The Origin of Species: Finch Evolution Quiz

Questions and Answers

Which is the most likely explanation for the presence of 13 different finch species on the Galápagos Islands today?

Many years ago, a small population of a single bird species migrated to the islands and evolved into the 13 species that live on the islands today.

These different beak structures are evidence of what?

Different finch species adapting to different environments over many generations.

Galápagos finches are more closely related to what?

Each other than they are to mainland finch species.

We know cactus finches and medium ground finches are distinct species because?

They only attempt to breed with members of their own species. Signup and view all the answers

A statement that describes geographically isolated populations is what?

The two populations live on different islands. Signup and view all the answers

What statements describe populations that are isolated in reproduction?

The two populations live on different islands, one population breeds in late spring and the other breeds in late summer, the males of one population sing different songs than the males of another population. Signup and view all the answers

How did the Grants test their hypothesis that differences in birds' songs can keep finches from breeding with members of other species?

They played the songs of medium ground finches and cactus finches through a loudspeaker at different times to see which species responded to each song. Signup and view all the answers

The result of the Grants' experiment was what?

Males only came to the loudspeaker when the song of their own species was being played. Signup and view all the answers

With the drought on Daphne Major, the size of the finches' beaks did what?

Increased from a common size of 8.8 mm to 10.3 mm. Signup and view all the answers

The offspring of Daphne Major finches' beaks were most commonly what size?

9.8 mm in size. Signup and view all the answers

How do finches recognize members of their own species?

Appearance and sound. Signup and view all the answers

The Galápagos islands are considered to be 'young' islands because?

They formed recently, from 0.5 million to 5 million years ago. Signup and view all the answers

What taxonomic ranks do the medium ground finch and cactus finch share?

The 'Geospiza' genus. Signup and view all the answers

What physical trait varies the most between the cactus finch and the medium ground finch?

Beak shape and size. Signup and view all the answers

What is a spectrogram?

A visual representation of sound frequencies over time. Signup and view all the answers

When do Galápagos island finches learn their songs?

Early life. Signup and view all the answers

From whom do Galápagos finches learn their songs?

Neighbors. Signup and view all the answers

Why would the song of an intermediate finch species not be intermediate as well?

The intermediate would learn its song from whichever neighboring species it had. Signup and view all the answers

Study Notes

Evolution of Finch Species

A single bird species migrated to the Galápagos Islands and evolved into 13 distinct species through adaptation to various environments.
The variation in beak shapes and sizes among different finch species indicates evolutionary changes driven by environmental pressures.

Genetic Relationship

Galápagos finches share a closer genetic relationship with each other than with mainland finch species.

Species Isolation

Cactus finches and medium ground finches are separate species because they only breed with their respective species.
Geographic isolation contributes to the distinctiveness of these populations, promoting species diversity.

Reproductive Isolation

Different breeding seasons (late spring vs. late summer) and unique songs of males help maintain reproductive isolation between finch populations on different islands.

Grants' Experiment Methodology

The Grants tested their hypothesis regarding song differences by playing respective finch songs through a loudspeaker to observe species response.

Experiment Results

Males only responded to the songs of their own species when played, confirming that song is a crucial factor in species identification and reproductive isolation.

Adaptation During Drought

During a drought on Daphne Major, the size of finch beaks increased from an average of 8.8 mm to 10.3 mm, showcasing changes in physical characteristics due to environmental stress.

Offspring Characteristics

The most common size for the offspring of Daphne Major finches’ beaks was recorded at 9.8 mm.

Species Recognition

Finch species recognition is based on both appearance and auditory signals, such as unique songs.

Geological Context

The Galápagos Islands are regarded as "young" islands due to their geological formation occurring between 0.5 million and 5 million years ago.

Taxonomy of Finches

Medium ground finches and cactus finches belong to the same taxonomic genus, "Geospiza."

Key Physical Traits

Beak shape and size are the most prominent physical traits that differentiate the cactus finch from the medium ground finch.

Understanding Sound Frequencies

A spectogram is a visual representation of sound frequencies over a period, capturing variations in the songs of finch species.

Song Learning Process

Galápagos island finches learn their songs during early life stages, crucial for their identity as members of specific species.

Influence of Neighbors

Finches learn their songs primarily from neighboring finch species, which impacts their own song characteristics.

Intermediate Finch Song Phenomena

An intermediate finch species’ song reflects influences from its neighboring species, making it unlikely to be an intermediate mix itself.

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Description

Explore the fascinating evolution of finch species in the Galápagos Islands through these flashcards. Understand how environmental factors contributed to the diversity of these birds and their adaptations over generations. Test your knowledge on the concepts presented in 'The Beak of the Finch'.