Title: Bird Beak Adaptations - Natural Selection
Standards : (California Science Standards)
7.3.a. Students know both genetic variation and environmental factors are causes of evolution and diversity
7.3.b. Students know the reasoning used by Charles Darwin in reaching his conclusion that natural selection is the
mechanism of evolution.
7.3.e. Students know that extinction of a species occurs when the environment changes and the adaptive Materials:
characteristics of a species are insufficient for its survival.
· 8 tweezers
· 8 spoons
· 8 forks
· 8 chop sticks
· 2 bag of beans
· 6-8 boxes of toothpicks
· 35 paper cups
· timer (stop watch or online timer)
· Student handout/data sheet (see attachment)
· laptop computer with attached projector
Prepare in advance:
1 feeding box per group containing the following items:
1 square plastic container
- Students will be working in groups of 4. Arrange seating so group members are facing each other and place feeding box in center of group table. Hand out Data Sheets (see attachment)
- Students will take a cup and one of the four beak utensils from the feeding box.(fork, spoon, tweezers, or chopsticks)
- Explain to students that they are birds and their environment has drastically changed due to drought. The birds' food supply has been limited to only beans in the mountains and toothpicks in the valleys
- Part 1 of activity - students are birds in the mountains and will only be able to collect beans from the feeding box.
- Set online timer for 30 seconds. Using only their beak utensil, students will collect as many beans as possible and place them in their cup.
- At the end of 30 seconds, students will record the number of beans they collected on their data sheet. **Each Student will be recording the results of all 4 group members on their data sheet.
- All food is put back in the feeding box and students will pass their utensil to the group member on their left.
- Once all students have a different utensil in hand, the procedure starts again (from step 5).Collect for 30 seconds, record results, return food, and pass utensil. Repeat until students have had a turn using each utensil to collect beans.
- After the 4 rounds are complete, move on to part 2. The procedure for part 2 is exactly the same as before except students are now birds in the valley and are only able to collect toothpicks. No beans.
- Proceed as before: Collect for 30 seconds, record results, return food, and pass utensil.
- Once students has had a turn using each of the four utensils to collect toothpicks and all the data is recorded, the data collection part of the activity is complete. Class can clean up - return tables to their right positions.
- Class will spend 5 – 10 minutes discussing data and interpreting results as a group
- Students will answer 2 questions on their data sheet independently.
Student prior knowledge:
- Natural selection is a process by which organisms with traits that best fit their environment are most likely to survive, reproduce, and pass on their genes to the next generation.
- Adaptations are traits that best fit ones environment and promote an increase in population over many generations.
- Evolution is a process in which inherited characteristics within a population change over generations such that new species sometimes arise
The shape of structures, such as a bird's beak, is related to its function and the role it plays in its environment. Bird beaks are adapted to the way that the bird obtains food. Many variations of the structure may be observed within a species. These variations are often adaptations that help improve an organism's rate of survival in their environment. These adaptations develop over generations through the process of natural selection.
To observe how some beak shapes can be more advantageous than others, students will role play birds gathering different types of food using only tools that simulate different types of beaks.
- How does the shape of a bird's beak affect its rate of survival?
In order to survive, birds must obtain an adequate amount of food from their environment.The tool that bird's rely on to obtain food is their beak. The more efficient the bird's tool is, the better the rate of survival will be. If the food source in an environment is altered, only the birds with beaks that can adapt to the new type of food will survive. Birds with beaks that are not as functional in obtaining the new type of food will eventually die off. The birds with the favorable beak design will survive and reproduce, passing on the favorable traits to their offspring.
- Based on the results from the activity, predict what will happen to the population of birds in the mountains over the next 1000 years.
If the food source remains the same, the number of birds with the spoon shaped beak will increase while the number of birds with chop sticks, fork, and tweezers shaped beaks will decrease. The birds with chop sticks and tweezers shaped beaks may disappear completely do to their inability to adequately gather food. The number of birds with the spoon shaped beaks will be controlled by the amount of food that is available in the environment.
- How can populations be affected by climate change in their environment?
Climate change can cause a change in the food source in the environment. This change can disrupt the food chain that exists in the environment at all levels. The population of plants in the area may increase of decrease due to the climate change. The number of primary consumers will change accordingly. Predators, or secondary consumers, will be directly affected by any increase or decrease in the number of prey in the environment. Over time, the climate change will change the population of all inhabitants of the environment. The organisms that survive will be those most adequately adapted to the new environment. Others, less adapted, will die off. Eventually, equilibrium in the environment will be reached again and a new food chain will exist.
Applications to Everyday Life:
Endangered Species - it is important for species to be able to adapt to changes in their environment.
Environments can change due to natural forces, such as climate change, or by man-made forces, such as
pollution or destruction of habitat. Species with low genetic variability are the most affected by a
change in their environment because they have a limited ability to adapt. Eventually, species can decline in
numbers to a level where they are considered to be an endangered.species.
Extinction - when a species' adaptations to a changed environment are not enough to help it survive, the
species becomes extinct. Species are becoming extinct almost everyday and once the species is extinct, it is
Environmentalist's concerns about going green. Many people are realizing all the damage that is being
done to the global environment due to human activity on Earth. The effects of global warming, the carbon
footprint, acid rains, the greenhouse effect, the depletion of the ozone layer, and the destruction of habitats
such as the rain forest are taking the toll on the organisms that share this planet with us. Many species are
struggling to adapt and survive in the world humans are creating. Environmentalists are trying to bring
attention to the probems - and want people to consider going green.
Photographs: Include a photograph of you or students performing the experiment/demonstration, and a close-up, easy to interpret photograph of the activity --these can be included later.
Videos: Links to videos posted on the web that relate to this activity.
1. Bird Beak Adaptation - http://youtu.be/5RzAmtCpP7g
2. Bird, Beaks, & Natural Selection - http://youtu.be/wV-cTYcOcrQ