California Biodiversity

Author: Alison Purcell

Overview: In this lesson students will be introduced to the extraordinary biodiversity of California. By reviewing several maps of California exhibiting features such as precipitation, topography, and vegetation students will look for patterns that might be the source of or influence biodiversity in different regions.

Lesson Concepts:

  • California is a very biologically diverse place.

  • California’s high biodiversity is due to the variety of climates, topography, and natural barriers to migration.

  • Many biotic and abiotic processes influence biodiversity.

  • Biodiversity is important for ecological, economic, and medicinal reasons.

Grade Span: 9–12

Materials: PowerPoint slides, html page of maps, and/or map handouts (one per student).

Advance Preparation: Review PowerPoint slides and copy handouts.

Time: 50 minutes

Grouping: Groups of 3-5 to answer the question: “Why is California so diverse?”

Teacher Background: See California Biodiversity facts below.

Teaching Tips: While this lesson can be done without visual aids (aka PowerPoint), I found it very helpful to have the CA biodiversity facts on PowerPoint slides and to have maps of CA to illustrate geographical barriers and characteristics of the state.

Vocabulary: Write terms only on board before class begins (students must fill in definitions as you go):
biodiversity — the diversity, or variety, of plants, animals and other living things in a particular area or region.
native — species originating naturally in a particular region.
endemic — unique to that place or region, found naturally nowhere else.
habitat — locality in which a plant or animal naturally lives.
biome — a major terrestrial ecological community. There are seven kinds of biomes in the world: tundra, taiga, temperate forest, tropical rainforest, desert, grassland, and ocean.
food web — a complex network of many interconnected feeding relationships.


  1. Write the vocabulary terms on the board and have students write down the definition of each as you cover it.

  2. Ask the class: “What is biodiversity?” See what types of ideas the students generate. Then go over the definition: Biological diversity, or the shorter "biodiversity," simply means the diversity, or variety, of plants, animals, and other living things in a particular area or region.
    Write on board the breakdown of the word:
    bio = life  +  diversity = variety, so
    biodiversity = the variety of life

  3. Once students are familiar with the term “biodiversity,” you can *wow* them with the California Biodiversity facts below, obtained primarily from the California Biodiversity Council website (see Acknowledgements below). Be sure to cover the definitions of the vocabulary words on the board as you go through the biodiversity facts and contrast “native” versus “endemic” species.

    California Biodiversity Facts
    California is one of the most biologically diverse areas in the world. Within its 160,000 square miles, California harbors more unique plants and animals than any other state.

    Each year, some 14 million wild ducks and geese funnel down the Pacific Flyway where 65 percent of them (over 9 million birds) winter in the wetlands of California’s Central Valley.

    There are about 30,000 species of insects recorded from California.

    There are 961 native vertebrates in California: 540 birds, 77 reptiles, 47 amphibians, 214 mammals and 83 freshwater fish. Sixty-five percent of these animals are found only in California!

    There are more than 5,000 native plant species in California. This is more than you will find in the northeastern United States and Canada combined, an area 10 times larger than California! At least one-third of these 5,000 plants are found nowhere else in the world (endemic).

    The California redwoods, the Coast Redwood (Sequoia sempervirens) and Giant Sequoia (Sequoiadendron giganteum), are the tallest and largest living organisms in the world.

  4. Next, ask the students: “Why is California so diverse?” Break them into small groups of 3-5 students per group to answer this question for ~5 minutes. When students have brainstormed the answer to this question within their group, have each group report back to the class one at a time. Write their responses on the board as bullet points. The major points that you will want to highlight or emphasize are:

    California’s diversity is a result of the diversity of climates and landscapes, and all the barriers to migrations such as rivers, mountains, and deserts, which have led over thousands of years to the evolution of a large number of isolated species and varieties of animals, many of which are found only here.

  5. Ask for specific examples of “barriers” in California (mountains, valleys, rivers etc.). Show maps of the California biomes, vegetation, soil, climate, and topography (powerpoint slides or handouts). Ask students if they see any reoccurring pattern in these maps (it should be very obvious).

  6. Next, ask students: “What creates/impacts biodiversity?” (a lot of this may have been answered by students in the previous question and by examining the maps). The main points to emphasize are:

    a. The geology of an area determines the soil type, which in turn determines the type of vegetation that grows in that soil and the vegetation influences what types of animals are found in that area. (geology › soil types › vegetation › animals)
    b. Climate has a large influence on biodiversity. The more climates or ‘microclimates’ present, the higher the biodiversity. Factors in climate include: temperature, precipitation/moisture and wind.
    c. Ecological processes:
        i. Immigration (causes extinction, speciation — the creation of species)
        ii. Species interactions (herbivory/predation, competition, mutualism)
    d. Evolutionary processes (extinction and speciation)

  7. Lastly, ask students “Why is Biodiversity Important?” (if there is time left). Some points to emphasize include (feel free to come up with your own answers too):

    a. Food webs/interactions. Everything that lives in an ecosystem is part of the food web, including humans. Each species of vegetation and each creature has a place on the earth and plays a vital role in the circle of life. Plant, animal, and insect species interact and depend upon one another for what each offers, such as food, shelter, oxygen, and soil enrichment. Maintaining a wide diversity of species in each ecosystem is necessary to preserve the web of life that sustains all living things.
    b. Economic (birds and insects control Agricultural pests and increase soil fertility) Example: Birds save farmers and timber owners an estimated $44 million in losses annually by eating damaging insects.
    c. Medicine (from plants and animals) Example: The Pacific yew, a small tree under 25 feet high, is playing a big role in the fight against cancer. Its bark produces taxol, a substance that has successfully inhibited the growth of certain tumors.

Extensions: This is a good introductory lesson to biodiversity and can be followed up with more specific lessons and activities about biodiversity such as the Biodiversity in the Schoolyard curriculum or fieldtrips/projects where the class measures and evaluates biodiversity through hands-on learning.

Acknowledgements: The California Biodiversity facts were primarily from the California Biodiversity Council website, here and here.

It was great to have the students work in groups to answer the question: “Why is California so diverse?” (instead of the entire lesson being a lecture), but groups came up with similar answers, so all groups may not need to “report back” to the larger group.

The students had difficulty coming up with answers to the last question (Why is biodiversity important?). You may want to rephrase the question: Why should we care about biodiversity? Why is biodiversity important to humans? It might be a better technique to have students first write down their answer to this question (~5 min) and then ask for responses orally so they have more time to think of an answer.