The Origins of New Species

What is a species? Biological Species Concept: A population or groups of populations whose members have the ability to breed with one another in nature and produce fertile offspring Members of one species cannot successfully breed with members of another species Excluding individuals who reproduce asexually A jaglion or jaguon is the offspring between a male jaguar and a female lion (lioness).

A species is organisms who have the ability to breed with one another in nature and produce fertile offspring (not including those organisms who breed asexually)

Micro- to Macroevolution Micro- is a change in the allele frequencies within a population Macro- are the biological changes that include the Origin of different species Extinction of species Evolution of major new features of living things Speciation: origin of new species Main focus for macroevolution because it leads to biological diversity

A species is organisms who have the ability to breed with one another in nature and produce fertile offspring (not including those organisms who breed asexually) Microevolution is a change in the allele frequencies within a population and can lead to…see below Macroevolution are the biological changes that include the: - Origin of different species - Extinction of species - Evolution of major new features of living things Speciation is the origin of new species

Reproductive Barriers Between Species Reproductive isolation Some kind of reproductive barrier which keeps two species from interbreeding Usually a result of two or more of the following barriers: Timing Behavior Habitat Others

Reproductive Barriers Between Species Examples: Timing Different breeding seasons Behavior Different courtship or mating behaviors Habitat Adapted to different habitats in the same general location Others Reproductive structures are physically incompatible Gametes may only be transferred among the single species Infertile offspring as a result of a hybrid fertilization

Macroevolution are the biological changes that include the: A species is organisms who have the ability to breed with one another in nature and produce fertile offspring (not including those organisms who breed asexually) Microevolution is a change in the allele frequencies within a population and can lead to…see below Macroevolution are the biological changes that include the: - Origin of different species - Extinction of species - Evolution of major new features of living things Speciation is the origin of new species How is a new species created? Reproductive Isolation: Some kind of reproductive barrier which keeps two species from interbreeding, like: - timing: different breeding seasons - behavior: different courtship or mating behaviors - habitat: adapted to different habitats in the same general location - others: incompatible reproductive structures or gametes, production of infertile/sterile offspring Salmon cuttlefish hehe birds frogs stickleback

Geographic Isolation and Speciation Separation of populations as a result of geographic change or dispersal to geographically isolated places Geographically isolating species can lead to speciation Mountain ranges, rivers, lakes, glaciers, etc can spilt populations of organisms that cannot cross the barrier If members of a population disperse and separate themselves to an isolated location can lead to speciation through geographic isolation

Geographic Isolation and Speciation Not all species are separated by the same barriers Wind can carry plants’ pollen and seeds across canyons and rivers Small rodents and other mammals usually don’t dare cross such barriers Speciation can result from “splinter” populations following their own evolutionary courses Genetic drift and changes in allele frequencies leading to microevolution play key roles in speciation

Geographic Isolation and Speciation Isolating populations through geographic barriers does not always lead to speciation Some species may not need to adapt to their new environments and remain the same, still able to reproduce with the original species Some species adaptations do not lead to a new species and are still able to reproduce fertile offspring when they encounter the original species Some adaptations do lead to new species These species are not able to reproduce with the old species In this model, arrows symbolize populations that become geographically separated, then come together again at a later time.

A species is organisms who have the ability to breed with one another in nature and produce fertile offspring (not including those organisms who breed asexually) Microevolution is a change in the allele frequencies within a population and can lead to…see below How is a new species created? Geographic Isolation: Separation of populations as a result of geographic change or dispersal to geographically isolated places, like: - Mnt. ranges, rivers, lakes, glaciers, etc can spilt populations of organisms that cannot cross the barrier; EX: birds, pollen can cross rivers and canyons speciation, small mammals usually can’t Macroevolution are the biological changes that include the: - Origin of different species - Extinction of species - Evolution of major new features of living things Speciation is the origin of new species How is a new species created? Reproductive Isolation: Some kind of reproductive barrier which keeps two species from interbreeding, like: - timing: different breeding seasons - behavior: different courtship or mating behaviors - habitat: adapted to different habitats in the same general location - others: incompatible reproductive structures or gametes, production of infertile/sterile offspring

Adaptive Radiation Islands are a great way to study speciation because of the isolation between species Islands often create unique habitats and conditions that favor one species over another Adaptive Radiation Evolution from a common ancestor that results in diverse species adapted to different environments Process of adaptive radiation The small population that colonizes the island may go through evolutionary change Some of these organisms may go to other islands The process repeats New species may adapt through genetic drift and adaptations to the different habitats

A species is organisms who have the ability to breed with one another in nature and produce fertile offspring (not including those organisms who breed asexually) Microevolution is a change in the allele frequencies within a population and can lead to…see below How is a new species created? Geographic Isolation: Separation of populations as a result of geographic change or dispersal to geographically isolated places, like: - Mnt. ranges, rivers, lakes, glaciers, etc can spilt populations of organisms that cannot cross the barrier; EX: birds, pollen can cross rivers and canyons speciation, small mammals usually can’t Macroevolution are the biological changes that include the: - Origin of different species - Extinction of species - Evolution of major new features of living things Speciation is the origin of new species How is a new species created? Reproductive Isolation: Some kind of reproductive barrier which keeps two species from interbreeding, like: - timing: different breeding seasons - behavior: different courtship or mating behaviors - habitat: adapted to different habitats in the same general location - others: incompatible reproductive structures or gametes, production of infertile/sterile offspring How is a new species created? Adaptive Radiation: Evolution from a common ancestor that results in diverse species adapted to different environments - easy to see on island communities

The Tempo of Speciation Darwin and the theory of natural selection set forth the model of gradual adaptation Successful species last about 1 to 5 million years Most of a species unique adaptations occur in the first 50,000 years (1/100th of the lifetime of a typical species) The adaptations follow the theory of natural selection Leading speciation to occur in a few hundred to a thousand generations The theory of gradual adaptation has been replaced with the theory of punctuated equilibrium

The Tempo of Speciation Species often arrive abruptly as evidenced through the fossil record Some new fossil species appear “suddenly” in a layer of rock and remain for thousands and millions of years without change and then disappear as suddenly as they appeared Punctuated equilibrium This model of evolution suggests that species often diverge in spurts of relatively rapid change and the new species may remain mostly unchanged Long periods of little change (equilibrium) are broken (punctuated) by shorter periods of speciation

Macroevolution are the biological changes that include the: A species is organisms who have the ability to breed with one another in nature and produce fertile offspring (not including those organisms who breed asexually) Microevolution is a change in the allele frequencies within a population and can lead to…see below How is a new species created? Geographic Isolation: Separation of populations as a result of geographic change or dispersal to geographically isolated places, like: - Mnt. ranges, rivers, lakes, glaciers, etc can spilt populations of organisms that cannot cross the barrier; EX: birds, pollen can cross rivers and canyons speciation, small mammals usually can’t Macroevolution are the biological changes that include the: - Origin of different species - Extinction of species - Evolution of major new features of living things Speciation is the origin of new species How is a new species created? Reproductive Isolation: Some kind of reproductive barrier which keeps two species from interbreeding, like: - timing: different breeding seasons - behavior: different courtship or mating behaviors - habitat: adapted to different habitats in the same general location - others: incompatible reproductive structures or gametes, production of infertile/sterile offspring How is a new species created? Adaptive Radiation: Evolution from a common ancestor that results in diverse species adapted to different environments - easy to see on island communities Tempo of Speciation: Originally thought: gradual adaptation: speciation to occur in a few hundred to a thousand generations Know now: punctuated equilibrium: species often diverge in spurts of relatively rapid change and the new species may remain mostly unchanged

______________________ are the biological changes that include the: A _____________ is organisms who have the ability to breed with one another in nature and produce __________ offspring (not including those organisms who breed asexually) ____________________ is a change in the allele frequencies within a population and can lead to…see below How is a new species created? _________________ Isolation: Separation of populations as a result of geographic change or dispersal to geographically isolated places, like: - Mnt. ranges, rivers, lakes, glaciers, etc can spilt populations of organisms that cannot cross the barrier; EX: birds, pollen can cross rivers and canyons speciation, small mammals usually can’t ______________________ are the biological changes that include the: - Origin of different _____________ - ________________ of species - Evolution of major new ______________ of living things ____________ is the origin of new species How is a new species created? ___________________ Isolation: Some kind of reproductive barrier which keeps two species from interbreeding, like: - ___________: different breeding seasons - ___________: different courtship or mating behaviors - ___________: adapted to different habitats in the same general location - ____________: incompatible reproductive structures or gametes, production of infertile/sterile offspring How is a new species created? _____________________: Evolution from a common ancestor that results in diverse species adapted to different environments - easy to see on island communities Tempo of Speciation: Originally thought: _______________________: speciation to occur in a few hundred to a thousand generations Know now: ___________ __________________: species often diverge in spurts of relatively rapid change and the new species may remain mostly unchanged