EQ: What factors are involved in the formation of new species? Speciation EQ: What factors are involved in the formation of new species?

How do changes lead to the formation of new species? Species- a group of organisms that breed with one another and produce fertile offspring and must share a common gene pool.

How do changes lead to the formation of new species? Because a population of individuals share a common gene pool, a genetic change that occurs in one individual can spread through the entire population as the individual and their offspring reproduces. If the genetic change increases fitness, that allele will eventually be found in many individuals in the population.

Isolating Mechanisms In order to have a species evolve into 2 different species, the gene pools of both populations must become separate and be reproductively isolated from each other Reproductive Isolation- when members of two populations cannot interbreed and produce fertile offspring

Behavioral Isolation Occurs when two populations are capable of interbreeding, but have differences in courtship rituals or other reproductive strategies that involve behavior. Ex. Certain species of crickets will only mate with males that produce a particular mating song

Geographical Isolation The two populations are separated by geographical barriers such as rivers, mountains, or large bodies of water. Geographical barriers do not guarantee the formation of new species as sometimes it can be temporary or might not effect the species (ex. A lake/river won’t effect bird species)

Two or more species reproduce at different times Temporal Isolation Two or more species reproduce at different times

How can natural selection lead to speciation? Founders- the first species to arrive to the location Ex. The finches on the Galapagos Islands came from the mainland

How can natural selection lead to speciation? Geographical isolation- Species become isolated due to geography features Ex. the finches don’t usually fly over open water, but some flew to other islands and thus were essentially isolated

How can natural selection lead to speciation? Changes in the gene pool- Over time, populations became adapted to their local environments. Ex. Finches’ beaks started to change shape to adapt to the local seeds How can natural selection lead to speciation?

How can natural selection lead to speciation? Reproductive Isolation- Mating behaviors and preferences change between the species. Ex. Among the finches it was the differences in beak sizes and different mating behaviors led to the separation of the species

How can natural selection lead to speciation? Ecological Competition- When the 2 species live together in the same environment they may compete for resources. However, over time, the species evolve in a way to increase the differences between them.

Amoeba Sisters: Speciation https://www.youtube.com/watch?v=udZUaNKXbJA Video Amoeba Sisters: Speciation https://www.youtube.com/watch?v=udZUaNKXbJA