Speciation Friday

Formation of New Species Species = individual organisms that can interbreed and produce fertile offspring

Hybrid = cross between two species Liger Zonkey Hybrid = cross between two species = often produce infertile offspring (mules)

Speciation = formation of two species from one original species

Allopatric vs Sympatric Speciation “Other homeland” “Same homeland” California Salamander Speciation

What type of speciation is this?

Hawaiian Honeycreepers Adaptive Radiation One ancestral species branches into many, each occupying a different NICHE

Reproductive Isolation - what prevents interbreeding between species? Temporal Isolation (breeding at different times) Prezygotic Barriers Blocks reproduction from taking place at all Habitat Isolation (living in different places) Mechanical & Gamete Barriers (anatomy & egg/sperm problems) Behavioral Isolation (mating, courtship behaviors) Damselfly penis

Post-zygotic barriers - egg and sperm produce offspring that don’t survive or are sterile

Rates of Speciation Slow change, small steps Rapid change, due to a major environmental disruption

Is a hybrid grizzly-polar bear a “PIZZLY” or a “GROLAR BEAR”