Natural Selection Investigation
results_for_natural_selection_activity_frogs.xlsx | |
File Size: | 19 kb |
File Type: | xlsx |
lab_report_template.doc | |
File Size: | 34 kb |
File Type: | doc |
Before you start
It is important you know exactly what to do before you proceed. Carefully read all the way through the investigation and then test your knowledge by telling your partner what you have to do and what you have to record.
Obtain your dice, frog cards, pond, and forest from your teacher.
Download the spreedsheet above to record your results as you go. This document will automatically generate the graphs you need for your report as you enter your data into the tables. You will need to edit the trendlines but apart from that most of the hard work is already done for you. Also download the laboratory report template. It will help you in writing your report.
Background
Natural selection is a process occurring in ecosystems where certain individuals in a population are more suited to the environment and therefore have a greater chance of surviving and passing on their genes to the next generation. Natural selection can be by biotic (living) or abiotic (non-living) factors.
You will be investigating the process of natural selection in two different and separate environments – a pond and a rainforest. The pond is surrounded by reeds and rushes that are yellowish in colour, while the forest is composed primarily of leafy green vegetation.
You will look at only two organisms in these environments – a frog that occurs in three colours (red, green, and yellow) and a snake that is a predator of the frog.
In this model, for simplicity, assume that each pair of frogs produces one offspring each year, and that snakes eat 15 frogs each year.
Aim: To use a model to show how natural selection affects two populations of frogs.
Materials:
- Three different colours of frog cards (30 red, 30 green and 30 yellow)
- A die
- A “Pond”
- A “Forest”
Method Part A: The Breeding of Frogs
1. Take your “Pond” and “Forest” and place them at opposite ends of your table. These represent the locations of your two different environments.
2. Count out 10 red frogs, 10 green frogs and 10 yellow frogs and place them in the “Pond”. Shuffle the cards thoroughly and place them at random into 15 pairs. These will be the breeding pairs of frogs.
3. Repeat step 2 for the “Forest”.
4. Each pair of frogs produces one offspring per year. To work out the colour of the offspring use Table 1 and Table 2 below. Then, using the remaining cards add the correct coloured frog to each pair.
NB: The three different colours of frogs are the same species and can interbreed and produce different coloured offspring in the same way that humans can interbreed and produce offspring of varying skin, eye or hair colour.
It is important you know exactly what to do before you proceed. Carefully read all the way through the investigation and then test your knowledge by telling your partner what you have to do and what you have to record.
Obtain your dice, frog cards, pond, and forest from your teacher.
Download the spreedsheet above to record your results as you go. This document will automatically generate the graphs you need for your report as you enter your data into the tables. You will need to edit the trendlines but apart from that most of the hard work is already done for you. Also download the laboratory report template. It will help you in writing your report.
Background
Natural selection is a process occurring in ecosystems where certain individuals in a population are more suited to the environment and therefore have a greater chance of surviving and passing on their genes to the next generation. Natural selection can be by biotic (living) or abiotic (non-living) factors.
You will be investigating the process of natural selection in two different and separate environments – a pond and a rainforest. The pond is surrounded by reeds and rushes that are yellowish in colour, while the forest is composed primarily of leafy green vegetation.
You will look at only two organisms in these environments – a frog that occurs in three colours (red, green, and yellow) and a snake that is a predator of the frog.
In this model, for simplicity, assume that each pair of frogs produces one offspring each year, and that snakes eat 15 frogs each year.
Aim: To use a model to show how natural selection affects two populations of frogs.
Materials:
- Three different colours of frog cards (30 red, 30 green and 30 yellow)
- A die
- A “Pond”
- A “Forest”
Method Part A: The Breeding of Frogs
1. Take your “Pond” and “Forest” and place them at opposite ends of your table. These represent the locations of your two different environments.
2. Count out 10 red frogs, 10 green frogs and 10 yellow frogs and place them in the “Pond”. Shuffle the cards thoroughly and place them at random into 15 pairs. These will be the breeding pairs of frogs.
3. Repeat step 2 for the “Forest”.
4. Each pair of frogs produces one offspring per year. To work out the colour of the offspring use Table 1 and Table 2 below. Then, using the remaining cards add the correct coloured frog to each pair.
NB: The three different colours of frogs are the same species and can interbreed and produce different coloured offspring in the same way that humans can interbreed and produce offspring of varying skin, eye or hair colour.
Method Part B: The Eating of Frogs
1. Around the pond, the red frogs are the most likely to be eaten and the yellow frogs the least. In the forest, the yellow frogs are most likely to be eaten and the green frogs the least.
2. Mix all the frog cards for the “Pond”, throw a die and use Table 3, below, to decide which 15 frogs are eaten. Remove an appropriately coloured frog each throw. If there are no frogs of a particular colour left, roll the die again. Continue until 15 frogs have been eaten.
3. Repeat this process for the “Forest”.
4. After 15 frogs have been eaten from each environment, tally the numbers of remaining frogs and record them in the Year 2 row of your results table (At the end of year one you had 10 frogs of each colour). At the end of each year you should still have 30 frogs in total but the relative proportion of each colour will likely differ.
5. Repeat parts A and B for ten years or until all the frogs are the same colour.
1. Around the pond, the red frogs are the most likely to be eaten and the yellow frogs the least. In the forest, the yellow frogs are most likely to be eaten and the green frogs the least.
2. Mix all the frog cards for the “Pond”, throw a die and use Table 3, below, to decide which 15 frogs are eaten. Remove an appropriately coloured frog each throw. If there are no frogs of a particular colour left, roll the die again. Continue until 15 frogs have been eaten.
3. Repeat this process for the “Forest”.
4. After 15 frogs have been eaten from each environment, tally the numbers of remaining frogs and record them in the Year 2 row of your results table (At the end of year one you had 10 frogs of each colour). At the end of each year you should still have 30 frogs in total but the relative proportion of each colour will likely differ.
5. Repeat parts A and B for ten years or until all the frogs are the same colour.
Discussion:
In this exercise you have attempted to model the process of natural selection.
- Suggest why the red frogs around the pond are most likely to be eaten by snakes. Why are the yellow frogs most likely to be eaten in the forest?
- Draw a fully labelled line graph of the changes in the numbers of the different coloured frogs around the pond over 10 years. Do the same for the forest.
- Explain how well you think your model relates to natural populations of frogs.
- Describe some differences you might expect between real populations and your model.
- Outline any ways that in your opinion would improve the modelling.
- Compare your results with those from other groups. Why are the results similar? Why are there some differences?
- What conclusions can you draw from your modelling?
- Explain how natural variation, such as the different colours of frogs, might have arison in the population.
- Write a conclusion for this experiment. Use the words model and natural selection.
Your final report should be a standard scientific report typed in 12 point font with figures included and should be submitted via Hand Up.
The amount of time you will have in class to work on this task and final due dates will be negotiated with your teacher.
When you are finished, click here to reflect on how well you have done with the task (required). Your task will be marked by your teacher according to the standards set out in this document. It is recommended that you read through this document before you start.
Good Luck & Have Fun!
In this exercise you have attempted to model the process of natural selection.
- Suggest why the red frogs around the pond are most likely to be eaten by snakes. Why are the yellow frogs most likely to be eaten in the forest?
- Draw a fully labelled line graph of the changes in the numbers of the different coloured frogs around the pond over 10 years. Do the same for the forest.
- Explain how well you think your model relates to natural populations of frogs.
- Describe some differences you might expect between real populations and your model.
- Outline any ways that in your opinion would improve the modelling.
- Compare your results with those from other groups. Why are the results similar? Why are there some differences?
- What conclusions can you draw from your modelling?
- Explain how natural variation, such as the different colours of frogs, might have arison in the population.
- Write a conclusion for this experiment. Use the words model and natural selection.
Your final report should be a standard scientific report typed in 12 point font with figures included and should be submitted via Hand Up.
The amount of time you will have in class to work on this task and final due dates will be negotiated with your teacher.
When you are finished, click here to reflect on how well you have done with the task (required). Your task will be marked by your teacher according to the standards set out in this document. It is recommended that you read through this document before you start.
Good Luck & Have Fun!