Migration introduction

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Migration introduction

  1. 1. Animal Migration
  2. 2. What is Migration? <ul><li>Prerequisites for migration: </li></ul><ul><ul><li>Sustained movement </li></ul></ul><ul><ul><li>Physical endurance </li></ul></ul><ul><ul><li>Mechanisms for storing energy </li></ul></ul><ul><ul><li>Designated food sources on the migration route </li></ul></ul><ul><li>Migration ensures animals will have adequate food supplies & will be able to reproduce. </li></ul>Migration is the regular movement of animals from one location to another.
  3. 3. Types of Migration <ul><li>Migration may occur: </li></ul><ul><ul><li>As a round trip </li></ul></ul><ul><ul><li>As a return migration </li></ul></ul><ul><ul><ul><li>Corresponds with the seasons </li></ul></ul></ul><ul><li>Some require a lifetime to complete: </li></ul><ul><ul><li>Ex: Pacific salmon </li></ul></ul><ul><ul><ul><li>Born in freshwater streams </li></ul></ul></ul><ul><ul><ul><li>Travel to the ocean </li></ul></ul></ul><ul><ul><ul><li>Return to the stream where they were born </li></ul></ul></ul><ul><ul><ul><ul><li>Spawn and then die </li></ul></ul></ul></ul>
  4. 4. Knowing When to Migrate <ul><li>How do animals know when it is time to migrate? </li></ul><ul><ul><li>Internal signals </li></ul></ul><ul><ul><ul><li>Hormones trigger an overwhelming urge to… </li></ul></ul></ul><ul><ul><ul><ul><li>eat, mate & reproduce </li></ul></ul></ul></ul><ul><ul><li>External signals (clues) </li></ul></ul><ul><ul><ul><li>Temperature change </li></ul></ul></ul><ul><ul><ul><li>Daylight hours </li></ul></ul></ul><ul><ul><ul><li>Scarce food supply </li></ul></ul></ul>
  5. 5. Migration Destinations <ul><li>How do animals know where to go? </li></ul><ul><ul><li>Specialized abilities to navigate </li></ul></ul><ul><ul><li>External forces </li></ul></ul><ul><ul><ul><li>Ex.: wind & water currents </li></ul></ul></ul><ul><ul><li>Landmarks: </li></ul></ul><ul><ul><ul><li>Ex.: coastlines, mountain ranges, river valleys & distinctive odors </li></ul></ul></ul><ul><ul><li>Sun: </li></ul></ul><ul><ul><ul><li>Track the passage of days and months </li></ul></ul></ul><ul><ul><ul><li>Track their position in relationship to the sun </li></ul></ul></ul>
  6. 6. Migration Destinations (cont.) <ul><li>Internal Clues </li></ul><ul><ul><li>Are sensitive to a mineral known as magnetite </li></ul></ul><ul><ul><ul><li>Found in many animals, including humans </li></ul></ul></ul><ul><ul><ul><li>Allows animals to use the earth’s magnetic field as a guide. </li></ul></ul></ul><ul><ul><ul><li>Ex.: Gray whales </li></ul></ul></ul><ul><ul><ul><ul><li>Large amount of magnetite in their retinas </li></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Helps them navigate their 10,000 mile journey </li></ul></ul></ul></ul></ul>
  7. 7. Migration: Behavior or Instinct? <ul><li>Monarch butterfly </li></ul><ul><ul><li>Migration is instinctive </li></ul></ul><ul><ul><li>Fly without guidance or previous experience </li></ul></ul><ul><ul><li>Use little or no directional clues </li></ul></ul><ul><li>Learning migration behaviors for most animals is critical to their survival. </li></ul>
  8. 8. Migration Behaviors <ul><li>Older members of the group teach the younger animals: </li></ul><ul><ul><li>The route traveled </li></ul></ul><ul><ul><li>Valuable strategies and/or behaviors </li></ul></ul><ul><li>Humans teach younger animals, too. </li></ul><ul><ul><li>Ultra-light aircraft </li></ul></ul><ul><ul><ul><li>Taught various species of cranes their migration routes </li></ul></ul></ul><ul><li>Most animals must learn their migratory routes. </li></ul><ul><li>Animals who are not taught these behaviors will not likely survive. </li></ul>
  9. 9. Why Migrate? <ul><li>Most animals migrate for two reasons: </li></ul><ul><ul><li>Food & water: </li></ul></ul><ul><ul><ul><li>Will migrate to find these resources </li></ul></ul></ul><ul><ul><li>Reproduction: </li></ul></ul><ul><ul><ul><li>Safe environment for bearing & nursing offspring. </li></ul></ul></ul><ul><ul><ul><li>Abundant food sources </li></ul></ul></ul>
  10. 10. Hazards of Migration <ul><li>Two categories: </li></ul><ul><ul><li>Natural hazards: </li></ul></ul><ul><ul><ul><li>Climate changes </li></ul></ul></ul><ul><ul><ul><li>Drought </li></ul></ul></ul><ul><ul><ul><li>Food Supply </li></ul></ul></ul><ul><ul><ul><li>Predators </li></ul></ul></ul><ul><ul><ul><li>Physical demands of migration </li></ul></ul></ul><ul><ul><li>Man-made hazards: </li></ul></ul><ul><ul><ul><li>Barriers (fences, dams, & skyscrapers) </li></ul></ul></ul><ul><ul><ul><li>Water, aircraft, & fishing practices </li></ul></ul></ul>

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