Why Bird Beaks are Adapted to the Food the Bird Eats
II. Purpose
Bird beaks are adapted to the specific types of food that they eat. Due to the environment, the degree to which each bird gathers food will vary. The purpose of the Bird Beak Lab is to establish and understand how and why bird beaks are adapted to the food they eat. It will show us how adaptations influence an organism’s ability to compete for natural resources.
Independent variable – the environment in which each bird gathers food
Dependent variable – the amount of specific food gathered by each bird
III. Hypothesis
I predict that the size and shape of the birds’ beaks will directly affect the type and amount of food source it gathers. Birds like the hummingbird and Avocet will be unable to gather certain foods because of their beaks, thus having a disadvantage. The finch and pelican will benefit the most from the size and shapes of their beaks and will benefit the most.
IV. Materials
Wire-nose (hummingbird)
Tweezers (finch)
Chopsticks (Avocet)
Test tube clamp (pelican)
Nickels (clams)
Plastic cups
Red plastic beads (flowers)
Paper clips (shrimp)
Rice
V. Procedure
THE GOAL: Compete with other birds to accumulate the most amount of food in each environment.
1. Place food on the lab table (be sure to spread it around)
2. Place the plastic cups (nests) an equal amount away from the feeding area.
3. Set timer to 30 seconds. Use your “beak” to pick up food during the allotted time and place it into your plastic cup. Gather as much food as possible.
4. When 30 seconds is up, count and record the amount of food gathered. Repeat procedure for different environment (ie – gather paperclips instead of red beads, etc.)
VI. Data Collection
See Appendix A
VII. Data Analysis
See Appendix B
Questions:
1. The bird that was least specialized in its feeding habits was the finch (tweezers). This bird was able to exploit so many different types of food because it is a species that can survive in a variety of different environments. A major factor in helping with this was the finch’s large flexible beak (the tweezers). It was able to pick up every type of food in large amounts. This type of species is called a generalized species.
2. The bird that was most specialized in its feeding habits was the hummingbird (wire-nose). This type of species is called a specialized species.
3. The hummingbird was unable to exploit a wide variety of food resources because it can only survive in a special environment due to its trait of a narrow and curved beak. It was because of this that the hummingbird was unable to pick up certain items such as rice and the nickel. It is also because of this that the hummingbird is a specialized species.
4. The bird with that gathered most food was the finch (tweezers). It was able to obtain so much food because of its large beak. This enabled it to literally pick up every type of food and rather quickly. This type of bird can survive in many types of environments and can adapt quickly to changes in that environment.
5. The competition from other birds affected my bird’s ability to obtain food. Most of the time, the other birds were gathering food rather quickly and leaving almost none left. This form of competition is also intraspecific competition, where members of the same species compete for the same resources. If this were to continue, my bird would most likely die because it wouldn’t be able to cope with so much competition and so little food.
6. Specialization makes a bird more effective in obtaining food. It is able to concentrate on a specific food and get large amounts of it. This is true in the case of the hummingbird (wire-nose) when it obtained large amount of red beads and paperclips. The hummingbird was able to get just as much food as the Avocet (chopsticks) which is considered a generalist species.
7. If a bird becomes overspecialized in its feeding habits, it faces some dangers. There may be an extinction of the food source that the bird specializes in feeding upon. This would cause the species of that bird to deplete because its food source is no longer available. Also, if two different types of birds competed for the same scarce resource, their niches would overlap each other. This would result in one of the species driving out the other that is less efficient, also known as the competitive exclusion principle.
8. This bird feeding lab relates to Darwin’s theory of natural selection in many ways. The different beaks of the birds show us that adaptations have allowed the birds to exploit certain food resources. Distinct beaks correspond to certain foods for that bird. Darwin’s natural selection theory tells us that there is a constant modification of a species’ physical characteristics that enhance its survival and therefore its reproduction rate within that community and environment. The species that have traits that allow them to best cope with biotic and abiotic factors in their environment survive (known as survival of the fittest). The theory of resource partitioning tells us that by adapting to each other’s presence over time, species are able to avoid competition and benefit. This is true in the case of the pelican and finch. The pelican was able to gather a lot of red beads, but not so many paperclips or rice. This was okay, because the pelican gathered the most amount of nickels, while the other birds didn’t get any nickels, except for the finch. Although the finch only gathered 2 nickels, it was able to make up for this in the large amount of red beads, paper clips, and rice it gathered.
VIII. Evaluation and Conclusion
The bird beak lab was very effective in demonstrating how adaptations influenced the birds’ ability to compete for natural resources. The different beaks for each bird directly affected what food source it gathered and how much of it. This showed how Darwin’s theory of natural selection worked because the physical characteristics of the birds enhanced its survival, such as the pelican. Although the pelican was unable to pick up paperclips and hardly any rice, its beak enabled it to pick up many red beads and the most clams (nickels) out of any other bird. This allowed it to survive, because it was able to gather many clams (the biggest food source), whereas the hummingbird and Avocet didn’t get any because of the size of their beaks. Thus, I was correct in my hypothesis: the size and shape of the beaks determined the amount and type of food each bird gathered.
Since the lab was very open ended in its procedure, our group determined the amount of feeding time allotted and the distance of the nest from the feeding source. We agreed that 30 seconds was a reasonable time, and we each placed our cups 4 inches away from the feeding area.
There may have been several areas of miscalculation in our procedure. Most of the time, the person in charge of the timer wasn’t paying much attention to it because she was very focused on obtaining food from the feeding area. This may or may not have resulted in us going over the time limit of 30 seconds and gathering more food in the process. Also, the distance of our nests from the feeding area changed very much in the course of dumping back food into the feeding area. The feeding area became very scattered, and I noticed that some of our cups were inching either closer or farther to the nests than others. This most likely affected our ability to place food in our nests faster or slower than others did.
In the Bird Beak Lab, there may be some weaknesses in this investigation of how different bird beaks adapt to the food they eat and enable them to survive. Our group did a series of rounds where we each tested the different beaks. This may have created an error in understanding the lab, because one of the beaks was chopsticks (the Avocet). One person may have had an advantage over another person who used the chopsticks because they had experience with using chopsticks. Therefore, they would be able to gather more amounts of food than the other person who didn’t know how to use chopsticks would. Our group establishing who could use what “beak” would allow everyone to have a fair advantage. Also, we shouldn’t have switched beaks because in a real environment, different birds wouldn’t be switching beaks with each other. We should have stuck with one beak, and practiced gathering certain types of food.
This lab showed me how Darwin’s theory of natural selection works. Beforehand, I didn’t understand it much. But through the Bird Beak Lab, I am now able to understand why birds have different beaks and how this establishes the form of resource partitioning. By having different beaks, birds can specialize in gathering certain foods, while maintaining a balance among the food source.
