more likely to freeze.
- FOR: Bears with thick coats — better insulation, more likely to survive cold.
> ✔ Answer:
> AGAINST: Bears with thin coats
> FOR: Bears with thick coats
---
b. Identify Darwin’s 4 points:
#### i. How does the population have variation?
- The bears vary in coat thickness: thick, medium, and thin coats.
> ✔ Answer: The population varies in fur thickness — thick, medium, and thin coats.
#### ii. Which variation is an adaptation (beneficial)?
- In cold weather, thick coats help retain body heat → survival advantage.
> ✔ Answer: Thick coats are an adaptation.
#### iii. How is the population overproducing?
- Each mother has 2 cubs, but due to extreme cold, many only have one cub left. So, more offspring are born than can survive.
> ✔ Answer: Bears produce more offspring (2 cubs per mother) than can survive the harsh conditions.
#### iv. Which population will descend with modification?
- The thick-coated bears are more likely to survive and pass on genes for thick fur. Over generations, the population will evolve toward thicker coats.
> ✔ Answer: The thick-coated bear population will descend with modification.
---
## ✔ Final Answers Summary
---
Question 1: Worms
a.
- AGAINST: Diurnal worms
- FOR: Nocturnal worms
b.
i. Variation: Worms differ in feeding time — nocturnal vs diurnal.
ii. Adaptation: Nocturnal behavior (avoids birds).
iii. Overproduction: 500 babies produced, only 100 survive to reproduce.
iv. Descend with modification: Nocturnal worms.
---
Question 2: Polar Bears
a.
- AGAINST: Bears with thin coats
- FOR: Bears with thick coats
b.
i. Variation: Bears have different coat thicknesses (thick, medium, thin).
ii. Adaptation: Thick coats (better insulation in cold).
iii. Overproduction: Mothers give birth to 2 cubs, but many lose one due to cold.
iv. Descend with modification: Thick-coated bears.
---
This worksheet illustrates how natural selection acts on variation in populations, favoring traits that improve survival and reproduction in a given environment.
Parent Tip: Review the logic above to help your child master the concept of evolution natural selection worksheet.
