Question

speciation
classify the following characteristics depending on what type of speciation is occurring.
a city is built in the valley between 2 hillsides and as a result, the populations of either hillside rarely interbreed with each other. over time, enough genetic differences accumulate so that a new species is formed.
black mussels in a pond occupy rocky shoreline. mutation in this population introduces a white mussel that occupies sandy shoreline. over time, the white mussel population does not breed with black mussels and evolves into a new species.
suggests that new species evolve when a population of an existing species moves into a new habitat
new species can evolve from a population of an existing species if a chromosome mutation, such as polyploidy, in one population prevents interbreeding with the other.
considered to be the most common way new species form
no physical barrier prevents mating between populations.
allopatric speciation sympatric speciation

Explanation:

To classify the characteristics, we recall the definitions:

• Allopatric Speciation: Occurs when a physical barrier (geographic isolation) separates populations, leading to speciation.
• Sympatric Speciation: Occurs within the same geographic area (no physical barrier), often due to genetic changes (e.g., polyploidy) or resource partitioning.

Allopatric Speciation Characteristics:

1. A city is built...: Physical barrier (city) isolates populations.
2. Suggests that new species...: Moving to a new habitat (geographic change) drives speciation.
3. Considered to be the most common...: Allopatric is the most common speciation mode.

Sympatric Speciation Characteristics:

1. Black mussels...: Same pond (no physical barrier), speciation via mutation/resource partitioning (rocky vs. sandy shore).
2. New species can evolve...: Chromosomal mutation (polyploidy) in the same area prevents interbreeding.
3. No physical barrier...: Defining trait of sympatric speciation (no geographic isolation).

Answer:

Allopatric Speciation:

• A city is built in the valley between 2 hillsides and as a result, the populations of either hillside rarely interbreed with each other. Over time, enough genetic differences accumulate so that a new species is formed.
• Suggests that new species evolve when a population of an existing species moves into a new habitat
• Considered to be the most common way new species form

Sympatric Speciation:

• Black mussels in a pond occupy rocky shoreline. Mutation in this population introduces a white mussel that occupies sandy shoreline. Over time, the white mussel population does not breed with black mussels and evolves into a new species.
• New species can evolve from a population of an existing species if a chromosome mutation, such as polyploidy, in one population prevents interbreeding with the other.
• No physical barrier prevents mating between populations.