Bird Beak Lab Conclusion

Data for Part 1 of the Bird Beak Lab

For Part 2, the environmental stressor that we experienced was a massive drought that cause all of the seed pod plants (toothpicks) to die out due to lack of moisture.

The first hypothesis was "Individuals with better traits leave more offspring". The tweezer beak birds demonstrated this because they picked up the most food. In Part 1, the tweezers birds produced 18 offspring. Compared to the spoon and binder clip birds, who produced 4 and 8 offspring, the tweezer beak birds produced more offspring because their "beak" made it easier to obtain more food. The evidence of this happening is that the tweezers picked up more food and it was easier for them to do so. This happened because the tweezers made is easier to pick up food with. There were 18 tweezer offspring compared to the 4 offspring from the spoon birds.

The second hypothesis was "Populations begin to look more like the winners". The tweezer birds produced 37% of the population. Pretty soon, that percentage will increase and eventually a majority of the population will be the tweezer beak birds. The evidence of this occurring would be the statistics saying that the 18 tweezer offspring of the entire total of 49 offspring of all the birds, make up 37% of the population. This happened because the tweezer birds were able to produce more offspring as well as pick up more food.

The lab question was "If natural selection occurs in a population, how do changes in selective pressures affect the evolution of that species?" The hypothesis was "If natural selection occurs in a population, then removing the seed pod plants should affect the population". We found that our selective pressure of removing the seed pod plants did not affect the overall population size very much. An example of this would be the scissor birds. They produced 17 offspring in both Part 1 and Part 2, even though in Part 2 the seed pod plants were removed from the types of food they could eat. This supported our claim because it proved that removing one type of food doesn't affect the population very much.

A possible error in the lab could have been due to people's strategies when picking up food. Most of us didn't bother picking up the toothpicks because they were a little bit difficult to pick up. So when we completely removed the toothpicks, we just picked up more of the other types of foods. Another error could have been due to not being able to hear the music when it first played. I know I was caught off guard when the music started a couple times, which means less time to pick up food as well as less accurate results. Everyone is different, so you never really know if the results are accurate or if the person is just really good at picking up things.

Very blurry picture of us picking up "food" with tweezers, scissors, a spoon, and a binder clip.

The purpose of this lab was to demonstrate how environmental changes affect a population with natural selection. From this lab I learned how changes in an environment can affect a population which helps me understand the concept of natural selection. Based on my experience in this lab, we can use this information to determine if a population will decrease due to a loss of a certain food type.