Studied by 2 people
Darwin’s Finches
Darwin’s voyage to the Galapagos Islands led him to observe diverse groups of finches. They have various beaks depending on their island of origin and which food is available.
Macroevolution
patterns and processes associated with evolutionary change at and above the species level, often leads to speciation
Biological Species
a (group of) population whose members can interbreed and produce fertile offspring
Speciation
the formation of new species that occurs when some members of a population can no longer successfully interbreed with the rest of the group
Divergent Evolution
Interbreeding species diverge into two or more evolutionary groups due to environmental changes or migration.
Convergent Evolution
Distinctly different species become more similar in structure and function, seen in different species that live in similar environments.
Parallel Evolution
Two species that have descended from a common ancestor develop similar traits because they adapt to similar environmental changes.
Co-evolution
Occurs when one of the species changes, then the other will also change in response so the relationship can continue.
Pre-zygotic Isolation
Occurs before the formation of a zygote by preventing reproductive attempts that make it unlikely that the fertilization will be successful if mating is attempted.
Types of Pre-zygotic Isolation
Habitat Isolation
Temporal Isolation
Behavioral Isolation
Mechanical Isolation
Gametic Isolation
Habitat Isolation
When two species occupy different habitats even within the same geographic range, they are less likely to meet and attempt to reproduce.
Temporal Isolation
Two species can live in the same local but if they reproduce at different times of the year, they do not attempt to mate.
Behavioral Isolation
Courtship patterns that attract mates and other behaviors unique to a species are effective reproductive barriers, even between closely related species.
Mechanical Isolation
When animal genitalia or plant floral structures are incompatible, reproduction cannot occur.
Gametic Isolation
Even if the gametes of two different species meet, they may not fuse to a zygote.
Post-Zygotic Isolation
Occurs after the formation of a zygote, this prevents hybrid offspring from developing or breeding, even if reproduction attempts have been successful
Types of Post-Zygotic Isolation
Hybrid inviability
Hybrid sterility
Hybrid breakdown
Hybrid Inviability
The genes of different parent species may interact in ways that impair the hybrid’s development or survival in its environment.
Hybrid Sterility
The zygote can develop into a sterile adult, but if the chromosomes of the parent species different number or structure, meiosis in the hybrids may fail to produce normal gametes.
Hybrid Breakdown
Some first-generation hybrids are viable and fertile, but when they mate with one another or with either parent species offspring of the next generation are feeble or sterile.
Modes of Speciation
the different ways speciation occurs
Allopatric Speciation
A new species forms when a geographical barrier physically separates a population into two that cannot interbreed.
Parapatric Speciation
Occurs when two population live in neighboring areas but share a border zone.
Sympatric Speciation
A population develops into two or more reproductive isolated groups without prior geographic isolation.
