Multiple Choice
During the droughts of 1977 and 1985 studied by the Grants on the Galápagos Islands, which of the following best compares the natural selection observed in finch populations during these two events?
1. Introduction to Biology
Natural Selection and Evolution
Multiple Choice
Branches in the cladogram occur when new key ________ are recognized within groups of organisms.
A
mutations
B
habitats
C
populations
D
innovations
Verified step by step guidance1
Understand the question: A cladogram is a diagram that shows evolutionary relationships among organisms. Branches in a cladogram represent points where a new characteristic or trait arises, leading to the divergence of groups.
Define the term 'key innovations': These are novel traits or characteristics that provide an evolutionary advantage, allowing organisms to exploit new environments or resources. Examples include the development of wings in birds or flowers in plants.
Eliminate incorrect options: 'Mutations' refer to changes in DNA, but not all mutations lead to key innovations. 'Habitats' describe the environment where organisms live, and 'populations' refer to groups of the same species. Neither directly explains branching in a cladogram.
Focus on the correct answer: 'Key innovations' are the traits that lead to the formation of new branches in a cladogram because they signify evolutionary divergence.
Conclude: The correct answer is 'innovations,' as they represent the novel traits that cause the branching points in a cladogram.
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