5) Speciation Through Isolation

Key Concept: New species can arise when population are isolated

What can lead to speciation?

The isolation of populations

What can the isolation of populations lead to?

speciation

When do population become isolated?

when there is no gene flow

What happens when there is no gene flow?

populations become isolated

Isolated populations adapt to what?

their own environments

What adapts to their own environments?

isolated populations

In isolated populations, genetic differences can what?

add up over generations

In isolated populations, what can add up over generations?

genetic differences

Where can reproductive isolation occur?

between isolated populations

What can occur between isolated populations?

reproductive isolation

In reproductive isolation, members of different populations -

cannot mate successfully

In reproductive isolation, what cannot mate successfully?

members of different populations

What is the final step to becoming separate species?

members of different populations cannot mate successfully in reproductive isolation

Members of different populations cannot mate successfully in reproductive isolation is the final step of becoming what?

separate species

What is speciation?

the rise of two or more species from one existing species

What is the rise of two or more species from one existing species?

speciation

What can cause isolation?

behavioral, geographic, and temporal

Behavioral, geographic, and temporal barriers can cause what?

isolation

Behavioral isolation includes

differences in courtship or mating behaviors, and prevents mating

What isolation includes differences in courtship or mating behaviors, and prevents mating?

behavioral isolation

Geographic isolation has

physical barriers, such as river, mountains, dried lake beds, that divide populations

What type of isolation has physical barriers, such as rivers, mountains, dried lake beds, that divide populations?

geographic isolation

Temporal isolation has

timing of reproductive periods that prevent mating

What type of isolation has timing of reproductive periods that prevent mating?

temporal isolation

What two types of reproductive barriers prevent mating between populations?

prezygotic and postgyzotic

prezygotic and postgyzotic are the two types of what?

reproductive barriers that prevent mating between populations

Prezygotic

before fertilization that involves several factors

before fertilization and involves several factors

prezygotic

Prezygotic involves what several factors?

isolation of habitat, differences in breeding season or mating behaviors, incompatibility of genitalia or gametes

Does prezygotic or postzygotic involve the factors: isolation of habitat, differences in breeding season or mating behaviors, incompatibility of genitalia or gametes?

prezygotic

postzygotic

after fertilization and has barriers that prevent development of viable, fertile hybrids, involve several factors

after fertilization and has barriers that prevent development of viable, fertile hybrids, and involve several factors

postzygotic

Does prezygotic or postzygotic involve several factors: genetic incompatibility, hybrid sterility, and hybrid breakdown?

postzygotic

What factors does postzygotic involve?

genetic incompatibility, hybrid sterility, and hybrid breakdown

What are the two types of geographic isolation that affect speciation?

sympatric and allopatric

Sympatric and allopatric are the two types of what?

geographic isolation that affect speciation

Sympatric isolation

groups from the same ancestral population evolve into separate species without any geographical separation and can occur within a geographic range of a parent population

groups from the same ancestral population evolve into separate species without any geographical separation and can occur within a geographic range of a parent population

sympatric isolation

Sympatric isolation is more common in plants or animals?

plants

What type of isolation is more common in plants than in animals?

sympatric

What are extra sets of chromosomes?

polyploidy

What is polyploidy?

extra sets of chromosomes

In sympatric isolation, polyploidy allows

most plants to continue to reproduce, but in animals it interferes with sex determination because animals are one sex or the other

What allows plants to continue to reproduce, but in animals it interferes with sex determination because animals are one sex or the other?

polyploidy in sympatric isolation

Allopatric isolation

through the geographic isolation of a small population from its parent population is when geographic isolated populations adapt to different environmental conditions

through the geopgrahic isolation of a small population from its parent population is when geographic isolated populations adapt to different environmental conditions

allopatric isolation

The rate of allopatric speciation is faster in small populations than in large ones because of

greater genetic drift

Because of genetic drift,

the rate of allopatric speciation is faster in small populations than in large ones