Species Concepts
What does the biological species concept define a species as?
An organism that can interbreed and produce fertile offspring
What is reproductive isolation?
Mechanisms that prevent different species from interbreeding
What is the main characteristic of macroevolution?
Evolutionary changes at or above the species level
What type of speciation occurs when a population is physically separated by a geographic barrier?
Allopatric speciation
What is the region where members of two different species meet and produce hybrids called?
The hybrid zone
What is the primary limitation of the Biological Species Concept?
It only applies to sexually reproducing organisms
What type of isolation occurs when two species' reproductive structures are incompatible?
Mechanical isolation
Which term describes when a species' reproductive success is influenced by mate preferences?
Sexual selection
Grand canyon squirrels evolving on opposite sides of the canyon is an example of which speciation?
Allopatric speciation
What is the primary cause of sympatric speciation in plants?
Polyploidy
What was the key finding of Darwin's observations in the Galapagos islands?
Geographic isolation can lead to the formation of new species
What type of mechanism occurs when species live in different areas and rarely encounter each other?
Habitat isolation
Which evolutionary process is responsible for the gradual accumulation of small genetic changes over time?
Gradualism
Which type of speciation occurs in the absence of geographic barriers?
sympatric speciation
What was the purpose of the fruit fly experiment?
To demonstrate and provide evidence for sympatric speciation
Which species concept relies on shared physical traits to define species?
Morphological species concept
What are the 3 postzygotic isolation mechanisms?
Hybrid inviability - embryo develops improperly and dies
Hybrid sterility - hybrid develops but is sterile
hybrid breakdown - hybrids are fertile but their offspring have defects/are infertile
What type of data includes DNA and protein sequencing to determine evolution relationships?
Molecular data
The fruit fly experiment demonstrated which type of speciation?
Sympatric speciation
What happens during reinforcement in a hybrid zone?
Hybrids are selected against, strengthening reproductive barriers
What are the 3 other species concepts aside from the biological species concept?
Morphological - species based on physical traits
ecological - species based on their ecological niche
phylogenetic - defines species as the smallest group sharing a common ancestor
What are the 5 prezygotic isolation mechanisms?
Temporal - reproduces at different times
Behavioral - different mating behaviors/ courtships
mechanical - different reproductive structures
gametic - sperm and eggs are incompatible
habitat - live in different habitats and do not run into each other
Which term describes a pattern where species remain unchanged for long periods, followed by rapid speciation?
punctuated equilibrium
Which speciation mechanism occurs when chromosomes are duplicated, affecting the offspring? Is it sympatric or allopatric?
Polyploidy
Sympatric
What is the result of allopolyploidy?
A hybrid species with double the number of chromosomes of its parents