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Questions and Answers
Which factor primarily drove the initial diversification of finch species on the Galapagos Islands?
Which factor primarily drove the initial diversification of finch species on the Galapagos Islands?
- Abundance of identical food sources across all islands.
- Adaptation to diverse habitats and food sources on different islands. (correct)
- Lack of predators, allowing for random mutations to accumulate.
- Frequent interbreeding between mainland finches and island finches.
The El Nino event of 1983 resulted in an increase in the average beak size of the medium ground finches on Daphne Major Island.
The El Nino event of 1983 resulted in an increase in the average beak size of the medium ground finches on Daphne Major Island.
False (B)
What primary factor prevents different Galapagos finch species from interbreeding?
What primary factor prevents different Galapagos finch species from interbreeding?
Mate selection based on song and appearance.
Peter and Rosemary Grant's study of the medium ground finches on Daphne Major Island began in the year ______.
Peter and Rosemary Grant's study of the medium ground finches on Daphne Major Island began in the year ______.
Match the following environmental events with their impact on the medium ground finch population on Daphne Major Island:
Match the following environmental events with their impact on the medium ground finch population on Daphne Major Island:
Which statement accurately describes how new species of Galapagos finches are typically formed?
Which statement accurately describes how new species of Galapagos finches are typically formed?
The Galapagos Islands are located approximately 6,000 miles from the coast of Ecuador.
The Galapagos Islands are located approximately 6,000 miles from the coast of Ecuador.
What characteristic of the Galapagos finches did Darwin bring to the attention of scientists?
What characteristic of the Galapagos finches did Darwin bring to the attention of scientists?
The average beak depth of the medium ground finches increased by more than ______% in the generation following the drought of 1977.
The average beak depth of the medium ground finches increased by more than ______% in the generation following the drought of 1977.
What is the significance of studying Galapagos finches in understanding evolutionary processes?
What is the significance of studying Galapagos finches in understanding evolutionary processes?
Flashcards
Galapagos Islands
Galapagos Islands
Volcanic islands located 600 miles from mainland Ecuador, known for unique species.
Galapagos Finches
Galapagos Finches
Thirteen species of finches with distinct beaks adapted to different food sources and habitats on the Galapagos Islands.
Daphne Major Island
Daphne Major Island
A location where Peter and Rosemary Grant studied medium ground finches since 1973, tracking individual finches and their traits.
Drought of 1977
Drought of 1977
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Natural Selection (Beak Size)
Natural Selection (Beak Size)
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El Nino of 1983
El Nino of 1983
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Species Definition
Species Definition
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Mate Selection (Finches)
Mate Selection (Finches)
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Evolution of Finches
Evolution of Finches
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Significance
Significance
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Study Notes
Galapagos Islands
- Located 600 miles from mainland Ecuador
- Volcanic islands are geologically young, rising from the ocean floor less than 5 million years ago
- Originally devoid of life but now support a modest number of species, including 13 species of finches
Galapagos Finches
- Charles Darwin brought the finches to scientists' attention
- Thirteen species exist on the islands in various combinations
- They live in diverse habitats
- The finches became distinct species based on different beaks
- DNA evidence indicates all finches are related to each other
Daphne Major Island
- Island where Peter and Rosemary Grant studied medium ground finches since 1973
- The Grants followed almost every individual finch on the small island
- They measured beak size and shape, weight, and tagged birds for identification
Drought of 1977
- Virtually no rain fell for 18 months, and vegetation disappeared
- Medium ground finches competed for scarce food (seeds)
- Only birds with large beaks could crack open the large and hard seeds
- Over 80% of the medium ground finches died
Natural Selection
- Surviving finches had larger beaks, and offspring inherited larger beaks
- Average beak depth was more than 4% larger in the next generation
- Natural selection changed the average beak size
El Nino of 1983
- Brought 10 times more rain than normal, and the island was overrun by vines
- Larger seeds became scarce
- Finches with small beaks survived, and their offspring inherited smaller beaks
- Selection swung in the opposite direction, resulting in evolution
Formation of New species
- Species are defined as populations whose members don't interbreed
- Typical scenario involves geographic separation, leading to changes and inability to mate upon contact
- Different species sang very different songs
Mate Selection
- Males only responded to the songs of their own species
- Males courted females with similar size and beak
- Song and appearance play a role in keeping different species from mating
Evolution of Galapagos Finches
- Two million years ago, a single finch population arrived from the mainland
- Descendants reached other islands and faced new conditions
- Isolated populations adapted, and their traits changed
- Changes in mating traits led to distinct species
Significance
- The Galapagos finches offer insight into why the world is populated with so many species
- More diverse environments create more opportunities for evolutionary change and new species
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