Sympatric Speciation | LB 3

These flashcards cover the mechanisms and examples of sympatric speciation in both plants and animals, as discussed in the lecture notes.

What is sympatric speciation?

A form of speciation that occurs without geographical isolation, allowing new species to arise from a single ancestral species.

What processes allow sympatric speciation in plants?

Polyploidy and allopolyploidy.

Define polyploidy.

A condition in which an organism has more than two complete sets of chromosomes.

What results from an error during meiosis in plants?

The production of gametes that have a diploid number of chromosomes, leading to the formation of a new species.

What is allopolyploidy?

A type of polyploidy that occurs through hybridization between two different species.

How many plant species are estimated to be polyploid or allopolyploid?

Between 30% and 80%.

What is a common mechanism for sympatric speciation in animals?

Sexual selection.

What unique characteristic about Lake Victoria contributes to sympatric speciation?

It has no internal barriers, which promotes gene flow between species.

What is sexual dimorphism in cichlids?

The differences in coloration and morphology between male and female cichlid fish.

What role does female mate choice play in cichlids?

It helps maintain genetic barriers between different cichlid species.

What is disruptive selection?

A form of natural selection that favors extreme traits over intermediate traits.

Give an example of disruptive selection in a mouse population.

Selection for light and dark fur colors while selecting against gray fur.

What are parasitic bird lice an example of in terms of speciation?

Sympatric speciation through specialization on different bird species and body parts.

What facilitated the speciation of Rhagoletis pomonella?

The shift from hawthorn fruit to introduced apple fruit, creating a habitat barrier.

What temporal differences contribute to speciation in Rhagoletis flies?

Hawthorns and apples produce fruit at different times of the year.

What advantages do light and dark mice have in their environment?

They are better camouflaged from predators compared to gray mice.

What is a significant impact of hybridization on speciation?

It can create new species through the combination of genetic material from different species.

Why is it significant that some fish species have very high chromosome numbers?

It suggests their speciation could arise from historical polyploidy events.

How does habitat differentiation lead to speciation?

Different species adapt to and specialize in distinct habitats, reducing gene flow.

What reinforces reproductive barriers between apple and hawthorn-infested Rhagoletis?

Differences in behavioral preferences and timing of fruit production.