Chapter 16 3 The Process of Speciation Introduction

Introduction • Speciation is the formation of new species • Different species can not

Reproductive isolation : • When members of the two different species do not interbreed

Three ways that reproductive isolation occurs. 1. Behavioral isolation 2. Temporal isolation 3. Geographic

Behavioral isolation • occurs when populations are capable of interbreeding BUT have differences in

Example: Eastern and Western meadowlarks -Their regions overlap -They can interbreed but do not

Geographic isolation - can occur when populations are separated by geographic barriers such as

Temporal Isolation • Occurs when two or more species reproduce at different times. Example:

Testing Natural Selection in Nature How could differences in beak size lead to reproductive

Studying Evolution Since Darwin • Why is the study of evolution important in the

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Chapter 16 -3 The Process of Speciation

Introduction • Speciation is the formation of new species • Different species can not interbreed to produce fertile offspring. – Individuals in different species have a different gene pool.

Reproductive isolation : • When members of the two different species do not interbreed and produce fertile offspring. • Populations must be reproductively isolated from each other for a new species to evolve.

Three ways that reproductive isolation occurs. 1. Behavioral isolation 2. Temporal isolation 3. Geographic isolation

Behavioral isolation • occurs when populations are capable of interbreeding BUT have differences in courtship rituals or other types of behavior.

Example: Eastern and Western meadowlarks -Their regions overlap -They can interbreed but do not -Different courtship rituals (attracted by different songs)

Geographic isolation - can occur when populations are separated by geographic barriers such as rivers, mountains, or bodies of water. Abert Example: -The Kaibab squirrel evolved from the Abert squirrel when it was isolated from the main population by Kaibab the Colorado River.

Temporal Isolation • Occurs when two or more species reproduce at different times. Example: three similar species of orchid in the same rain forest releases pollen on different days.

Testing Natural Selection in Nature How could differences in beak size lead to reproductive isolation? • Birds with the same beak size prefer to mate with each other. • Since, big-beaked and smaller-beaked birds would not choose to mate with each other, their gene pools would remain isolated.

Studying Evolution Since Darwin • Why is the study of evolution important in the scientific world? • By understanding evolutionary theory, we have been able to respond to changes in the living world in ways that have improved human life.