7.10 Speciation

• Populations become physically separated in geographic isolation
• What is adaptive radiation?

  Diversification into ecological niches
• Adaptive radiation results in the rapid diversification of a species into various niches.


  True
• How does geographic isolation lead to speciation?

  Physical separation prevents interbreeding
• Examples of speciation types

  1️⃣ Darwin's finches on the Galapagos Islands

  2️⃣ Sympatric speciation in apple maggot flies

  3️⃣ Cichlid fish in African lakes
• Without gene flow between isolated populations, natural selection can lead to genetic divergence in allopatric speciation.

  True
• What is sympatric speciation?

  Speciation within the same area
• What are three factors that facilitate sympatric speciation?

  Disruptive selection, mutations, behavior
• Reproductive isolation occurs when populations develop barriers to interbreeding
• Geographic isolation is a main mode of speciation


  True
• Steps in allopatric speciation

  1️⃣ A population becomes physically separated

  2️⃣ Interbreeding is prevented between groups

  3️⃣ Genetic divergence occurs due to natural selection

  4️⃣ New species form as they can no longer interbreed
• Match the mode of speciation with its characteristic:

  Allopatric ↔️ Geographic isolation prevents interbreeding

  Sympatric ↔️ Speciation occurs within a single population

  Adaptive Radiation ↔️ Ancestral species diversifies into new species
• Sympatric speciation involves geographic separation

  False
• Match the prezygotic isolation mechanism with its definition:

  Habitat Isolation ↔️ Species occupy different ecological niches

  Temporal Isolation ↔️ Species have different breeding seasons

  Behavioral Isolation ↔️ Incompatible courtship rituals

  Mechanical Isolation ↔️ Structural differences prevent mating
• Prezygotic isolating mechanisms prevent fertilization
• What is one factor that can increase the pace of speciation?

  Environmental pressures
• Larger populations have more genetic variation, allowing them to diverge into new species more readily.


  True
• Speciation is a key mechanism of natural selection.


  True
• Allopatric speciation occurs when populations are physically separated, preventing interbreeding.


  True
• Sympatric speciation involves geographic separation, unlike allopatric speciation.

  False
• Match the type of isolation with its definition:

  Prezygotic Isolation ↔️ Barriers that prevent fertilization

  Postzygotic Isolation ↔️ Barriers after fertilization
• Hybrid inviability occurs when hybrids die before reaching maturity
• What is speciation?

  Process of new species arising
• Reproductive isolation occurs when populations develop barriers to interbreeding, such as differences in mating behaviors.


  True
• Geographic isolation involves physical separation that prevents interbreeding
• Adaptive radiation occurs when a single species diversifies into multiple new forms
• What is the primary cause of allopatric speciation?

  Physical isolation
• Populations become physically isolated in allopatric speciation
• Sympatric speciation often occurs when reproductive isolation mechanisms evolve within the same geographic area.

  True
• New species evolve within the same geographic area in sympatric speciation
• What is adaptive radiation?

  Diversification into ecological niches
• Speciation facilitates natural selection by enabling populations to adapt to distinct environments
• Allopatric speciation requires geographic isolation

  True
• The key distinction of allopatric speciation is the role of geographic isolation in driving genetic divergence
• What is the primary factor driving sympatric speciation?

  Reproductive isolation
• Sympatric speciation is facilitated by factors like disruptive selection or genetic mutations
• What is hybrid inviability in postzygotic isolation?

  Hybrids are weak or die
• Prezygotic and postzygotic isolation can both contribute to speciation


  True
• The stronger the reproductive isolation mechanisms, the faster speciation can occur.
• Speciation is the process by which new species arise.