1. Speciation Pt 1
-Species – a group of organisms that can continue to interbreed with each other and where their offspring are fertile (meaning, the offspring can have offspring as well)
-organisms are considered separate species if they are unable to breed with each other
-evidence: different species of fishes found in smaller
ponds produced after a lake dried up; tigers and lions –
can interbreed to produce ligers, but ligers are sterile

2. Speciation Pt 1 How does speciation occur?
-Genetics becomes too dissimilar that they can no longer produce fertile offspring
-These barriers occur in two ways:
Prezygotic – “Before Fertilization”: factors that occur before fertilization such as separation by geography, differences in mating seasons, or incompatible genitalia
Postzygotic – “After Fertilization”: factors that occur after fertilization such as infertile offspring

3. Speciation Pt 1 Two ways for reproductive barriers to occur:
Sympatric: isolation from within the same habitat
-ex: flies mating originally on hawthorns, then some
started to mate on apples – flies continue to mate on
the fruit they grew up in
Allopatric: geographic isolation
-ex: Northern Spotted Owl, located in Northwestern US,
and Mexican Spotted Owl, located in Southwestern US
and Mexico – similar in genetics and appearance, yet
unable to breed together
-ex. experiment with fruit flies fed different foods and
isolated from each other led to flies that preferred flies
that ate same food