Rosemary and Peter Grant have studied how natural selection works on ______ of the Galápagos Islands. Eagles Crows Finches Sparrows
Added by Daniel R.
Close
Step 1
Step 1: Rosemary and Peter Grant are famous for their research on the evolution of Darwin's finches. Show more…
Show all steps
Your feedback will help us improve your experience
Madhur L and 85 other Biology educators are ready to help you.
Ask a new question
Labs
Want to see this concept in action?
Explore this concept interactively to see how it behaves as you change inputs.
Key Concepts
Recommended Videos
'The Grants Have Observed Natural Selection in Galapagos Finches Answer the following questions about the work of Rosemary and Peter Grant: With what species did they work and where does this species live? What is the average peak size? What is the relationship between the size of the beak and the seeds that it consumes? What happened to the population of finches and to the seeds after the drought? How did the population change in response to changes in the size of the available seeds? Do you think this experiment shows that evolution occurs?'
Madhur L.
Scientists have long believed that the 14 species of finches on the Galapagos Islands evolved from a single species of finch that migrated to the islands one to five million years ago (Lack, 1940). Recent DNA analyses support the conclusion that all of the Galapagos finches evolved from the warbler finch (Grant, Grant & Petren, 2001; Petren, Grant & Grant, 1999). Different species live on different islands. For example, the medium ground finch and the cactus finch live on one island. The large cactus finch occupies another island. One of the major changes in the finches is in their beak sizes and shapes. What is the best way to describe the evolutionary changes that occur in a finch population over time? Group of answer choices: The frequency of finches having different traits within a population change Successful behaviors learned by finches are passed on to offspring The traits of EACH finch within a population gradually change Mutations occur to meet the needs of the finches as the environment changes
Kelan H.
Peter and Rosemary Grant and their colleagues have studied Galapagos finch populations every year since 1976. The Grants found changes from one generation to the next in beak shape distribution with the medium ground finch on the Galapagos island of Daphne Major. The birds have inherited a variation in their bill shape with some having wide deep bills and others having thinner bills. During a period in which rainfall was higher than normal because of an El Niño, there was an abundance of the small soft seeds which the small-billed birds ate. During a period of drought, small seeds became scarce and only those birds with larger beaks could survive on the large, hard seeds still available. Average beak size shifted to larger beaks in the next generation. During a period in which rainfall was higher than normal because of an El Nino, there was an abundance of vines with small soft seeds which the small-billed birds ate. In the years following this El Nino, a drought occurred. With food becoming scarce, and an abundance of small seeds, the Grants measured beak sizes in the population and found that the average beak size became smaller. Why were these measurements important? They showed that birds with different bill sizes eat different types of food and therefore do not compete with one another for resources. They provided strong evidence of evolution by natural selection because birds with small bills had more offspring in years where small seeds were prevalent, and large-billed birds were more likely to survive and breed in years with large seeds. They revealed that weather can have a strong effect on the food preferences of the birds. They showed that bill size changes in response to the available food supply. This was a unique adaptation not formerly seen in any species of bird.
Adi S.
Recommended Textbooks
Biology for AP Courses
Objective Biology for NEET
Introduction to General, Organic and Biochemistry
Transcript
Watch the video solution with this free unlock.
EMAIL
PASSWORD