Chapter 24 - Speciation Flashcards
What is speciation?
The process by which new species arise from existing species.
True or False: Speciation can occur through both gradual and rapid processes.
True
Fill in the blank: The two main types of speciation are _______ and _______.
allopatric; sympatric
What is allopatric speciation?
Speciation that occurs when populations are geographically isolated.
What is sympatric speciation?
Speciation that occurs without geographical isolation, often through mechanisms like polyploidy.
What role does natural selection play in speciation?
Natural selection can drive the divergence of populations and lead to the formation of new species.
Define the term ‘reproductive isolation’.
A set of mechanisms that prevent species from interbreeding and producing fertile offspring.
What are the two main categories of reproductive isolation?
Prezygotic and postzygotic isolation.
Give an example of prezygotic isolation.
Temporal isolation, where species breed at different times.
Give an example of postzygotic isolation.
Hybrid inviability, where hybrid offspring do not survive to maturity.
What is the biological species concept?
A definition of species based on the ability to interbreed and produce fertile offspring.
True or False: The biological species concept can be applied to all organisms.
False
What is adaptive radiation?
The rapid evolution of diversely adapted species from a common ancestor.
What role does genetic drift play in speciation?
Genetic drift can lead to changes in allele frequencies that contribute to speciation, especially in small populations.
What is a hybrid zone?
An area where two closely related species meet and interbreed.
What can happen in a hybrid zone over time?
Reinforcement of reproductive barriers, fusion of species, or stability of the hybrid zone.
What is polyploidy?
A condition in which an organism has more than two complete sets of chromosomes.
How can polyploidy lead to speciation?
It can create reproductive isolation from the parent population, leading to the formation of a new species.
What is the difference between microevolution and macroevolution?
Microevolution refers to small-scale changes within a species, while macroevolution refers to large-scale changes that result in the emergence of new species.
True or False: Speciation is always a slow process.
False
What is a key factor in sympatric speciation?
Resource competition or niche differentiation.
Define ‘speciation rate’.
The speed at which new species are formed in a particular group or environment.
What is the impact of environmental changes on speciation?
Environmental changes can create new ecological niches, leading to speciation.
What is a common misconception about speciation?
That it is a linear process; in reality, it can be complex and involve various mechanisms.
Fill in the blank: The process of speciation often involves _______ and _______.
mutation; selection
What is the significance of the founder effect in speciation?
It can lead to genetic divergence when a small group establishes a new population.
What is an example of a species that underwent adaptive radiation?
Darwin’s finches.
True or False: Allopatric speciation is more common than sympatric speciation.
True
What is the role of sexual selection in speciation?
It can lead to the development of traits that enhance reproductive success and promote divergence.
What is a ‘phylogenetic tree’?
A diagram that shows the evolutionary relationships among various biological species.
How does the concept of ‘morphological species’ differ from the biological species concept?
Morphological species are defined based on physical characteristics, regardless of reproductive isolation.
Fill in the blank: The process by which reproductive barriers evolve is called _______.
reinforcement
What does the term ‘speciation event’ refer to?
A point in time when a new species is formed.
What is the significance of the concept of ‘gene flow’ in speciation?
Gene flow can prevent speciation by allowing genetic exchange between populations.
True or False: Speciation can occur in both plants and animals.
True
What is ‘ecological speciation’?
Speciation that occurs due to the adaptation to different ecological niches.
What is a key factor that can lead to the extinction of a species during speciation?
Inability to adapt to changing environmental conditions.
What is the role of isolation in the process of speciation?
Isolation prevents gene flow and allows populations to evolve independently.
