How do you locate a specific place on Earth?
How do animals find a place?

In the Film

A satellite view of the west coast of North America zooms in on the Baja California peninsula, the Gulf of California, and the mainland of Mexico. This area is the destination for a number of migratory species. Several of these species, such as the Elegant Tern, Heermann's Gull, elephant seal, and gray whale, are featured in the film.

Concept

Any place on Earth can be identified using a coordinate grid system of latitude and longitude. Some animals migrate great distances between specific places.

Objectives

To locate places in Baja California and elsewhere using latitude and longitude; to explore animal migration

Content

Science, history/social studies, mathematics, language arts

Background

Mapmakers think of the world as a globe divided by vertical and horizontal lines. The lines running north and south are lines of longitude, or meridians. These lines of longitude come together at the North and South Poles and the distance between them is greatest at the equator. The Prime Meridian, 0 degrees, passes through Greenwich, England. Measurements are then made 180 degrees to the west and 180 degrees to the east from Greenwich. East-west lines of latitude circle the Earth parallel to the equator, which is 0 degrees. The poles are 90 degrees north and 90 degrees south latitude. Like an hour of time, a degree of latitude or longitude is divided into 60 minutes, and a minute is divided into 60 seconds. Any point on Earth can be identified using this coordinate system of longitude and latitude. For example, Washington, D.C., has the coordinates 38° 53´, 77° west.

For various reasons humans have been moving from place to place for thousands of years. They have found their way using the sun and stars, sextants, maps, charts, compasses, and recently the Global Positioning System, or GPS.

Many animals migrate, or move from one place to another place on a seasonal basis, seeking food or places to breed. Unlike humans, they do not use charts or instruments. How do they find their way? In Ocean Oasis, several migratory animals are featured. Gray whales, for example, migrate from summer feeding grounds around the Bering Sea near Alaska to lagoons along the west coast of Baja California—a journey that, in each direction, takes nearly four months and spans approximately 5500 miles (9000 km). The fact that animals migrate is well documented. However, much work needs to be done to understand how they find their way to the same area year after year and generation after generation.

On the Web

See the Ocean Oasis Field Guide for more about the Elegant Tern, Heermann's Gull, elephant seal, and gray whale.

Part A   Location
Map of Baja California, chart with coordinates, pencil, graph paper

Part B   Migration
Map of Western Hemisphere, ruler, pencil, graph paper

Part A   Location (individuals, small groups)

• Discuss the concept of longitude and latitude.
• Use the map of Baja California (click on small map to right). Locate the town identified by the coordinates 31° north latitude, 114° 52´ west longitude. Record the name of this town.
• Select a different place in Baja California. Determine its coordinates and record them.
• On a piece of graph paper set up a grid, marking latitude on the vertical axis and longitude on the horizontal axis. On the grid plot and label the two Baja California sites. Is the second site north or south, east or west of the first site? How many degrees north or south? How many degrees east or west?

Part B   Migration (individuals, small groups)

• Discuss animal migrations, noting reasons for migrating and some well-known migratory animals.
• Find the migration chart on the map of the Western Hemisphere. Select one of the following animals: gray whale, Heermann's Gull, Elegant Tern, or elephant seal. On the map, locate the start and end destinations of its migration. Draw a line connecting the two points—representing a possible migratory route.
• Use the mileage/kilometer key to estimate the number of miles/kilometers covered in this migratory route.
• If a habitat at one end of a migratory route is altered or destroyed, what might the consequences be for that animal?

Local Connection

• Using a map of your local area, select a place and determine its coordinates.
• Refer to Part A. How many degrees north or south, east or west is this town in relationship to 31° north, 114° 52´ west—the town in Baja California?
• Investigate:
  1. the use of the Global Positioning System to determine latitude and longitude
  2. the history of mapmaking
  3. other animals known for migrating
  4. how animals find their way over migratory routes

Continue to Activity 2: What's an Oasis?