The word “biodiversity” is short for biological diversity; bio means life, and diversity means variety. It is a way to describe the variety of living organisms and the diverse interactions they have with other organisms and their environment. These organisms are the many types of plants, fungi, algae, animals, and bacteria. The environment they are found in varies in scale. It can include ALL the organisms found on Earth or the organisms found, on a smaller scale, in a pond habitat or forest ecosystem. (We covered this in our first lesson How Nature Works). 

The biodiversity of ecosystems found on Earth today comes from more than 4.5 billion years of evolution, during which species have adapted their behavior to survive the presence of other species and environmental changes and, over time, physically evolved into new species. From the birth of the first first single-celled organism, bacteria and land-based plants evolved and changed our atmosphere into an oxygen-rich ecosystem where insects, reptiles, birds, and mammals, including humans, evolved into existence.

Not only have living organisms adapted and evolved to the environments they live in, but they have adapted to the presence of other species that share their habitat. (See Lesson 2, Pollinators, about how pollinators and plants adapt and evolve in response to each other, making them more efficient pollinators and better at reproduction.)

Biodiversity is essential to life as we know it, but did you know that we are currently experiencing Earth’s sixth mass extinction event? The difference between this one and the other five, such as the one that caused the extinction of the dinosaurs, is that human activity is the core reason for the decline in species and their population sizes! The International Union for Conservation of Nature (IUCN) Red List of Threatened Species tracks global species populations. Their report, An Assessment of Endangered Primates, dated June 21, 2021 reveals that almost 70% of all non-human primate across the globe are Critically Endangered, Endangered, Threatened, or Vulnerable to extinction. To understand more about these Conservation Statuses, visit The Alphabet Soup of Conservation.

Since human activity is causing this decline, we also have the power to prevent it. That is is why, in this lesson, we are going to learn how biodiversity supports a healthy ecosystem and is essential in supporting human life.