Problem 7 - Campbell Biology Concepts & Connections

Question

Biologists have found more than 500 species of fruit flies on the various Hawaiian Islands, all apparently descended from a single ancestor species. This example illustrates a. polyploidy. b. temporal isolation. c. adaptive radiation. d. sympatric speciation.

Step-by-Step Solution

Answer

c. adaptive radiation.

Step 1 - Understand the Concepts

First, understand the definitions of the terms provided in the options. Polyploidy refers to an organism having extra sets of chromosomes. Temporal isolation occurs when species breed at different times. Adaptive radiation is when a single species evolves into multiple species to fill various ecological niches. Sympatric speciation is the evolution of a new species from a surviving ancestral species while both continue to inhabit the same geographic region.

Step 2 - Analyze the Given Information

The question mentions that more than 500 species of fruit flies found on Hawaiian Islands have descended from a single ancestor species. This means that these flies diversified from one species into many, exploiting different ecological niches.

Step 3 - Match Concepts with Information

Compare the definitions from Step 1 with the information from Step 2. Polyploidy, temporal isolation, and sympatric speciation don't fit the scenario described. Polyploidy involves chromosomal changes, temporal isolation involves different breeding times, and sympatric speciation occurs in the same geographical area without physical barriers.

Step 4 - Identify the Correct Answer

Adaptive radiation fits the scenario well because it describes how a single ancestor species can evolve into multiple species that occupy different niches, exactly as described for the fruit flies on the Hawaiian Islands.

Key Concepts

Biological Diversity

Biological diversity, or biodiversity, is a term encompassing the variety of all life forms on Earth. This includes diversity within species, between species, and of ecosystems. Biodiversity is significant for several reasons:

• It boosts ecosystem productivity.
• Greater species diversity ensures natural sustainability for all life forms.
• A healthy biodiversity can provide humans with numerous ecosystem services and biological resources.

In the example of the fruit flies in Hawaii, biological diversity is demonstrated by the presence of more than 500 species, all originating from a single ancestor. These species adapted to various ecological niches, increasing biodiversity in the Hawaiian Islands.

Evolutionary Biology

Evolutionary biology is the study of the evolutionary processes that produced the diversity of life on Earth. These processes include natural selection, genetic drift, mutation, and genetic recombination. Key points to remember about evolutionary biology:

• It explains how organisms evolve and adapt over time.
• It is foundational to understanding the relationships between different species.
• It examines the patterns of resemblance and diversity among organisms.

The example with fruit flies on the Hawaiian Islands illustrates evolutionary biology through adaptive radiation. This is where one species evolves into many to exploit different environmental niches. Each new species is adapted to its own niche, demonstrating the dynamic and ever-changing nature of evolution.

Speciation

Speciation is the formation of new and distinct species in the course of evolution. There are several types of speciation:

• Allopatric speciation: Geographic separation leads to the formation of new species.
• Sympatric speciation: New species evolve from a single ancestral species while inhabiting the same geographic region.
• Peripatric speciation: A small population becomes isolated at the edge of a larger population.
• Parapatric speciation: Neighboring populations become distinct species while maintaining a common border.

The fruit flies in Hawaii are an example of adaptive radiation, which often involves allopatric speciation. The original species colonizes different islands or habitats, leading to the development of distinct species as they adapt to different niches. This diversification is a clear illustration of how speciation contributes to biological diversity.